Model Hot Air Pumping Engine

For the crankshaft bearings, I used an SKF computer drive, thin section ball bearing (#WEA-406-2Z-RT-5G68R). This gives a really free rolling shaft, compared to the bushings called for in the print. Also, I used 'Oilite' bushings on every moving part. To slow down the amount of wear, I changed all the ¹/₈' diameter pins to 3/16' diameter. This is the size that is called for on the Rider Ericsson engine.

The machining of the beam is critical and also difficult because of its odd shape. One way to hold it would be to mount it securely to a piece of cold rolled steel plate that has been machined square. Drill and tap all the holes before removing the beam from the plate.

The brass tube can be held into the water pump casting very easily with 'Loctite Retaining Compound'. Use ³/₈ inch O.D. x 1/32 inch wall brass tubing.

As with the other engine, the bore was professionally honed. Use graphited string for the power piston packing, and make the displacer cylinder and displacer piston as described above, not like on Eisner's prints. Also, use the same burner as used on the Rider Ericsson engine, not the one shown in the Eisner prints.

The engine could be either painted all black, or in the orange and black color scheme that is on my engine. Brad Eisner's 8' engine had original paint and was in this color scheme. The builder's plate that is supplied with the kit is fastened to the top of the cylinder, behind the pump rod. This is also a very good running engine, and quite powerful, due to the inertia in the cast iron flywheel.