Wes submitted this idea :
Vernon wrote:

Admittedly, my post does not dovetail with this thread since you're
talking electric motor driven compressors. However, I simply must
brag and chortle about my air cooled DIESEL milsurp air compressor.
Apparently it was designed to air up tires on jets. It's similar to
the "wheel barrow" compressors that carpenters use. It has a single
tank and a two stage compressor (175 psi!) compressor, belt driven by
a Yanmar 3 hp, fuel sipping, air cooled engine. It is well balanced
and light weight. It CHURNS out air. It starts from a battery or
with a rope. I swoon over its efficiency, reliability, and fuel
economy. In fact, I think I'll go give it a hug right now. Vernon

The planes I worked on were inflated at 275 psi or better with nitrogen.

Wes

I have a question about compressors-that is what kind/type of
compressors were used in WWII submarines-German or allied.I've read a
few books about War and subs but the there is very little technical
info about the role compressors played and probably stil do in
underwater warfare.