Hot Air Fan

[Rocket Man]

Powered by a 2" bore BETA style hot air engine. The base of the fan is a zinc casting of a 7" diameter bowl I snuck out of the kitchen without my wife catching me. I did a lot of experimenting with this engine, high radiant metal works best like cast iron for the top cold section of the engine. Copper and aluminum does not work well for the top or bottom of the engine. The thinner the metal is on the hot side the better the engine runs. The bottom is .020" wall thickness steel with a steel cup bottom silver soldered to the end. The engine has more power and runs more efficient because the displacer piston is made extremely light weight. After experimenting with several different designs the one that works best is, turn the lower part of the .250" displacer shaft down to .187 to reduce weight. Silver solder 2 flat washers .020" thick to the displacer shaft 3" apart. Wrap the displacer washers with 1 layer of kitchen aluminum foil. Fold foil over the ends of the flat washers and make a fold where the ends come together. This makes an extremely light weight displacers 1.880" x 3". Very low mass requires very little power to move the displacer up/down. The power piston is made of aluminum for low mass too, I milled out the whole inside so the piston is .090 thick. The power piston has ????? groves in it to simulate frictionless piston rings across the pressure drops of each groove. The grooves that advantage of the laws of physics and act like piston rings. I wish I could remember the scientific name of those grooves. Power piston stroke is .562" and displacer stroke is 1.5". Clearance between the power piston and cylinder wall is .001" but that changes to .0005" after the engine gets hot. I made a plywood jig to bend the wires for the blade cover. Improved efficiency makes this engine an amazing runner. The fan turns 450 RPM with the blades on a small flame using cotton rope as a wick in oil or wax. Replace the blade with a flywheel the engine runs 900 RPM on the same flame and 1200 RPM on a larger flame. I built several other hot air engines using the basic 2" bore beta engine.

https://www.youtube.com/watch?v=iSBXcn4u4es

http://i43.photobucket.com/albums/e358/gary350/allcool2.jpg