Below, you will find a great test stand video of the Pratt & Whitney 4360 Wasp engine introduced in 1944. Basically, the engine was 28-cylinder four-row air cooled radial engine. Each row of pistons was slightly offset from the previous, forming a semi-helical arrangement to facilitate efficient airflow cooling of the successive rows of cylinders, with the spiraled cylinder setup inspiring the engine's "corncob" nickname. A mechanical supercharger geared at 6.374:1 ratio to engine speed provided forced induction, while the propeller was geared at 0.375:1 so that the tips did not reach inefficient supersonic speeds. Initially, it developed 3,000 horsepower, later models gave 3,500 horsepower.
The 4360 powered the B-50, successor to the B-29 and later the B-36, to name a few. And although reliable in flight, the Wasp Major was maintenance-intensive. Improper starting technique could foul all 56 spark plugs, which would require hours to clean or replace. As with most piston aircraft engines of the era, the time between overhauls of the Wasp Major was about 600 hours when used in commercial service.
It looks and sounds neat. A test stand video of a newly restored engine. Turn the speakers all the way up. Bask in the roar of twenty-eight cylinders belching the sound of freedom. Also, the sound will most likely clear out the cat, your wife and any other extemporaneous people not accustomed to military sounds and the glorious roar of a Pratt & Whitney "round" engine. As the Warbird people say, "Jets are for kids."