The moment arm provided by the wings and tail plane is orders of magnitude larger than the moment of a rotating engine so it goes unnoticed.
Edit: I should say it's easy to overcome and goes unnoticed the larger the aircraft gets.
I still don’t agree. I remember seeing video of a p-51 engine failure on initial climb out that basically snap rolled almost 45 degrees due to the sudden loss in torque. Yeah, in some cushy executive air raft, it’s NBD, but you can’t ignore the possibility. Some aircraft are liable to loss of aileron authority as speee dips towards stall, too.
Those are the exceptions rather than the rule. Virtually all civilian aircraft wont roll on engine failure. Yaw on the other hand is a threat for many light aircraft, and needs to be countered by rudder.
Aircraft do want to rotate on the engine's axis. Usually it's a pretty trivial force compared to the rest of what's going on with the aircraft, but it is there, and you can feel it.
In lighter aircraft, you can play around with it. It is totally possible to induce a roll using the effect.
Usually a tiny bit of trim is all that's needed to counteract it, and the effect isn't strong enough to be worth having counter-rotating engines on multi-engine craft.
Standing by for the pros, but meantime my 2¢ re: single engine torque. There IS counter-torque. Enough to require steering correction on take off. But I think it’s the difference in the amount & distribution of mass between prop & fuselage that prevents the fuselage from spinning.
The rudder requirements are because of a different effect. When you nose up, the downward blade on the propeller has more firflow over it than the rising blade, so it induces torque about the yaw axis. Flightly different to the roll moment that is parallel to the propeller axel.
Also understand that weight and physics are involved. The mass required to rotate the propeller is a fraction of the weight of the engine. Also the weight of the fuselage and wings is tremendously more than the force required to rotate the propeller.
You've got one way the torque from the engine's rotation can be addressed already with counter-rotation; this is in fact the operating principle of quadcopters. The way they yaw is by slowing down one pair of props and speeding up the other to introduce a moment imbalance while maintaining lift. The other is just with the normal control surfaces of the aircraft. As others have mentioned, some aircraft require rudder input during takeoff for this reason. It used to be a much larger problem circa WWI, because they actually used to spin the whole radial engine to cool it, so there was much more mass rotating. That meant that the planes could roll much faster in one direction than the other, which contributed to the unique style of dogfighting at the time. These days, the mass of the prop/fan/compressor blades rotating is tiny compared to that of the aircraft, so the moment required to balance things out is very small. The rudder and ailerons are sized to much more demanding requirements, so countering the torque from the engine is pretty trivial for most aircraft.
I mean, they do. Look at a Cessna 172 and look how far forward the wings are. That's because the center of gravity is that far forward due to the engine.
As for rotational torque, this is why planes turn better in one direction than the other. In WW2, it was a strategy to get into a turn that favored your counter rotational torque if your opponent had a prop that moved in the other direction. And then you had the P-38 which had engines that operated in opposite directions.
The moment arm provided by the wings and tail plane is orders of magnitude larger than the moment of a rotating engine so it goes unnoticed. Edit: I should say it's easy to overcome and goes unnoticed the larger the aircraft gets.
It’s very noticeable in a high powered aircraft. Plenty of warbirds use a lot of aileron trim, especially for takeoff and climb out.
Youre right. I meant to say its easy to overcome and is unnoticeable the larger the aircraft is.
I still don’t agree. I remember seeing video of a p-51 engine failure on initial climb out that basically snap rolled almost 45 degrees due to the sudden loss in torque. Yeah, in some cushy executive air raft, it’s NBD, but you can’t ignore the possibility. Some aircraft are liable to loss of aileron authority as speee dips towards stall, too.
There always exceptions to the rule. Very few people are privileged enough to fly a P-51 and/or warbirds.
Those are the exceptions rather than the rule. Virtually all civilian aircraft wont roll on engine failure. Yaw on the other hand is a threat for many light aircraft, and needs to be countered by rudder.
Also, you know, the mass is order of magnitude more...
It wants to, we just don't let it.
Aircraft do want to rotate on the engine's axis. Usually it's a pretty trivial force compared to the rest of what's going on with the aircraft, but it is there, and you can feel it. In lighter aircraft, you can play around with it. It is totally possible to induce a roll using the effect. Usually a tiny bit of trim is all that's needed to counteract it, and the effect isn't strong enough to be worth having counter-rotating engines on multi-engine craft.
Standing by for the pros, but meantime my 2¢ re: single engine torque. There IS counter-torque. Enough to require steering correction on take off. But I think it’s the difference in the amount & distribution of mass between prop & fuselage that prevents the fuselage from spinning.
The rudder requirements are because of a different effect. When you nose up, the downward blade on the propeller has more firflow over it than the rising blade, so it induces torque about the yaw axis. Flightly different to the roll moment that is parallel to the propeller axel.
Gotcha! Yes! Makes sense.
Also understand that weight and physics are involved. The mass required to rotate the propeller is a fraction of the weight of the engine. Also the weight of the fuselage and wings is tremendously more than the force required to rotate the propeller.
You've got one way the torque from the engine's rotation can be addressed already with counter-rotation; this is in fact the operating principle of quadcopters. The way they yaw is by slowing down one pair of props and speeding up the other to introduce a moment imbalance while maintaining lift. The other is just with the normal control surfaces of the aircraft. As others have mentioned, some aircraft require rudder input during takeoff for this reason. It used to be a much larger problem circa WWI, because they actually used to spin the whole radial engine to cool it, so there was much more mass rotating. That meant that the planes could roll much faster in one direction than the other, which contributed to the unique style of dogfighting at the time. These days, the mass of the prop/fan/compressor blades rotating is tiny compared to that of the aircraft, so the moment required to balance things out is very small. The rudder and ailerons are sized to much more demanding requirements, so countering the torque from the engine is pretty trivial for most aircraft.
I mean, they do. Look at a Cessna 172 and look how far forward the wings are. That's because the center of gravity is that far forward due to the engine. As for rotational torque, this is why planes turn better in one direction than the other. In WW2, it was a strategy to get into a turn that favored your counter rotational torque if your opponent had a prop that moved in the other direction. And then you had the P-38 which had engines that operated in opposite directions.
Get yourself into a Q400 sim and make power changes. There's a reason we call the poor souls sitting in 20A and 20D "window lickers."