Fiesler Fi-156 Storch (stork)
In 1935, the RLM (Reichsluftfahrtministerium, Reich Aviation Ministry) directed several companies for a new Luftwaffe aircraft suitable for liaison, artilliary co-operation (aka FAC: forward air control), and medical evacuation.
Conceived by chief designer Reinhold Mewes and technical director Erich Bachem, Fieseler's design had a far better short take off and landing ("STOL") performance than other competitors. A fixed slat ran along the entire length of the leading edge of the long wings, while a hinged and slotted set of control surfaces ran along the entire length of trailing edge. This was inspired by earlier 1930s Junkers Doppelflügel, "double-wing" aircraft wing control surface design. This setup along each wing panel's trailing edge was split nearly 50/50 between the inboard-located flaps and outboard-located ailerons, which themselves included trim tab devices over half of each aileron's trailing edge length.
Fi 156 in flight
A design feature rare for land-based aircraft enabled the wings on the Storch to be folded back along the fuselage in a manner similar to the wings of the US Navy's Grumman F4F Wildcat fighter. This allowed the aircraft to be carried on a trailer or even towed slowly behind a vehicle.
The primary hinge for the folding wing was located in the wing root, where the rear wing spar met the cabin. The long legs of the main landing gear contained oil-and-spring shock absorbers that had a travel of 450 mm (18 inches), allowing the aircraft to land on comparatively rough and uneven surfaces.
In flight, the landing gear legs hung down, giving the aircraft the appearance of a long-legged, big-winged bird, hence its nickname, Storch. With its very low landing speed the Storch often appeared to land vertically, or even backwards, in strong winds from directly ahead.