conversion factors

tekman · Post by **tekman** » 23 Jun 2006, 12:26

Probably an old chestnut this one but I gotta ask

Would anyone be able to explain to me in the simplest of mathematical terms how to convert Shaft horse power to foot pounds please.
I realise that Flightsim does not emulate real world dynamics to quite the same degree but I figure getting as accurate data as possible is still a good starting point even if I do have to make adjustments to get it all working properly.
Ok to be fair my algebra is rubbish, therefore the formula I found for this just reads like double dutch.

DispatchDragon · Post by **DispatchDragon** » 23 Jun 2006, 13:03

Peter

Shaft Horse poweer to Foot pounds?????? DO I smell a mamba engined
Marathon in our future???

Leif

DanKH · Post by **DanKH** » 23 Jun 2006, 13:07

You might find what you need here:

http://www.nickles.com/common/convs.asp

tekman · Post by **tekman** » 23 Jun 2006, 18:58

Leif, you're sense of smell is incredible...

Model already completed as indeed is the Alvis upgrade version I said I wouldn't do. May release all three as a package but that does rather depend on getting the mamba flight dynamics sorted as it's a bit too eager to roll at the moment. My fathers working on that aspect.
to the other chap many thanks for the link and I will check it out

regards

Peter

cstorey · Post by **cstorey** » 23 Jun 2006, 19:55

I hope i've got these equations the right way up as I'm doing them from memory

HP = Torque @given rpm X given rpm/5252

so 5252HP = torque X rpm

so torque = 5252X HP /given rpm

e.g. for 2000lb.ft at 10,000 rpm, power is

2000X 10000/ 5252 = 3808 shp

FWIW Chris

tekman · Post by **tekman** » 23 Jun 2006, 21:59

Strewth, wish I could remember things like that off the top of my head!.
Nice one thank you, I'll certainly give it a try and let you know if it worked
Cheers

Peter

TobyV · Post by **TobyV** » 23 Jun 2006, 23:16

tekman... not sure quite of conversion factor because I work in metric, but beware that SHP is a measurement of Power and that Foot-Pounds is a measurement of torque (force applied around an axis), so the two things are not equivalent quantities. Only when a force (torque) is multiplied by a velocity (in this case rotational velocity) do you get a value for power

tekman · Post by **tekman** » 24 Jun 2006, 15:03

Fair do's Toby and point taken. However although the formula previously posted I believe gave me my SHP which I already knew I managed to convert it to a workable foot pounds and touch wood apart from a little lack of top end speed, she's now stable on the ground. The formula still gave me a breakthrough as It led me into other area's which needed a little tweaking.
Having said that, it's Microsofts way of doing things and it's all too easy to fall into the trap of making it even more complicated than it needs to be.
I've learn't that a certain amount of compromise is required to get as close to real world figures as possible and also taking into account that flightsim doesn't employ totally true aerodynamics.
If it takes off, Flies and lands within acceptable parameters then hopefully most people should be quite happy with the performance.

Cheers
Peter

d0mokun · Post by **d0mokun** » 24 Jun 2006, 15:36

Peter,

Could you PM me please regarding the Mamba data- i'm trying to do exactly the same conversions for the Gannet but can't work my way around it..

Many thanks
Dan.

Post by **Rick Piper** » 24 Jun 2006, 16:38

:sad:

I don't remember Alphasim helping any of us with data or anything that i can remember.

I only send info to freeware developers.
If you want to charge for models you have to do your own homework.

Rick