pavlin
Posts: 391
Joined: Sun Oct 23, 2005 5:34 am

Conversion From Lb To HP (thrust)

Sat May 20, 2006 9:51 pm

We all know that we can't convert directly beetwen one another. But unwritten rule is that 1 lb of thrust equals 2 HP. But there is a big difference when you compare A340 and An-22. They have almost same MTOW 250.000 kg (An-22 has less speed), but the A340-200 has 4 30000 lb thrust engines. AN-22 has 4 15000 HP engines. So the A340-200 would have around 240000 HP versus only 60000HP for An-22 at very similar performance. So why the big difference?
 
timz
Posts: 6114
Joined: Fri Sep 17, 1999 7:43 am

RE: Conversion From Lb To HP (thrust)

Sun May 21, 2006 10:45 am

Quoting Pavlin (Thread starter):
But unwritten rule is that 1 lb of thrust equals 2 HP.

So the An-22 has 30000 lb of thrust by the unwritten rule... which makes its acceleration 1 knot per second at MTOW?
 
pavlin
Posts: 391
Joined: Sun Oct 23, 2005 5:34 am

RE: Conversion From Lb To HP (thrust)

Sun May 21, 2006 6:14 pm

that is way I have written the topic in first place. An-22 has around 60000 horspower. That should do for the acceleration
 
rsbj
Posts: 105
Joined: Sun Jan 29, 2006 4:49 am

RE: Conversion From Lb To HP (thrust)

Sun May 21, 2006 8:51 pm

I've heard the conversion is around 3 to 5 : 1. 2:1 may be accurate at zero airspeed.
Prop decay factors into the equation too. At 0 knots, the ratio would be less than at cruise speed because a prop loses power as speed increases. Turbofans do too, but not as much; though I do not know the percentage differance.
I fly really fast and take a lot of chances.

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