SNCASO Deltaviex

The SNCASO Deltaviex or SNCASO-ONERA Deltaviex was a small French experimental jet aircraft, first flown 30 April 1954 and distinguished by highly swept, small span wings. It was designed to explore the possibility of controlling roll and yaw with fine jets of air bled from the engine's compressor.

Design and development

The Deltaviex, its name derived from the Delta VX design of Alliet at ONERA and built by SNCASO at Courbevoie, was intended to explore lateral control by blown flaps instead of ailerons. Despite its name it did not have a delta wing but wings which were strongly swept and straight tapered to pointed tips. The leading edge sweep was 70°, that of the trailing edge about 40° and the thickness to chord ratio less than 6%.

The wing trailing edges carried flaps from the wing roots almost to the tips and these were blown with air bled from the centrifugal compressor of the Deltaviex's Turbomeca Marboré gas turbine engine, exiting the flap trailing edges via 700 μm (0.028 in) holes. There were also more conventional ailerons, though they were unusual in that they were irregular quadrilaterals in shape and formed the wing tips.

Yaw was similarly controlled by passing more of the compressor bleed out though fine holes in the tall fin, which was swept on both edges and straight tapered to a squared-off tip; there was no rudder. The horizontal tail was likewise straight edged and swept, though its trailing edge was less strongly swept than that of the wing. Its tailplanes were triangular and the elevators balanced.