Yvan Makhonine, a Russian expatriate conceived the idea of the telescopic wing. The wing outer panel 'telescoped' into the inner panel to reduce span and wing area for high speed flight and was extended for economic cruise and landing. His first design was the MAK-10 first flown 11 August 1931 which proved the concept but was severely underpowered.  The sliding wing was pneumatically powered and a standby manual system was provided. French Government support carried the test programme a further stage culminating in the MAK-101 of 1935. This machine achieving 233mph with the outer wing panel retracted.
The original configuration of the 1931 Makhonine 10 was updated with a new engine - the Lorraine 12EB engine being replaced by a Gnome Rhone K14, and the fixed trousered gear was replaced with retractable units. The modified airframe was re-designated MAK101. It resumed flight testing in 1935. Makhonine was still persisting with the testing when WW II began, the programme having been the subject of a one million francs grant from the French government. The German occupation authorities permitted the tests to continue, albeit under RLM supervision, after France's defeat. However, in 1941, the RLM decided that the Makhonine101 should be ferried to the Rechlin test centre. Makhonine requested permission for his test pilot Burtin to make one more flight before the aircraft was flown to Rechlin, and this being granted, the pilot deliberately crashed the aircraft which suffered just sufficient damage to prevent its removal to Germany. The Makhonine 101 was subsequently stored in a hangar at Villacoublay where it was eventually destroyed in a USAAF bombing attack. The original drawings of the variable-span aircraft had been destroyed at the French Air Ministry to prevent them falling into German hands, but detailed drawings of the damaged plane were made by German technicians and sent to Germany where considerable interest was shown in them. (Sources: Air International March 1975, Le Fana de l'Aviation 365)

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