# Thrust in propeller engines

## Main Question or Discussion Point

Can anyone help me?

I'm doing a question on aircraft propulsion technology and i'm stuck.

The question is:

'If the mass of air through a propeller is 1000 Kg/s, the aircraft's velocity is 100 m/s and the slipstream velocity is 120 m/s, calculate the thrust?

Surely if F = ma then the equation should be F = 1000 * 100 = 10000 Kg/s

But I don't think this is the right answer as I have not taken the slipstream velocity in to consideration.

The only other equation I can find is

F = (m dot * V)e - (m dot * V)0 + (pe - p0) * Ae

But I don't have pe or p0 or Ae neither do I understand what they are.

Can someone please steer me in the right direction?

Thanks

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Hi, with the given conditions, thrust can be calculated by using the formula:
Thrust = Mass airflow X (slipstream velocity-aircraft velocity).
Below website has good information may be it helps you.

http://www.flightlearnings.com/basic-propeller-principles-part-two/384/" [Broken]

Last edited by a moderator:
Thanks very much.

It seems so simple now, just couldn't see it.

Thanks again