A right angle gear box starts to look attractive. Probably a billet
case, bevel gear and pinon and perhaps the end bell from a mini sprint
car quick change rear end. The pinion would be driven by belts from
the engine. It is an ideal way to drive the tail rotor shaft as well.
This is the basic way almost all horizontal engine helicopter drive
trains are set up. The gear box does not need to contain the main
rotor shaft. If the heli is small it can drive a final belt drive (see
Mosquito) which is not a bad system.

I may try the one of the vertical engines mentioned because I have a
helicopter that used a vertical Rotax 582 two stroker, but I'm looking
seriously at a right angle gear box arrangement too. Then, a single
rotor Mazda looks like a possibility, but maximum weight reduction
will be needed. That leads me to new questions. By the way, the
engines are becoming more interesting than the helicopter itself.

John McEverett


Why not use a rear-end from a car to turn the drive 90 degrees to vertical
and then you could leave the engine horizontal;
Strange engineering has specialized Ford 9 inch diffs that have a 'spool'
(differential part removed)
Get a Ford 9" and buy a spool shaft for $49 to lock the diff. They also have
aluminum versions.
Then use a belt reduction to proper speed.

BrianG
Iowa


Too big and heavy. We don't need the 800 HP these 9 incher are
capable of. That is why we are looking at the mini sprint car rear endsd.

Paul Lamar