Question for turbo prop pilots

[no1pilot2000]

What is torque as it relates to a turbo prop?

Thanks.

 

[Kaman]

Torque is a measurement of twist measured in foot pounds typically or a percentage...It is also from a physics point of view a measurement of "work". Chemical energy converted into heat and kinetic energy.

 

[kf4amu]

I don't think torque is work. You need motion for work.

 

[Flyin2low]

Torque is the amount of power usually expressed in %. Pratt / Whitney likes to use it.

 

[SpauldingSmails]

What is torque as it relates to a turbo prop?

Thanks.

Torque is a measure of force. In the case of a turboprop we are measuring the force which the engine exerts upon the shaft that drives the propeller, or prop gearbox.

Power is computed by multiplying the torque that an engine produces by its rotational speed at it's drive shaft.

In simple terms of operation, in most turboprops, torque is the primary indication that the pilot will use for setting power for take-off, climb, cruise, descent, approach and landing.

If you're familiar with a piston engine aircraft equipped with a constant speed prop - you set the manifold pressure with the throttle and then set the propeller speed to maintain a desired power setting.

Torque, although a completely different type of measurement, would be the analog of setting manifold pressure in a piston engine airplane with a constant speed propeller.

There are many variations of engine control schemes for turboprops with regard to what levers control what, many aircraft combine functions power and propeller control.

Most basic turboprop engines use three levers to control their function: power lever - used to set torque, prop lever - used to propeller speed, and a condition lever - used to set the idle speed of the engine and function as a fuel cut-off lever. The power levers also usually provide for a propeller reversal setting (beta) to help slow the aircraft on the ground, and the prop lever will allow for feathering of the propeller.

 

[pilotyip]

Torque ='s Shaft Horse Power. We had a gauge on the L-188, CV-580 and P-3 that measured the Horsepower out put of each engine, same engine a C-130 measured it in foot pounds. P-3's L-188's and CV-580 had one lever for each engine like a jet.

 

[SpauldingSmails]

Double posted - disregard.

 

[Golden Falcon]

torque is a force extracted from a rotating power source...a car engine in neutral has no load on it, so the engine is not supplying any torque...a propellor spinning in a Piper Cherokee in idle is demanding no, or very little torque from the engine...as the throttle is opened and the rpm increases, the propellor creates thrust, which in turn causes drag, and the engine has to work to turn the propellor...this "work" is torque...turboprobs tend to have two engine operating limitations...temperature...due to internal metallurgy/construction of the engine, and a torque limit due to strength of the reduction gearbox on a cold day most turboprops will reach the torque limit before the temp limit..higher density altitudes/ambient temperatures the temp limit may be reached first...

 

[livin'thesim]

Real pilots fly props - down in the weather, in non-radar areas, etc.

Jet pilots are just a bunch of coffee-sipping dandies. And yes, I fly a jet.

 

[wms]

Force- amount of energy needed to change the state of motion of an object.
Work=force x distance
Power= f • d divided by time
HP = force x speed divided by 550
Comparison of thrust is HP= thrust • velocity in kts divided by 325.
Torque is a value some manufacturers use to determine percentage of power produced.