DFS 40

{{Short description|Type of aircraft}}

{{Infobox aircraft

|name = DFS 40

|image =300px

|caption =

|type = Experimental Tailless aircraft

|national_origin = Nazi Germany

|manufacturer = Deutsche Forschungsanstalt für Segelflug (DFS)

|designer = Alexander Lippisch

|first_flight = 1939

|introduction =

|retired =

|status =

|primary_user =

|more_users =

|produced =

|number_built = 1

|program cost =

|unit cost =

|developed_from = Lippisch Delta IV

|variants = DFS 194

}}

The DFS 40 was a tailless research aircraft designed by Alexander Lippisch as the Delta V in 1937.Alexander M. Lippisch. Errinneruingen (Memoirs). Luftfahrtverlag Axel Zuerl. Germany. Pages: Front endpapers, pp.185-6, 192-3) The DFS 40 was a more advanced design than the previous DFS 39 (Delta IV), and was built for comparison with that aircraft.Albert C. Piccirillo. "The Me 163B Komet, Development and Operational Experience". SAE Transactions. Vol. 106, Section 1: Journal of Aerospace (1997), pp. 1828-1845 (18 pages). See p.1829.

Where the DFS 39 had a pronounced fuselage with low-mounted wing, the DFS 40 was closer to a flying wing, with the wing-fuselage junction blended so that there was no clear dividing line.Alexander M. Lippisch. "Tailless Tailpiece". Air Enthusiast. September 1972. pp.136-138, 50.

The DFS 40 was flown for the first time by Heini Dittmar in 1938, shortly before Lippisch departed the DFS (Deutsche Forschungsanstalt für Segelflug - German Research Institute for Sailplane Flight) to begin work at Messerschmitt, taking much of his design team with him. Soon afterwards, without Lippisch there to supervise the project, the aircraft was crashed due to an error in center of gravity calculations that resulted in it entering a flat spin during flight. While the test pilot escaped by parachute, the DFS 40 was destroyed.{{sfn|Ethell|1978|pp=37–40}}