Armstrong Whitworth Ape

The Ape was an English experimental aeroplane built by Armstrong Whitworth Aircraft in the early 1920s and first flown in 1926 to "answer all the questions of aerodynamics." The biplane was designed to be "infinitely" adjustable: The fuselage could be lengthened or shortened, different fins and tailplanes could be fitted, the incidence angle of both the tailplane and the wings could be altered and the wings could be additionally changed in stagger, rake and dihedral. Curiously, the plane could not be converted to a monoplane configuration, nor could it be fitted with a more powerful engine. Additionally, the entire tail was a single unit and the incidence angle of the tailplane could not be changed without also changing that of the fin. It was equipped with a comparatively small 180hp Lynx engine that did not deliver nearly as much power as the relatively heavy plane needed, and certainly prohibited the Ape from experimenting to its full potential. The second Ape had a bigger engine than the first, but additional gadgets added weight that mostly negated the extra power.

The Ape would continue to see occasional use throughout the 1920s but more powerful, single-configuration experimental aircraft, such as the long-range Spirit of St. Louis and the U.S. Air Force's later X-planes would see the way of aviation forward.