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Old Jan 14, 2003, 09:49 PM
Registered User
Sandston Va USA
Joined Mar 2001
294 Posts
Watts per pound

I was just wondering what the rule was on how many watts per pound a motor needed to supply to give a plane very good vertical or unlimited vertical.
Thanks..
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Old Jan 14, 2003, 09:58 PM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
Well, I have two planes that are just about 100 W/lb and they have what I would call very good vertical, but not unlimited. I'm thinking 120 W/lb is probably the starting point for unlimited.


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Old Jan 14, 2003, 10:22 PM
Registered User
Lambertville,nj, usa
Joined May 2000
352 Posts
400 watts/Lb makes for an extremely agressive climb rate. My F5B surprise is at the limits of visibility in @ 9-10 seconds. 150-200 watts/Lb will usually give unlimited vertical, just not @ 80 MPH!

Ed
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Old Jan 15, 2003, 06:37 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
Ah, Ed beat me to it.

You can get unlimited vertical at 50W/lb or less, but only with the right design - many small heli's can do it, for example! There is no guideline for vertical performance, but the *calc programs can help you here. Look for thrust at pitch speed to exceed model weight, and you'll have the performance you're looking for.

..a
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Old Jan 15, 2003, 08:32 AM
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Steve McBride's Avatar
Agra, Oklahoma
Joined Feb 2000
5,390 Posts
Quote:
Originally posted by Andy W
(stuff deleted) Look for thrust at pitch speed to exceed model weight, and you'll have the performance you're looking for.

..a
And don't forget to make sure pitch speed is a couple times above stall Unless you are making a helicopter.......

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Old Jan 15, 2003, 09:03 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
.. oh yeah, that too!
..a
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