Kellner-Béchereau EC.4

Kellner-Béchereau EC.4
Role	Side by side basic trainer
National origin	France
Manufacturer	Avions Kellner-Béchereau
Designer	Louis Béchereau
First flight	1937
Number built	1

The Kellner-Béchereau EC.4 and Kellner-Béchereau ED.5 were a pair of French training aircraft with side-by-side seating and a novel "double wing" patented by their designer, Louis Béchereau. The principal difference was that the EC.4 had an all-wood structure whereas the ED.5 was all-metal. Both were single-engine, mid-wing cantilever monoplanes.

In the 1930s the veteran aircraft designer Louis Béchereau set up Avions Kellner-Béchereau, a collaboration with the well-known automobile coach builders Kellner. In 1936–37 this company built a short series of small monoplanes exploiting one of Béchereau's patents, a full span lateral division of the wing into two sections forming a "double wing", a little like that used by Junkers but with a more equal division of area. The wing was first tested on the single-seat Kellner-Béchereau E.1 on 1936, which was followed by two larger and more powerful two-seaters, the EC.4 and ED.5. Both of these were designed to meet the French Air Ministry's requirement for a pre-military trainer aircraft to be used by the clubs set up in the "Aviation Populaire" programme.

Like the E.1, the EC.4 was a wooden aircraft with spruce frames and plywood covering. It was a mid-wing cantilever monoplane with straight, thick section, constant chord wings of quite high aspect ratio (9.45). The lateral division was at about 65% chord, with the rear part joined to the front with conspicuous V-shaped faired underwing hinges. In normal flight the two parts were close together and the rear sections acted both as lifting surface and, differentially, ailerons but they could also be lowered together as slotted flaps, moving rearwards as well as down to produce a slot between fore and aft parts.

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