Tail-sitter

Programmes to develop manned tail-sitters were typically terminated in the form of the more practical thrust vectoring approach, as used by aircraft such as the Hawker Siddeley Harrier and Yakovlev Yak-38.

As observed by the aviation author Francis K. Mason, a combat aircraft that possessed such qualities would have effectively eliminate the traditional reliance on relatively vulnerable runways by taking off and landing vertically as opposed to the conventional horizontal approach.

[6] One company that opted to engage in VTOL research was the French engine manufacturer SNECMA who, beginning in 1956, built a series of wingless test rigs called the Atar Volant.

Only the first of these was unpiloted and the second flew freely, both stabilized by gas jets on outrigger pipes The third had a tilting seat to allow the pilot to sit upright when the fuselage was level and had the lateral air intakes planned for the free flying aircraft, though it always operated attached to a movable cradle.

[8] The eye-catching design of the Coléoptère rapidly made waves in the public conscious, even internationally; author Jeremy Davis observed that the aircraft had even influenced international efforts, having allegedly motivated the United States Navy to contract American helicopter manufacturer Kaman Aircraft to design its own annular-wing vehicle, nicknamed the Flying Barrel.

The Convair XFY Pogo was one such aircraft, featuring a delta wing with cruciform tail configuration; initial test flights were conducted inside of a naval airship hangar at Moffett Field in Mountain View, California.

The Dornier Aerodyne is of ducted-fan configuration similar to a coleopter, and a test UAV flew successfully in hover mode in 1972, before development was discontinued.

[17] Another contemporary UAV project was the NSRDC BQM-108 that was developed by the United States Navy; although work was discontinued almost immediately after its single successful test flight.

[18] During the 1970s, several studies and wind tunnel models were made of a tail-sitting version of the General Dynamics F-16 Fighting Falcon that was intended for use on board ships; however, it was decided not to pursue further development of the concept due to the large thrust requirement involved, as well as the need for extensive apparatus to handle take-off and landing.

[19] At present, most of the tail sitter projects or proposals fall under the category of unmanned aircraft such as Bell Apt or Northrop Grumman Tern.