Russia needs VTOL aircraft. Hello student Short takeoff and landing aircraft
An increase in aircraft flight speeds leads to an increase in takeoff and landing speeds, as a result of which the length of the runways reaches several kilometers. In this regard, SKVP and VTOL are being created.
At high cruising speeds (600-800 km/h), SKVPs have a take-off and landing distance of no more than 600-650 m. Reducing the take-off and landing distance is mainly achieved by:
* the use of powerful wing mechanization,
* control of the boundary layer (a layer of gas formed near the surface of a streamlined solid body and having a flow velocity much lower than the velocity of the flow incident on the body),
* use of accelerators on takeoff and devices for dampening speed during landing,
* deviation of the thrust vector of marching (i.e. main) engines.
Vertical takeoff and landing of VTOL aircraft are provided by special lifting engines, either by deflecting jet nozzles, or by turning the main engines, usually turbojet.
Typical VTOL schemes are shown in fig. 9.
Rice. 9. VTOL aircraft
Control questions
1. Name and briefly describe the main parts of the aircraft design.
2. Tell about the power structure of the wing (Fig. 1).
3. Tell about the elements of the control system located on the wing (Fig. 1 and 5).
4. Tell about the tail unit of the aircraft (Fig. 3 and 5).
5. Tell what kind of aircraft are by type (Fig. 8) and the location of the plumage.
6. Tell how the wing is attached to the fuselage (using what - show in Fig. 3 and 5 and about mobility).
7. What are the aircraft in terms of the number and arrangement of wings?
8. Tell about the fuselage of the aircraft (purpose, what is inside, what is a lantern).
9. Tell what kind of aircraft there are according to the type of engines and what is taken into account when choosing the installation site, the number and type of engines.
10. Tell what kind of aircraft there are according to the way the engines are located.
11. Tell about the landing gear of the aircraft (purpose, weight, where it is located during the flight).
12. Tell what kind of aircraft there are according to the type of chassis.
13. Tell about the purpose and classification of civil aircraft.
14. Tell about the purpose and types of military aircraft.
15. Name the classifications of aircraft by design. About one of the classifications (on the instructions of the teacher) to tell in more detail.
16. Write down and explain the formula for the Mach number. What are the types of aircraft depending on the speed of flight?
17. Describe the aircraft control system (types, how the crew affects it, what is installed to improve flight safety)?
18. What is used to reduce the effort to deflect the aircraft rudders? Tell me when air rudders are ineffective, and what is done in this case?
19. List the equipment available on the aircraft.
20. Tell about instrumentation, high-rise and household equipment.
He is called "the last great aircraft designer of the 20th century." He created 22 types of aircraft, including the largest and most lifting in the world, which have become the "visiting card" of our country. It is his car that holds the absolute record for the duration of active service - the legendary An-2 has been mass-produced for more than half a century! And in total, the famous Antonov Design Bureau has about 500 aviation records, most of which have not been broken so far.
Although Oleg Konstantinovich Antonov received worldwide recognition as a designer of civil and transport aircraft, his design bureau also actively worked in the military field, which was not customary to mention before. Only experts know that among the first independent projects of Antonov were the development of a front-line jet fighter and a jet "flying wing". And even the "corn" An-2 had to have several combat modifications: a night reconnaissance and spotter of artillery fire, a high-altitude balloon fighter and even a turbojet "stratospheric biplane" with a "ceiling" of about 20 km!
The new book by the leading aviation historian tells in detail about ALL aircraft of the great aircraft designer, both civil and military, serial and experimental, well-known and almost forgotten - from gliders of the 1930s to the transport giants Ruslan and Mriya, which have no equal in the world.
Sections of this page:
SHORT TAKE OFF AND LANDING AIRCRAFT
An-72
In the 1960s, specialists from the TsNII-30 of the Ministry of Defense (now 30th TsNII MO) developed tactical and technical requirements for a light vertical take-off and landing military transport aircraft. Similar projects were widely discussed in the foreign press at that time. Arguing from the standpoint of today's knowledge, it is quite obvious that the world had the opportunity to create such aircraft, but from the point of view of the economy, this was a utopia. So far, no country, even with a highly developed industry, has operated such aircraft. Short takeoff and landing (SKVP) aircraft looked much more attractive. The creators of the future An-72, which received the designation "200" in the Design Bureau, went along this path.
According to information received from the ASTC them. O.K. Antonov, the basis for the development of the future An-72 was the project of the An-60 passenger aircraft, which was created in accordance with the October 1967 decree of the USSR Government. However, the An-60 project, which, by the way, won the competition for a short-haul airliner, was treated rather harshly at the Ministry of Aviation Industry, giving an order for such a machine to the design bureau headed by A.S. Yakovlev.
An-72 (product "77") was created to solve special problems, for example, to deliver saboteurs to a given area. In fact, this is a further development of the idea of the "partisan" aircraft "Bee", from which the famous "Bee" An-14 eventually originated. Proceeding from the task of landing landing of the sabotage group literally on the "patch", the appearance of the car was formed.
The first prototype of the An-72 short takeoff and landing military transport aircraft
The creation of the SKVP is associated with the search for ways to significantly increase the wing lift coefficient. Only by traditional means of mechanization of the bearing surface, such an effect cannot be achieved. However, if the flaps are blown with the exhaust jets of turbojet engines, using the Coanda effect, then it is possible to obtain the much-needed increase in lift, including due to some component of the engine thrust.
For this reason, the engines were located on the upper surface of the wing, which made it possible, when basing the machine on unpaved airfields, to minimize the suction of foreign objects into them. Much later, when the An-74 aircraft visited international exhibitions, O.K. Antonov explained: “We adopted this scheme not because of the imitation of the very interesting Boeing YC-14 aircraft, but to protect the engines from foreign particles that could damage the compressor blades, including when flying in the harsh Siberian winter.
Short takeoffs and landings and concern for engine protection are a must for an aircraft that will operate on poorly trained, sometimes random airfields.”
I would like to add to this that the resemblance to the YC-14 is only the outer side of the machine, in fact, the work of hundreds of aircraft builders who created it from scratch is hidden inside the aircraft.
Computational and experimental studies have confirmed the possibility of achieving the specified parameters of the aircraft, but "appetite", as you know, comes with eating. There were proposals to expand the functionality of the machine, in particular, to use it for the transportation and landing of military equipment. As a result, the "commercial" load increased to 7500 kg, which entailed an increase in the take-off weight of the aircraft. Despite this, the takeoff and landing characteristics remained unique, the run did not exceed 500 meters.
The design of the An-72 (Ya.G. Gorlov was the first lead designer of the aircraft) was completed in 1975. Speaking about the An-72, with all the desire, one cannot avoid the technical details that actually form the basis of the concept of this aircraft. The use of the Coanda effect, associated with the non-separated flow of gas jets around aerodynamic surfaces, makes it possible in some modes to increase the lift force of the wing by almost 20 percent. Moreover, the higher the area of the blown surface, the higher this increase. To this end, the engines were moved to a decent distance from the leading edge of the center section of the wing, and the nozzles were shaped to facilitate the spreading of gas jets of the TRDZ over the bearing surface.
The Coanda effect was most fully manifested when the wing mechanization was released. Almost all of its trailing edge was occupied by double-slotted flaps on the center section and three-slotted flaps on the consoles, and slats were located along its leading edge.
During factory tests, it was found that the gas jets of the engines "stick" to the wing unevenly and their behavior depended on the flight mode. As a result, additional research had to be carried out to select the most appropriate shape for the nozzle part of the engine nacelles. If one of the TRDs failed, due to the difference in the lift coefficients of the left and right halves of the wing, there was a tendency for the aircraft to roll over on its back, and special attention was required from the pilots in flight. The way out of this situation was found by fending off the roll caused by the asymmetrical thrust of the engines, the deviation of the spoilers located on the opposite wing console.
On the first experimental machine, apparently, there was no thrust reverser device, and a brake parachute was used to reduce the run. A fixed deflector of the slat type was installed on the stabilizer, which ensures its non-separated flow around in short takeoff and landing modes.
So, creating the An-72, they gradually came to a look reminiscent of the American YC-14. OKB solved the problem. But as the subsequent experience of operating the An-72, and the An-74 as well, showed, their ability to take off and land on small, sometimes unprepared sites remained practically unclaimed. But it's not the car's fault.
The power plant of the first An-72s included two D-36 series 1A turbofan engines with a bypass ratio of 5.6. Engines developed by the Zaporizhia Design Bureau "Progress" under the direction of V. A. Lotarev develop a thrust of 6500 kgf at takeoff with a specific fuel consumption of 0.34 kg/kgf.h.
The aircraft could carry bulky cargo and self-propelled equipment in a sealed compartment, including GAZ-66 and UAZ-469 vehicles, aircraft engines, standard containers and cargo on pallets, provided seats for paratroopers.
Particular attention was paid to the choice of chassis layout, which was supposed to ensure the "all-terrain" of the machine. Even an air cushion take-off and landing device was considered. However, having weighed all its positive and negative sides, the designers settled on the classical scheme with an independent wheel suspension linkage and a controlled nose strut, allowing the aircraft to operate both from concreted and from wet unpaved runways.
The main landing gear did not have locks in the retracted position, their wheels lay on the doors of the landing gear niches. In case of failure of the aircraft hydraulic system, such a technical solution allows the wheels to take up a landing position under their own weight and, in extreme cases, land with one unreleased support.
The vertical tail is distinguished not only by a large area, but also by a two-link rudder, which provides the required reserves of directional controllability at low speeds.
To reduce efforts in the control system in a wide range of flight modes and aircraft balances, the rudders have weight and aerodynamic balancing, the lower section of the second link of the rudder is equipped with a trimmer, and the elevator is equipped with trimmers and servo compensators. This solution enables pilots to parry the imbalance of the aircraft during the release of the wing mechanization, when the pattern of air flow around the aircraft changes dramatically and at low speeds it literally “hangs” on the engines, and to pilot the aircraft manually even if the boosters fail.
The crew of the aircraft consisted of three people: two pilots and a flight engineer.
The first An-72 prototype was built at the Kiev Mechanical Plant, the production base of OKB O.K. Antonov in cooperation with the Kiev Aviation Production Association (now the Aviant plant), where working drawings were transferred as soon as they were ready. The remaining four aircraft, including machines for static and endurance tests, were built on Aviant.
Aircraft No. 004 was the first to be rolled out of the plant's assembly shop. Tersky (co-pilot V.I. Gorbik, flight engineer A.A. Kruts and lead flight test engineer A.T. Romanyuk), took to the air for the first time. In December of the same year, the media informed Soviet citizens about the birth of a new winged car, and TASS distributed its photographs.
However, even before this event, US intelligence identified the An-72, giving it the NATO code name Coaler.
One of the experimental An-72s with a modified rear fuselage and a short wing
In the same 1977, the chief designer of the aircraft, Ya. G. Orlov, in an interview with a Pravda correspondent, said that “An-72 is intended to replace the well-known An-26 cargo aircraft.
For static and life tests, two prototypes were built, No. 001 and No. 002, respectively, and for flight tests, additionally No. 003, 005 and 006. Externally, the prototype aircraft were distinguished by a short wing and a pair of tail ventral ridges, similar to those that stood on An -10A.
It was not a very good technical solution. The first experimental aircraft had two cargo hatch doors, including a retractable ramp of the An-26 type and a rear one that opened to the side. In flight, when the side flap was opened, the piloting of the aircraft became more difficult, and on the ground, the access of vehicles to the cargo hatch was difficult. All this greatly delayed the testing and fine-tuning of the machine.
The second experimental flight machine (USSR - 19773, serial number 003) was built in 1979. The reader has the right to ask why the first plane to take off was No. 004 and not No. 003? But not a single publication of authors close to the ASTC im. O.K. Antonov and KSAMC, in the Ukrainian publications does not give an answer to this question, and the archival documents of the Ministry of Aviation Industry of the Soviet Union for those years still remain classified. It remains to be assumed. In my opinion, this is due to the protracted studies of the rear fuselage and the development of a thrust reverser. But in order not to waste time, we built a simplified version of the car, because we lived in a tough planned economy. However, as far as I guessed, time will tell.
In 1979, the first aircraft was modified by replacing the fuselage tail fairing and the rear cargo hatch, and removed the fuselage ridges. At the same time, the design of the nozzle part of the engine hoods was changed and thrust reverser shields were installed. After modifications, the aircraft received the identification mark of the USSR - 83966 and in the same year was demonstrated at the aerospace show in Paris with serial number 350.
After the launch of the An-72 into mass production, aircraft No. 004 was again “re-registered”, and it received another identification mark of the USSR - 72004, under which it was operated for a long time. Looking ahead, I note that after an emergency landing, the first flight prototype of the An-72 was laid up, besides, it had a fairly large flight time. Subsequently, this machine was converted into the first prototype of the long-range radar surveillance aircraft (AWACS) An-71.
In the same 1979, the third flight copy of the An-72 (USSR - 19795, serial number 005) took off, followed by the fourth aircraft, built a year later.
In 1985, the author had a chance to visit Kiev at the first meeting of light aviation enthusiasts; on the final day of its work at the Chaika airfield, a demonstration of new aircraft of the ASTC named after O.K. Antonov, including the An-72 in the configuration with the old wing and modified rear fuselage. What kind of car it was is unknown, since only the inscription "USSR" was present on it.
In December 1979, the modified aircraft No. 003 and No. 005 were submitted for state tests to the branch of the 8th GNIOLKI of the Air Force. So the abbreviated name of the Air Force Research Institute. V. P. Chkalov after merging it with the 6th State Research Institute of the Air Force and rewarding him in 1970 with the Order of Lenin. The Chkalovskaya airfield near Moscow became the main test base for the aircraft. In 1980, the third aircraft No. 006 was connected to the tests, which made it possible to conduct them very quickly - within one year.
The leaders of the car at the stage of state tests were engineer I.P. Potihenchenko, test pilots V.V. Usenko and Yu.P. Resnitsky. The main volume of tests of the An-72 fell on the share of Lieutenant Colonel Usenko. According to the results of state tests, the aircraft was recommended for adoption, of course, after the elimination of all identified defects, without which, unfortunately, experimental aircraft cannot do. During the tests, it was jumped by paratroopers, which did not reveal any special "anomalies", but they did not have time to check the possibility of landing a car with an open cargo hatch, which, however, was never required during the operation of the An-72.
But in this form, the An-72 did not get into mass production. The fact is that in the late 1970s, the main aircraft of polar aviation was the Il-14, which was living out its life.
In the fall of 1975, the State Research Institute of the Ministry of Civil Aviation developed technical requirements and issued an assignment to industry for the development of an aircraft for operation in the northern regions of the Soviet Union. At the same time, a flight range of 4500 km was set. It was difficult and expensive to create a special aircraft for the needs of polar explorers, and no more than two dozen of them were required, especially since the design of the An-72 was being completed by that time. However, its range and carrying capacity left much to be desired.
Based on this and taking into account the wishes of the military, in June 1977, by a decree of the USSR government, Kiev aircraft builders were instructed to finalize the machine, making it multi-purpose. In December 1980, an order was signed by the MAP on the development of a single machine for both military and civilian operators. The MAP's decision was almost two years ahead of the proposal to create the An-74, developed by the specialists of the State Research Institute of Civil Aviation in 1982, and the terms of reference for it appeared only the following year.
It was possible to satisfy the requirements recorded in the government document by improving the aerodynamic characteristics of the machine and increasing the fuel reserve. To do this, first of all, it was necessary to design a new wing of greater elongation with the placement of additional fuel tanks in it. But in this case, it was almost impossible to meet the deadlines set by the government.
The way out was found by lengthening the wing. At the same time, the former consoles turned into the middle parts of the wing, and new end parts were docked to them. The area of the wing, which contained an additional almost 2500 kg of fuel, increased by 9.12 m 2, and its elongation - from 7.45 to 10.29. Subsequently, this wing was installed on the An-72 and An-74 production aircraft. The ailerons became two-section: the inner ones were intended for roll control in cruising flight, and the outer ones were included in the work at low speeds. At the same time, the fuselage was lengthened by installing three additional frames, and the tail section was modified, abandoning the ventral fins. The upper, rolling back, cargo hatch cover was made of carbon fiber (composite) material.
At the same time, to improve the controllability of the machine at low speeds, the area of the lower section of the outer rudder was increased. All this increased the weight of the airframe. I can’t say whether a radar was installed on the first prototype, but on the second flight prototype (USSR - 19773), which after another revision received the designation An-74 and the identification mark of the USSR - 780334, there was a Gradient station.
In 1979, this An-74 entered the test, during which it turned out that the maximum flight range increased to 5000 km, and with a load of 1500 kg and a two-hour fuel reserve - up to 4200 km. During the factory tests of the An-74, four sections of insufficiently efficient spoilers were removed from the center section, which were in the engine jet and were shaded by engine nacelles during landing, installed new radio equipment and a navigation complex, and added a navigator's workplace.
Despite numerous improvements, the appearance of the car was still far from the final version. Only at the final stage of testing, the Gradient radar, which was distinguished by low reliability, was replaced by the Buran with a new geometry of the nose cone of its antenna.
Since this machine was created from the very beginning for the military, and ahead was the development of its mass production and adoption into service, the aircraft manufacturers returned to its previous designation - An-72A, where the letter "A" denoted (according to the existing legend) "Arctic". The An-74 designation will be returned later, during serial production.
An-72 from the very beginning was created for the needs of military aviation, and, despite a significant alteration of the machine, its economic characteristics left much to be desired. For this reason (ignoring the Aeroflot symbols that are on most aircraft of this type today) it was not widely used in the Soviet Aeroflot and airlines that bred after the collapse of the Soviet Union. It should also be taken into account that civil aviation still operates many An-26 aircraft with turboprop engines, which are a significant competitor to the An-74. In 1979, as already mentioned, the aircraft was first demonstrated at the next aerospace show in Paris, but this event did not contribute to the expansion of its "geography".
To this day, the An-72 is the only aircraft with such unique takeoff and landing characteristics, and it is not surprising that it has set 20 world records in different weight categories, many of which have not been surpassed to this day. In particular, the record in the class of aircraft with a takeoff weight of 25,000-35,000 kg, set by the crew of M. L. Popovich in November 1983, when a load of 5,000 kg was "delivered" to a height of 11,380 meters. A month later, the aircraft showed remarkable agility, climbing 9,000 meters in 10 minutes 4.3 seconds. In November 1985, test pilot S.A. Gorbik flew a closed 2000-kilometer route at an average speed of 681.68 km/h.
In August 1991, military test pilot M. Kosarev set a world speed record on the An-72 along a closed 100-kilometer route. Prior to that, he held the speed record set on a 1000-kilometer closed route with a load of 1000 and 5000 kg.
The aircraft was well received by the pilots, who appreciated its takeoff and landing qualities, simplicity and ease of control, and for the humpbacked outlines, the sharp-tongued aviators gave it the nickname "Camel". But the nickname "Cheburashka" took root more for its characteristic front view with high-mounted large-diameter engines.
An-72 tried to adapt to the needs of civil aviation. To this end, the An-72AT was developed for the transportation of standard aviation containers, the administrative An-72S, the predecessor of the VIP version, and the export modification of the An-72V, developed by order of the Peruvian Air Force.
After the collapse of the Soviet Union, when the production of the An-72 ceased, KSAMC offered the airlines the An-72G aircraft, which was nothing more than a cargo version of the An-74. But these projects remained on paper.
An-72 for the characteristic arrangement of engines was nicknamed "Cheburashka"
Today, the St. Petersburg enterprise Kontur-NIIRS offers the option of installing multifunctional indicators on the An-72 and replacing the Buran radar with the Kontur-10Ts radar with a phased slot antenna, which makes it possible to detect the coastline and ships at sea at a distance of up to 300 km.
In 1981, the Kharkov Aviation Production Association began to master the serial production of the An-72, but with a reduced size of the radar antenna, which once again led to the alteration of its antenna radome. Serial aircraft for the military received the designation An-72, and for civilian operators - An-74.
The first serial An-72 at the direction of the Minister of Aviation Industry of the Soviet Union I.S. Silaev was to be built by January 1983. But this timeline turned out to be unrealistic. By that time, the plant continued to produce Tu-134 aircraft.
The constant changes made to the design of the An-72 greatly complicated the situation at the serial aircraft plant, where the development of the aircraft was already going with great difficulty. The enterprise turned out to be completely unprepared for the transition to a fundamentally new machine. There was no experience in the manufacture of large-sized solid-milled panels, parts made of composite materials and titanium, glued and honeycomb structures, and the use of new assembly methods. As a result, the production of carbon fiber parts (chassis doors, cargo hatch and folding wing panels) began with a delay of a year due to the fact that the State Planning Committee of the USSR did not order carbon fiber to chemical plants in time. The production of the modified An-72 also required new technological equipment. All this led to the fact that the first serial An-72s were all-metal, without the use of composite materials in the airframe design.
Only on December 22, 1985, the crew of test pilot V.A. Tkachenko lifted the first serial An-72 into the air. In NATO, the An-72 received the code designation Coaler-C (“Coal Miner-S”). In 1986, the An-72 (serial number 0103) entered the Air Force Research Institute for control tests (lead engineer V.K. Polusmyak), but it never became a standard. One of its significant defects was the deadwood on the wing due to different angles of installation of its consoles. The usual leveling failed to eliminate the drawback, and the car was returned to the factory. Only after working out the assembly technology, the An-72 began to be handed over to the customer.
The first serial An-72s were equipped with D-36 series 1A engines and TA-8V auxiliary power units. The assigned resource was small - 15,000 hours (15,000 landings, 25 years of operation).
The military acceptance of the An-72 at the Kharkov Aviation Plant was carried out by test pilots M.I. Ivantsov, Bityuzhsky, S.E. Kuznetsov, flight engineer V.G. Bochko, radio operator V.V. Krivoruchenko. According to Ivantsov, when they started to fly(on An-72. - Note. ed.), there were many inconsistencies with the chassis. Our struts broke five or six times. Through improvements, all this was brought to mind. Initially, the takeoff weight limit was 31,200 kg, and after modifications, the landing gear could withstand up to 40,000 kg. According to the instructions, you can land on the An-72 with a side wind of 15 meters per second, we flew at 20 and even 25.
An-72 left the factory with red stars - the symbols of the Soviet Army. For the cars intended for the 8th Akdon, they made an exception, painting them in the colors adopted by Aeroflot and applying state registration designations.
In operation, the An-72 proved to be a fairly reliable and unpretentious machine. Serious malfunctions and defects after the elimination of "childhood diseases" were practically not observed. At the same time, its design turned out to be rather “gentle”, and even during the tests of the An-72, restrictions were imposed on landing speed and operating conditions from various airfields. More complex, in comparison with the aircraft of previous types, the An-72 also needed more thorough maintenance. Especially inconvenient for work was the high location of the engines, requiring bulky stepladders.
The machine has passed long-term operational tests in different climatic conditions, including in the Arctic regions, at high-altitude and southern airfields. According to their results, the scope of the aircraft was expanded. In the overload version, the takeoff weight of the An-72 was increased to 34,000 kg (test pilots noted a deterioration in the controllability of the machine, and flights in this case were recommended only for experienced pilots).
Although it was assumed that the An-72 would replace the An-26, but with a carrying capacity of 7500 kg, it occupied an intermediate niche between a light military transport aircraft and the medium An-8, which was then in service.
The An-72 did not reach military transport aviation. It is often written that its carrying capacity and capacity did not allow placing military equipment on parachute platforms in the cargo compartment, and leaving the aircraft in the air is hampered by a strong bevel of the flow behind the wing. There were cases of jamming of the retractable ramp in flight. This is not entirely true.
In fact, the main reason for the rejection by the command of the An-72 military transport aviation was the absence of a navigator's workplace on board. The generals could not understand that the pilot-navigation system at the disposal of the pilots made it possible to automatically take the car to the desired point, for this it was only necessary to program the flight route. There were no places on board for on-board equipment and equipment for airborne transport equipment. For these reasons, the military transport aviation (VTA) did not have a single regiment or squadron equipped with An-72 aircraft. The only exception was the 8th Red Banner Special Purpose Aviation Division (now 8th Adon), stationed in Chkalovskaya near Moscow, where from the spring of 1987 to 1988 24 An-72s, a separate transport regiment of the Navy aviation in Ostafyevo near Moscow and aviation of the Ministry of Internal Affairs arrived, but they did other things. The rest of the 96 Anas built were distributed among various regiments and power structures, where to this day they are used mainly for transporting personnel, and sometimes also official vehicles.
One of the An-72s, after the collapse of the Soviet Union, was purchased by Sudanese President Omar Ilbashir, who considered that this aircraft was the most suitable for state visits. Unlike the Falcon, the An-72 takes on board not 14 passengers, but 30, including journalists with television equipment.
The An-72 is considered a fairly reliable aircraft, although its operation, as, indeed, of any type of equipment, is not without incidents. The first flight accident, information about which became available thanks to the journalists on board the aircraft, occurred on October 23, 1994. On that day, the plane of the Federal Border Service with tail number 960 (ship commander Lieutenant Colonel Vladimir Talanov) was supposed to fly from Vorkuta to Moscow. Shortly after takeoff, the aircraft's hydraulic system failed, and they decided to return to Vorkuta. The landing gear and flaps were not easily released with the help of an emergency hydraulic system, but after landing the brakes and the mechanism for turning the front landing gear failed, and on the run it was necessary to maintain a straight direction (if it can be called that) by alternately turning on the thrust reversers of the left and right engines. However, the car still went off the runway, breaking the nose and main landing gear located on the right side of the fuselage. Four crew members were seriously injured, and five passengers received bruises of varying severity.
On February 10, 1995, a tragedy broke out in the sky near Kiev. An-70, performing another test flight, crashed. As a result of a collision with an An-72 escort aircraft, seven crew members were killed.
I never found out a clear explanation of the reasons for what happened, but, as the press reported in those days, the An-70, flying in the normal mode, suddenly began maneuvering that was not foreseen by the task. Approaching the escort aircraft from the right below and behind, the An-70 hit its fuselage with its keel in the area of the emergency hatch. Then, with the keel and the left half of the stabilizer, he destroyed the right flap and crushed the fairing of the An-72 chassis. The left half of the stabilizer and part of the keel came off from the impact of the An-70. The uncontrolled experimental vehicle went into a deep slip and, going into a dive, almost plummeted to the ground. The crew of the An-72 managed to land the damaged aircraft at their airfield.
There is a certain oversight of the organizers of the test flight in this tragedy. As an escort aircraft with a cameraman on board, a more maneuverable aircraft of the Czechoslovak L-39 Albatros type should have been used, and not a transport, although relatively light, but less "mobile" An-72. Perhaps this would allow to increase the distance between the cars in time and avoid the tragedy.
The first An-72 crash, which occurred on December 22, 1997 in Abidjan (Cote d'Ivoire), claimed the lives of five people. It was a military aircraft that remained in one of the countries of the near abroad, later ended up in the airline and registered under the index ER-ACF (Renan).
Anything can happen in aviation, but the event that took place on July 7, 2000 in the sky over the North Caucasus struck the imagination of not only ordinary people, but also specialists. It was the 27th minute of the flight of the An-72 aircraft, carrying passengers from Mozdok to the Chkalovskaya airfield near Moscow.
At an altitude of 3900 meters in the cockpit, the sign "Use oxygen" lit up. Alas, the crew did not heed the signal, considering it to be erroneous, and continued the flight. At an altitude of 8500 meters, the car completely depressurized, and all 29 people flying in it, including the crew, lost consciousness. As a result, the aircraft spontaneously began to descend at a high vertical speed in a steep spiral, going into a dive.
Passengers were mixed with things falling on them. One of them hit pilot V. G. Shelagin on the leg. Waking up from pain, Valery Gennadievich, as later presented this information on the Internet with reference to the Trud newspaper, made it to the cockpit with some effort and dragged the commander who had lost consciousness. Having brought the plane into horizontal flight at an altitude of just over a kilometer, the pilot, who had previously flown independently only in helicopters, could not land it and tried to wake the crew.
The flight ended successfully with an emergency landing at the Rostov airport. The case in aviation is unique, and Shelagin's actions, in my opinion, bordered on a feat, but this event passed like an ordinary one.
On April 21, 2002, during a rough landing at the airport of the city of Wamena (Indonesia), the An-72 of the Estonian airline Enimex (registration index ES-NOP, serial number 36572060642, released on May 19, 1988) “skipped”, and then, hitting the front pillar on the runway, broke her. The resulting fire destroyed a significant part of the fuselage. There were four crew members on board the plane, but no one was hurt.
The An-72, created in accordance with the requirements of the Air Force and the Airborne Forces for the transportation of goods expanded in comparison with the An-26 nomenclature and at a higher speed, became a universal machine, but did not fully justify the hopes of the military. Remained unclaimed and its excellent takeoff and landing characteristics. At the same time, the feedback from pilots about this car is the most flattering.
On the serial An-72 (serial number 0106), the wing and fuselage were reinforced especially for demonstration flights, and this "acrobatic" aircraft was able to perform aerobatics - rolls and half loops.
After the collapse of the Soviet Union, many An-72s remained in the former Soviet republics, including Ukraine and Estonia. In the Republic of Moldova in 2003, the only An-72 was registered with the VICRI airline. An-72 can be found in Liberia and Colombia.
An-71 - An-72BR
Significant reserves built into the airframe of the An-72 military transport made it possible to create the An-71 aircraft of the ground-based early warning radar complex on its basis. The development of the aircraft began in 1982, and the E-700 radio engineering complex with the Vega-M coherent-pulse radar became its basis. The antenna of this radar is placed in a fairing at the top of the keel, which, unlike the base machine, was made with a negative sweep angle. In this case, the horizontal tail was transferred to the fuselage.
Powerful radio equipment, as well as means of protecting the crew (three people - the main and three operators) from electromagnetic radiation, significantly weighed down the car. This made it necessary to replace the standard D-36 turbofan engines of the An-72 aircraft with the D-436 with a thrust of 7500 kgf and supplement them with an RD-38A booster engine with a thrust of 2900 kgf, installed under the rear fuselage with an air intake in one of the fairings of the main landing gear.
Observing air and surface space, the radar, thanks to a digital system for selecting moving targets, allows you to simultaneously detect up to 400 objects, track them and, if necessary, direct ships and aircraft at them. From a height of 8,000 meters, the aircraft's equipment detects targets within a radius of 350–370 km moving at altitudes from 100 to 30,000 meters in all directions. At an altitude of 8000 meters, the aircraft can loiter for up to five hours, taking into account the air navigation fuel supply, at a speed of 500-530 km / h and be operated not only on paved airfields, but also from unpaved runways.
The first aircraft, which received the identification mark of the USSR - 780151, was converted from aircraft No. 004 of the experimental series (originally the USSR - 19774). Remodeling the An-72, the fuselage was lengthened by 990 millimeters due to the insertion in front of the wing, and the tail section was made anew, with the cargo hatch “sewn up”.
An-71 was built in June 1985, and on July 12 the crew of test pilot A.V. Tkachenko made the first flight on it.
The second flying machine (USSR - 780361) with an inscription on board the EU ATC (Unified Air Traffic Control System. - Note. auth.) assembled using units of the serial An-72. For static tests, the glider of the experimental An-72 No. 001 was redone.
Testing and fine-tuning of the AWACS complex continued until the end of 1990. During this time, both machines took to the air 749 times, having flown over 1000 hours, but the An-71 was not handed over to state tests due to a reduction in the military budget.
The volume of tasks solved with the help of the radio equipment of the An-71 aircraft, both military and civilian, is very extensive, if there were a customer. But two experimental aircraft were left without work.
Among the little-known variants of the aircraft is the An-72BR (An-72R, product "88"), developed in the second half of the 1980s. Little information about him has been published, and all of them are contradictory. According to one of them, the aircraft with radio antennas on the sides of the fuselage was intended for reconnaissance, according to others - for relaying data transmitted from the An-71. An-72BR was built in three copies, but in the early 1990s, work in this direction was stopped. The glider of one of them, which in September 2004 was still in the parking lot of the ASTC im. O.K. Antonov in Kiev.
1. An-71 early warning aircraft
2. An-72BR reconnaissance aircraft with dismantled equipment
In addition to the ground-based complex, since 1983, the Antonov Design Bureau has been developing a carrier-based version of the An-71K AWACS aircraft for the Tbilisi heavy aircraft-carrying cruiser (TAKR). To do this, it was necessary to increase the thrust-to-weight ratio of the An-71K. In addition to the main D-436K engines, it was necessary to install three booster turbojet engines RD-38A. The preliminary design of the An-71 K was prepared for the fall of 1984, however, the military opted for the project of an aircraft of a similar purpose, the Yak-44, which more fully met the requirements for placing the aircraft on the TAKR, but it only reached the mock-up stage.
There were other projects for military aircraft based on the An-72, but they all remained on paper.
Aircraft for the border troops
The development of a patrol aircraft for the Border Troops of the KGB of the USSR was completed much more successfully. The range, flight duration and carrying capacity of the An-72 made it quite suitable for patrol flights to protect the sea border and the economic zone. The equipment of the aircraft was supplemented by satellite navigation systems, long-range radio navigation and an optical television complex, the cameras of which are capable of detecting objects at sea from a long distance and in bad weather (they are located in the left chassis fairing and have windows that are closed by shutters in the non-working position). The aircraft is equipped with a set of photographic equipment under the sliding flap of the cargo hatch. At night, aerial photography is provided by lighting bombs or SFP-2A cartridges. The aircraft can take on board 22 paratroopers or 44 soldiers with personal weapons and equipment. For placement in the cargo compartment of ammunition and cargo with a total weight of up to five tons, there is an electric hoist with a lifting capacity of 2500 kg on the ceiling of the cargo compartment, and roller table equipment can be installed on the floor. There is also a sanitary option for transporting up to 16 wounded on a stretcher, accompanied by a paramedic.
An-72P of the Border Troops of Russia
The armament of the An-72P consists of a UPK-23-250 container suspended on the fuselage pylon in front of the right fairing of the chassis of the container UPK-23-250 with a double-barreled gun GSh-23/1 (rate of fire 3200 rounds per minute, ammunition load 250 rounds), 100 kg bombs and 64 unguided aircraft missiles C -5 in two blocks UB-32M on two wing pylons. If necessary, life rafts and buoys can be dropped from the aircraft through the cargo hatch, and additional bombs can be hung on the electric hoist.
The wing of the aircraft was reinforced for flight conditions in difficult weather conditions and stormy weather (later it was unified for all serial aircraft).
An experimental car was tested in the air on November 29, 1984. It took almost five years to test the An-72, and only on April 5, 1990 did the production aircraft take off.
The first An-72P entered service with the border aviation in the Far East. It was in the Far East that the first case of combat use of the An-72P was noted. According to the Flight magazine, in 1994, the border troops of the Russian Federation had six An-72Ps.
On February 22, 2001, the crew of the An-72P aviation of the Russian border service near the island of Shikotan in the North Kuril ridge, after several attempts to detain, sank the violating vessel, the seiner Albatros-101, which did not have any identification marks. As it turned out, Albatros-101 was assigned to the port of Kholmsk (Sakhalin Region) and belonged to CJSC Albatros.
The day before, on February 21, at about eight o'clock Moscow time, in the exclusive economic zone of Russia, the crew of the Pagella patrol vessel discovered an unidentified Japanese-built ship, the crew of which did not respond to requests and signals from border guards. The persecution of the intruder began together with the border guard ship (PSKR) "Kamchatka". An An-72P border service plane took off from the Yelizovo airport in Kamchatka to assist in detaining the offending vessel.
At 09:35, warning fire was fired from the An-72P, but there was no reaction from the intruder. At ten o'clock, shooting to kill, the crew of the aircraft recorded a shell hitting the ship, on the deck of which a fire started. A few hours later, Russian border guards again took to the air the An-72P, which at 23:40 went to the intruder and fired first warning fire, and then to kill. To prosecute the offender
Soon the intruder got in touch and reported about the wounded on board. However, when the border guards arrived to provide assistance, Albatros-101 changed course and attempted to exit the exclusive economic zone of Russia.
The crew of the An-72P again warned the captain of the offending vessel about the use of weapons and his responsibility for possible victims. After using weapons to kill for the third time, shells hit the side and stern of the vessel, which stopped, and the crew members moved to three life rafts. In the morning the offending vessel sank.
According to the latest version of the border guards, shooting at the seiner could not lead to his death, because, as follows from a press release from the Federal Border Service of Russia, "during the rescue operation, the Kamchatka PKR went around the schooner several times, but did not find holes below the waterline" . It was this circumstance that gave the border guards reason to assume that the crew sank their ship, which now lies at a depth of 5000 m.
Four years later, the An-72P again entered the battle. On December 23, 2005, the Danube border guard ship entered the Sea of Okhotsk to detain the intruder, and the An-72P took off from the Yelizovo airfield. While pursuing the intruder, the An-72P fired warning shots, but the ship did not comply with the demands of the border guards, and then the aircraft opened fire to kill. The ship was defeated and stalled.
An-72P is in service with the border troops not only in Russia, but also since November 1996 in Ukraine. The aircraft was built in cooperation with aircraft factories in the cities of Arseniev, Omsk and Kharkov.
But the expansion of the functionality of the An-72 did not end there. In 2006, at the Aviasvit XXI Aviation and Space Salon, information was received about the development of an aircraft variant that can be placed under the wing on a BDZ-USK holder of an aviation container (KMGU modification) with a solid-fuel engine.
An-74 - a civilian version of the military "airliner"
Speaking about the aircraft created in the ASTC im. O.K. Antonov, it should be noted that among them there were practically no experimental machines. All cars bearing the name "Antonov" were built and are being built in series. Among them there is an aircraft, created a quarter of a century ago, but the demand for which exists today. This is a universal An-74. The secret of the An-74 lies primarily in its reliability, excellent flight and takeoff and landing qualities, its unpretentiousness in operation and compliance with modern strict environmental requirements.
The first flight of the An-74 prototype (USSR - 780334), as mentioned above, was performed by the crew of test pilot S.A. Gorbika September 29, 1983. Compared to the An-72, the car became noticeably heavier, which negatively affected its takeoff and landing data, but the carrying capacity and range increased.
The plane turned out to be “strong”, suffice it to say that during special tests of the An-74 at high angles of attack at the State Research Institute of Civil Aviation, the pilot, who was not prepared for this, overtightened the steering wheel and fell into a tailspin. The plane withstood off-design loads, did not fall apart, however, the airframe was severely deformed.
And although the efficiency of the An-74, associated with its layout, left much to be desired, the aircraft was quite suitable for some civilian operators.
Speaking of the An-74 aircraft, it is often claimed that it was the first Arctic version of the military An-72. In fact, the An-74 did not immediately take on the appearance of an aircraft for the Arctic, since it did not have the equipment and equipment necessary for this, with the possible exception of side blisters. At the beginning of the design, the Arctic version of the An-74 was supposed to be equipped with an electrically heated ski chassis and braking devices, but this did not come to that.
An-74, then renamed An-72A, is, first of all, a demonstrative model of the aircraft, in which the wishes of both military and civilian customers were most fully taken into account.
The first aircraft for the Arctic was the pre-production An-74 (An-72AT) with the identification mark of the USSR - 58642 (serial number 0202), built in Kharkov according to the terms of reference developed at the State Research Institute of Civil Aviation in 1984, and took off on June 26, 1986. This aircraft, intended for testing, was equipped with navigator and hydrologist jobs. Two months later, the first international demonstration of the aircraft took place at an aviation show in the Canadian city of Vancouver.
In March 1986, the expedition of Dmitry Shparo, who made a ski crossing between the stations "North Pole-26" and "North Pole-27" through the Pole of Inaccessibility, was on the verge of disaster. On the way of the athletes, due to the movement of the ice, large leads were formed. Overcoming natural obstacles, travelers reached their destination with severe frostbite, and many needed hospital treatment. The evacuation of athletes by helicopters was out of the question due to the insufficient range of their flight. In addition, only a flat section with a length of about 600 meters remained from the runway at SP-27.
There was only one hope for an experienced short takeoff and landing aircraft An-74. The operation to rescue travelers was completed successfully, and the An-74 passed another test, once again demonstrating its unique capabilities.
This was followed by cars registered under the identification marks of the USSR - 72001 and the USSR - 72003, transferred to the state joint tests, which began in 1989 and lasted until 1994. In 1990, the aircraft was tested in high altitude conditions at the Murghab airport (lead test pilot K. Malinin).
On September 13, 1990, the Ministry of Civil Aviation of the USSR ordered to begin operational testing of four pre-production An-74s that had not yet passed state tests at the Chersky airport of the Kolyma-Indigirsky air squadron. For three months, "Ana" visited the airports of Sochi, Ashgabat, Borispol, Gostomel and Petropavlovsk-Kamchatsky.
In the process of fine-tuning the aircraft on a machine (serial number 0404), the TA-8 auxiliary power unit was replaced with a more powerful TA-12, which provides electric power to the aircraft's systems in flight at altitudes up to 9000 meters and engine start at high-altitude (up to 3600 m) airfields and in flight at altitudes up to 6000 meters above sea level. At the same time, the navigation system was updated and a radar with a larger antenna was installed, which made it necessary to increase the nose fairing.
An-74 belongs to a number of world achievements. In particular, in flight in the spring of 1987, the crew of pilot V.A. Tkachenko set (in the class of machines weighing 35,000-45,000 kg) five records at once, lifting a load weighing 15,000 kg to a height of 10,960 meters. Two months later, the same crew set a world record for horizontal flight altitude - 11,210 meters. In May of the following year, the crew of the pilot Yu.N. Kotova flew 6341.973 km in a straight line.
As expected, about two dozen An-74s were required for polar explorers, therefore, in the Soviet Union, with the beginning of perestroika and the transfer of industry for conversion to the ANTK im. O.K. Antonov and at the Kharkov Aviation Plant began looking for ways to expand the functionality of the An-74 and create competitive products. The first to appear was a cargo version of the aircraft - An-74T with a carrying capacity of 7500 kg. The aircraft successfully passed state tests from 1992 to 1995.
It was followed by the An-74T-100 with a crew of four (commander, co-pilot, navigator, flight engineer) and the An-74T-200 with a crew of two (commander and co-pilot), capable of carrying up to 10,000 kg of cargo. A feature of these aircraft is that cargo can be placed not only on the floor of the cargo compartment, but also on the ramp, and the weight of the latter reaches 1000 kg.
On December 24, 2004, at the Kharkiv State Aviation Production Enterprise (KSAMC), the aircraft completed its first run.
The An-74T-200A differs from its predecessors in an improved digital flight and navigation system, which can significantly reduce the workload on pilots and improve the accuracy of aircraft navigation. The aircraft also used the so-called "semi-glass" cockpit.
The aircraft is equipped with all the necessary modern equipment, including satellite navigation systems, mid-air collision avoidance and ground proximity warning systems, indication of flight parameters, as well as a number of other important systems mounted on a single tire.
The navigation complex of the aircraft fully complies with the prospective requirements of the international civil aviation organization ICAO until 2015, the requirements of B-RNAV aircraft navigation and RNP-5, RNP-1 separation. 13 variants of its application also contribute to the promotion of the An-74T-200A to the world market.
On April 28, 2005, the crew, led by test pilot A.I. Tatarchuk, performed the first flight on the An-74T-200A.
The first version of the An-74 in the Arctic version
Known project light military transport aircraft An-74T-200V, capable of carrying cargo weighing up to 10 tons or up to 44 soldiers and parachuting fighters and equipment.
The transport-convertible An-74TK-100 and An-74TK-200 were created in 1995. According to the developer, aircraft of the An-74TK family fit perfectly into the fleet of air carriers in Siberia, the Far East and the Far North - regions for which it is typical to deliver cargo in one direction, and passengers or cargo and passengers at the same time in the other.
Folding passenger seats are placed in the passenger cabin of transport-convertible aircraft of both variants. Along the sides there are also folding closed luggage racks with lighting and oxygen equipment, speakers, and buttons to call the conductor. In front of the cabin there is a place for a flight attendant, there is also a small kitchen. The aircraft also has a stationary toilet with the necessary set of sanitary equipment.
For emergency evacuation of passengers, the aircraft has four emergency exits. Entry and exit of passengers in normal mode are carried out through a cargo ramp, supplemented by a folding ladder. In the tail section of the fuselage there are spacious luggage racks for hand luggage. The luggage compartment is separated from the passenger cabin by a rigid, easily removable partition.
The convertibility of the aircraft is achieved thanks to the combined set of transport and passenger equipment installed on it, which makes it possible to switch from one option to another in a short time.
On lines with a constant cargo flow, the aircraft can be equipped with roller conveyor equipment for loading and mooring pallets and containers. Transportation of goods is possible in containers LD-3, LD-6 or packaged on pallets 2L3P and LD-3 pallet.
Unlike trucks, they can carry up to 52 passengers. The first version of this family was the An-74TK-100 with four crew members. Its state tests were completed in 1995, and in August the Interstate Aviation Committee (IAC) issued an appropriate certificate to the An-74TK-100 aircraft, which allowed it to begin operation in airlines.
An-74TK-10 °C became a further development of the transport-convertible aircraft. The new car is designed to transport two bedridden patients, accompanied by four medical workers, as well as 6 passengers in the VIP cabin.
On board the aircraft, all conditions have been created to provide the seriously ill with the necessary medical care and high comfort for passengers who are served by three flight attendants. The latter have at their disposal a complete set of household equipment and the necessary supply of food.
On board the An-74TK-10 °C, resuscitation and oxygen-air stations of rapid transformation are installed, on the ground and in the air, ensuring the maintenance and control of the vital functions of the patient's body for 12 hours.
An-74TK-10 °C can also be used to transport 22 people: several VIP passengers and persons accompanying them in two separate cabins. In this version of the aircraft, the medical compartment has been converted into a passenger cabin, which has twin seat units, a buffet with the possibility of heating food and preparing hot drinks, a trunk with a load capacity of up to 600 kg, as well as luggage racks and a toilet. Instead of accompanying persons in the second compartment, it is possible to transport a luxury car.
Then came the An-74TK-200 with a crew of two, put into production in 1995. This aircraft has become truly universal. From its predecessor, he inherited high flight characteristics, allowing the machine to be operated in all climatic zones at temperatures from -60 to +45 degrees Celsius, in mountainous areas, on unpaved, sandy or snowy runways. If necessary, takeoff and landing from short runways is possible. at the same time, the angles of the glide path of planning and climbing make it possible to operate the machine from airfields surrounded by high obstacles.
The D-36 engines of the ZA series installed on the aircraft have a significant service life, high reliability and meet the requirements of the International Civil Aviation Organization (ICAO) in terms of noise and emission of harmful substances. At the same time, their takeoff thrust remains constant up to an outside temperature of +33 degrees, allowing the operation of the machine in hot climates.
The An-74TK-200 aircraft was designed for flights on lines where passengers are transported in one direction, and cargo is transported in the opposite direction. The possibility of cargo-passenger flights is also provided.
I have ever flown on this unusual-looking machine, and it is very difficult to keep from emotions. It should be said that there are two cabins on the plane: the front VIP class and the cargo-passenger cabin. The decoration and amenities in the front cabin are beyond praise.
You can not ignore the cargo-passenger compartment. First of all, the blocks of passenger seats attract attention. Extremely comfortable and lightweight, they can be folded up and placed along the sides of the car in minutes. The configuration of the rear compartment depends on the volume of the transported cargo. At the same time, the aircraft can carry up to 52 passengers or 10 tons of cargo, as well as their various combinations.
In addition to the side door for boarding passengers, a cargo ramp is used, complemented by a folding ladder. In the tail section of the fuselage there is a spacious luggage compartment for hand luggage, separated from the cabin by a rigid, easily removable partition.
To simplify rigging operations with containers and palletized goods weighing up to 2500 kg, an onboard hoist is designed. Loading and unloading of wheeled vehicles are carried out on their own or with the help of a tractor or winch.
The noise level in the cabins is very low, which is facilitated by the placement of engines above the wing. For the same reason, the ingress of foreign objects from the runway into them is practically excluded.
The large thrust-to-weight ratio of the machine, the presence of an auxiliary power unit for autonomous starting of engines and onboard means of mechanization of loading and unloading operations, a landing gear with low-pressure pneumatics ensure autonomous operation of the aircraft from almost any airfield.
An-74TK-200 fully complies with modern ICAO requirements; it can be found on all continents - from the Sahara desert and the mountainous regions of Afghanistan and Peru to the Arctic and Antarctic.
An-74TK-200 is a new machine in all respects and gradually reveals its capabilities. In particular, InterAMI Interior has recently developed a new interior for the An-74TK-200. In addition to comfortable seats with high backs and headrests, it includes anti-noise panels, individual ventilation, multimedia centers and video systems, a modern galley and a toilet. Despite the high ceiling, the optimal distance between the seats, spacious luggage racks, and lighting contribute to an even greater increase in the visually perceived space of the cabin.
On August 2, 1991, the creators of the An-74TK-200 were awarded a type certificate issued by the State Aviation Register of the Soviet Union (its successor was the Interstate Aviation Committee). The aircraft to this day complies with the requirements of European airworthiness and exhaust emission standards.
The versatility of the An-74TK-200 makes it possible to use it not only for the transport of passengers and cargo, but also as a "flying hospital" and patrol aircraft, to carry out parachute landing of people and cargo.
In addition to the options described above, an An-74D administrative aircraft was created, designed to transport
12 passengers in comfortable conditions in three cabins for a distance of 3950–4000 km. Additional heat and sound insulation and an in-flight audio and video entertainment system are installed on the machine. The variant of the aircraft with a crew of two received the designation An-74-200D.
The AH-74VIP variant has become even more comfortable. Its concept is based on a combination of high comfort in the cabin with an additional compartment designed to carry both accompanying persons and oversized cargo, including a car.
The logical conclusion of the An-74 aircraft family was the transport-convertible An-74TK-300 with D-36 series 4A engines placed on pylons under the wing. The aircraft is designed to carry up to 10,000 kg of cargo or 52 passengers. Initially, as follows from press reports, it was planned to replace the engines with more economical D-436T1 take-off thrust of 7600 kgf, placing them on pylons under the wing.
Abandoning the modes of short takeoff and landing characteristic of its predecessors, and retaining the same carrying capacity, the speed of the new "Ana" was increased by 50 km/h, and the range - by 1.2 times. In addition, it became possible to increase the take-off weight of the machine when operating in hot climates, as well as to provide the possibility of take-off from high-altitude airfields. This significantly expands the capabilities of the machine and makes it more competitive in the aviation market.
The first flight of the An-74TK-300 took place in April 2001 in Kharkov. In November of the following year, the An-74TK-300 flew on the route Kharkiv - about. Yeish (Iran) - Zhuhai (PRC) - Ras El Khaim (UAE) - Kharkov, and a month later P.V. Balabuev - General Designer of the ASTC im. O.K. Antonov was awarded Type Certificate No. ST-208-An-74TK300, certifying the compliance of the An-74TK-300 with the Airworthiness Standards AP-25. The aircraft fully complies with the requirements of Chapter 3 of Appendix 16 of the ICAO Standards for noise level, emissions of harmful substances into the atmosphere and navigation accuracy and has no restrictions when flying on airways around the world.
A purely transport version of the An-74T-300 with a cargo compartment 2.15 meters wide (on the floor), 2.2 meters high and 10.5 meters long (with a ramp) is also being considered. The range of the machine with loads of 10,000 kg and 3600 kg will reach 2130 and 5050 km, respectively. An-74TK-300, like its predecessors, can become the base for the creation of aircraft of the most wide range.
In December 2002, the aircraft received a type certificate, and the following year, the first An-74TK-300 in the VIP version began to be operated by Ukraine Airlines. In 2004, this enterprise received one more aircraft, and in the following year, three AH-74TK-300VIPs were delivered to the Aeromost-Kharkov airline, which won the tender of Ukrtransleasing.
The An-174 aircraft was developed - a variant of the An-74TK-300 with an extended fuselage, intended to be replaced by the An-12 airlines. But it looks like it will remain on paper.
Since the production of the An-72 has long been discontinued, a patrol version of the An-74P was developed for the needs of the border guards. This machine, like its predecessor, is designed to carry out patrol service in the 200-mile sea zone adjacent to the coast. The sighting, navigation and flight equipment of the aircraft provides automatic navigation at all stages of flight, its output to a given point, instrumental search, determination of the coordinates of surface vessels, their speeds and courses of movement. To stop the actions of violating ships, the An-72P is armed with a GSh-23L cannon with an ammunition load of 250 rounds, two unguided missiles and four 100 kg bombs. The photographic equipment available on board provides aerial photography of targets in the daytime, and with the help of lighting cartridges SFP-2A even at night.
An-74MP-300 with D-36 series 4A engines is also designed to patrol the sea borders at any time of the day and in adverse weather conditions. It can be used for landing up to 22 paratroopers with personal weapons and equipment, transporting up to 44 soldiers or 16 wounded on a stretcher, accompanied by a paramedic, transporting ammunition and other cargo weighing up to 5000 kg. The crew of the An-74MP-300 consists of four people, but in case of airborne landing, a navigator's workplace is provided. The armament and equipment are similar to the armament and equipment of the An-72P and An-74P aircraft.
In addition to the modifications mentioned, in 1990 the State Research Institute of Civil Aviation developed technical specifications for the An-74GF aircraft for studying the Arctic, Antarctic and the World Ocean and the An-74 Cyclone for meteorological research.
The first serial An-74 (serial number 0706), built at the Kharkov Aviation Plant, took off in December 1989. This and subsequent An-74s were sent to the Yakut air squadron. In NATO, the aircraft received the code designation Coaler-B ("Coal Miner-B").
In 1991, the Council of Ministers of the USSR allocated 220 million rubles for the development of one of the most promising aviation enterprises - the Omsk Production Association Polet. In accordance with the decree of the Russian government of June 3, 1992, from next year there, together with the Arseniev Aviation Production Enterprise named after. N. I. Sazykina and KSAMC began mass production of the An-74. The first car was built in Omsk a year later as an ice scout. However, the volume of production turned out to be small, and then Kharkiv residents built not much more aircraft of this type for the needs of the national economy. Suffice it to say that by the spring of 1998, Russian airlines, including the Ministry of Emergency Situations, operated only nine aircraft of this type.
In 1992, the initial assigned resource of the An-74 was seven years of operation, two years later it was extended to 10 years.
In 1995, preparations began in Omsk for the production of the transport-convertible An-74TK-200 and cargo An-74T-200. However, the political events that took place in the country in those years actually led to the curtailment of production, the civilian customer received only three An-74s, and the law enforcement agencies received two aircraft in the cargo version.
On April 5, 2006, during a meeting of KSAMC representatives with Russian colleagues in Omsk, an agreement was signed on the production of parts for the An-74 aircraft manufactured in Kharkov by the Polet production association. According to Valery Blyum, First Deputy General Director for Production of the Omsk Polyot Production Association, “Kharkov is ready to cooperate with us in the cooperation that we had planned 15 years ago, to resume it and continue to operate. And we will also produce certain components for Kharkov that they need.”
The economic characteristics of the An-74, created on the basis of the military An-72, still leave much to be desired. For this reason, at first it did not find wide application in airlines. As already noted, in 1979, in an attempt to attract the attention of foreign airlines to the An-72, the aircraft was first demonstrated at the aerospace show in Paris, but this event did not contribute to the expansion of the “geography” of the aircraft. The situation changed after the collapse of the Soviet Union, but despite the emerging demand, the An-74 is still a "piece" product.
In 1994, the Kharkov Aircraft Plant sold four An-74s. In accordance with the contract signed in 1995, it was planned to supply 12 An-74T-200 and AN-74TK-200 aircraft to Iran.
In September 2003, a contract was signed for the supply of nine An-74T-200A aircraft to the Arab Republic of Egypt.
Three years later, on September 16, the first An-74 aircraft of the new modification T-200A was handed over to the leading customer, the Arab Republic of Egypt, at the airfield of the Kharkov State Aviation Production Enterprise. This solemn event took place on the eve of the 79th anniversary of the founding of the aviation plant - September 7, 2005. Two weeks later, the operation of the An-74 began, and on the very first day, the Egyptian crews, trained in Kharkov, performed two flights on it. The pilots highly appreciated the flight characteristics and the level of saturation of the machine with navigation equipment.
From 1999 to 2004, the company sold 19 aircraft, including two An-74s in 2004. In 2005, five aircraft and several kits were delivered to airlines for assembly in Russia and Iran.
On April 11, 2005, after Nikolai Patrushev, director of the FSB of Russia, visited the Omsk aerospace enterprise Polet, the press service of the administration of the Omsk region announced the intention of the FSB of the Russian Federation to purchase a second An-74 aircraft. Patrushev inspected the An-74 under construction. One of these machines, purchased by the FSB of Russia, successfully passed flight tests and underwent special modifications. According to the chief engineer of the aircraft plant, Grigory Murakhovsky, Patrushev confirmed his readiness to conclude an agreement with Polet for the second An-74.
Currently, the Omsk Production Association Polet and KSAMC are studying the issue of joint production of the An-74, since there are more and more people who want to buy this aircraft, and there is not enough production capacity in Kharkov due to the parallel production of the An-74 and An-140.
As already noted, there are no analogues close in terms of the An-72 and An-74 scheme or in terms of dimensions with turbojet engines, but there are competitors, and the main ones are turboprop transport aircraft - the Spanish CASA 295 and the American C-27J of Lockheed Martin ".
The closest to the An-74 in terms of flight performance data is the C-27J Spartan, created by the joint efforts of the Italian company Alenia Aerospace (Alenia Aerospazio) and Lockheed. Like the An-72, the predecessor of the C-27, the Italian military transport aircraft G.222 made its first flight in 1973 and was mass-produced until 2000. They were built 124 copies, which is a third more than the An-72.
The first prototype C-27J converted from a production G.222 first flew on 24 September 1999. The main external difference between the C-27J and its predecessor was the Rolls-Royce AE 2100D2 turboprop engines with a take-off power of 4640 hp. and equipped with six-bladed propellers with saber-shaped blades that reduce noise levels. This is the main and essential difference between Spartan and An-74. The choice of the theater was also determined by the location of the horizontal tail not on the keel, but on the fuselage, in the aft part of which, like the An-74, there is a ramp-type cargo hatch, however, of a completely different design. As on the Russian-Ukrainian aircraft, the fuselage of the Spartan is completely pressurized.
The C-27J airframe is mainly made of aluminum alloys. The aircraft is equipped with an AN/APN-241 airborne radar, and practically all the information required by the crew is displayed on LCD multifunctional color displays, which is also implemented on the An-74.
Another An-74 competitor on the foreign market is the C295 light multi-purpose transport aircraft, created by the Spanish company CASA and being a development of the CN-235 aircraft. The new model outperforms its predecessor by 50 percent in terms of carrying capacity and range. The C-295 uses 85 percent of the components from the CN-235. The aircraft is equipped with the Topdeck avionics complex by Sextant Avionika, which includes a radar and a GPWS satellite navigation system and other equipment necessary for a modern aircraft.
The aircraft production program started in November 1996. In June of the following year, the C295 was officially presented at the Paris Air Show. The aircraft made its first flight on December 22, 1999. Serial production began in 1999. The aircraft can carry up to 68 fighters, or 48 paratroopers, or 27 wounded, accompanied by four medical workers.
Since 2000, the C295 began to enter the Spanish Air Force. The Australian Air Force also became interested in this machine to replace the DHC-4 Caribou, as well as Greece and Switzerland. CASA hopes to get orders for it in Brazil and Taiwan. It is planned to build about 300 aircraft of this type, although, according to the company's forecast, the world market may demand up to 1,200 aircraft of this class.
Like the An-72/74, the C-27J and C295 aircraft are made according to the high-wing scheme with landing gear mounted on the fuselage, and are capable of solving the same tasks. Loading of all aircraft is carried out through the ramp-type tail cargo hatch. With a close carrying capacity, their external difference lies not only in the power plants and the location of the horizontal tail.
All aircraft are distinguished by highly mechanized wings, some of which are blown by propellers (C-27J and C295) and turbofan exhaust jets (An-72/74). Judging by the published data, the C-27J has a higher thrust-to-weight ratio (3.43 kg / e.l.s.), which allows it to be operated from short runways, which cannot be said about the C295 (4.32 kg / e.l.s.) . At the same time, the specific wing load at the maximum takeoff weight of the C-27J and C295 aircraft is significantly higher than that of the An-74. The use of TVD on the C-27J and C295 contributes to an increase in fuel efficiency and, as a result, a reduction in the cost of transporting goods, but it should be taken into account that the An-72/74 are faster machines.
A comparison of these aircraft allows us to make a general assessment that the Russian-Ukrainian An-74 aircraft is more preferable for both airlines and the armed forces in terms of performance. It is not inferior to "foreigners" either in service life, or in ease of maintenance, or in comfort for both passengers and military personnel. And another important "detail" - the cost of the An-74 is still significantly lower than the C-27J and C295.
In January 2006, information appeared about the plans of the Boeing Corporation to offer the US Department of Defense as a platform for the promising An-72 light military transport aircraft. Most likely we are talking about the An-74, since the An-72 has not been produced for a long time. In their opinion, this machine is superior in all respects to Italian, Spanish and American competitors. But the C-27J Spartan won.
While operational tests were underway, in November 1987, the first expedition to the Arctic took place with the participation of the An-74. Then the crew of the Antonov Design Bureau delivered a stationary radio station to Sredny Island. A year later, the crew of test pilot V. Lysenko on a pre-production vehicle (tail number 72003) delivered the first Antarctic inspection led by A. Chilingarov to the Vostok station, located at an altitude of 3488 meters above sea level, while flying around almost the entire sixth continent.
In April 1991, the An-74 was allowed to operate in civil aviation, and on August 2, the ASTC im. O.K. Antonov issued a type certificate for the car. An-74 was originally intended to perform transport operations in the organization and operation of scientific stations in the Central Arctic Basin and Antarctica, visual ice reconnaissance. At the same time, the joint transportation of ten passengers and 2300 kg of cargo in a container or 7500 kg of cargo was allowed.
In June 1991, two An-74s took part in the evacuation of the North Pole-30 drifting station.
Since 1993, the aircraft regularly provided the participants of the Paris-Dakar rally.
Most aircraft of the An-74 family are operated by Gazpromavia. In 1998, there were three aircraft, in 2002 - five An-74-200D and An-74TK-100, as well as one An-74D and An-74T-100. February 26, 2005 ASTC im. O.K. Antonov handed over to RAO "Gazprom" the sanitary version of the An-74TK-10 °C, made to his order.
In 1998, five crews on an An-74-200 aircraft of the Gazpromavia airline provided for the participants of the Paris-Dakar rally. Flying in difficult navigational conditions over the unorientated terrain of the African continent, the crews of the An-74 perfectly coped with the tasks assigned to them.
On April 26, 2003, after a twelve-year break, the national flag was raised at the Russian drifting station "North Pole-32", created in the Arctic for scientific research and weather observations. Less than a year later, due to a broken ice floe, the station almost completely went under water, and there was a threat to the lives of its 12 employees.
Once again, the An-74 of the Gazpromavia airline came to the aid of the polar explorers. On March 7, 2004, the An-74 with the rescued polar explorers from the SP-32 station flew to St. Petersburg from Svalbard, and then to Moscow. For participation in 2003-2004 in the implementation of the North Pole-32 drifting station project, as well as for the rescue of polar explorers, the crew of the An-74 aircraft and the Gazpromavia airline were awarded the gratitude of the President of Russia.
On April 5, 2006, an operation began to deliver to the drifting scientific station "North Pole-34" named after. Yu. B. Konstantinov of ten polar explorers of the seasonal research team, equipment for software experiments and fresh food. On that day, an AN-74TK-100 plane of the Gazpromavia airline took off from the Moscow Vnukovo airport to the Borneo ice airfield, located 90 km from the North Pole. In addition to polar explorers, there were 1,500 kg of cargo on board the aircraft.
On the way, the aircraft landed at Longyearbyen Airport (Svalbard) for refueling. From the Borneo ice airfield, Russian polar explorers and cargo were transferred to SP-34 by two Mi-8 helicopters. Until April 30, 2006, the An-74TK-100 crew performed over 50 flights.
A month earlier, on March 6, Gazpromavia launched a humanitarian program in the interests of the African Union, having won a tender for air transportation. Two An-74-200 aircraft will deliver humanitarian aid, primarily food and medicine, to various settlements in Sudan, based in the capital of Sudan, Khartoum, for six months.
In 2005, the airline "SHAR Inc LTD", stationed in Ostafyevo near Moscow, had three An-74T and one An-74T-200 in 2005. Two An-74s were operated by Koryak Aviation Enterprise.
The rest of the airlines (Ministry of Emergency Situations, Norilsk State Unitary Enterprise, Sibaviatrans, Yakutia) each had one aircraft from the An-74 family.
An-74s are also listed in the Alyansavia and Russian House Selenga airlines.
Such a big difference between the aircraft listed in the airlines and in the register of the operator is due to the fact that many An-74s are on the ground waiting for spare parts, engines and repairs due to lack of money. Just one example. In March 2006, the Samara plant Aviakor completed the overhaul of the cargo-passenger An-74TK with tail number 74039 of the Koryak Aviation Enterprise.
For seven years, he stood motionless at the airport in the village of Ossora due to a faulty engine. During this time, many components and assemblies fell into disrepair. And only after the appearance of money, the specialists of the Koryak Aviation Enterprise restored the aircraft to flying condition and, having issued the necessary documents, including insurance, in July 2004, with the help of test pilots from the State Research Institute of Civil Aviation, they overtook the An-74TK to Samara.
Until recently, the An-74 was used mainly for charter flights, but on June 30, 2008, Gazpromavia began regular flights on the Astrakhan-Rostov-on-Don and Astrakhan-Sochi routes.
An-74 has gained wide popularity abroad. Due to its unpretentiousness and equipment with modern flight and navigation equipment, the An-74 can be found on the sandy sites of the Sahara desert, high-mountainous airfields in Afghanistan and Peru, in the Antarctic. Since 1993, the An-74 has regularly provided air support for the Paris-Dakar rally, which is evidence of the international recognition of the reliability and efficiency of the aircraft.
Is it any wonder that businessmen from many countries turned their attention, in particular, to the An-74TK-200 in the VIP configuration.
For example, in 2003 a contract was signed for the delivery of three An-74T-200A in 2005 to the ARE. Then it was increased by another six cars. Then KSAMC agreed with Sudan on the supply of four An-74TK-200 and An-74TK-300 worth $85 million.
Statistics testify to the high reliability of the An-72/74 aircraft. Nevertheless, troubles are not ruled out with it. The first crash with an An-74 aircraft (USSR - 74002), which claimed the lives of 13 people, occurred on September 16, 1991. Five years later, the second An-74 (RA - 74037) of Vossibaero airlines was lost. During takeoff from the airfield in Mirny, the thrust reverser flap of the right power plant spontaneously opened. There were no casualties, but the plane was written off.
On the evening of December 17, 2002, at the airport of the city of Sovetsky Khanty-Mansiysk Autonomous Okrug, due to damage to the hull skin, the An-74 aircraft, which was flying Sovetsky - Moscow, made an emergency landing, there were no casualties.
April 23, 2006 lost the third An-74. The accident occurred on the banks of the Chari River, which flows along the border between the Republic of Chad and Cameroon near the village of Kousseri (Cameroon), while landing at the airport of N'Djamena (the capital of the Republic of Chad). The Ukrainian aircraft An-74TK-200 (UR - 74038) was flying on the route Tripoli - Sebha (Libya) - N'Djamena (Republic of Chad). On board was a humanitarian cargo from Libya. Six crew members died in the crash.
Six months later, on the morning of November 27, a message was received about the crash of the fourth An-74, this time in Iran.
Anatomy of a STOL aircraft:
Designing a modern aircraft with short takeoff and landing.
"Form follows function"
The world really does seem smaller today, thanks in large part to aviation. In many of us, this has sparked an interest in seeing what is around us, and not just rushing to our destination as quickly as possible. Although there are certainly those among aviation enthusiasts who prefer high-speed aircraft, I think that most of us are primarily motivated to continue flying by the great emotional excitement, pleasure and rapture of flying our own aircraft. We would like an aircraft to give us the ability to cross the whole country, but we would also like to see and visit the area over which we are flying.
The Piper Cube's popularity lasted for years and was not only driven by nostalgia, but also by the fact that these aircraft are great fun, easy to fly, well adapted to taking off and landing on grassy fields (most classic aircraft were developed during the paved landing strips were rare). However, due to their age, many of these designs lack the modern enhancements that most of us take for granted, such as modern electrical equipment, side-by-side seating, all-metal construction, steerable front wheel chassis, etc. And, of course, the classic aircraft are becoming rare and need substantial maintenance to stay flying.
For the most part, we amateur pilots are already where we want to be when we take off, and therefore we enjoy flying most in an aircraft that is easy and enjoyable to fly, that provides comfort and good visibility, and has low operating costs (if anyone cares about miles per gallon, then we want low hourly running costs). When we fly over a country, the journey itself is just as important (if not more important) than arriving at our destination. STOL (S hot T ake- O ff and L anding), a short takeoff and landing aircraft, gives us the opportunity to visit more places, especially in remote areas where the world becomes our runway (this is also an important safety component). With a good load capacity, we are able to carry the necessary luggage (tourist equipment), the ability to install floats gives us additional opportunity and freedom to use the aircraft on the water. And of course, the STOL design gives us the opportunity to fly literally almost from our own garden. STOL-type aircraft are gaining popularity among amateur pilots in the same way that SUVs once won it among motorists, thanks to their off-road capability and unpretentiousness.
S T O L C H 8 0 1
The short takeoff and landing ultralight aircraft provide an easy and inexpensive option for recreational flying, and the popularity of whale-based ultralight and light aircraft has proven the need for "low and slow" flight. However, ultralight aircraft, while attractive, have many limitations: relatively low speed, wind speed limitations, difficulty achieving sufficient payload and comfort levels. Here are just a few of their inherent limitations.
Today, thanks to the knowledge accumulated in world science over more than a century about aerodynamics, structural strength, methods of dealing with various undesirable phenomena (such as flutter), ergonomics, and also due to the availability of modern powerful, reliable and light engines, almost everyone a sufficiently inquisitive person could explore the area described above with relative ease and design a light aircraft capable of carrying two to four people.
As a professional light aircraft designer and engineer, I have done just that quite a few times. In the mid-eighties, I decided to design a lightweight kit that would combine the advantages of an ultralight aircraft with the characteristics of a modern full-size one. This is how I designed the STOL CH 701: It was necessary to achieve the shortest and roughest possible take-off and landing, acceptable cruising performance, good crosswind stability, excellent visibility, crew comfort (which was achieved by placing the seats side by side). The rugged all-metal housing made it easy to build and maintain. The STOL CH 701 design was a success (over 400 STOL CH 701s are currently flying) and I subsequently developed a practical four-seat version of this aircraft, the STOL CH 801 (introduced in 1998). And in 2008, with the introduction of the new Sport Pilot category, the two-seat STOL CH 750 was introduced, featuring a larger cabin than the original 701 and new engine choices.
My STOL aircraft designs were sometimes called "ugly" because of their unusual shape. But be that as it may, form follows function, and a close examination of the unique outlines of these aircraft reveals the beauty that determines their exceptional aerodynamic and structural properties. The following is an explanation of the basic design concept that I applied in the development of my STOL aircraft:
POWER
Increasing the power of an existing aircraft is the easiest way to achieve short takeoff capability (with enough power, any aircraft will take off at short range). But this requires more fuel to provide the required flight duration and is an expensive, heavy and inefficient solution. Such an aircraft also does not provide good slow flight and payload due to the greater weight of the engine and fuel. My experience is that it takes 60 to 100 hp for a two-seat aircraft and 150 to 200 hp for a four-seat aircraft with a load of 1000 pounds (about 450 kg*). As an aircraft designer and builder (not an engine manufacturer), I have designed aircraft for existing standard, readily available engines. To maximize versatility and keep costs low, the aircraft kit must be designed to accommodate different types of engines. Then the owner of the aircraft will be able to choose between existing and new power plants.
To fulfill its mission, a STOL aircraft must be able to fly at very low speeds and still have reasonably good cruising performance. So the next big challenge is to design a wing with a high lift coefficient, so that the wing has as little area as possible, but at the same time provides the lowest speed of takeoff and landing. The relatively short wing makes it easier to control the aircraft on the ground, especially outside airfields, in the presence of ground interference, and require less space in the hangar. At the same time, they are easier to build and stronger (less weight with smaller wing sizes).
The separation of the air flow from the wing occurs at the maximum lift coefficient, when the flow can no longer flow around the toe of the wing profile and is separated from the upper surface of the wing.
Rice. one– Separation of the air flow from the surface of the wing
To push back the flow separation to a higher lift coefficient, many aircraft are equipped with flaps (deflectable surfaces attached to the trailing edge of the wing). Also, some designs use slats (attached to the leading edge of the wing) to reduce stall speed. The following diagram shows the effect of using flaps and slats to increase the lift coefficient of a wing.
Rice. 2– Dependence of the lift coefficient on the angle of attack
Thus, the lift coefficient can actually be doubled with simple fixtures (flaps and slats) if they extend the full span of the wing.
SLATS
Leading edge slats prevent stalling until about 30 degrees of angle of attack by trapping air from below where the slot is large (Fig. 3), increasing air velocity in the narrowing channel (Venturi effect) and directing this fast air tangentially to the upper surface wing through a much smaller upper slot. This "pulling" of air around the front surface of the wing suspends the stall to a much higher angle of attack and lift coefficient. The disadvantage of slats is that the air accelerated in the slotted channel requires additional energy to push through, which means higher drag. Since a lot of lift is only needed for slow flight (takeoff, climb, approach and landing), the designer is tempted to use a retractable device that folds at high speeds to reduce drag.
Rice. 3– Slats
This can be done in various ways: the slats can be mounted on roller guides so that at a higher angle of attack they are automatically drawn out by the air flow around the leading edge of the wing, and at cruising speed (at a lower angle of attack) they are retracted. This is a relatively simple system, not difficult to construct, but it has one major disadvantage: in windy conditions, only one slat can be extended and the other remains retracted, potentially creating a significant problem for the pilot, who will need all the aileron thrust just to hold the aircraft. !
This disadvantage can be eliminated by mechanically connecting the right and left slats to prevent asymmetric extension. However, the creation of such a structure is more complicated and requires a more sophisticated approach. At the same time, the effect achieved from such a system should be large enough to justify the trade-off in the form of additional weight of the device itself (not to mention cost and complexity). Another approach, the pilot-operated slat extension system, still suffers from the same disadvantages of weight and complexity.
Rice. 4– The ratio of lift and drag of a wing with fixed slats
But there is a simple solution: the increase in drag created by a slotted hole depends on the volume of air passing through this hole, which is different for different stages of flight. During takeoff and landing, maximum lift is required, and during cruising, minimum drag is required. By equalizing the air pressure on the upper and lower surfaces at the front of the wing, where the slats are located, in cruise mode, the air flow does not pass through the slot, so there is no loss of energy (and additional drag). Air pressure equalization in cruising is easily achieved with a slight upward fold in the trailing edge. illustrates the ratio of lift and drag coefficient for this wing design.
The above diagram shows that a fixed slat wing with a raised trailing edge is the optimal solution for slow flight, where high lift is needed, and has only slightly increased drag in cruise flight, while being relatively light due to the absence of moving parts. A notable disadvantage is the relatively small drag range, which means a narrow range of economical speeds for long-range flight, but in general this configuration provides the most optimal wing design for STOL aircraft.
Thus, I chose this fixed slat configuration for the two-seat STOL CH 701 and the new four-seat STOL CH 801. Despite its lightness, the wing of this design has a very high lift coefficient, which makes it a very reliable, simple and economical element of these two developments.
In addition, to further increase the lift, I used a relatively large wing chord. A large wing chord combined with a relatively short span also gives maximum strength and light weight. Additionally, a fixed chord wing is easier to build than a tapered wing.
WINGS
I've been arguing for a long time that Horner endings are optimal for most light aircraft designs because they increase the effective wingspan by 8” to over a foot (20 to over 30cm*) without adding weight to the structure. As we know, the pressure on the bottom surface of the wing is greater than on the top, this difference in pressure creates the lift that makes flight possible. At the wingtip, the pressurized air on the lower surface "feels" a close area of lower pressure, on the upper surface, just behind the wingtip, and rushes there to equalize the pressure, creating a secondary airflow around the wingtip, as shown below. This flow generates a vortex that continues behind the wing.
Rice. 5– Whirlwind at the wingtip
With rounded or rectangular wing tips, vortex flow occurs near the wing tip, as shown above.
When the ends of the wing are bent up or down, the vortex is pushed further from the end of the wing. Downturned wingtips are common on STOL aircraft, but they add weight because they must be “added” to the wing.
Rice. 6– Curved up and down wingtips
If the wingtip surface is beveled at a 45 degree angle with a slight rounding at the bottom and a relatively sharp edge at the top, the air flowing out from under the bottom surface cannot go around the sharp top edge and is pushed to the side.
Rice. 7– Horner wingtips
Aircraft performance depends on the distance from the left to the right tip vortex (effective wing span), and not on the actual measured geometric wing span. Horner endings provide the largest effective span for a given wing span and weight.
GOVERNING BODIES
Since the STOL aircraft can fly at very low speeds and is intended for use in undeveloped areas rife with obstacles, controllability of the aircraft at low speeds is vital. According to my observations, this point is overlooked in many designs of light aircraft with a high lift wing. Despite the fact that many of these aircraft have low stall speeds, the pilot is forced to maintain a significantly higher speed in order to maintain the required controllability of the aircraft.
FLAPS, AILERONS AND FLAPERONS
To solve the above problem, you can use flaperons - ailerons that occupy the full span of the wing, which, in addition, function as flaps. Using the full span of the wing gives the flaperons maximum lift like flaps, and at the same time maximum roll control like ailerons. This combination of functions is achieved with a minimum weight of the structure by means of a simple mechanical mixed control device.
We all know that near an airfoil, air slows down due to friction. This slow layer of air is called the boundary layer. The boundary layer becomes thicker as one moves from the leading edge of the airfoil to the trailing edge. Another factor affecting the thickness of the boundary layer is the so-called Reynolds effect, whereby the slower the flight, the thicker the boundary layer becomes. Friction and the Reynolds effect result in a boundary layer approximately 0.5” (12 - 13 mm*) thick near the trailing edge of a 4-5 ft (1.2-1.5 m*) chord wing designed for low altitude flight. speeds.
Conventional flaps or ailerons thus have very low efficiency in the range of 1 to 2 degrees of deflection because the deflection occurs in this not very active aerodynamic boundary layer. To prevent loss of controllability, the flaperon can be designed as a separate small wing moving outside the boundary layer of the wing itself and the air flow entrained by the wing. Such a flaperon system (often referred to as Junkers-type or slotted flaperons*) is effective even at high angles of attack, as it is located under the wing and therefore continues to receive "fresh" undisturbed air even when the wing is at an extreme angle of attack (See ).
Rice. eight– Boundary layer
HORIZONTAL TAIL
In addition, because a high-lift wing is designed to fly with an unusually large range of angles of attack (up to 30 degrees compared to 15-17 degrees for a conventional wing), additional tail-down force is required to achieve such angles. Not being able to build a horizontal tail of an increased area, we are faced with the need to give it a large negative lift coefficient. This is achieved on the one hand with the help of an inverted stabilizer airfoil, and on the other hand with the help of an additional Venturi effect (or Bernoulli *). As is known, the Venturi effect creates a lower pressure and a higher velocity in a converging section. This narrowing occurs when the front of the deflected elevator protrudes above the stabilizer surface, as shown in *.
Rice. 9– Venturi effect
On the one hand, reduced pressure increases the effectiveness of the elevator deflection, on the other hand, the increased airflow speed reduces the tendency for the deflected airflow to separate from the elevator surface*.
RUDDER
In my STOL aircraft designs, I used the same all-moving keel (rudder) that I used in many of my early models, as it provides exceptionally effective crosswind resistance. As far as STOL designs are concerned, when the crosswind speed is higher than the stall speed of the plane (it does happen), you can simply turn the plane into the wind and literally climb vertically (even turning across the runway)! Another advantage of the keel is that it is physically smaller than a traditional rudder vertical tail and therefore lighter; it is easier to design and build because it consists of one part. It also makes it easier to recover from a spin due to the larger actual deflection surface. The rudder itself has a full symmetrical aerodynamic profile (and not just a flat "board"), which increases its efficiency and expands its range towards low speeds.
The wing planes of STOL aircraft gradually decrease at the root so that the air flow from the propeller can freely blow over the tail unit. plumage position above the fuselage also improves propeller flow and improves low-speed controllability compared to the reduced controllability at such modes in the case of a conventional configuration.
SHORT TAKEOFF AND LANDING
Optimal short takeoff performance requires a high angle of attack on or near the ground, and we therefore need a general aircraft configuration to achieve this angle of attack. This can be achieved either by using very long main landing gear in a tailwheel configuration (raising the nose) or by raising the rear fuselage in a tricycle configuration.
Rice. 10– Chassis configuration
In the tailwheel configuration, the entire cockpit is tilted uncomfortably with respect to the ground, and the long landing gear makes the structure flimsy and heavy. Access to the cockpit is also difficult, especially for passengers and cargo, and forward visibility on the ground is seriously impaired during taxiing and takeoff.
Rice. eleven– Cabin tilt
Most pilots these days find it more comfortable and safe to have a three-wheeled landing gear configuration, and almost all training aircraft are three-wheeled. The tricycle undercarriage is very stable on the ground, while the tailwheel undercarriage is less stable and requires constant control, especially in crosswind conditions. Incidentally, this moment is also reflected in insurance rates for aircraft.
The wing of a tricycle aircraft has a neutral angle of attack when on the ground, while a tailwheel aircraft has an angle of attack for maximum lift (See ). Tailwheel aircraft are therefore more sensitive to wind when moving on the ground and more susceptible to wind when parked (where the aircraft will spend most of its life, except when in the hangar).
Despite the many advantages of a tricycle landing gear design, the tailwheel configuration is used in both many older models and many modern STOL aircraft, mainly due to a lack of technology and experience in building light and strong nosewheel structures, and a lack of development experience. chassis designs or interest in them by many of today's designers.
Off-aerodrome operation requires STOL aircraft to have a robust and rough-tolerant landing gear design. The undercarriage is the weakest point of many light aircraft models, making them dependent on paved runways despite being able to take off and land at short range.
In my STOL models, I used a simple double-curved spring beam to support the main chassis. Although not the lightest chassis design, it is well suited for rough terrain, especially when combined with large wheels, very strong, simple and virtually maintenance free. The nose wheel strut is steerable, directly connected to the rudder pedals. For depreciation, a single reinforced elastic harness (bungee) is used. The STOL CH 801 adopted the nose gear design from the ZENITH CH 2000, my type certified serial training aircraft. The main landing gear wheels are equipped with individual hydraulic disc brakes activated by pressing the end of the foot (toe brakes) providing exceptional ground handling. Practice has shown good suitability of such landing gear for grass fields, as well as suitability for pilots with a limited time resource. (Nose strut and wheel wear is minimized by reducing the pressure on the nose wheel due to the moment from the horizontal tail, which is a feature of my STOL aircraft designs.
The rectangular cabin provides maximum comfortable space for passengers and cargo. The cockpit of the four-seat STOL CH 801 is long enough to accommodate a stretcher along the starboard side on the folded co-pilot's seat and still leave adequate space for the pilot and one passenger. Two crates up to 50 gallons (0.2 cubic meters*) can be carried in the tail section. Naturally, the STOL CH 801 is a practical sport aircraft with enough interior space for two people overnight and more than enough luggage space for extended off-airfield travel. The double STOL CH 701 is surprisingly spacious for an aircraft of this size and weight.
Perhaps not the most aesthetically pleasing, the rectangular fuselage is very easy to build and improves directional stability, as well as further resisting spin due to flat surfaces and right angles.
CAB/OVERVIEW
Visibility for the pilot and passenger is an important feature of an aircraft, but it is often overlooked by designers. Good visibility is especially needed in STOL aircraft when the pilot needs to see obstacles when flying over wilderness. Passengers also need a good view to enjoy a low and slow flight. They do not want to be content with a small porthole, like in a commercial liner.
Although the open cockpit provides an unobstructed view, the presence of insects, wind, cold air necessitates a closed cockpit for a modern aircraft in order to provide the minimum level of comfort familiar to a person. The enclosed cabin also allows for good ventilation and heating, and protects electronic equipment and luggage. Large doors allow easy access to the cabin for passengers and bulky luggage. The doors can also be removed for maximum visibility and an 'open air' feel.
The high wing configuration provides a better downward view to enjoy the view during slow and low flight and gives the pilot the ability to see and avoid obstacles needed when flying in the wilderness. In my STOL designs, the wing panels are also additionally raised above the cockpit. This also increases horizontal visibility. Also, reducing the thickness of the wing in the area of the center section allows you to make this part glass and create an upward view. The glazed roof of the cockpit is desirable for the pilot's view in a highly maneuverable aircraft.
The wing tapering towards the root, combined with a glass ceiling, provides good visibility. The design of the wing minimizes the counter surface in the airflow behind the propeller, improves flight performance, provides a direct flow of air from the propeller to the fin, and contributes to excellent controllability during slow flight.
An additional benefit of this tapered wing configuration over the cockpit, in addition to visibility, is a smaller counter-surface, which means less drag (higher speed for the same power), and excellent low-speed handling as the air flows unhindered from the propeller to the tail.
Crew Seats Side by Side: Front View
As with most modern aircraft, I used side-by-side seating to give pilot and passenger maximum comfort. In addition, the cockpit is ergonomically designed to provide maximum comfort and efficiency for the pilot. Internally, the cabin of the STOL CH 801 is designed to provide comfort for four large adults. At the same time, it can be easily converted to carry cargo. Large doors on each side provide easy access to the cab from both sides. The adjustable front seats fold forward for easy access to the rear seats/cargo area. If such a purpose is intended, the rear compartment can be converted to accommodate cargo, including boxes of up to 50 gallons (0.2 cubic meters *), or the cab can be converted to a recumbent position (patient on a stretcher) in place of the front and rear seats on the right side, with the pilot in the left front seat and a doctor or attendant in the left rear seat. Travel pilots can literally camp at STOL CH 801.
STRENGTH OF ALL-METAL CONSTRUCTION
Aircraft used in the wilderness need to be strong, reliable and easy to maintain. The term “field maintenance” takes on a new meaning when a pilot literally needs to carry out basic maintenance and repairs, as they say, in an open field.
Based on my over 30 years of experience designing and building all-metal aircraft, and over 60 years of experience in the load-bearing and semi-monocoque industry, I chose all-metal construction for both the STOL CH 701 and STOL CH 801 aircraft. Despite the ever-increasing number of new modern materials, quite traditional aluminum alloy structures are not going to become obsolete and are an excellent choice for the designer.
Aluminum alloys have the following advantages:
- good strength characteristics with low weight
- corrosion resistance, especially when using the latest alloys and advanced coatings
- low cost and wide availability
- Proven durability and resistance to sun and moisture
- the availability of extensive empirical data on the properties
- ease of handling: tools and processes are quite simple, do not require special temperature conditions, dust-free environment, as in the case of composite materials. Modern pop rivets have greatly simplified the assembly of an all-metal aircraft structure from a whale.
- plasticity: the ability to easily give various shapes, almost without restriction
- more environmentally friendly: no health hazard when working with sheet metal that is also recyclable
- ease of inspection: defects and damage to the material or construction are clearly visible
- ease of repair: rivets can be easily removed to replace damaged parts or assemblies; individual parts can be replaced without a complete replacement of the entire section of the aircraft body
Thus, aluminum alloy structures are excellent for aircraft used in the wilderness: 1) they can be stored outdoors for a long time, 2) they are strong and reliable, 3) they are easy to inspect, maintain and repair in the field. For example, a simple sheet metal patch can be riveted over the damaged area and the aircraft can fly to its home airport.
A well-designed sheet metal aircraft has increased safety in collisions with obstacles, as the energy of the collision is absorbed by the progressive deformation of the metal structure, as opposed to splitting or crushing from impact. The chassis of my STOL absorbs a lot of energy. Therefore, much more energy is required to “pull out” them. And even after that, aluminum frame with load-bearing skin needs much more energy to start bending, warping and twisting. The robust cockpit frame will protect passengers even in the unlikely event of a three-wheeled aircraft nosed, and the wing panels, located much higher than the passengers' heads, will additionally absorb impact energy. Another important benefit, often overlooked, is the good lightning protection provided by the metal construction.
For me, as an aeronautical engineer, it is very easy to design a complex aircraft and more difficult to create a simple one. For an aircraft kit to be successful, it must be relatively simple in terms of design, assembly, and equipment. A simple design is not only easy and affordable to build, it is also more amenable to do-it-yourself construction, as it reduces the possibility of errors and the consequences of poor workmanship. For a simple design, the construction time will be shorter, fewer tools and hands-on skills will be required than for complex projects. After the construction is completed, such an aircraft will be easier to operate and maintain. Simple equipment maximizes reliability while minimizing pilot work. With 24 years of experience in designing and manufacturing kits for DIYers, we have learned to design aircraft specifically for DIYers and sport pilots, offering them complete kits that are easy to assemble with a minimum of tools and hands-on skills.
In accordance with the principle that form follows function, my two STOL aircraft designs have their own specific beauty that is more than just external beauty for someone who understands the aerodynamic and design features that these designs have and that make them high-performance aircraft with short takeoff and landing, which are easy to build and maintain, and which have high reliability and versatility.
The original STOL CH 701 and the new STOL CH 750 offer excellent performance, off-airfield capability, light weight and a very economical two-seat design. They are easy and pleasant to fly. Whereas the new STOL CH 801 is a really practical sport aircraft with a payload of 1000 pounds (about 450 kg*).
Photo of a real short takeoff
For me, as a developer, it is really a reward to see how my developments are used around the world to carry out humanitarian missions in remote areas, and also to read in letters from pilots that the aircraft "starts like a cork from a bottle of champagne"!
*Note/translator's adaptation
0The design of aircraft with vertical takeoff and landing is associated with great difficulties associated with the need to create light engines, controllability at near-zero speeds, etc.
Currently, there are many projects of vertical takeoff and landing aircraft, many of which have already been implemented in real vehicles.
Aircraft with propellers
One of the solutions to the problem of vertical takeoff and landing is the creation of an aircraft in which the lift force during takeoff and landing is created by turning the axis of rotation of the propellers, and in horizontal flight - by the wing. Turning the axis of rotation of the propellers can be achieved by turning the engine or wing. The wing of such an aircraft (Fig. 160) is made according to a multi-spar scheme (at least two spars) and is hinged to the fuselage. The wing turning mechanism is most often a screw jack with synchronized rotation, which provides a change in the wing installation angle by an angle of more than 90 °.
The wing is equipped throughout the span with multi-slotted flaps. In areas where the wing is not blown by the air flow from the propeller, or where the blowing speeds are low (in the central part of the wing), slats are installed to help eliminate flow stall at high angles of attack. The vertical tail is relatively large (to improve directional stability at low flight speeds) and is equipped with a rudder. The stabilizer of such an aircraft is usually controlled. The angles of installation of the stabilizer can vary within wide limits, providing the transition of the aircraft from vertical takeoff to horizontal flight and vice versa. The base of the keel passes into the rearward tail boom, on which a small-diameter, variable-pitch tail rotor is mounted in a horizontal plane, providing longitudinal control in hovering and transient flight modes.
The power plant consists of several powerful turboprop engines, which are small in size and have a low specific gravity of about 0.114 kg / l. with., which is very important for a vertical takeoff and landing aircraft of any scheme, since such devices during vertical takeoff must have more thrust than weight. In addition to overcoming weight, thrust must overcome aerodynamic resistance and create acceleration to accelerate the aircraft to a speed at which the wing lift will fully compensate for the weight of the aircraft, and the control airfoils will be sufficiently effective.
A serious design flaw of VTOL aircraft with propellers is that ensuring flight safety and reliable controllability of the aircraft during vertical takeoff and in transitional flight modes is achieved at the cost of weighting and complicating the design through the use of a wing turning mechanism and a transmission that synchronizes the rotation of propellers. .
The aircraft control system is also complex. Control during takeoff and landing and in cruise flight along three axes is carried out using conventional aerodynamic control surfaces, but in hover and. transition modes before and after cruising, other control methods are used.
During vertical climb, longitudinal control is carried out using a horizontal tail rotor (with variable pitch) located behind the keel (Fig. 160, b), directional control is carried out by differential deflection of the end sections of the flaps blown by a jet from propellers, and lateral control is differential changing the pitch of the extreme propellers.
In the transitional mode, a gradual transition to control using conventional surfaces is carried out; for this, a command mixer is used, the operation of which is programmed depending on the angle of rotation of the wing. The control system includes a stabilization mechanism.
Improving the performance of VTOL aircraft with propellers is currently possible due to the fact that the propeller is enclosed in an annular channel (a short pipe of the appropriate diameter). Such a propeller develops thrust by 15-20% more than propeller thrust without a "fence". This is explained by the fact that the walls of the channel prevent the flow of compressed air from the lower surfaces of the screw to the upper ones, where the pressure is reduced, and exclude the dispersion of the flow from the screw to the sides. In addition, when air is sucked in by the screw above the annular channel, a low pressure area is created, and since the screw throws down the compressed air flow, the pressure difference on the upper and lower cuts of the channel ring leads to the formation of additional lifting force. On fig. 161, and shows a diagram of a vertical takeoff and landing aircraft with propellers installed in the annular channels. The aircraft is made according to the tandem scheme with four propellers driven by a common transmission.
Three-axis control in cruising and vertical flight (Fig. 161, b, c, d) is carried out mainly by differentially changing the pitch of the propellers and deflecting the flaps located horizontally in the jets thrown by the propellers behind the channels.
It should be noted that VTOL aircraft with propellers are capable of speeds of 600-800 km/h. Achieving higher subsonic, and even more so supersonic flight speeds is possible only with the use of jet engines.
Jet-powered aircraft
There are many schemes of vertical takeoff and landing aircraft with reactive thrust, but they can be quite strictly divided into three main groups according to the type of power plant: aircraft with a single power plant, with a composite power plant and with a power plant with thrust amplification units.
Airplanes with a single power plant, in which the same engine creates vertical and horizontal thrust (Fig. 162), theoretically can fly at speeds several times greater than the speed of sound. A serious disadvantage of such an aircraft is that an engine failure during takeoff or landing threatens with disaster.
An aircraft with a composite power plant can also fly at supersonic speeds. Its power plant consists of engines designed for vertical takeoff and landing (elevating) and engines for horizontal flight (marching), fig. 163.
Lifting engines have a vertically located axis, and marching engines have a horizontally located one. Failure of one or two lift engines during takeoff allows vertical takeoff and landing to continue. TRD, DTRD can be used as marching engines. Propulsion engines on takeoff may also be involved in the creation of vertical thrust. The thrust vector is deflected either by rotary nozzles or by turning the engine along with the nacelle.
On aircraft with jet engines, stability and controllability during takeoff, landing, hovering and transitional modes, when aerodynamic forces are absent or small in magnitude, is provided by gas-dynamic type control devices. According to the principle of operation, they are divided into three classes: with the selection of compressed air or hot gases from the power plant, using the magnitude of the propulsion thrust and using devices for deflecting the thrust vector.
Control devices with the selection of compressed air or gases are the most simple and reliable. An example of the layout of the control device with the selection of compressed air from lifting motors is shown in fig. 164.
Airplanes equipped with a power plant with thrust amplification units can have turbofan units (Fig. 165) or gas ejectors (Fig. 166), which create the necessary vertical thrust on takeoff. The power plants of these aircraft can be created on the basis of turbojet and diesel turbojet engines.
The power plant of the aircraft with thrust amplification units, shown in fig. 165, consists of two turbojet engines installed in the fuselage and creating horizontal thrust. During vertical takeoff and landing, turbojet engines are used as gas generators to drive two turbines with fans located in the wing, and one turbine with a fan in the forward fuselage. The front fan is only used for longitudinal control.
Aircraft control in vertical modes is provided by fans, and in level flight - by aerodynamic rudders. An aircraft with an ejector power plant, shown in fig. 166, has a power plant of two turbojet engines. To create vertical thrust, the gas flow is directed to an ejector device located in the central part of the fuselage. The device has two central air channels, from which the air is directed to the transverse channels with slotted nozzles at the ends.
Each turbojet is connected to one central channel and half of the transverse channels with nozzles, so that when one turbojet is turned off or fails, the ejector device continues to work. The nozzles go into the ejector chambers, which are closed by shutters on the upper and lower surfaces of the fuselage. During the operation of the ejector installation, the gases flowing out of the nozzle eject air, the volume of which is 5.5-6 times greater than the volume of gases, which is 30% higher than the thrust of the turbojet engine.
The gases flowing out of the ejector chambers have a low speed and temperature. This allows the aircraft to be operated from runways without special coating, in addition, the ejector device reduces the noise level of the turbojet engine. Aircraft control in cruise mode is carried out by conventional aerodynamic surfaces, and in takeoff, landing and transitional modes - by a system of jet rudders that provide stability and controllability of the aircraft.
Thrust vectoring power plants have several very serious drawbacks. Thus, a power plant with a turbofan unit requires large volumes to accommodate the fans, which makes it difficult to create a wing with a thin profile that normally operates in a supersonic flow. Even larger volumes require an ejector power plant.
Typically, such schemes have difficulties with the placement of fuel, which limits the range of the aircraft.
When considering the schemes of aircrafts of the VVP, an erroneous opinion may arise that the possibility of vertical take-off should pay off by reducing the payload lifted by the aircraft. Even approximate calculations support the conclusion that a vertical take-off aircraft with high flight speed can be created without significant losses in payload or range if the requirements of vertical take-off and landing are taken as the basis from the very beginning of aircraft design.
On fig. 167 shows the results of the analysis of the weights of conventional aircraft (normal takeoff) and GDP. Aircraft of equal takeoff weight are compared, having the same cruising speed, altitude, range and lifting the same payload. From the diagram in fig. 167 can be seen, but the VTOL aircraft (with 12 lift engines) has a power plant heavier than a conventional aircraft by about 6% of the takeoff weight of a normal takeoff aircraft.
In addition, lift engine nacelles add another 3% of the takeoff weight to the weight of the aircraft structure. Fuel consumption for takeoff and landing, including movement on the ground, is 1.5% more than that of a conventional aircraft, and the weight of the aircraft's additional equipment of GDP is 1%.
This additional weight, which is inevitable for a vertically taking off aircraft, equal to approximately 11.5% of the takeoff weight, can be compensated by reducing the weight of other elements of its structure.
So, for the aircraft of the GDP, the wing is made smaller in comparison with the aircraft of the usual scheme. In addition, there is no need for wing mechanization, and this reduces the weight by about 4.4%.
Further savings in aircraft weight can be expected from a reduction in the weight of the landing gear and tail unit. The weight of the undercarriage of a runway aircraft designed for a maximum sink rate of 3 m/s can be reduced by 2% of the takeoff weight compared to a conventional aircraft.
Thus, the weight balance of a runway aircraft shows that the weight of the runway aircraft structure is greater than the weight of a conventional aircraft by approximately 4.5% of the maximum takeoff weight of a conventional aircraft.
However, a conventional aircraft must have a significant reserve of fuel for holding operations and for searching for an alternate aerodrome in bad weather. This reserve of fuel for a vertically taking off aircraft can be greatly reduced, since it does not need a runway and can land on almost any site, which may be small in size.
It follows from the foregoing that an aircraft with a take-off weight of the same as that of a conventional aircraft can carry the same payload and fly at the same speed and for the same range.
Used literature: "Fundamentals of Aviation" authors: G.A. Nikitin, E.A. Bakanov
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Most UVP aircraft are designed to operate on unprepared sites, although some, such as the De Havilland Canada Dash 7, require a runway. Also, most of them have a tailwheel, although there are exceptions, for example: Quest Kodiak en , De Havilland Twin Otter or Peterson 260SE en . Autogyros are also aircraft with ATL capabilities, since they have a short takeoff run, but they are able to land with little or no run.
The required length of the runway for a certain type of aircraft depends on the square of its stall speed, therefore, all developments in the SUVP are aimed at reducing this speed. High thrust-to-weight ratio and low drag make it possible to quickly achieve lift-off during takeoff. When landing, the mileage is reduced by powerful brakes, low landing speed; thrust reversers and spoilers are less common. In general, the belonging of an aircraft to the AWP class is determined by the largest distance of the two: takeoff and run.
Equally important is the ability of an aircraft to avoid obstacles such as trees during takeoff and landing. During takeoff, this is facilitated by thrust-to-weight ratio and low drag. When landing, drag is increased by the use of flaps, as well as a special piloting technique - sliding, when the aircraft, using the rudder, flies slightly "lag" (while the course is not equal to the direction of flight). The increased drag allows for steep descents without excessive acceleration, which would lead to a lengthening of the run.
Normally, a UVP aircraft has a relatively large wing area for its weight. The wing is often equipped with aerodynamic devices: slotted and retractable slats, turbulators. As a rule, the development of an aircraft with excellent air-to-air characteristics leads to a decrease in the maximum flight speed, but not to a decrease in payload. Carrying capacity is extremely important for such aircraft, because for many small, isolated settlements they serve as the only link to the outside world; northern Canada or Alaska is an example.
Most UVP aircraft are capable of landing on an unprepared surface. Habitual landing sites are snow or ice areas (on skis), meadows, pebbly river banks (on special wide low-pressure aircraft tires), water surface (on floats). Such areas are usually extremely short and blocked by hills or tall trees. Often such aircraft are equipped with a combined wheel-ski or wheel-float landing gear, which provides more freedom when choosing a landing site.
The most common Soviet aircraft UVP An-2 has a braced biplane with a tail wheel. Pilots testify that it is capable of maintaining controlled flight at a speed of 50 km/h.
