Here are three engines that I have for the thrust motors. Two of them both 440 Rotax snowmobile motors.
These 40 HP motors were FREE. All I had to do was to remove them from the sleds. The larger one is a Rotax 640. Not sure of the HP on this one.
640 being broking down for complete rebuild.
All three motors were completely rebuilt by me. They had the cylinders bored and honed.
Two 440 Rotax engines complete.
440 Rotax engine .
The other 440 Rotax engine .
One of these engines is going to be installed in my UH-12T4
I feel the need for MORE POWER.
Here is the 640 Rotax engine.
Look at the difference in cylinder size. 640 Rotax engine.