HANGAR 9 Piper J-3 Cub 40 Conversion
Hi,
I just bought the new Hangar 9 Piper J-3 Cub from my hobby shop (It was on sale for $200.00 and I could not pass it up). I opened up the kit and I must say, they did a fantastic job. The quality is EXCELLENT.
The airplane comes in a nice clean Cub yellow and black trim. If I go the gas route, I am going to have to install a fuel tank, cut out a filler port, and cut into the cowling. Then after all that work, the nice cub yellow is going to get hosed in all that engine oil. I love the sound of a gas engine, but I am starting to HATE the mess they make.
In short, I would like to turn it into a Electric flyer. Here are the airplane specs from the manufacturer, and I think they will be critical to your input.
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Specifications:
Wingspan:............. 80"........................ Weight: 6.75-7.5 lbs (3-3.4 kg)
Fuselage Length:... 49.9"........................Engine: .36-.46 2-stroke, .56-.82 4-stroke
Wing area:............ 919 sq. in................ Radio: 4-channel w/ 5 servos
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Ok, so now you know the requirements. Below is a list of some electric stuff that I do have. It would be great if I could use what I already have, but the stuff I have is for a smaller electric (which is not yet finished). I have a feeling I will need bigger equipment for my cub.
My junk:
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*Apache Smart Charger Li-Poly
Charges:
4cell 14.8V
3cell 11.1V
2cell 7.4V
1cell 3.7V
Then below this it says:
2500mA
2000mA
1700mA
1200mA
700mA
250mA
(These are current values, so I am not sure what these are for??)
*JETI model Advance 30 plus electronic speed controller (Brushless Motors)
(I can find out more specs on this particular model if necessary and provide it)
*I also have a wall plug AC-DC coverter by (Hangar 9?) that outputs 12V DC at 600 mA. This is used to charge a torquemaster motorcycle battery for my field box. I don't think it has the necessary Amps for my Apache. I know for a fact that Radio Shack does sell a nice 12V 15A power supply that accepts banana clips. (I would probably need that, yes?)
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I figure that I will have to put the batteries where the fuel tank would normally go. Replacing the engine with an electric motor is going to make the nose much lighter. I would suspect that the batteries will want to go as close to the firewall as they can go to balance the CG (But that will be solved by moving it around until the airplane balances).
I have not opened the Apache Charger yet, so I can always return it to my local hobby shop and get my money back and order a different charge if it becomes necessary.
I need to know which brushless motor unit should I buy to power this airplane. I want it to fly like a nice piper cub, not do prop hangs. I want it to have enough power to be nimble, but not fly 3-D (This is a cub afterall!!) The prop is probably going to want ~8000 RPM at the most? So a reducer gear might be necessary. (It would be great if the motor came in a unit with the reducer gear already attached!)
Also, what kind of batteries should I buy, (I guess the voltage and mA rating will depend on the motor I select, how long a flight time I want, and most importantly how much am I willing to spend <Not too much!>)
I may or may not need a new electronic speed controller. If I do need a new one, is there a nice (and affordable!) one out there that you would recomend?
This will all run on my JR system.
It would be great if I can walk away from this post with a general idea on how to pick a motor, battery, charger ETC for any airplane in general.
Thank you for your input. If you happen to have a link for your recomendations that would be a great help too!
Many thanks,
-Cyrus A.