Wingless Airplane Snecma C-450 Coleoptere

31 October 2020, 07:40

The 1950s were full of crazy airplane production ideas of the eastern and western bloc.

They wanted to produce aircraft that did not require long runway distances and could take off and land vertically. French companies Dassault and Snecma were seriously investing in different aircraft design concepts.

This company, now known as Safran, formerly Snecma, was in favor of using a turbojet engine, not a propeller turboprop like other countries (for example, the USA) that had the idea of ​​producing an airplane capable of vertical landing and take-off.

Turning these thoughts into action, Snecma tested the turbojet engine they developed for vertical landing and take-off aircraft design in 1958, and in the first test, it could take off for 800 meters without any external power support.

After the test was successful, the design of the aircraft started.

This turbojet engine, called ‘’Atar Volant’’, which managed to land and take off vertically, had serious stability problems during landing and take-off, and the designers decided that the design of the aircraft could not be a classical winged design.

Because they saw it quite risky. In this direction, it was decided to implement a design named “ring wing” contrary to the classical wing structure we know. In 1959, the first C-450 prototype with a Atar Volant engine started flight tests.

There was a worry about the flight of this very different design. In this unusual ring wing design, there were four vanes between the fuselage and the wing.

These vanes did not provide any lift, but they were responsible for moving the aircraft on axes and fixing the ring. In the first tests, this aircraft which could take off with a weight of 3000 kg, flew 100-200 meters and started to show hope, but it had some problems in flight controls and these problems caused the end of the design work.

In the 9th flight test of the Coleoptere, it was aimed to make it fly to a horizontal position with the control surfaces after taking off vertically, fly for a while like a normal airplane, and then return to the vertical position from the horizontal position and make a vertical landing.

The plane was successful until the normal flight phase but as soon as it started landing, the control surfaces started to get serious malfunctions. The plane stalled and crashed quickly. As a result, Snecma firm stopped investing in the production of the aircraft.

This aircraft did not allow time to tolerate a possible engine failure, compared to the classical winged aircraft.

Even if the engine fails in normal wing aircraft, it is possible to ensure a safe landing or engine restart thanks to the lift force on the wings.

In the ring wing structures, when the engine stops, the lift force also disappears and a sudden stall occurs. This was the biggest reason the design failed.

Technical Characteristics Of The Aircraft:

WINGS – Annular wing of light alloy construction, comprising two skins and internal structure. Chord 3.0m.

FUSELAGE – Conventional light alloy structure. Retractable fore-planes on nose.

TAIL UNIT – Cruciform fins and rudders of light alloy construction, mounted on trailing-edge of wing, to provide directional control in all axes.

LANDING GEAR – Four oleo-pneumatic legs mounted on trailing-edge of wing. Small castering wheels with rubber tyres. Wheel track 2.95m.

POWER PLANT – One SNECMA Atar 101E.V turbojet (3,700kg of thrust) mounted aft of cockpit in fuselage. Integral fuel tanks with total capacity of 700kg of fuel.

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