From: Dismal Seepage Indiana
I learned to fly a Piper J-3 "Cub" when I was still in high school in the sixties.
Beyond that, my actual flying time is likely much less than the average private pilot, and certainly nothing compared to some "stove jockeys" on this forum, (Elf immediately comes to mind)..
That said, I have also tried my hand at designing wargames, aviation related from the cardboard days.
You can find a formula of your own for the speed of aircraft if you can calculate the square footage of wing surface and divide it by the power of the engine.
(Wight to power ratio is also calculated to your formula but it has been over 30 years since I developed my numbers.
Too, you must calculate the environment of the location your planes are flying in, the air itself may be
more 'rarified" in different locales.
The less molecules of air to sustain lift will favor a higher wing surface.
As you can see, when dealing with the thousands of planes in the game, you can see your research would be calculated in years, not days, if done to the "nth" degree of accuracy.
Too, the type of carburation in rarified oxygen environment comes into play as well, as in the case of the P-39 which had no supercharger on their Allisons, limiting their practical use to 10k or less.
I know for a fact if you look in the forum notes of the original WITP, you will see a thread I started for researchers, and one of the internet threads within that forum topic will take you directly to the formulas to calculate what you seek.
BTW, I use Firefox for my browser, and it offers a really nice app called "Ghostery" which will even locate internet sites which have been inactive for years!..(Nothing is completely deleted from the internet), perhaps something our governments should learn, lol)