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Jun 08, 2005, 04:31 AM
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glide's Avatar

Looking for ways of holding down batteries in J3 Cub


Aloha to all. I am converting a Black Horse J3 Cub (six foot wing span) ARF to electric. This ARF plane is similar to the Graupner plane featured in Hobby Lobby and reviewed in E Zone. I am wondering if anyone could give me an idea of how to setup my battery hold downs. I will be using two 8 celled battery packs consisting of RC2400SCR cells (side by side flat config). I saw how the E Zone reviewer Fitz cut out the firewall and fitted the two battery packs snugly in the hole he cut out. I am hoping that I could keep from doing that. I would rather go through the top of the fuse through the opening where the wing sits to install the motor packs and somehow fit them where the fuel tank would normally reside. But how would I get the packs from moving around? I was thinking of placing a piece of wood that the packs could lay on and use Velcro tape on the batteries and the wood then strap them down with a Velcro belt. In any case, I was hoping others that may read this post may come up with other ideas that would be easy for me to install and remove my packs with the least amount of cutting and addition of weight. Photos of their setup would be really be a big help.

Mahalo to all on RC Groups.
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Jun 08, 2005, 11:41 AM
Visitor from Reality
Quote:
Originally Posted by glide
Aloha to all. I am converting a Black Horse J3 Cub (six foot wing span) ARF to electric. This ARF plane is similar to the Graupner plane featured in Hobby Lobby and reviewed in E Zone. I am wondering if anyone could give me an idea of how to setup my battery hold downs. I will be using two 8 celled battery packs consisting of RC2400SCR cells (side by side flat config). I saw how the E Zone reviewer Fitz cut out the firewall and fitted the two battery packs snugly in the hole he cut out. I am hoping that I could keep from doing that. I would rather go through the top of the fuse through the opening where the wing sits to install the motor packs and somehow fit them where the fuel tank would normally reside. But how would I get the packs from moving around? I was thinking of placing a piece of wood that the packs could lay on and use Velcro tape on the batteries and the wood then strap them down with a Velcro belt. In any case, I was hoping others that may read this post may come up with other ideas that would be easy for me to install and remove my packs with the least amount of cutting and addition of weight. Photos of their setup would be really be a big help.

Mahalo to all on RC Groups.

You have it right! In that little parkflier Cub in my avatar (Sig 1/5th, 84.5" span) I had two 8 x GP 3300 Velcro'd to ply plates glued to the fuselage floor - this was made too 'lumpy' to velcro the packs to directly, due to UC beams, floor angle changes and the like. I had the packs pretty close up behind the firewall and the CG was about correct, slightly nose heavy if anything. Kept meaning to move them aft, but the model was a PITA to haul around in my shop (car, pits, pretty much everywhere) so I left them there until I sold her.

My access was made far easier by the Sig kit having the scale opening door and window in the port side - could about get my hand in through it.

You might want to check out the scale forum for pictures - there's been about every Cub in the IMAA legal bracket converted, usually many times over. Never heard of one that didn't fly great either.

Regards

Dereck
Jun 08, 2005, 09:52 PM
AMA 7014
jbj620's Avatar
Hello, Do not know if this will help but this is the battery tray built for my "Taxi Cup" today. The chute on front has a top tapered foward so the pack can be raised for removal. Chute is lined with the loop side of Velcro for a safe secure fit. This assembly is not that heavy but on this model I may end up with the reciever pack mounted on top of the chute (need the nose weight, weight of the tray is not important.) Has a single blind nut on the front ply vertical plate, the bottom of this plate also sits on the fuse floor so one screw through the firewall was all that was required foward plus two socket head servo screws that secure it aft. Works great The pack cannot be moved fore or aft to balance the Taxi Cup. This model will be balanced with the reciever pack. Sorry for the poor pics...
Last edited by jbj620; Jun 08, 2005 at 10:07 PM.


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