Hidden Allied planes during the war (part 1) — Vought V-173

In the 1940s, the South American engineer Charles Zimmerman (not to be confused with its namesake German) designed a unique aerodynamic design of their own plane, which so far affects not only their unusual appearance and unique aerodynamic configuration, and flight characteristics. For its own unique appearance aircraft received a huge number of nicknames, among which can be identified such as the "Flying Pancake", "Flying parachute", "Skimmer Zimmerman." In these days of can confidently say that this aircraft, together with the German Fi-156, was one of the first devices of vertical / short takeoff and landing.

History of Creation

In 1933, the American scientist-recognizable aerodynamics Charles Zimmerman performed a series of experiments with a low aspect ratio wing. Conducted theoretical studies have shown the effectiveness of the scheme. According to his idea at the wing ultra-low elongation were supposed to be the screws that would be spun in a direction opposite the direction of rotation of the air coming off the wing vortices. This allowed snizat inductive reactance of the "wing-screws" and build a car with a huge range of speeds. With all of this low-speed implementation of large diameter screws if there is sufficient power available would allow the machine to perform a vertical take-off and hang in the air like a helicopter to cross the circuit, and low drag would increase the speed.

The first manned model under the scheme with a wingspan of 2 meters Zimmerman built in 1935. The model was equipped with 2 air-cooled engines, "Cleon" to 25 hp This model was never able to get off the ground because of the inability to achieve synchronization of propeller rotation. After that, Zimmerman designed the latest rubber-eye model with a wingspan of 0.5 meters. This model successfully flew. After that, the designer headed for support at NASA, where he previously rejected development as very modern. In the summer of 1937 Design work for a company called "Chanc-Vought." Then taking advantage of the huge potential of laboratories, Charles Zimmerman was able to build elektrolet V-162 with a wingspan of 1 meter. This elektrolet successfully flew in the hangar.

Secret Allied planes during the war (part 1) - Vought V-173

Later in 1938 the development of Zimmerman intrigued by the military, and the first of 1939 he took part in the competition for the creation of non-standard fighter. Work under this competition funded by the U.S. Navy. That's when Zimmerman started creating light aircraft V-173. The aircraft had a rather complicated wood construction, which was covered with a cloth. The model was equipped with a 2nd synchronized engines "Continental" A-80 with a capacity of 80 hp These motors via a gear spinning tremendous 2-bladed propellers, the diameter of which was 5.03 m wingspan of the aircraft was 7.11 m, wing area was 39.67 m. m total length of 8.13 m was equal plane aircraft landing gear to facilitate the construction was carried out non-retractable. At the rate of plane driven by 2-keel with rudders, the pitch and slope machine governed by all-moving elevons.

Because of the revolutionary concept that has been implemented in the V-173, it was decided to purge the plane in one of the larger wind tunnel in the world at that time located in the test facility Langley Field. Tests in the tube which ended in December 1941, then ran across the plane for flight tests. After a little jogging at the airport in the town of Stratford, chief pilot of "Chanc-Vought" Boone Guyton lifted the car into the air. It happened Nov. 23, 1942.

At take-off weight of 1,400 kg. Power 2-80-horsepower engines the car was obviously not enough. With all this as a result of failure motor V-173 a couple of times obliged to commit landing, and at one point even on the sandy beach skapotiroval. But each time the strength of the design and the small plane landing speed rescued from severe damage. With all of this major drawback of the machine pilot test called a bad view from the cockpit during taxiing and taking off. A prerequisite for this was a very large parking angle 22 degrees. The run test aircraft V-173 was only 60 meters, and in the presence of head wind of 46 km / h and it could take off vertically. The highest speed was 222 km / h, the highest ceiling — 1,524 m

Secret Allied planes during the war (part 1) - Vought V-173

In addition, the developers were creating a fighter who has had trade designation VS-315. By June 1942, the technical proposal for the airplane was transferred to the Bureau of Aeronautics. The new fighter adopted in accordance with the U.S. Navy naming scheme was designated XF 5U-1. The main feature of this machine was the ratio between the landing and the highest rate of flight — about 11, whereas the ordinary scheme for the aircraft was typical value of 5. Estimated range of speeds fighter had to be from 32 to 740 km / h

To achieve the stated features of the machine, you had to solve a number of problems. For example, at very low speeds grew angle of attack. Because of the asymmetry of the flow still at the experimental swatch V-173 were observed quite strong vibrations that threatened the strength of the structure. In order to get out of them was created by an engine which has received the title of "floating propeller." It was a wood propeller is very complex shape. Complex shape of the blade wide butt joined to the iron lugs, which in turn were associated with the swash plate. With its help you can have to change a repeating step of the propeller blades.

In the development of the new propeller fighter took the role of the company, Pratt & Whitney, which is designed and manufactured engines synchronizer for R-2000-7, clutches, gearboxes fivefold that bring us which of the 2 engines shut off in case of overheating or damage. Specialists also assist the company to design a fundamentally latest fuel system, which allowed power the motor fuel during prolonged flight at large angles of attack (up to 90 degrees with a hanging them in a helicopter).

Secret Allied planes during the war (part 1) - Vought V-173

Unfortunately, from the creation of the first prototype fighter XF5U-1, which was rolled out of the hangar more June 25, 1945, before the first flight in the middle of January 1947 was a very long time. "Skimmer", dubbed as fighter XF5U-1 for the firm, with honorably discharged program from flight tests and even set a high record of those years, showing the speed of 811 km / h This unofficial speed record belonged to Richard Burovs which is headed for its afterburner at an altitude of 8808 meters. In addition to that, the plane showed the ability of vertical take-off with a special trapezoid. The plane soared into the helicopter-with screws, raised up, as do at least some helicopter, he could hang in the air.

But, looking at the unique
design, project fighter XF5U-1 has been closed. The main causes of this decision were two: money problems at the company, with the abandonment of the project "skimmer" was a more common method of saving, and the fact that the U.S. Air Force began to rearm a reactive technique. According to the annotations in the spring of 1948, the Navy with the aircraft were stripped of all valuable equipment, after their cases were crushed by bulldozers into scrap metal. At this time the most experienced model V-173 was transferred to the museum at the Smithsonian Institute, where it is safely stored up to date.

Description of construction

Fighter XF5U-1 to form the outer repeats the V-173 and represented the dvuhkilevoe monoplane, which has an integrated assembly and elliptical wing symmetrical NACA 0015 profile across the span. Structurally fighter consisted of 3 main parts: the front, middle and rear. Placed in front of the cockpit, cut in small arms and vozduhopoglotiteli with forced cooling fan motors. The middle part of the fuselage fighter was formed with 2 frames, spars force between which housed motors, shafts and gears, basic and consumable fuel tanks, drives screws. At the bottom of the power to a front bulkhead mounted main landing gear. At the rear of the fuselage were located fighter tail wheel, the main machine controls, also arresting hook.

Secret Allied planes during the war (part 1) - Vought V-173

Short set design XF5U-1 was made of aluminum alloy, while the aircraft trim made of advanced composite material entitled metals, which was patented by Vought and is a bonded and molded in an autoclave quite bolshennom sandwich of 2 thin duralumin sheets, which were divided between a layer of ultra-light of the wood — balsa. The hardness and strength of the material used plating is allowed to reduce the number of structurally reinforcing ribs and lining machine frames, turning almost monocoque construction.

The cockpit was sealed shut and had a teardrop-shaped lantern, which was sliding. Drive his shift was electronic. The seat was a fighter pilot ejection, used chair JD-1, made by British company Martin-Baker. The main flight and navigational instruments, control devices and propulsion systems, fighter located on the front panel of the dashboard. On the left panel control knobs were repeated pitch screw, engine, trim tabs, brake and chassis hook. The right panel was occupied by the control panel and radio stations.

Powerplant fighter included chetyrnadtsatitsilindrovyh 2-lane motor Pratt & Whitney R-2000-2 (D) with a capacity of 1600 hp each. On the front of the crankcase of each motor was mounted gearbox with bevel gears that transmit torque to a single cross-shaft screws. In addition to the gear was connected to a fan cooled motor. At the top and bottom of the fuselage contained special sash, through which the exhaust hot air. The exhaust gases are vented under the body of the machine through a special U-shaped exhaust pipe and manifold. In this case, if one engine fails, the pilot can turn it off from the gearbox, using a suitable clutch. The blades were wood screws, and the screws themselves were changeable common and repetitive step.

Secret Allied planes during the war (part 1) - Vought V-173

The aircraft was equipped with tricycle landing gear with a tail wheel, hydraulic-system cleaning. All landing gear were two-wheeled fighter. Large parking corner of the car forced the designers place the arresting hook on the upper surface of the fuselage. The control system has a mechanical fighter, tough. Pitch and rake it was run with the help of differential deflected all-moving stabilizers. The stabilizers were equipped with external weight compensators and trimmers. Stabilization of the fighter in the direction performed by the 2-trapezoidal fins with rudders having a huge area. In the rear of the aircraft were automatic flaps, used for landing.

On standards experienced fighter XF5U-1 weapons do not install, but it was envisaged that production aircraft will be armed with six 12.7-mm machine guns Browning (ammunition 400 rounds per gun) or 4-20mm aerogun M-39. Also could be placed under the fuselage pylon 2 to install fuel tanks 568 liters or 2-bombs weighing up to 454 kg. Dive bombing or the use of rockets at one hundred percent ruled out because of the very large diameter screws.

Sources disk imaging:

-http://warplanefuns.ru/planes-main/amerika-main/item/33-f5u.html
-http://www.airwar.ru/enc/fighter/f5u.html
-http://www.aviarmor.net/aww2/aircraft_exp/usa/Vought% 20V-173.htm

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