Catching up to this late in the game. I've ranted about wood in the past. As a maintainer wood sucks, I hate inspecting and repairing it. Although there were many great aircraft made of wood, what you basically build is a "throw-away airplane." There are tons of discussions about this through out this forum.
As far as a wood P-38? Not going to happen. The area where the tail plane was connected to the booms were difficult to manufacture with aluminum, I could imagine trying to build the same structure out of wood.
Great post FB. I found this in Wiki about the Dh 88 racer and the lengths taken, in a wooden structure, to produce an advanced design.
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Aerodynamic efficiency was the design priority and it was therefore decided to use a thin wing of RAF34 section. This was not thick enough to contain spars of sufficient depth to carry the flight loads and so the wing skin would have to carry most of the loads. However, the complex curves required for aerodynamic efficiency could not be manufactured using plywood. A construction technique previously used for building
lifeboats was adapted. The majority of the wing was covered using two layers of 2 inch (50mm) wide
spruce planking laid diagonally across the wing, with the outer layer laid crosswise over the other. These strips were of variable thickness, according to the loads they carried, reducing over the span of the wing from 0.5 in (12.5mm) at the root to 0.14in (3.5mm) towards the tips. It was built as a single assembly around three box-spars located at 21, 40 and 65 percent chord: there was an intermediate spruce stringer between each pair of spars to prevent buckling. The ribs were made of birch ply and spruce. The outboard 6 ft (1.5m) were skinned with various thicknesses of ply because of the difficulty of machining spruce planking to less than 0.07in thickness. The leading edge, forward of the front spar, was also ply covered. The centre section was reinforced with two additional layers of 0.07 spruce.
[8] This method of construction had been made possible only by the recent development of high-strength synthetic bonding resins and its success took many in the industry by surprise.
[9]
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In the 1930s and 40s and in time of war all aircraft were disposable. If the Merlin used in combat needed a rebuild after 250 hours how many aircraft had their engine rebuilt more than once? I never considered the question in the original post to literally make a P-38 out of wood, wood and metal are completely different and need different designs. I believe a twin engine fighter could have been produced but it would have looked like a Hornet. The point made previously deserves repeating, wood is not a miracle material, de Havilland really knew what they were doing not only in wood but also aerodynamics including cooling technology. Lockheed, by the same token, were not fools. Just building a P38 out of wood would result in a disaster, if it made a first flight I doubt it would make a first landing. The compressibility problems of the P-38 were new but not unique to the P 38 and wooden construction woulnt have helped.
As a guy who worked with steel and stainless steel all my life I have a view on how quality is maintained controlled and assured. This is always based on chemical analysis, heat number, lot number, item number (or similar). In various steel production methods the names change and the meaning changes slightly but the principle remains the same. When it comes to wood, I have no idea how they maintained quality assurance between trees on a material that changes so obviously that by grandmother used to say things were "dry as sticks". The performance difference of a living tree in a high wind, bending with no permanent (plastic) deformation, compared to the same tree when cut and dried splitting and splintering is akin to the difference between normalised steel and cast iron.
For those working in metals they had to develop new metals/treatments/processes but to those using wood they had to look for different woods and combine them in different ways.
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