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Radio Control Forum => Electrics => Topic started by: Starduster on January 06, 2018, 06:06:23 PM



Title: Motor/Folding prop combo for old-school 2m sailplane
Post by: Starduster on January 06, 2018, 06:06:23 PM
I picked up a old kit for an all balsa (some Spruce) 84 inch sailplane (Competition Models "Easy Riser")

I'm going to stick an electric on the nose. Don't need (or want) Rocket like performance, just enough to get it to altitude.

Any suggestions for a motor? I will be using the same battery pack(s) that I use for my Free Flight "A" size airplanes - 3S 1350mAh

Thanks
Rich


Title: Re: Motor/Folding prop combo for old-school 2m sailplane
Post by: steveair2 on January 06, 2018, 08:23:15 PM
This thread may help.  http://www.rcuniverse.com/forum/rc-gliders-sailplanes-slope-soaring-112/11625479-building-carl-goldberg-gentle-lady-electric.html



Title: Re: Motor/Folding prop combo for old-school 2m sailplane
Post by: Konrad on January 06, 2018, 08:23:47 PM
3 cell 1300 mAh is looking like a Speed 400 to Park 480 size power plant. Do you want a slow steady vertical climb (to keep the wing out of flutter)? Do you want some pitch speed to perform aerobatics? What weight do you think the ship will have?

Old school sounds to me as something like an Astro Challenger. I flew one in the early 80's on 8.4 volt drawing about 25 amps (200 watts). Later upgraded to an Astro 05 FAI drawing 30 amps (250 watts).  On 250 watts and an 11x8 Aeronaut prop I could climb at a slow 70° plus angle.

The power system found on the foam ARFs like the Radian 2 meter or the Calypso 1.8 meter should do.


Title: Re: Motor/Folding prop combo for old-school 2m sailplane
Post by: lincoln on January 07, 2018, 04:20:34 AM
Concur that Radian package is probably good. Maybe more powerful than you need. The prop assembly could be more robust, so you might want to use something else for that. I suspect there are less expensive options.

If you need nose weight, the Astro 035 cobalt geared can sometimes be found on ebay. Just use a smaller prop than would be used with 7 nicads. If you really need nose weight, and the nose is fat, there's the 05 geared.