[Dantheman62]

I like the motor because he's done away with valves, camshafts, and rocker arm assembly, so there's a lot less moving parts. But I have a ton of questions!
How is it cooled?
How is it lubricated?
Testing it on air only, provides no proof of reliability.
True reliability tests can only come from running it on fuel, so then you'll have heat and lubrication and torque during constant running under load and full throttle to test the real reliability of the motor.
I like the fact that it develops high horsepower at low rpm, very similar to a diesel engine which in turn should make it last longer!

Jnana, you mentioned power-to-weight ratio which is really the whole key here.
If we didn't have 4,000 lb. cars and trucks we wouldn't need so much horsepower.

As far as getting 2 to 4 horsepower out of a small 2 inch motor, that's been done for a long time now and in fact I've got several in my house now! They power my radio controlled trucks that I have and run on nitro-methane fuel.