Number 21 was the name of an aircraft that aviation pioneer Gustave Whitehead

Gustave Whitehead

Gustave Albin Whitehead, born Gustav Albin Weisskopf was an aviation pioneer who emigrated from Germany to the U.S., where he designed and built early flying machines and engines meant to power them....

 claimed to have flown near Bridgeport, Connecticut

Bridgeport, Connecticut

Bridgeport is the most populous city in the U.S. state of Connecticut. Located in Fairfield County, the city had an estimated population of 144,229 at the 2010 United States Census and is the core of the Greater Bridgeport area...

 on August 14, 1901.

The flight was reported in the August 18, 1901 issue of The Bridgeport Sunday Herald but the claims have been disputed.
A monoplane

Monoplane

A monoplane is a fixed-wing aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the most common form for a fixed wing aircraft.-Types of monoplane:...

 design powered by a 20 hp acetylene

Acetylene

Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because...

 engine - it started the takeoff run using the engine to power the wheels; upon takeoff, power would be switched to the propellers.

Design

The No.21 was a wire-braced monoplane with bat-like wings and triangular horizontal tail. There was no vertical fin, and lateral control was intended to be accomplished by shifting the pilot's body sideways.

The wing

Wing

A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...

s were constructed of cloth or silk

Silk

Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...

, with radial bamboo ribs, and reached a span of 36 ft (11 m). They had noticeable dihedral, which would have contributed to the aircraft's stability had it ever flown, and could be folded like a fan for transport.

The fuselage was of rectangular box section with constant height, curved to taper inwards at front and rear when seen from above. Four small wheels were fixed to the bottom.

Although having two engines and twin propellers, the aircraft was not a conventional twin. It had separate engines for ground running and flight, both designed and made by Whitehead. The ground engine was of 10 hp (7.5 kW) and drove the wheels to reach takeoff

Takeoff

Takeoff is the phase of flight in which an aerospace vehicle goes from the ground to flying in the air.For horizontal takeoff aircraft this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft , no...

 speed. Propulsion was then changed to a 20 hp (15 kW) acetylene engine driving two counter-rotating

Counter-rotating propellers

Counter-rotating propellers, found on twin- and multi-engine propeller-driven aircraft, spin in directions opposite one another.The propellers on both engines of most conventional twin-engined aircraft spin clockwise . Counter-rotating propellers generally spin clockwise on the left engine and...

 tractor Maxim

Maxim

Maxim may refer to:*Maxim , a principle that an individual uses in making a decision*Maxim , a type of aphorism*Legal maxim, certain guiding principles of law and jurisprudencePeople:*Maxim *Maxim...

-type propellers mounted on outriggers. The aircraft could supposedly take off under its own power and without assistance.

History

According to Whitehead and a reporter supposedly at the event, the monoplane's longest flight was 60 meters (200 feet) above ground for 800 meters (0.5 miles). These claims are contested. Whitehead did not keep a log book or document his work.

In an article in the August 18, 1901 issue of The Bridgeport Sunday Herald the reporter states he witnessed a night test of the plane, at first unpiloted but loaded with sand bags, and later with Whitehead at the controls.

Whitehead reportedly made four flights that day, supporters of Whitehead's claims offer that as the reason for conflicting accounts from different witnesses. The conflicts have been used by opponents of the claims to question whether any flights took place.