F5U

The sole completed XF5U-1
Type	Fighter
Manufacturer	Vought
Maiden flight	1942-11-23
Status	Cancelled 1947-03-17
Number built	2

Vought V-173

The Vought XF5U-1 Flying Flapjack was an experimental U.S. Navy fighter aircraft which was designed during World War II by Charles H. Zimmermann. It is one of the most unusual-looking aircraft ever designed, consisting of a flat, somewhat disk-shaped body (hence its name) serving as the lifting surface. It was powered by two piston engines buried in the body, driving propellers on shafts which protruded from the leading edge at the wingtips. The original prototype, designated the V-173 (Flying Pancake), was built of wood and canvas and featured a conventional, fully symmetrical aerofoil section (NACA 0015). The development version, the XF5U-1, was a larger aircraft with all-metal construction, and was almost five times heavier, with two 1,600 hp Pratt and Whitney R-2000 radial engines. The configuration was designed to create a low aspect ratio aircraft with a low takeoff and landing speed and high top speed. Because of its very low stall speed it could possibly have proven itself to be an excellent reconnaissance aircraft. An aerospace manufacturer is a company or individual involved in the various aspects of designing, building, testing, selling, and maintaining aircraft, aircraft parts, missiles, rockets, and/or spacecraft. ... Vought is the name of several related aerospace firms. ... The Maiden flight of an aircraft is the first occasion on which an aircraft leaves the ground of its own accord. ... This article is about the year. ... November 23 is the 327th day of the year (328th in leap years) in the Gregorian Calendar, with 38 days remaining. ... 1947 (MCMXLVII) was a common year starting on Wednesday (the link is to a full 1947 calendar). ... March 17 is the 76th day of the year in the Gregorian Calendar (77th in Leap years). ... Vought is the name of several related aerospace firms. ... The United States Navy (USN) is the branch of the United States armed forces responsible for naval operations. ... Combatants Allies: Soviet Union United States United Kingdom and others Axis Powers: Germany Japan Italy and others Commanders Joseph Stalin Franklin Roosevelt Harry S. Truman Winston Churchill Adolf Hitler Hideki Tojo Benito Mussolini Casualties Military dead: 17,000,000 Civilian dead: 33,000,000 Total dead: 50,000,000 Military... An airfoil (or aerofoil in British English) is a specially shaped cross-section of a wing or blade, used to provide lift or downforce, depending on its application. ... The NACA airfoils are airfoil shapes for aircraft wings developed by the National Advisory Committee for Aeronautics (NACA). ... Pratt & Whitney is an American owned aircraft engine manufacturer whose products are widely used in both civil and military aircraft. ... The low aspect ratio wing of a Piper PA-28 Cherokee In aerodynamics, the aspect ratio is an airplanes wings span divided by its standard mean chord (SMC). ...

The first flight of the V-173 was on November 23, 1942. Flight testing of the V-173 would continue for over a year. During that time it would be flown successfully by Charles Lindbergh, who found it surprisingly easy to handle. On one occasion the V-173 was forced to make an emergency landing on a beach. As the pilot made his final approach he noticed two bathers directly in his path. The pilot locked the plane's brakes on landing causing the aircraft to flip over onto its back. Remarkably, the airframe proved so strong that neither the plane or the pilot sustained any significant damage. November 23 is the 327th day of the year (328th in leap years) in the Gregorian Calendar, with 38 days remaining. ... This article is about the year. ...

The aircraft's most significant problem concerned its complicated gearbox, which permitted power from the engines to be transferred to its two long propeller shafts. In ground testing the gearbox produced unacceptable amounts of vibration, delaying the aircraft's first test flight for months. To make matters worse, the gearbox was constructed partially out of silver, making the aircraft unusually expensive.

The lone XF5U-1 had undergone ground runs, but the vibration problem was never overcome. It is believed that on one occasion the XF5U-1 actually became airborne for a short period, but the height and duration of the flight, if indeed it actually occurred, is unknown.

Though the design was promising, it came at the time where the United States Navy was switching from propeller driven planes to jet propelled planes. By 1946 the XF5U-1 project was already long over its expected development time, and well over budget. With jet aircraft coming into service the Navy finally cancelled the project on March 17, 1947 and the prototype aircraft (V-173) was transferred to the Smithsonian Museum for display. The only completed XF5U-1 proved to be so structurally solid that it had to be destroyed by a wrecking ball. The scrap was sold to a salvage company which would later become involved in a government investigation when it attempted to resell the recovered silver. March 17 is the 76th day of the year in the Gregorian Calendar (77th in Leap years). ... 1947 (MCMXLVII) was a common year starting on Wednesday (the link is to a full 1947 calendar). ... The Smithsonian castle, as seen through the garden gate. ...

It is possible that with further development the XF5U-1 could have entered production, but it would have been a very complicated aircraft both to produce and maintain and like its sibling, the F7U Cutlass, would likely have had a short service life.

How it works

The XF5U looks like it should not be able to fly, as its wing area looks so small. Normally, a wing with such a low aspect ratio will suffer from very poor performance due to the degree of induced drag created at the wingtips, as the higher pressure air below spills around the wingtip to the lower-pressure region above. In a conventional aircraft, these wingtip vortices carry a lot of energy with them and hence create drag. The usual approach to reducing these vortices is to build a wing with a high aspect ratio - i.e. one that is long and narrow. However, such wings compromise the maneuverability and roll rate of the aircraft, or else will present a structural challenge in building them stiffly enough. The XF5U overcomes the tip vortex problem in a radical way, by using the airscrews to actively cancel the drag-causing tip vortices. The propellers are arranged to rotate in the opposite direction to the tip vortices, which retains the higher-pressure air below the wing. Since this source of drag is eliminated, the aircraft will fly with a much smaller wing area, and the small wing will yield high maneuverability and present no structural difficulties. The low aspect ratio wing of a Piper PA-28 Cherokee In aerodynamics, the aspect ratio is an airplanes wings span divided by its standard mean chord (SMC). ... In aerodynamics, lift-induced drag, or more simply, induced drag, is a drag force arising from the generation of lift by wings or a lifting body during flight. ... Vortex created by the passage of an aircraft wing, revealed by coloured smoke A vortex is a spinning, often turbulent, flow (or any spiral motion) with closed streamlines. ...

An obvious problem with this arrangement on the XF5U-1 was that the propeller's radius covered nearly the entire frontal area of the aircraft. A typical installation of any forward-firing weapons such as machine guns, cannon, or missiles would be virtually impossible. Any machine guns or cannon were to be placed against the nose on either side of the cockpit. Also, the radar would have to be mounted forward of the air screws to prevent interference. (Similar problems were to be encountered in the design of the Bell/Boeing V-22 Osprey). Look up bell, Bell in Wiktionary, the free dictionary. ... The Boeing Company (NYSE: BA, TYO: 7661 ) is the world’s largest aircraft manufacturer. ... The V-22 Osprey is a joint service, multi-mission military aircraft with vertical take-off and landing (VTOL) capability. ...

Specifications (XF5U-1)

General characteristics

• Crew: One, pilot
• Length: 28 ft 7 in (8.73 m)
• Wingspan: 32 ft 6 in (9.91 m)
• Height: 14 ft 9 in (4.50 m)
• Wing area: 475 ft² (44.2 m²)
• Empty weight: 13,107 lb (5,958 kg)
• Loaded weight: 16,722 lb (7,600 kg)
• Max takeoff weight: 18,772 lb (8,533 kg)
• Powerplant: 2× Pratt & Whitney R-2000-7 radial engine, 1,350 hp (1,007 kW each) each

Performance

• Maximum speed: 425 mph (775 km/h)
• Range: 1,064 miles (1,703 km)
• Service ceiling: 34,492 ft (10,516 m)
• Rate of climb: 718 ft/min (219 m/min)
• Wing loading: 35 lb/ft² (172 kg/m²)
• Power/mass: 0.16 hp/lb (0.27 kW/kg)

Armament

• 6x .50 machine guns or
• 4x 20 mm machine guns or
• 2x 1000 lb. bombs

For an explanation of the units and abbreviations in this list, please see Wikipedia:WikiProject Aircraft/Units key. The distance AB is the wing span of this Aer Lingus Airbus A320. ... In aviation, the Maximum Take-Off Weight (or MTOW) is the maximum weight with which an aircraft can achieve flight. ... VNO of an aircraft is the V speed which refers to the velocity of normal operation. ... The maximal total range is the distance an aircraft can fly between takeoff and landing as limited by its fuel capacity. ... In aeronautics, the service ceiling is the maximum density altitude where the best rate of climb airspeed will produce a 100 feet per minute climb(twin engine) and 50 feet(single engine) at maximum weight while in a clean configuration with maximum continuous power. ... This page is a candidate to be moved to Wiktionary. ... In aerodynamics, wing loading is the loaded weight of the aircraft divided by the area of the wing. ... Power-to-weight ratio is a measure commonly used when comparing various vehicles (or engines), including automobiles, motorcycles and aircraft. ... A . ... A machine gun is a fully-automatic firearm that is capable of firing bullets in rapid succession. ... The 20mm caliber is a specific size of cannon or autocannon ammunition, commonly the smallest caliber which is unambiguously a cannon (or more commonly today, autocannon) and not a heavy machine gun. ...

External link

• The XF5U story

Related content

Comparable aircraft

• V-22 Osprey

Designation sequence

F2U - F3U - F4U - XF5U - F6U - F7U - F8U The V-22 Osprey is a joint service, multi-mission military aircraft with vertical take-off and landing (VTOL) capability. ... The Vought XF2U-1 was a prototype biplane fighter aircraft evaluated by the United States Navy at the end of the 1920s, but already outclassed by competing designs and never put into production. ... The Vought F3U-1 was the prototype of a two seat, all metal biplane fighter built by Vought Aircraft Company of Dallas, Texas for the US Navy. ... Chance Vought F4U Corsair. ... The Chance Vought F6U Pirate was the companys first jet fighter. ... The Chance Vought F7U Cutlass (Vought V-346A Cutlass) was a U.S. Navy carrier based jet fighter and fighter-bomber of the early Cold War. ... F-8C digital fly-by-wire testbed (NASA) Two F-8 Crusaders Prepare to Launch from the USS Midway (CV-41). ...

Related lists

• List of fighter aircraft
• List of military aircraft of the United States

  A fighter aircraft is a military aircraft designed primarily for attacking other aircraft, as opposed to a bomber, which is designed to attack ground targets, primarily by dropping bombs. ... This list of military aircraft of the United States includes prototype, pre-production and operational types. ...