The original post:
Originally Posted by Centaurus
With a turbo-prop single engine aircraft is there any engine torque on take off like there is on a piston engine powered type? There is propeller effect (down going blade etc) that causes a yaw - but engine torque?
Clearly caused a mixed spread of views, but some of you have got it very wrong (LOMCEVAK & RatherBeFlying). As already mentioned, if you have a shaft sticking out of an aeroplane with a propeller attached to it, there will be a torque on said shaft to drive the propeller. This torque is, for given conditions, the same regardless of engine type (piston, turbine, electric, steam, hydraulic). Any 'machine' with a spinning output shaft will be subject to an equal and opposite torque to that applied to the shaft by the load (prop). (Have you seen Wallace & Grommit building the rocket in A Grand Day Out, when the drill bit jam's in the wood being drilled?)
As mentioned earlier, any propeller aircraft is subject to various forces as it takes off: be it prop slipsteam, assymetric thrust etc. But the only
torque effect is produced by the action and reaction to the torque driving the propeller. Watch a car engine when accelerated (in neutral) and you'll see it rock in it's mounts due to the change of torque needed to accelerate and decelerate the moving parts. The engines flywheel is the biggest cause of this.
So back to our aeroplane and the original question; yes there is a torque effect - the engine type is irrelevant (ish). The one caveat being, as I mentioned in an ealier post, the torque needed to accelerate the propeller from idle to full power is not needed if it is already running at a constant speed, like most turbo-prop aircraft. If you watch a big piston start (BBMF Lanc is a good example) you'll see each engine rock in its mounts as it accelerates the big heavy prop to groung idle. The fine pitch and low rpm put almost no aerodynamic load on the prop. It's a TORQUE action/reaction as the engine accelerates the props which are only acting as a flywheel.
