I bought The World Models Paulistinha P-56 over a year ago with the intention of converting it to electric power and flying it at a couple of electric events last summer. I really like cubs in general and wanted to do a 40 class one. I saw an ad for it in a model aviation magazine and both liked its unusual looks and the fact that its was fairly light for a scale 40 class cub, making a good electric conversion.
The basic build was simple and routine, it was the electric conversion that got a bit fussy. While the motor mounting was no problem using a gp mount and a BP 3520-6 motor, the battery placement for balancing, plus how to mount and access the batteries was much harder.
Long story made short, the plane didn’t get done on time and wound up getting shelved until recently when I got motivated and finally got it done.
Since I didn’t want to cut up the cowling, that meant that the battery had to be in the cockpit area. Even by placing it on end andflat against the firewall, it was still tailheavy, so I added a second battery to make it balance. I am using velcro to hold them in place, and have made them accessable by making the windshield removable.
Running up the motor, my batteries held a solid 14.4v under load, ( a benefit of only drawing them at around 7.5c) which gave me 40 amps and 575 watts into the apc 12-6e prop. The balanced prop was very smooth, and pulled the plane forward about like you would expect from a 40 size glow motor. The plane came up right at 5lbs without the batteries, and 6lbs 3 oz with, for about 92 watts per lb.
I am excited that this plane is finally done and am hoping to get it airborn this weekend, and will post about how it went.
Dean