View Full Version : Brushed to Brushless Upgrade

06-18-2006, 03:21 PM
I have an old 2- channel sailplane I used to launch with a hi start that I would like to motorize. I've been considering mounting a brushless motor on the front- the model has a solid bulkhead that could easily be strengthened to handle the motor. I would plan to use Li battery packs to power the model. I also want to attach a folding prop directly to the motor if that would be suitable...

I expect the model will weigh about 900 gm when fitted with motor and battery.

I don't want to do anything fancy with the model, just get it up to a decent altitude and then shut it down for soraring and to have a simple aircraft to teach my young boys how to fly RC.

Does anyone have suggestions on the appropriate brushless motor and prop combination that would suit this situation? Thanks for your assistance,


Sky Sharkster
06-19-2006, 02:00 AM
Hello JCB, Welcome to Wattflyer! For your glider conversion, I would suggest an "Outrunner" B/L, they are fairly easy to mount with available radial mounts and don't need a gearbox to swing a reasonably large prop. If your sailplane is (I'm guessing) a 2 meter you're looking for the B/L equivilent of a "Speed" 600 or so. There's lots of choices in this size, I've selected two "packages", one is the low cost option, the other is near the high end, both in quality and price.

BP 2915-5D Outrunner KV 1100, Max Voltage 12.6V, Max Current 40A, Max Watts 450W, Weight 123gr/4.32oz. Price $49.95
BP 40A Brushless ESC Price $44.95
Total $94.90 + S+H

AXI 2808/16 Brushless Outrunner Price $76.90 + Radial Mount $14.50=$91.40
Jeti 30A B/L ESC, Combo package w/AXI 2806/16 $142.00+radial mount ($14.50) = $156.50
www.hobby-lobby.com (http://www.hobby-lobby.com)

Another great choice for ESC's is the Castle Creations Phoenix-35 B/L ESC. BPHobbies has these for $84.96. This will work with either motor.
Both motors will swing a 9" x 6" folding prop, I recomend the CAM series from Hobby-Lobby. Whatever motor you decide on, make sure the prop shaft size matches the diameter of the prop hub, they're available in several sizes.
Well, this will give you a "range" of prices, there's sure to be other suggestions. Good Luck!

06-19-2006, 01:40 PM

In your situation where you only need power to get up there (LMR=limited motor run) I have had success with a brushed motor and gearbox purchased from Tower. Did a search there and they no longer carry the Kyosho Magnetic Mayhem. Was about $20. So much for that idea.

Might suggest you check out Dymond Motorsports

www.rc-dymond.com (http://www.rc-dymond.com)

The owner, Helmut, is very good at setting up sailplanes with power and his prices are great. He also carries most folding props and the necessary adaptors, yokes,spinners, etc. Also good prices on lipos.


06-20-2006, 07:29 AM
Look at the Graupner Sytems at Hobby Lobby. You know the weight of your plane, so go there and find the motor that would carry your plane. You do didn't say what you had, size wise, so there is a guide line there.

They do have support that can advise you of what would be a good setup for you.

This is the direct drive group that I am sending you to.


Try it you might like it.....:)

EDIT: With this system everything fits, collets spinners and all. It is a set.

07-04-2006, 05:20 AM
You might find some useful tips in these threads.

Sizing Electric Power Systems - Starts at post 2
http://www.rcuniverse.com/forum/m_4304029/anchors_4310056/mpage_1/key_/anchor/tm.htm#4310056 (http://www.rcuniverse.com/forum/m_4304029/anchors_4310056/mpage_1/key_/anchor/tm.htm#4310056)

Spectra Select & e-Aspire
http://www.rcuniverse.com/forum/m_3274520/tm.htm (http://www.rcuniverse.com/forum/m_3274520/tm.htm)
http://www.rcgroups.com/forums/showthread.php?t=406132 (http://www.rcgroups.com/forums/showthread.php?t=406132)
http://www.wattflyer.com/forums/showthread.php?t=593 (http://www.wattflyer.com/forums/showthread.php?t=593)

07-06-2006, 03:18 PM
a 45 to 75 grams outrunner would do the job.

I Fly a Easyglider on a Typhoon 6/3D (35 grams 1500KV) with a 8,5x4,5 folder prop. 1100mah (90 grams) lipo. Total weight 760grams. Fly's nice.

Don't take a to large motor, becaust the weight wil stack up fast....
Large motor needs a big lipo, just go for the sweet spot. 120/150W/kg.
And keep thinking light. It'll stil have to glide, right..