bdk wrote:
I believe the Vampire has a steel frame underneath to handle the structural loads and the wooden components are primarily the aerodynamic fairing around the cockpit (and act as the pressure compartment).
I really don't know where these myths come from, except that there's clearly some deep suspicion of wood as a high-capability structural element. (I'm sure bdk knows this and is just repeating canards he's heard in the engineer's lunchroom)...
From the armour bulkhead behind the nose cone, forward of the cockpit, to behind the gun ammunition bay aft of the cockpit, the Vampire fuselage pod is an all wooden monocoque 'sandwich'. There is
no main metal structural members.
From David Watkins'
de Havilland Vampire, the Complete History:
Quote:
The airframe was a composite construction, having both wooden and metal components in its structure. The wooden section comprised that part of the fuselage extending from bulkhead no. 1 to bulkhead no. 4 at the rear, with the remainder of the aircraft being of metal construction. This form of composite construction not only served to reduce weight and improve performance, but also, coincidentally, conserved cockpit warmth; it had been developed by the company in 1937 for the four-engined DH 91 Albatross airliner and was later successfully employed in the Mosquito and Hornet fighters.
He goes on to describe the construction method, which, more briefly, is in two half sections, where a layer of birch ply laid over a male wood or cement mould, and then built up with spruce insets (acting like stringers and frames) and the gaps filled with Balsa or Quipo wood, after which another layer of birch ply was laid over, each layer being glued, pinned and held in place by steel bands while it cured. Afterwards sanding back, a layer of Madapollam fabric was used as a final covering and took the Aluminium dope for UV and other protection, and then the appropriate camouflage.
This wooden structure had the four 20mm cannon barrels under the cockpit, with the breeches behind and the ammunition tanks above. Bulkhead 1 had a hefty piece of armour plate, and all this, plus the cockpit pressurisation and the (later) insertion of a Martin Baker ejection seat in some models, was entirely supported by the wooden structure described above.
Here's a photo of the Vampire under static restoration at The Old Aeroplane Co, Tyabb, Victoria, Australia. The tan and green areas are the wooden structure, the metal fairings on the nose and wing root are light aluminium forms, no structural load.
My favourite piece of disinformation about wooden warbirds was a comment by a poster here that:
"BTW. the engine is mounted to an oak beam behind the wood pod." 
Bruce, "DH Guru" (IMHO) posted
this in
that thread later:
Quote:
The engine mount is NOT wood, it is steel. The engine mounts are attached to the carry through spars, which I grant you are bolted to the wooden fuselage. However, the carry throughs are steel, and are the heart of the aircraft. In effect, the engine is bolted to the wing, rather than the fuselage.
Lets be clear about what the fuselage does - it is basically a fairing that encloses the pilot. The important bits are the cockpit floor, and the bulkhead just forward of the tank bay. If you get problems in those areas, then its not looking good!
http://warbirdinformationexchange.org/p ... 2&start=30And those bulkheads are wood.
Regards,
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