Probably difficult to find something off-the-shelf that would be suitable for aviation because industrial units are typically heavy.What is the best way to do contra-rotating propellers? Are there any off-the-shelf kits that can be used to modify an existing propeller-hub-shaft assembly?
=very light and simple (circa 3 kg/100 HP)a differential gearset
Now I am confused. The leading prop seems to be solid drive from the hub/gearbox but the trailing prop only driven from an open set of bevel gears (open diff). The only torque it could transmit would be from frictional losses in the spider gears and their bearings (clearly demonstrated in the video).=yes,CR, but NOT differential...
=loses are very small =at 70 HP (G13) temperature of litle gear <50 deg.Celsi...The only torque it could transmit would be from frictional losses in the spider gears and their bearings
If A rotates and C is fixed then B will rotate in opposite direction.What is being driven and what is driving what?
=coloures and indexes are right,If you drive through A and attach a prop to C and another prop to B
then if the load on each is equal prop C will turn the same way as input and prop B will turn the other way.
Thanks Henryk I have edited my post.=coloures and indexes are right,
INPUT (crancshaft) on "B", f.e. 6000 RPM,
AUTPUT "C" (propeller "A")=2000 RPM (the same direction),
AUTPUT "A" (propeller "B") =2000 RPM (opposite direction).
If A rotates and C is fixed then B will rotate in opposite direction."
"If A rotates and B is fixed then unit C will rotate in opposite direction to input. "
=on video "hand propeller breaking"=
"A"(propeller "B") stopped, propeller "A" rotate 3000 RPM !
From the airboat world, a company called Rotator used to sell them. Don't know if they still do.
=I was "hand breaking" inner propeller too,but not so easy (asymmetrical !)I can see that would allow stopping the outer prop and holding it,
6,000 rpm is common in automobile and motorcycle engines.Probably difficult to find something off-the-shelf that would be suitable for aviation because industrial units are typically heavy.
They require sophisticated components ... a differential gearset to reverse one shaft ... plus one shaft turns inside the other so at 3000 prop rpm the internal support bearings are seeing 6000 rpm .... not stuff easily found at your local bearing supply store.
Good luck with your experiments.