Geodesic airframe

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Wellington Mk.X HE239 of No.428 Sqn. RCAF, illustrating the geodesic construction and the level of punishment it could absorb while maintaining integrity and airworthiness.
Wellington Mk.X HE239 of No.428 Sqn. RCAF, illustrating the geodesic construction and the level of punishment it could absorb while maintaining integrity and airworthiness.
A section of the rear fuselage from a Warwick showing the geodesic construction in duralumin. On exhibit at the Armstrong & Aviation Museum at Bamburgh Castle.
A section of the rear fuselage from a Warwick showing the geodesic construction in duralumin. On exhibit at the Armstrong & Aviation Museum at Bamburgh Castle.

A Geodesic airframe (alternatively, Geodetic) is a type of construction for the airframes of airships and aircraft. It makes use of a space frame formed from a spirally crossing basket-weave of load-bearing members[1]. The principle is that two geodesic arcs can be drawn to intersect on a curving surface (the fuselage) in a manner that the torsonial load on each cancels out that on the other[2].

Contents

[edit] Development

The geodesic construction method was developed by the British aeronautical engineer Barnes Wallis for use in airships, beginning with the R100. The system was later used by Wallis' employer, Vickers-Armstrongs in a series of bomber aircraft, the Wellesley, Wellington, Warwick and Windsor. In these aircraft, the fuselage was built up from a number of duralumin alloy channel-beams that were formed into a large framework. Wooden battens were screwed onto the metal, to which the skin of the aircraft could be applied; linen stiffened with aircraft dope.

The metal lattice-work gave a light structure with tremendous strength[1]; any one of the stringers could support some of the load from the opposite side of the aircraft. Blowing out the structure from one side would still leave the load-bearing structure as a whole intact. As a result, Wellingtons with huge areas of framework missing continued to return home when other types would not have survived; the dramatic effect enhanced by the doped fabric skin burning off, leaving the naked frames exposed (see photo). The benefits of the geodesic construction were countered by the difficulty of modifying the physical structure of the aircraft to allow for a change in length, profile, wingspan etc.

[edit] References

[edit] Notes

  1. ^ a b Buttler, p.93
  2. ^ Buttler, p.94

[edit] Bibliography

  • Buttler, Tony (2004). British Secret Projects: Fighters & Bombers 1935-1950. Hinckley: Midland Publishing, 240 pages. ISBN 1857801792.