I know that I've mentioned the P-40 a couple of times, and even though it wasn't a great performer in the ETO (basically too slow for northern European operations, and not a good altitude performer even with the Merlin), it was cheap, simple (for a modern aircraft) and robust
We may mean different things.
1, The P-40 wasn't actually slow. At altitudes where it's engine worked it was fast as a Spitfire V. So for installed horsepower it was actually pretty good.
2, The engine did crap out at much over 12-13,000ft with Allisons before the P-40M and those only picked up about 3-4,000ft.
3. The P-40F was good for around 360-365mph at 20,000ft in US figures and the A&AEE tested one at 354mph at 20,400ft. British figures are for a weight about 400lbs heavier than the US figures (?) which leads us to.
4. while fast it couldn't climb even if you strapped a rocket to it. The British were testing it at 8900lbs. or about 27% heavier than Spitfire MK V.
5. Cheap is certainly debatable, An almost 6500lb empty weight fighter, while cheap compared to a P-38 or P-47 is not a cheap airplane compared to a Spitfire or 109 or???
They also had a huge production operation going and some months they rolled over 400 P-40s out the door. There is a certain economy of scale.
6. Simple, compared to what? yes it was simple compared to a P-38 (2 engines). P-47/F6F/F4Us thousands of pounds heavier, 18 cylinder engines and two stage superchargers.
Now engines aside, what WW II fighters were more complicated? They all had similar instrument panels, most had similar radios, they all used similar controls (at least until the P-38 with the powered ailerons), we can argue about hydraulic landing gear retraction vs electric or even hand cranks but most planes had retracting mechanisms and flaps (no double slotted flaps) so most single engine fighters used pretty much the same number of systems.
7. Robust, OK but that was part of the weight and part because the P-36 was not as robust as desired. But they paid for it with several hundred pounds of extra weight.
And of the Soviet fighters, they were, especially the Yakovlev and Lavochkin fighters were noted for being high performance while being insanely simple to built and maintain, even allowing for the fact that wood wasn't the best material to build planes out of in the Russian climate (which resulted in the all metal Yak-3 M-107 and La-9/11 post war).
Insanely cheap looks a little looking at. Soviet wooden fighters were not built with slabs of wood dragged to the factory by wood cutters and horse drawn sleds.
They used laminated veneer plywood. See Wiki
"The I-301 airframe was partially made of "delta wood": a material composed of very thin (0.35–0.55 mm) layers of birch or pine wood veneer, and a phenol-formaldehyde resin known as VIAM-B-3, which together were baked at high temperatures and pressures. Delta wood was used for critical parts of the airframe. This novel construction material had tensile strength comparable to that of non-hardened aluminum alloys and only 30% lower than that of precipitation hardened D-1A grade duralumin. It was also incombustible and completely invulnerable to rot, with service life measured in decades in adverse conditions."
Now you need veneer lathes that will cut the selected logs to the required thickness and widths. You need a chemical industry that can provide the required resin glue in the required quantities ( dozens of gallons per plane ?) and you need the autoclaves to bake the sheets and structures at the temperature and pressures needed.
Once you have established the supporting supply network actual assembly may be easy but trying to figure out the cost of some the supply network is hard. Some of the supply network could be supplying several different airframe companies including rival design teams.
Also note that some of the claims did not prove out in practice under mass production. Some areas got too much resin and some got too little and if not baked at the proper temperature/pressure/
time you don't get the results you want.
Also note that slopping on extra glue to poorly fitted parts does NOT make up for sloppy fit. It also makes some the parts a lot heavier than designed.
Hammering metal bolts though miss aligned wooded holes makes for insanely simple construction, you also have to have insanely simple pilots to fly such things (or be threatened with death).
If you don't have enough aluminum it is a solution, but people often confuse wood with cheap. A lot depends on the woods, the availably of the woods and the availability of the glues/adhesives and other things.
I would also suggest that NO country and the number of piano or fine cabinet makers needed to turn out hundreds of wooden aircraft a month.
The construction was also bulky. the wing spars actually took up a fair amount of room inside the wing and when they started using metal spars they could fit in larger fuel tanks and the all metal wings allowed for even more volume for fuel (or allowed for more strength which allowed for greater load? or both?)
a quicky claim that plane X cost $43,256 actually doesn't tell us a whole lot without some context.
