Some Unusual Aircrafts

Vought XF5U

The Vought XF5U "Flying Flapjack" was an experimental U.S. Navy fighter aircraft designed by Charles H. Zimmerman during World War II. This unorthodox design consisted of a flat, somewhat disc shaped body (hence its name) serving as the lifting surface. Two piston engines buried in the body drove propellers located on the leading edge at the wingtips.

A developed version of the original V-173 prototype, the XF5U-1 was a larger aircraft. Of all-metal construction, it was almost five times heavier, with two 1,600 hp (1,193 kW) Pratt & Whitney R-2000 radial engines. The configuration was designed to create a low aspect ratio aircraft with low takeoff and landing speeds but high top speed.

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 present a structural challenge in building them stiff enough. The XF5U overcomes the tip vortex problem using the propellers 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. The propellers envisioned for the completed fighter were to have a built-in cyclic movement like a helicopter's main rotor, with a very limited ability to tilt up and down to aid the aircraft in maneuvering. An ejection seat was fitted to allow the pilot to clear the massive propellers in the event of an in-flight emergency. Although the prototype was unarmed, a combination of machine guns and cannons would have been installed under the nose.

The XF5U design was promising: specifications given at the time promised the ability to hover like a helicopter while having an airspeed range of 0 to 550 mph (885 km/h). However, it came at the time when the United States Navy was switching from propeller driven to jet propelled aircraft. 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 canceled the project on 17 March 1947 and the prototype aircraft (V-173) was transferred to the Smithsonian Museum for display. Although two aircraft were constructed, a lone XF5U-1 underwent ground runs but never overcame vibration problems. Hence dropped.

Lockspeiser LDA-01

Lockspeiser LDA-01 (Land Development Aircraft-1971) was a British research and development aircraft, which was designed and built by David Lockspeiser. He made this to prove a concept for a low-cost utility transport.

The LDA-01 was a single-seat canard monoplane, fabric covered with metal construction. It had a canard foreplane which was the same size as each mainplane. The wing was mounted at the rear-end of the box structure fuselage which was fitted with a four wheeled landing gear. It was designed to be fitted with a detachable payload container to allow easy conversion between roles, and was powered by a rear-mounted pusher engine. The aircraft was cancelled from the aircraft register as destroyed in 1987.

NAC Fieldmaster

The NAC Fieldmaster(1981) was a British agricultural aircraft of the 1980s. It was built in small numbers and used both as a cropsprayer and a firefighting aircraft.

The resulting aircraft, the NDN-6 Fieldmaster was a large single-engined low-winged monoplane with a fixed nosewheel undercarriage, powered by a Pratt & Whitney Canada PT6 turboprop engine, the first western-built agricultural aircraft to be designed for turboprop power. Novel features included an integral hopper made of Titanium to carry its chemical payload, which was dispersed via spray nozzles built into the flaps under the aircraft's wings.

NAC went into receivership in 1988, after the production of six Fieldmasters, including the prototype. Brooklands Aerospace attempted to continue production, rebuilding one of the Fieldmasters with a more powerful engine as a specialised fire-fighting aircraft as the Firemaster 65, but these attempts were stopped by the outbreak of civil war in Yugoslavia.

Rutan Voyager

The Rutan Model 76 Voyager was the first aircraft to fly around the world without stopping or refueling. It was piloted by Dick Rutan and Jeana Yeager. The flight took off from Edwards Air Force Base's 15,000 foot (4,600 m) runway in the Mojave Desert on December 14, 1986, and ended successfully 9 days, 3 minutes and 44 seconds later, on December 23. The aircraft flew westerly 26,366 statute miles (42,432 km; the FAI accredited distance is 40,212 km) at an average altitude of 11,000 feet (3,350 m). This definitively broke a previous record set by a United States Air Force crew piloting a Boeing B-52 that flew 12,532 miles (20,168 km) in 1962.

The airframe, largely made of fiberglass, carbon fiber, and Kevlar, weighed 939 pounds (426 kg) when empty. With the engines included, the unladen weight of the plane was 2250 lb (1020.6 kg).

Voyager had front and rear propellers, powered by separate engines. The rear engine, a water-cooled Teledyne Continental IOL-200, was planned to be operated throughout the flight. The front engine, an air-cooled Teledyne Continental O-240, was operated to provide additional power for takeoff and the initial part of the flight at heavy weights.

Voyager's takeoff took place on the longest runway at Edwards AFB at 8:01 am local time with 3,500 lbs.

Rutan Proteus

The Scaled Composites Model 281 Proteus is a tandem-wing high-endurance aircraft designed by Burt Rutan to investigate the use of aircraft as high altitude telecommunications relays. The Proteus is actually a multi-mission vehicle. An extremely efficient design, the Proteus can orbit a point at over 65,000 feet (19,800 m) for more than 18 hours. It is currently owned by Northrop Grumman.

Proteus has an all-composite airframe with graphite-epoxy sandwich construction. Its wingspan of 77 feet 7 inches (23.65 m) is expandable to 92 feet (28 m) with removable wingtips installed. Proteus is an "optionally piloted" aircraft ordinarily flown by two pilots in a pressurized cabin. However, it also has the capability to perform its missions semi-autonomously or flown remotely from the ground. Under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, NASA's Dryden Flight Research Center assisted Scaled Composites in developing a sophisticated station-keeping autopilot system and a satellite communications (SATCOM)-based uplink-downlink data system for Proteus' performance and payload data.

All the above Aircrafts we seen are made by the innovative thinkers. Burt Rutan was the important person in this category who made lot of innovative and successful designs. His most successful design is voyager. He was just retired from Rutan aircraft industory recently in April 2011.