Approaching the speed-of sound, skin-panel and flight-control 'buzz' due to air-flow, shock and high torsional loads/distortion [control reversal!] is a major factor in transitioning to stiffer all-sheet-metal or metal-honeycomb or composite-honeycomb or solid-composite structure.
Also, the use of fabric covered surfaces presents an environmental deterioration problem [recurring fabric inspection and eventual replacement] that is labor/skill intensive to repair/replace. I remember my dad having the linen coverings on his 1950-era Piper Tri-Pacer being tested EVERY annual inspection for deterioration [specialized puncture-test]. 'Passing' meant that the test-hole was patched, doped re-painted and noted in maintenance log by the mechanic. 'Failure' meant the entire fabric cover had to be replaced... new material, cut, stitched, doped, painted, log-entry, etc.. by a certified mechanic.
In WWII there where thousands of low-wage, textile-skilled, workers who could install/repair/maintain fabric coverings.
And lets get serious... these WWII aircraft were simply not designed/built to last more than a few years or a few hundred hours total service, before being worn-out or destroyed or obsoleted by new models. Watch videos of B-29s being built: clad-aluminum sheet metal was left 'bare', with extruded or otherwise machined-parts simply alodined or anodized with [maybe] zinc-chromate primer on fay surfaces. Fast-simple-cheap.
My dad flew P-40s in the CBI: the general expectation for these [surviving] airframes was no-more than 500-hours and 2-years... then the bone-yard.
PS: anybody ever examine how the compound-curved fuselage of a early F4F was put together? see attached photo for the 'simple sheet-metal tricks' employed to KISS manufacturing.
Regards, Wil Taylor
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