check out airplane retracts and stuff, some of those are air powered.
i built a dump truck with a robart air cylinder a while ago, worked ok, but never tried to lift anything heavy. and i made the air tanks out of pvc and put them in the stock king hauler fuel tanks. used a hand pump to pressurize. worked most of the time until the glue failed on one of the air tank end caps at like 50 psi....
i'll stick with firgelli actuators from now on..lol
https://www.firgelliauto.com/