For aeronautics students only...?

Question

I want to know the rate of climb of an airplane at sea level, I know wing geometry, weight, cruise speed and density, number and engines power, I know it can be calculated with the equation: (Power available - power required)/ weight, but my problem is that I don´t know the power available, How can I calculate it? Thrust x Speed? How to measure Thrust?

Answer 1

its way more complicated than you think.

Power available is subject to many variables other than just being at sea level. Temperture, humidity, engine time..

Also aircraft loading, center of graviy, climb gradient, and weight of the a/c can all effect climb gradient.

Also thrust vs speed is also subject to aircraft loading as a aft center of gravity will actually be more efficent on top speed.

With all that being said, it depends on the aircraft. Usually an manufactor will give certain performance data under certain conditons to give pilots knowledge of how the aircraft will perform.

Answer 2

Okay what do you meen sea level, its climbing  , how can you measure it at sea level. You need to specify weight air temperture alttimeter engine and other things.

Answer 3

Sorry--you're oversimplifying several things at once.

And what is "aeronautics?"  Do you mean aeronautical engineering?

Answer 4

Assume something the size of a Cessna 172.  The stock aircraft now comes with a 160 hp engine; the propeller efficiency is about 70% so you have about 112 hp available for propulsion.  The best glide speed is about 70 knots; that's the speed at which the parasitic and induced drag are equal.  In that configuration, the airplane (when gliding) descends at 800 feet per minute; this (times the weight, assume 2500 pounds) gives the total power required to overcome the drag.  Work this out, subtract from the 112 hp available, and get the power available for climb.  Divide by the weight to get the rate of climb, which will be about 700 fpm.  Your mileage may differ.