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Old Dec 15, 2002, 10:21 PM
Registered User
Hong Kong, Kowloon, Hung Hom
Joined May 1999
115 Posts
power system for 5-6 oz twin

I'm looking to make a differential thrust flyer with an AUW of around 5-6 ounces. I plan on using nimhs and am hoping that i can get a duration of more than 7 minutes. any ideas for the power system? would 2 geared n20's do the trick? what about something direct-drive?

Sean
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Old Dec 16, 2002, 09:51 AM
Registered User
Walled Lake, MI, USA
Joined Feb 2000
11,182 Posts
Two GWS IPS motors with 3x2 props would weigh a little over 1 oz. total (the weight listed on the GWS site is incorrect; these motors weigh ~.5 oz. each, not .25 oz.) and produce a total of ~4 oz. thrust @ 7.2V.

http://www.gws.com.tw/english/produc...stem/edp50.htm
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Old Dec 16, 2002, 11:25 AM
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Fly_joy's Avatar
Rochester, NY
Joined Mar 2001
226 Posts
For a slowflyer with low wingloading I think the geared n-20's would be a good choice.

Lithium-poly cells will give good duration.

For comparison. I have a 2.6oz plane on a single geared n-20 that flys for 8 minutes. http://www.rcgroups.com/forums/showt...threadid=71947



Larry
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Old Dec 16, 2002, 12:10 PM
Fly Backwards
hcopter's Avatar
Pittsburg KS, USA
Joined Dec 2000
810 Posts
Twin pizza box

I have a twin pizza box using two GWS "A" motors set up with differential thrust on the rudder stick. It weighs around 6.5 oz flying it with a 2 cell Kokam 1020. Hovers just over 1/2 throttle and will just hang there torque rolling for as long as I can keep up with it (a little over a minute was my longest so far).
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Old Dec 17, 2002, 02:40 PM
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billwhit's Avatar
Seattle, Wa
Joined Dec 2002
2,263 Posts
HCOPTER
How did you set up your differencial thrust? Is there a place you can buy an ESC to do it?
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Old Dec 28, 2002, 06:11 AM
Mie oo Karjala poikii
Tyson's Avatar
Ruokolahti, Finland
Joined Apr 2001
704 Posts
How about GWS LPS-B2C http://www.gws.com.tw/english/produc...stem/012-4.htm

I am using 2 of those (A-gear) on my profile P-61. AUW is 125 grams (4.4 oz) with 2-cell 560mAh Li-Poly pack.

-=Mike=-
http://www.careliawin.com/tyson
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Old Dec 28, 2002, 03:33 PM
Fly Backwards
hcopter's Avatar
Pittsburg KS, USA
Joined Dec 2000
810 Posts
dual esc

billwhit,

I simply used two GWS esc's, made up a Y connector to plug both into the battery. Plugged one esc into throttle channel and the other into rudder channel. I then mixed rudder (slave) to throttle (master) so both motors power up with the throttle stick, then created a second mix of throttle (slave) rudder (master) which provides the differential thrust when rudder stick is moved. On initial flight the "rudder" was very touchy so I put in 80% expo on rudder channel to soften it yet leave me full differential thrust at max stick deflection.

Hope that's not too confusing of a description

Mike
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Old Dec 28, 2002, 08:41 PM
bob h
Oklahoma
Joined Oct 2001
88 Posts
Hi Mike,
Did you make it up to Springfield Friday? Sure wanted to but had other things to do. Darn!

What transmitter are you using to get a double mix set up? I have a Hitec Eclipse and don't think it will do that. I have been trying to figure out how to set up a twin but it's a no-go so far.
Bob H
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Old Dec 28, 2002, 10:05 PM
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Allan Wright's Avatar
Lee, NH, USA
Joined Jun 2001
5,188 Posts
6 ounce twin will fly great on 2 direct drive N-20 motors with B-2 props on 7 cells (280 NiMh would be good).

Worked great on this plane at just under 7 ounces:



http://pease1.sr.unh.edu/aew/rc/EmiteTwin/
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Last edited by Allan Wright; Dec 28, 2002 at 10:07 PM.
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Old Dec 28, 2002, 11:49 PM
Registered User
Hong Kong, Kowloon, Hung Hom
Joined May 1999
115 Posts
this is exactly what I was hoping for. Are those N20's the high voltage GWS "B2" types or the low voltage surplus kind? How is flight performance? what kind of duration do you get(on what batts) ? also, wing span area?
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Old Dec 29, 2002, 12:04 AM
Fly Backwards
hcopter's Avatar
Pittsburg KS, USA
Joined Dec 2000
810 Posts
Mix

Hi Bob,
Yes I did make Springfield, missed seeing the gyrocopter fly again. I may go over Tuesday morning for their normaly scheduled flying time.

I have a JR 8103 Tx, not sure about the Eclipse, thought it had multiple mixes, but they may have the channels factory assigned. I need to ask Troy, he has an Eclipse.

Mike
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