18 Cylinder Radial Engine | Horse Drawn Sled | Clockwork Jack

Pratt & Whitney R-4360 Wasp Major

Photo of a Pratt & Whitney R-4360 Wasp Major on a display stand. Note the size of the engine compared to the boy underneath the engine.

A SolidWorks drawing of the engine. I have drawn most of the engine including all internal parts to ensure proper fit and location. The engine will have 28 cylinders, 7 independent electronic ignitions, a pressure and scavenge oil pump. 5 main bearings, & 5 cams.

Four aluminum engine case segments are bolted together being machined for cylinder placement. There are 28 cylinders of 1” bore and 1 ¼” stroke.

Brass Main Bearing with cam gear ring & cam gear bearing holes. The bearing is mounted in an aluminum fixture for machining.

Crank case section with two piece brass main bearing. The main bearing shows the cam ring to support the hardened cam. Also shown are the cam drive gear flange bearings.

Main bearing with cam gears. The cam rotates 1/8 the speed as the crank shaft. The cam is shown but does not have the cam lopes machined onto it yet. The internal teeth on the cam were cut with a wire EDM. The other drive gears were machined from round stock on an indexer.

Main bearing with cam, cam gears, and cam retaining plate. The tappet holes are shown above the cylinder holes.

Gear blanks were made from round bar stock and machined on an indexer. The individual gears were machined from the gear blanks. All the distributor gears are 32 diametrical pitch.

Machining the distributor drive bevel gear.

Distributor case with gears. Shown are the bevel gears from the previous photo. The distributors need to turn ½ the speed as the crankshaft.

3D machining the supercharger housing using a ¼" ball end mill. I started with a 7" diameter solid aluminum stock. The photo shows a finished integral motor mount. To the left of the end mill is a motor mount that has not been machined yet. This piece will also house the supercharger fan, radial motor mounts, and intake manifold tubes.

Mock up of the Pratt & Whitney R-4360 Wasp Major engine crank case with distributor case and 32” diameter prop.