Were WW2 American fighters designed to operate from dirt airstrips? Fighter or fighter-bomber planes built in America during WW2, such as the P-36, P-39, P-47, P-51. Were these designed to takeoff and land on dirt airstrips?

My impression, and correct me if I'm wrong, is the following: Most airbases inside USA/Canada at this time had paved runways. At least half the fighters were designed to takeoff and land on carriers. Also, I think every single photo in wikipedia I've seen of these planes on the ground, is on a paved runway.

Now there is of course the Western Front in Europe, and some American aircraft did get sent to the USSR in lend-lease. I do not know if Britain and France had the luxury of paved runways at the time, but in Russia, most certainly did not. So you would think at least some of them had to had the strong undercarriage required for dirt airstrips. But I am not sure if they came that way or had to be modified after arriving in Europe.

One way to investigate this is to start looking at the airfields America had during WW2. Wikipedia has a giant category page for this, but even tho most of those pages have a history section, sadly I could find nothing about paved/unpaved. However, this photo from Midway shows paved runways, and I'm pretty sure Wheeler Airfield during Pearl Harbor had a paved runway too. If they were doing that in the middle of the Pacific, my guess is that most airbases in the 48 states and east/west coast mainland also had paved runways.

The reason I ask is because a stronger undercarriage requires more weight. Dirt landings require bigger wheels which take up room in the fuselage that could otherwise be used for fuel or bombs. Therefore, if paved surfaces are available, it makes sense to take advantage of it in your design. But as I said above, I can't be sure if paved surfaces would be available everywhere they intended to use them.
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Opening theaters in the Pacific, for example, using fighters/bombers fitted with bush tires would not have been a good choice indeed. Maybe one pilot can pull it off. But not all, and certainly not the damaged planes.

As planes got heavier before WWII, and especially during WWII due to the massive engines and the all-metal construction, came the need for inflated tires, paved runways, hydraulic brakes...

... and the need for the Marston Mat. By using perforated steel planks, a runway can be built almost anywhere in a relatively short time (source).

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Above shows a North American P-51 taking off from Iwo Jima. Note the pattern on the ground. From far away in other B&amp;W images the pattern does not become clear and the planes look as if they're using pure dirt runways.


  Marston Mats were among the most important inventions of World War II (airspacemag.com).


As seen in your other question, How are modern jets modified to takeoff/land on a dirt runway?, Russian fighters are built with unpaved runways in mind. As are modern military transports. Transports have the luxury of space for many tires. But for jet fighters, it was the advances in tire manufacturing, which itself was due to the jet age that brought the swept wings and consequently the faster takeoff and landing speeds.

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Of course a humid tropical rainy island is different from a bone dry desert. The different soils and the water content affect their bearing and shear strengths. In North Africa, you may not need special reinforcements for the soil where its strength can be 4 times as high (think dry lakebeds).