gosleddog
Well-Known Member
Ok - for non counter-rotating, standard configuration (wing mounted) engines, with 2 bladed prop, typically the right engine's produces more thrust from the outboard prop as it is headed "down" - and has a longer arm from the CG, which means that the left engine is critical, anyone that has gone through multi training has learned this. In all the material that I have found on this, there is no mention of the impact that a 3 bladed prop has on the equation. To me, it seems like in a 2 blade prop, it is straightforward, the prop headed down will crank more thrust. In a 3 blade, the "most outboard" prop while coming through the down stroke has 2 blades that are inboard, and that the 2 blades should be more than enough to counteract the "advantage" that the down stroke blade attains. Not only that, it seems like that by having the 3 blades, the thrust is coming from more ( a higher percentage of ...) the entire prop arc, and that this keeps the thrust more uniform.
On the other hand, on the dead engine, until it is feathered, the impact of the 3 blades windmilling is a much higher producer of drag, and that it will increase the yawing moment / need for counteracting rudder force.
This is just an academic exercise for me, as its not likely to be an examiner question. I would have thought that there would be some mention of it in the text books, and what not. (All "real" twins have 3 blade props, so someone must have real info on it!)
On the other hand, on the dead engine, until it is feathered, the impact of the 3 blades windmilling is a much higher producer of drag, and that it will increase the yawing moment / need for counteracting rudder force.
This is just an academic exercise for me, as its not likely to be an examiner question. I would have thought that there would be some mention of it in the text books, and what not. (All "real" twins have 3 blade props, so someone must have real info on it!)
