Fighter VOUGHT F6U PIRAT. The appearance at the end of the war, military jet aircraft in Germany and Japan forced the command of the naval forces of the United States to start a program to re-deck aircraft with new equipment. In 1944, the three leading aviation companies: McDonnel, Vought and North American was requested to develop preliminary designs of jet fighters to provide air defense of an aircraft carrier in a radius of five kilometers.
In addition to this difficult task, the aircraft was loaded urgent orders of the leadership of the U.S. Navy, which was slow to rearm aircraft fleet before the invasion of Japan, scheduled for 1945. Each of the firms in an effort to create the best aircraft used in our projects the new technical solutions the Most advanced of the three proposed was a project of the fighter V-340 firms Vought. The contract to build three prototypes of this aircraft and 65 production vehicles under the designation F6U was signed on 29 December 1944. Traditionally, companies use the names of their aircraft pirate vocabulary, the fighter assigned the proud name of PIRATE.
When you create a F6U most serious problem was the provision of minimum drag. With the purpose of lowering the midsection of the fuselage, the designers chose a turbojet engine with an axial compressor Mod 24C firm Westinghouse, which was developed in 1944 by order of the fleet. When the specialists Vought began preparations for the construction of the first sample, the Westinghouse company began the production of this turbojet with assigned resource 250 hours and a mass of 530 kg under the designation J34-WE-22. The nozzle went under the short tail boom, which is attached to the empennage classical scheme, and a small NACA air intakes of the laminar type was located under the root parts of the wing. The wing was designed straight, laminar, supercriti is helping 65-212 NACA profile with a relative thickness of 12%.
The most striking feature of the fighter PIRAT was used in the construction of new durable and lightweight material patented by Vought firm represented a kind of sandwich of two aluminum sheets between which was laid a layer of ultra-light wood — balsa. The layers are glued together and molded in a large autoclave. Composite material received the name metallit. Its strength and rigidity are given the opportunity to radically reduce the number of supporting aircraft frames and ribs, making the design almost monocoque.
Panels from metallit trimmed almost the entire surface of the airframe, and the panel fastened by rivets with countersunk heads. High precision manufacturing of these panels allowed us to minimise the gaps between the plates. Thus, after painting and polishing aircraft surprised even the experts with their clean aerodynamic shapes and looked as if it were cast integral of metal. In comparison with the plane XFJ-1 FURY, created by North American, metalicana design F6U gave the win to weight about a ton.
The first prototype consume gels Pirat XF6U-1 in flight
Short rounded nose part of the fighter F6U provides the pilot excellent visibility forward and down, which is very important when landing on the deck. First aircraft company Vought F6U had a tricycle landing gear with nose wheel.
In the design of machines, great attention was paid to reduce the efforts of the pilot attached to the controls. On the ailerons, set the internal aerodynamic compensation that does not have protrusions and do not spoil the flow pattern of the wing. Elevators equipped with a trim tab and a servo tab. The complex of these solutions helped to reduce the effort on the control handle up to 4.5 kgs.
Purge in a wind tunnel have confirmed the design characteristics, but at the time of research was not considered the behavior of the machine at transonic speeds and phenomena associated with the compressibility of air. The developers decided to do it the easy way, they put on the plane automatic air brake with hydraulic drive, which restricted the airspeed and did not allow the exit of the plane to unexplored regimes.
PIRAT was distinguished by a powerful built-in armament consists of four 20-mm guns with ammunition 150 rounds per gun located under the cockpit; the barrels of guns came out in the nose of the fuselage. Here at the bottom were the air intakes, the Probability of ingress of powder gases when firing was very high. This assumption was confirmed already in the first firing tests. However, to spend time addressing such a serious lack of steel. The leadership of the company wanted as soon as possible to lift the fighter into the air, and to finalize a design was possible and then, in preparation for serial production.
A more serious concern of designers was caused by the location of the engine nozzle construction below the horizontal plane, which could result in a change of pitch when you change thrust. To verify the behavior of the machine model was established F6U scale 1:7. The gas jet from the nozzle simulated six compressors, air nagnetic one connected to the hose model. The purge was carried out in a wind tunnel a low-speed Research Division of United Aircraft in Hartford. Aerodynamic experiments showed that in four different modes of the simulated flight, the nozzle does not create any moment on the pitch and his unusual (reganne) the location is left unchanged.
The first prototype XF6U-1 with serial number 33532 collected in the summer of 1946 at the plant of the company in Stratford (Connecticut). After ground testing the machine was dismantled, Packed in crates and transported by truck to the airbase Muroc to California and re-assembled. 2 Oct 1946, test pilot Boone Guyton raised a new fighter into the air. First flight almost ended in failure. The air at XF6U-1 PIRAT stopped the engine. Fortunately, the pilot managed to plan and make an emergency landing on a huge dry lake Rosamond, the surface of which was used in Moroka as a runway.
“Fault” in the engine was the new lubrication system with makarapa-piece, which was developed by the Westinghouse firm. 23 liters of oil poured into the oil tank of the aircraft, was used in less than an hour — about the time it took to gazovka. trial run and take-off. When the oil ran out, the engine just clicked. To replace the turbojet engine turned out to be nothing, and the flight tests had to be interrupted.
The next flight was only 45 days. After the third flight at the airbase Murok it started pouring rain. If you recall, that base was in the Mojave desert, 160 km northeast of Los Angeles, you can imagine how rare this phenomenon for those places. The hard surface of the dry lake bed turned to mud. The flights were discontinued.
During downtime the team of testers studied the materials of objective control In 1946 these materials were mined in a primitive photographic, representing a a box with a set of aircraft instruments, lamp lighting and the shot-method. The last continuously filmed evidence the shooter devices. Installed in the data logger devices dubbed signposts, standing in the cockpit: air speed, rate of climb. pressure altitude, air temperature, fuel consumption and other important parameters of the TRD.
Unfortunately, the analysis of these data had little to say about the flying qualities of the machine. Angular velocity, position, linear acceleration, overloading and other important parameters were not recorded. Even the determination of the number M of the flight had to spend a lot of time in searching for the relationship of airspeed to the speed of sound in these conditions using the slide rule.
Few weeks the bottom of the lake dried up and the flights resumed. In the tenth flight, when the plane was flying at extreme speeds, corresponding to the number M = 0.8, and the pilot felt a sharp blow on the foot controls. Information obtained in subsequent sorties with velocities lying in the range from M = 0.76 to M = 0,8, is not possible to establish a pattern between the appearance of bumps and speed of flight Convened a Council aerodynamicists came to the unanimous view that “fault” in hitting the rudders of local shocks arising at the junction of the stabilizer and fin. It was just those phenomena of compressibility, which was not considered during the design of the fighter.
Carrier-based fighter F6U PIRAT:
1 — the hood of the instrument compartment; 2 — canopy canopy of psuta; 3 — movable part of the lamp; 4 — anti-flatter load; 5 — tail ANO; 6 — LDPE; 7 — flame tube; 8 — exhaust device; 9 — retractable step in the retracted position; 10 — upper footrest; 11 — 20 mm gun M3; 12 — cover the outside of the instrument compartment; 13 — whip antenna; 14 — Kiel larger; 15 — modified LDPE; 16 — brake flap; 17 — additional washers directional stability; 18 — Luke usska weapons; 19 — additional washers directional stability; 20 — wing of ANO; 21 — antenna altimeter; 22 —the hood in the open position; 23 — ejection seat; 24 — the movable part of the lamp in open position; 25 — landing light; 26 — ANO; 27 — filler cap end fuel tank; 28 — terminal wing fuel tank; 29 — rudder; 30 — trimmer rudders; 31 — brake hook to a released position; 32 — wheel main landing gear; 33 — fold niche cleaning the nose landing gear; 34 — the kickstand in the extended position; 35 — nose strut; 36 — Aileron; 37 — filler cap fuselage fuel tanks; 38 — trimmer Aileron; 39 — trimmer of the Elevator; 40 — handlebar height; 41 — the tail Assembly of the second prototype (view sverchu); 42 — the tail Assembly of the first prototype (top view); 43 — fairing cylinder rod release the landing flap; 44 wing main landing gear; 45 — intake; 46 — the window BFC; 47 — fold niche cleaning the nose landing gear (in closed position); 48 — landing the hook in the retracted position; 49 — landing flap; 50 — fold niche cleaning wheel main landing gear; 51 — the tail Assembly of the first prototype (bottom view); 52 — front of the main chassis
The redesign of the tail section of the firm had neither the time nor the funds. In this case, the only and most simple solution was the installation of a torpedo-like fairing on the place of articulation of horizontal and vertical surfaces of the tail, which was done on the second prototype, being built at the plant in Stratford.
The post-war reduction in military spending has affected the order of the fleet on F6U PIRAT. The number of production aircraft was reduced to 30 units. Appropriate changes to the contract was signed on 5 February 1947.
In April 1947, the firm Vought completed the construction of the second XF6U-1 with serial number 33533, and his speed flew to Muroc. The flight took place with four intermediate landings on the airfields it was expected by the technical team of the company to prepare for a future flight.
Another serious problem discovered during flight tests became insufficient directional stability and tendency of the aircraft to the slowly damped oscillations in yaw, the Pilots said that the car did not react properly to the position of the rudders. The third prototype, this disadvantage was eliminated, which had to increase the area of the keel. Added section not only improved stability but also increased local critical number M of the zone of joining of the stabilizer. This allowed to remove the front part of the torpedo-like fairing.
In the autumn of 1947 the first two prototypes of ferried to the flight test center at the U.S. Navy Patuxent river to assess the quality of marine pilots. The leading pilot of the Navy has appointed Paul Thayer. By the way, later he became President of Vought, and when this firm was included in the LTV group. P Thayer was appointed as the managing of the Affairs and Deputy Chairman of the Board of Directors.
Reviews all military pilots regarding flight characteristics F6U PIRAT was unflattering And really — they were mediocre mainly because of the low acceleration and engine thrust J34-WE-22. Just at this period, the Navy began the certification of turbojets in accordance with the new requirements, which included the increase of time testing the combat modes 2.5 times. New requirements included reducing the time of acceleration from idling conditions up to a maximum of six times compared to the old specifications. Against the background of these more stringent disadvantages of the power plant F6U could put an end to all work on the final design of the fighter.
The first certified turbojet engine was the Westinghouse J34-WE-30 and its modification with afterburner from the company Solar — J34-WE-30A. Forced thrust option reached 1900 kgf (540 where more than WE-22). Naturally, experts Vought decided to install a new engine in your plane. In 1948 prototype XF6U-1 was returned to the factory in Stratford to replace the power plant.
Increasing the length of the engine resulted in major changes in the design of the aircraft. Given increased temperature, the tail part of the machine stitched aluminum leaves that to study the temperature regime was painted with thermosensitive paint. To compensate for the changed alignment and increased take-off weight had to increase wing area, which were large, almost a quarter of the scale, triangular fairings on the trailing edge. Remembering about the problems with ground stability, the designers put on the horizontal tail is a small oval vertical surface.
The plane was equipped with an afterburner, though installing it was a conventional operation, since the use of the camera was subjected to severe restrictions. According to the instructions, the pilot was allowed to turn it on just two or three minutes during takeoff and climb to 9000 m, the same two-three minutes was limited to the time you turn the camera on and in a dogfight. When running afterburner fuel consumption increased by 30%. However PIRAT became the world’s first serial fighter with afterburner Characteristics of the aircraft improved When you turn on the afterburner flight speed was 80 km/h. After completions of the designations of the planes withdrew the letter “X” and presented them to the military as pre-production samples of fighter F6U-1.
Flight tests F6U PIRAT the final was held at the marine test center. In one of the scheduled flights before P. Thayer set a target maximum speed when the fast and furious at a height of 3658 meters Up in the air, the pilot headed East and moving away from the base 48 km, turned on the afterburner. Almost immediately after that, according to Thayer, in the area of the engine there was a loud explosion. On the plane refused hydraulics and part of the instruments in the cockpit, but he continued to listen to the rudders. Thayer didn’t become puzzled and, having reported the situation on Board a flight Director, started planning in the direction of the airport. With aircraft maintenance F8F Bearcat said that F6U no visible damage and signs of fire after Hearing a report on the failure of the speed indicator, the pilot of the F8F flew very close to the Thayer I. flying with him fender to fender, was on the radio to report to the F6U PIRAT readings his device, without which to put the damaged car would be impossible.
Check hydraulic landing gear on the production batch of the fighter F6U
Landing with landing gear retracted was extremely successful, Thayer not received a single scratch. However, the aircraft are not subject. Salvation machine allowed the exact cause of a flight accident. It turned out that part of the collapsed front bearing of the turbine shaft got into the compressor and destroying everything in its path, flew the entire air path of the engine. Torn blades struck the fuselage, broke the tube and durotomy hydraulic hose speed indicator. Only by pure luck that the shrapnel didn’t hit control wiring. In this accident metallicana durable design of the fighter showed his best side.
In 1949 tests F6U PIRAT ended, and a fighter jet was officially adopted by the Navy. Deliveries of production aircraft delayed the relocation of the firm Vought on new production base near Dallas, Texas. The new plant was previously owned by the firm North American, which after the war turned the mass-production P-51 MUSTANG.
The firm Vought had to move more than 7,200 tonnes of goods by road for a distance of over 2200 km, and Simultaneously with the load to a new territory moved about 13 thousand employees of the company “Great migration” ended in April 1949.
Along with the equipment were delivered and the first three serial F6U-1. They were gathered and checked already in Dallas. Runway of the new plant was too short and while it was extended, fly the new machines had to be in nearby Ardmore. The first flight of the production aircraft took place on 29 June 1949.
The pace of the production F6U-1 was one aircraft in a week. In accordance with the order was built 30 cars with factory rooms with 122478 at 122507. The last production car left the shop in February 1950. One aircraft with serial number 122483 was modified into a scout designation F6U-1P.
In 1950, with test pilot Navy Chan Chandler, who test flew the serial fighters, there was a curious case. Observers stationed at the control and control tower of the airfield, watching the takeoff FбU. Suddenly, instead of gradually away from the strip, he dramatically, almost vertically soared a while Chandler didn’t respond to requests on the radio. Finally, the headphones sounded: “Phew..”, after which the fighter has leveled off and went to the landing. Wet from sweat Chandler got out of the cab and said that during takeoff, he applied ORE forward, turned on the afterburner, and a glove worn on left hand stuck between Rude and thumbwheel trimmer. Trying to free jammed thumb, the pilot inadvertently pulled the arm and spun the wheel of the trimmer. Slight movement was enough to install the rudders on the pitch, and the machine rushed up the candle. Fortunately, pressed against overload and confused Chandler was able to quickly recover and land the plane.
Career jet fighter F6U PIRAT in the Navy has not developed. Against the background of accepted on arms fighter F2H (1949), F7U (1950) and a F9F (1949) it was considered obsolete by the machine and used solely in the training or research purposes. Average flight time per aircraft from 30 built amounted to 945 hours. However, note that the actual RAID, some machines was only six hours. It turns out that these planes were in the air only when flying over the factory and to fly the aircraft home base. Most of all flying fighter jets belonging to the research squadron VX-3, located on the Patuxent river.
Description of the design of the fighter F6U PIRAT
Fighter F6U-1 Pirate was a monoplane with low wing and single-fin tail To improve longitudinal stability of the wing were installed with a small positive cross V, and the horizontal stabilizer there are two additional vertical surfaces.
The fuselage is oval section is structurally divided into three parts. In front is the cockpit, equipped with ejection seat JD-1 made by British company Martin-Baker. The cockpit was closed with a teardrop lantern slide type. Under the cabin floor mounted four guns and boxes of ammunition. The service of the guns and ammunition boxes installation was carried out through a wide rectangular hatches, located on both sides of the fuselage.
Rounded and short nose part in front of the cockpit was divided by a horizontal partition into two parts: upper and lower. At the top stood the radio equipment and shot-method, and the lower was occupied by the gun barrels and the front of the chassis. Guns ports were closed teardrop-shaped fairing.
For the cockpit was located PROTEK-based fuel tank filler neck which was from above, from behind the lantern. The fuel tank capacity was 1211 L.
The base of the fuselage was its middle part with massive power frame to which is attached the main wing spar, the nodes of the engine mounting, and landing the hook. Front and middle portion were trimmed with panels of metallit. After painting, the surface was polished to a mirror finish. In the tail of the fuselage covered by dural panels, was the afterburner dual-mode camera Solar model AND 103B. closed steel casing. Between the camera and the casing was run outside air for cooling the walls of the chamber. The air is fed from two conformal air intakes in the lower part of the fuselage. Due to this the temperature of the outer aluminum cladding does not exceed 600°C.
At the top, over the engine and afterburner, were the power beam, which is attached to the keel. Tail and middle parts separated of the firewall.
The wing trapezoidal, straight profile NACA 65212; equipped with ailerons and flaps. At the root of it had big fairings are triangular in shape in plan. The winglets could be attached extra fuel tanks, capacity 530 liters In the front of each tank was a landing light. Wingtips had a special aerodynamic profile that generates airflow, discarded fuel tanks limit the separation of them from the plane to the side.
The tail unit consisted of a vertical fin of large area and horizontal stabilizers with elevators. To facilitate balancing and reduce the efforts of the elevators were equipped with trim tabs with control from a handwheel on the left side of the cockpit. On the top of the keel was fixed to the receiver of air pressure.
Landing gear is tricycle, with steerable nose wheel. After landing on the deck of an aircraft carrier and the front leg could be shortened. Thus the tail part of the plane rose up. In this position the pilot could steer the deck using turbojet engines, not fearing for the lives of technicians, standing behind the aircraft on the deck.
On production aircraft F6U-1 had an engine Westinghouse J34-WE-30A has a static thrust of 1360 kgs. When you turn on the afterburner thrust increased up to 1900 kgs. When in the Western literature indicate engine thrust, usually lead, stand characteristics; the engine installed on the aircraft, the thrust will be less. For F6U this reduction in thrust was as much as 12 percent. The J34 engine was an 11-stage axial compressor, annular combustor and two-stage turbine. The engine intakes were at the lower surface of the wing roots.
The aircraft was equipped with air brakes with hydraulic drive, which is automatically produced when the critical flight speed, corresponding to the number M = 0,8.
F6U armament consisted of four 20-mm guns M-3 with ammunition 150 rounds per gun. The radio equipment consisted of a radio station, radiolucent and used for the first time in the United States system of identification “friend or foe” ARCH-1 IIF.
Flight-the statement of characteristics of the aircraft F6U-1 PIRAT
Length of aircraft, m…………………………….11,48
Wing span, m……………………………….10,1*
Height, m………………………………………….3,95
The wing area. m:……………………………18,91
Empty weight, kg……………………………….3320
Maximum takeoff weight…………..5942**
The maximum flight speed, km/h….959***
Landing speed, km/h…………………158
The rate of climb, m/s………………………43
Practical ceiling, m…………………….14 110
The maximum flight range, km…..1851
*Excluding the fuel tanks. **With full ammo, a pilot, a fuel in the internal and external tanks ***included With afterburner.
N. Food reserve was, A. CHECHIN
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