How do you convert jet engine thrust into Horsepower. Show formula.?

Question

I would like to know how to convert thrust into hosepower, eg. when aeroplane is standing still with engine at full power, is this the same horsepower being developed as when in flight at , say, 500 mph. ?

Answer 1

While the others are strictly correct there is an approximate conversion.

When Frank Whittle was trying to get the RAF to pay attention his engine was producing about 1,000 pounds of thrust. The thing that got the RAF to pay attention was that that's about what a Rolls Royce Merlin was producing in a Spitfire at the time.

So we can say that under limited circumstances it's about 1:1.

Does this bear any sort of examination? One of the difficulties is that when gas turbine cores are put to other uses they are often run at more or less conservative power levels. A Rolls Royce Olympus engine produced about 19,000 pounds of thrust in aircraft uses and 25,000hp in marine uses.

So 1 to 1... sometimes... roughly.

Answer 2

I can't remeber the formula exactly (except I think one horsepower is equal to 33,000 ft lbs/ second).

When you rewrite the formula you put the engine thrust in for pounds and the aircraft velocity in feet per second and you get a horsepower figure.

The horsepower of a stationary jet at full thrust would be zero.

Answer 3

The answer relates to the way in which each of these engines works. Turbojet, turbofan, and/or rocket engines all work by directly accelerating a fluid (air)to produce a thrust force, so it is most straightforward to rate these engines in terms of the size of that force. A piston engine, turboprop, or turboshaft is designed to perform mechanical work that turns a shaft. In other words, the engine creates a torque that is measured in HP>

Answer 4

Aircraft speed in feet/second x thrust in pounds divided by 550. That's why jets are only efficient at higher speeds.

Answer 5

Turbine engines are measured in Thrust because there is no conversion to Horsepower.

Answer 6

The link below has a good explanation. One of the crude conversion factors is 550 lb-ft/s = 1 hp

Answer 7

Propeller driven airplanes and jet airplanes use the power of their engines in completely different ways. There is no reason to convert from one to another.