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sizing elec by thrust outpu

Old 06-30-2003, 05:17 PM
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Default sizing elec by thrust outpu

Hy there,

I should size an electrical motor by thrust. I want something that output about 35 lbs. I have already checked MotoCalc but I can't have this option to search for suitable motors. Furthermore, though I'm a completely newbie to electrical motors, I believe a motor of that output is a bit difficult to find, isn't it?

I would appreciate very much if you could please shed some light over this matter and provide a list of possible engines/manufacturer and prop configurations to satisfy the above requirement.

Another critical point would be flight time. What would be the mean availabe flight length with such configuration? I accept trading off weight with flight time.

Thanx very much in advance,
Biga
Old 07-02-2003, 02:10 PM
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Default sizing elec by thrust outpu

No, you should NOT size motors by thrust alone. You also need to consider pitch speed.

Pitch speed is the pitch of the propeller multiplied by the RPM of the motor. It's the theoretical maximum speed at which the airplane can fly. Generally, the plane will be slower because of drag, but you get the idea.

For example, you have a 27lb airplane with a stall speed of 23 MPH. You put an electric motor on it that produces 35lb of thrust, but only has a pitch speed of 19 MPH. The plane will not fly.
Old 07-02-2003, 04:17 PM
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Default sizing elec by thrust outpu

Thanks, mkirsch

Actually, I'm not interested in this motor for an aeroplane configuration. It's much more like a helicopter or something. I want to place the motor aligned with the vertical line, along with the weight vector direction. That's why I should need to size it in terms of the weight lifting capability.

The resulting speed will be determined by the props pace, as you've properly placed.

Have you got any clue about possible engines to satisfy this necessity (need, for americans )?

Thanks once again,
Biga
Old 07-03-2003, 12:02 AM
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Default sizing elec by thrust outpu

200 watts is about 71" lbs 565"= 35lbs you are looking at about
1600 watts that is a lot of poop about 40 oz's of motor alone
that's not a model but a UAV WOW. CU
Old 07-03-2003, 12:57 PM
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Default sizing elec by thrust outpu

Geez! You've got it... it's much more like a UAV indeed!

As I'm a newbie on the electric motor subject, I didn't quite understand those numbers you've writen. However, I believe it is important to know them, so could you please explain it to me? =D
Old 07-03-2003, 01:21 PM
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Default sizing elec by thrust outpu

Take a look at the LRK site also look under ebay sports, scooters
there are some big ones that are brushless exposie 2 or 3 stators
togeather. Poke around some.
[email protected] CU
Old 07-03-2003, 02:01 PM
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Default sizing elec by thrust outpu

Thanks for your reply,
Could you please give the internet address of this LRK site? =D
I'll surely check under ebay too.
Thanx,
Biga
Old 07-03-2003, 04:39 PM
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Default sizing elec by thrust outpu

I am sorry I missed the LRK site. CU
http://groups.yahoo.com/group/lrk-torquemax/

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