LTD weight ratio?

[fullofhotair]

Is there a weight ratio between the displacer and the flywheel? How light should the flywheel be compared to everything else? This is all in the interest of using the least amount of heat. Is 1 to 8 a good ratio for power piston to displacer diameter? I know everything should be made of light material.

[jimlarsen]

1:8 should be very good. I have made LTD engines with a 1" drive diaphragm with a displacer as small as 4".

The weight of the displacer will contribute to friction and balance. If you can make the displacer very light, you will not need to add a counterbalance. If it is heavier, it will require a counter balance. Adding weight adds friction, so lighter usually works better with LTD engines.

Flywheel design has lots of room for variables. Lighter, smaller flywheels will move faster with lower torque. Heavier or larger flywheels will move slower with greater torque. Heavy flywheels do not accept energy as well as light flywheels, but they have more storage capacity.

I have made LTD engines with thin 1/16" x 4 1/2" flywheels, and with 1/4" x 6" acrylic flywheels. You should plan on experimenting with several options to see which gives you the performance you want.

http://www.youtube.com/watch?v=STTnC6vK ... ozyZpL8hSQ

http://www.youtube.com/watch?v=ABKmm_aB ... ozyZpL8hSQ

http://www.youtube.com/watch?v=2mmSALw8 ... ozyZpL8hSQ