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

### Conversion From Lb To HP (thrust)

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: 6318
Joined: Fri Sep 17, 1999 7:43 am

### RE: Conversion From Lb To HP (thrust)

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

### RE: Conversion From Lb To HP (thrust)

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)

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.

### Who is online

Users browsing this forum: CCA, MUHAMMADYUSUF and 18 guests

### Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos