OT-Propeller Torque-OT

[randroid]

Gents,

Anybody have a formula for pitch\diameter\wind speed to the torque produced by that prop? Needless to say this is a non-automotive application.

Aero, you out there?

-Randy

[moose]

Are you asking how much torque does the engine produce, or how much torque is exerted on the airframe?

Because those two torques are directly related to each other. The engine produces a certain amount, and then depending on the efficiency of the propellor(might be something like 80%) It is directly applied back to the airframe. Action reaction sort of thing.

Is that what you mean?

[aero3113]

Not 100% sure what you are asking? Is this to choose the correct size prop for a specific aircraft?

[Plymouthy Adams]

I is with the moose on this..explain your application..prop on a possible wind genertor is the first application that came to mind then I fhought of aircraft, followed next by airboast..and lastly the torque/pitch relationship of a boat prop be it for power or speed...

here is a ton of calculators for you to peruse and see if one is suitable to your app..

http://www.csgnetwork.com/converters.html

[Billy Austin]

Randy,

Look up P factor and Gyroscopic Precession.

-Billy-

[randroid]

Gents,

Sorry. I knew exactly what I was talking about so why didn't you?

Hypothetically let's say I have a 12" x 12" prop in a 10 mph wind; how do I calculate the torque generated by that set?

I have an idea for a stationary device that is wind-driven through a propeller. Parts of the device (for the sake of argument let's call it a frog) will move slightly and I want to calculate the size of an airfoil necessary to drive it.

I suppose that should have been my question in the first post but I was (am) on an excitement program about this and was asking questions faster than I was thinking about them.

-Randy

[randroid]

Billy,

I have never studied precession and found that a fascinating read. I began with the Wikipedia models and checked a few other spots but I'm afraid it didn't explain my question. On my theoretical model I can set the precession to zero because I don't anticipate it being a factor, but it was fun to read about it because it's been a while since I've scratched my noggin on a concept new to me. Thanks, but the propeller will not be shifting on its axis other than through sloppy workmanship on my part.

-Randy

[randroid]

Gents,

Thanks for your responses but I may be making too big a deal out of this. I was hoping there might be a quick and dirty solution for this in case I choose to alter the scale of the finished product but I'm not trying to put a man on the moon for the first time. What I'll do is make a mock-up, set it on a table in front of a fan, and see how many grams\ounces\pounds it wants to lift. That will get me in the ballpark, which is about as close as I need to get.

(I just watched the pairs ice dancing freestyle and all I could think about was their application of gyroscopic precession. Think I'll go have a beer and slow it down a notch.)

-Randy