The propellors on the B-36 were driven by Pratt & Whitney R-4360 radial piston engines that produced up to 3800 horsepower each. They were turbocompound engines, where exhaust gases spun a turbine that fed additional power to the crankshaft. The first versions of the plane had 6 piston engines and later versions added 4 turbojets (hence the expression "6 turning and 4 burning").

The NB-36H was an attempt to develop a nuclear powered airplane. It actually flew with a small nuclear reactor on board but it was never used to power the plane.

There was a turbojet version of the B-36 (YB-36G but later redesignated the YB-60) but it wasn't put into production.