Great Planes 81" Cub - Electric Conversion

[whizzard]

I got a Great Planes 81" Cloth Covered Cub for Christmas .

Since I am only flying electric planes I also got:
E-Flight Power 46 Outrunner Motor
Jeti 75A ESC
35A UBEC
4 Standard Futaba Servos
APC 13X8 E Prop

I am using 2 2100mAh 3s 11.1V 15C Apex Lipoly batteries in parallel for a total of 4200mAh at 11.1V.

I mounted the Power 46 motor using a 1 1/2" electrical conduit coupler behind the motor and some 2 1/2" long screws through the motor mount - alongside the coupler and into T-Nuts installed behind the firewall.

I cut the electrical conduit coupler to allow the prop adaptor come through the motor cowl and at about a 3 degree angle on 1 end so I could just turn the coupler around behind the motor and adjust motor thrust angle.

The only other modification I did to the ARF was to put a bamboo skewer through the fuselage at the low corner of the windshield and drill a hole at the corners of the windshield to pop it on.

This allows me to install the batteries through the windshield area, and with some packing tape "handles" manouver the batteries under the front part of the fuselage. I used an empty bottle of CA glue inserted upside down in a hole in the forward fuselage center brace to keep the batteries secure. Again I used a packing tape handle with a small square of velcro to pull the CA glue bottle forward against the batteries and secured to the front of the "instrument panel".

To hide the junky look of all the "handles" and wiring, I lightly sprayed some black paint inside the windshield.

I also installed the ESC and UBEC aginst the forward fuselage walls to help CG, added 2 3/8 oz flattened fishing line lead weights inside the fuse just forward of the firewall, drilled several 1/2" holes in the firewall to allow cooling air over the batteries and ESC. I also left one of the rear windows out for cooling air exit from the fuse.

Maidened the Great Planes Cub on Thursday, Dec 28th and it has plenty of power to fly slow like a Cub should and it maintains level altitude at about 1/2 - 3/4 throttle. So far have only flown in 5 - 10 mph winds and look forward to flying in calm conditions.

[adrian]

[SargeNZ]

Wow, that cub is going to be lightly set up at 81", that power system is often at home in a 50 sized sport model! You could even go up to a 15x8 and 5000mah cells for a good duration / power compromise.