Russian AV-60K propeller manual
- Thread starter Tzaw1
- Start date
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
Really thanks to Tzaw1. This is manual directly of construction maintenance of counterrotating AV-60K propeller. It says absolutly nothing regarding reduction gear box, which I think relates to the engine.
Last edited:
I am pleased to have the manual. The reason I asked about the gear is that once I saw a video in which a ground personnel turns the propeller of a parked Tu-95 or 142 by his hands where the forward and the rear propeller turn independently and there seemed no such a "geared" motion was observed.
The turbine drives the sun gear of a compound planetary gear. The sun has 36 teeth, and it meshes with the 48-tooth side of the planets. The other side of the planets has 24 teeth, which meshes with a 93-tooth ring gear (I assume the teeth are a different size on the second mesh, since the radii don't add up).
One propeller is fixed to the planet carrier, and the other is fixed to the ring gear. Hence, they must rotate in different directions if they rotate at all. The only thing that makes them both rotate is that each absorbs torque which feeds into the gear and forces the other free part to rotate.
On startup, the forward prop generates about 120% of the torque of the aft prop, which has been mistaken for them having gearing to rotate at different rates. With identical torque on each propeller, they will rotate in opposite directions at a reduction from the input shaft of 11.33:1. In-flight, torque balance is maintained by adjusting blade pitch...increasing pitch on one prop increases torque on that prop, which slows it down and speeds up the other prop. I don't know to what extent this control is compensated through some mechanical or electric system, or if is controlled by the crew. I can imagine having a control for each engine for absolute (both props) pitch, and a fine control for relative (one prop to the other) pitch.
