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Old Oct 18, 2004, 09:22 AM
Quit Chucking My Wood
rthorne's Avatar
USA, TX, Amarillo
Joined Dec 2003
1,263 Posts
Scale Conversion: Watts to Weight Ratio?

I'm in the process of determining which motor/battery combo to put in an HF Model ASW28 3 meter bird. I'd like to run an AXI 2826/10 or /12 with a 3s2p 2200 lithium pack

I'm not looking for a rocket ship, just something to get it up in the air a couple of times so I can thermal around.

I was thinking that 50 watts per pound ought to handle it.

Whats the wisdom of this group think?


Thanks

Rich
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Old Oct 18, 2004, 01:20 PM
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Lenny970's Avatar
Greeley, Colorado, USA
Joined Feb 2000
2,790 Posts
Rich,
I've converted several (3.5-6.6 meter) scale sailplanes to electric. I generally design the power system for about 75 watts per pound. This gives a strong, not rocket ship climb rate. I'd guess the typical climb angle would be around 30 degrees. I'm sure you could safely use something less than 75, but 50 watts per pound sounds a bit low to me.

Good luck,
Lenny
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Old Oct 18, 2004, 02:36 PM
Quit Chucking My Wood
rthorne's Avatar
USA, TX, Amarillo
Joined Dec 2003
1,263 Posts
Hi Lenny:

Thats what I needed to know.

I have a AXI 4120-18 on a Hanger 9 Funtanna with 6s2p 2200 irate cells. However, I think the motor is too big as well as the batteries from a weight stand point.

What do you recommend for a motor and/or gear box combination to put in a 80 to 90 oz scale bird?\

Rich
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Old Oct 20, 2004, 08:05 AM
Gustavo Exel
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Switzerland, GE, Geneva
Joined May 2003
1,763 Posts
Quote:
Originally Posted by Lenny970
I'm sure you could safely use something less than 75, but 50 watts per pound sounds a bit low to me.
Hello,

Are you speaking motor input or output watts ?
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Old Oct 20, 2004, 09:30 AM
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Andy W's Avatar
Marietta, GA
Joined Jun 1999
43,312 Posts
We use input watts..
..a
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