Why couldn’t your car engine run at, say, 2,seven-hundred rpm all the time, about the identical as that of many piston aircraft engines producing full power? Reciprocating aircraft engines generally spin a propeller through direct drive, with the prop basically bolted to the crankshaft. Typically, piston aircraft engines produce peak energy output at a redline close to 2,700 rpm. But in contrast with automobile engines, aircraft engines produce gobs of torque at relatively low rpm. Auto engines, then again, usually produce little or no torque at those settings, whereas additionally counting on liquid cooling.