PDA

View Full Version : Want to But Brushless motors on Sailplanes


Armound
08-11-2005, 08:15 PM
Hi Folks, We have the following sailplanes, "Wanderer, Soar Birdy, And a Gentle Lady." Any suggestion on how we can put brushless motors, Li-Poly batteries on these planes. Want to do some Aerial photography using the Blip camera. Camera weight is 65 Grams. Was told by a hobby store that we could snap the wing. Thought of Carl Goldburgs Electric Pod. Per them the Pod is Glude to the wing. Building the Slow Stick from GWS.
Thank You

Armound & Anna :)

Darrell_F
08-11-2005, 10:09 PM
Just cut the nose off, add a very well reinforced ply 'firewall' and mount a motor. Mount your firewall or motor so that you have about 5 or 6 degrees of downthrust. On a 2 meter sailplane, I use an AXI 2808, CC 25 ESC, 3S-2100 li-poly, 9X6 folding prop. I get at least 10 flights to altitude. It's nearly vertical climbs.

Hobby store is wrong about snapping wings. Flying up with a motor puts far less stress on wings than winch or hi-start launch. Motor in nose is better and easier than pod; less thrust problem.

Following are some photos of a Wanderer that I converted to electric.

Darrell_F

Darrell_F
08-11-2005, 11:01 PM
I cut at about 6 degrees for down thrust.

Darrell_F
08-11-2005, 11:03 PM
Use epoxy and reinforcement as the brushless has a lot of thrust. The wire running across the back of the motor is to keep the motor power supply wires off the motor. The cross member was added to prevent the battery from sliding forward into the motor. I also added a piece of balsa for the battery as the fuselage was rather thin for the weight of the battery

Darrell_F
08-11-2005, 11:07 PM
I used hook and loop fastner to hold battery in place.

Darrell_F
08-11-2005, 11:08 PM
Check the motor spec to get the correct size prop for the motor/battery combo that you have. For my Axi 2808 I used 9X6 and 10X6. Correct your COG by moving battery.
Go fly!!

If you buy new motor, ESC, and 3S li-poly, expect to pay around $175. With careful shopping for used items, you can get by with about one half of that.

Armound
08-11-2005, 11:50 PM
Hi Darrell, Many thanks for the info and photos. I would like to keep in contact with you and have you as a mentor. meyerrm@bacavalley.com
A few years ago I was in the precess of doing just what you showed and told us. We are retired folks and it sure is great to be retired. I will take inventory and let you know what I have as a motor, prop and etc. My biggest problem is how to set up the down thrus angel and etc. If you don't mind, I will copy your photos and study them. Thanks again. New to this Fantastic Form. I see that Your on Line. Going to give it a shot before I get a call for dinner.
Very Best Regards
Armound & Anna

Darrell_F
08-11-2005, 11:59 PM
I've been called a lot of things, but very seldom called a mentor. There are a number of motors other than AXI that will work, just try for something that will provide enough thrust for the weight of your glider. A good start for thrust alignment is 6 degrees down and 2 or 3 right. That may sound like a lot of down thrust, but I still have to hold a little down elevator at full throttle. I did it by installing firewall with appropriate angles, but you could also install the firewall straight and just use washers under your motor to get the thrust angle.

I'll be glad to offer any advice that I can.

Sky Sharkster
08-12-2005, 01:56 AM
Hi Armound, welcome to E-Flying! First I want to say that Darrell gave you some very good advice, I have a similar set-up (AXI 2808/16, 9 X 6 CAM folder) on a 2 meter glider called the "Glassaire" and it flies great. On the downthrust angle, this can be hard to figure on a fuselage that's already built but you can try taping the motor and battery on the outside of the fuse, sliding them forward and back until you get the correct C.G. Mark on the nose where you need to cut to to install the motor. Now lay the fuse on it's side on your board-the stab will have to hang off the edge to get the fuse (nose) flat. Mark a line that is horizontal along the nose-like a thrust line. You can use the stab bottom as a reference. You only need this line on the front 6" inches of the nose. Get a protractor and set the long edge on the line, the 90 degree line of the protractor should be over the mark to cut off the nose. You will see the angle for 5-6 degrees downthrust easily. Mark this line carefully. Now do the same thing on the TOP of the nose and add 2-3 degrees RIGHT thrust. That's where to cut the nose and add firewall. For a front mounted outrunner it's easier to drill the mounting holes before gluing the firewall on. A last suggestion for motors (don't get me wrong, I love my AXI's!) is the Plettenberg Typhoon-Micro 15/10. It sounds like you will need more than one motor! These are $ 75.00 from http://www.icare-rc.com Good Luck, Ron

Armound
08-12-2005, 03:28 PM
I've been called a lot of things, but very seldom called a mentor. There are a number of motors other than AXI that will work, just try for something that will provide enough thrust for the weight of your glider. A good start for thrust alignment is 6 degrees down and 2 or 3 right. That may sound like a lot of down thrust, but I still have to hold a little down elevator at full throttle. I did it by installing firewall with appropriate angles, but you could also install the firewall straight and just use washers under your motor to get the thrust angle.

I'll be glad to offer any advice that I can.

(You might want to go back and edit your post to remove your phone number. Too many nuts on the internet to let them have your number that easily.)

Darrell, thanks for the return reply and the advice on phone.
Very Best Regards
Armound & Anna

Armound
08-12-2005, 03:41 PM
Hi Ron, Many thanks for your information. And thanks for the welcome and Good Luck to E Flying. If I have senior moment and get lost, we may drive to Denver and buy you lunch with you. Will be in touch and let you know the progress. Have to get the motor and etc.
Very Best Regards

Armound & Anna

Tucson Don
02-27-2006, 02:17 PM
I have an AXI 2820 in a Sig "Riser'. With a Graupner folding Prop it
goes like a mad bat. Lots more power than I need, but flies great.
Don

Armound
02-27-2006, 08:11 PM
I have an AXI 2820 in a Sig "Riser'. With a Graupner folding Prop it
goes like a mad bat. Lots more power than I need, but flies great.
Don

Hi Donald Santee, thanks for the info.
Armound :)