Avistar conversion - battery compartment
 

Hi all.

I'm in the process of converting a Hobbico Avistar to electric, and all I really have left to do is build a nice cosy spot for the battery.

I've attached the ESC externally, which means that the whole nose is available. I've bought a Turnigy 5s 5000mah lipo for the plane, which weighs in at a hefty 665g, so I need something solid to keep the pack secure, and I don't think velcro will cut it.

Any ideas?

RE: Avistar conversion - battery compartment
 

Bleebs ... it depends on the CG. Stick the pack into the fuel tank compartment and check your CG. That will give you an idea how to secure it. If it needs to be really in the compartment then:

i. cut an access hatch from above
ii. build a platform for the batt
iii. stick velcro to the platform (hooked side) and the base of battery needs one too (fluffy side)
iv. use a strap for double security

If it does not need to be pushed so far up front, like my GP Big Stick, then build the same platform and access via the electronics compartment. In the case of my WM Sky Raider Mach II, it needs to be right in the compartment, I was kinda lazy so I stuffed it with a lot of foam to keep it in place. Not the wisest of methods but it worked.

RE: Avistar conversion - battery compartment
 

Hey tIANci

Thanks for the reply - had a look at your Big Stick thread and took a few pointers from there.

I have checked the COG and seen that the battery needs to sit quite deep in the nose. My concern is that velcro alone, or even with a strap, won't be strong enough to hold such a heavy battery in place during steep climbs etc.

Was thinking of maybe constructing a rectangular battery holder out of ply, which I could secure through the firewall with a bolt and a nut. Just loath to add any more weight than I absolutely have to.

RE: Avistar conversion - battery compartment
 

Question for bleebs: whose moter and esc are you using? Did you need to do any extra strenthening to the plane?
Gary
aka Red Baron Gary

RE: Avistar conversion - battery compartment
 

Hey Gary.

Using a Scorpion 3026-12 running an APC 11x5.5 on 5s for 50 amps, 860 watts, 3250g thrust (motor is rated at 60A, 1kW)

Using a Turnigy Plush 80 amp ESC, BEC disabled, and running a separate 4.8v power supply for the receiver.

The motor is attached to a Hyperion motor mount, which is attached to the firewall (6mm ply) via 4 bolts and to the cheeks via another 4 bolts on either side.

If anything, I've built it too solidly, but I figured I'd need some extra weight up front to get the balance right, and I'd rather add it with reinforcement than dead weight.

Actually solved the battery problem last night. I lined the nose with polystyrene with a compartment that the battery slides into snugly. Then attached 2 large velcro straps at the back that cross over to hold it in place. Realise that polystyrene is an insulator, but it's a 30C 5Ah battery, and it'll never run at more than 10C, even at full throttle, so I don't think heat will be a problem. Guess I'll have to fly it and see!

Will post pictures soon as I have a chance.

Cheers.

RE: Avistar conversion - battery compartment
 

Bleebs ... sounds good. My BS40 does not have much airfow. Battery is good for 100A but am only pulling a mere 35A max. Batts are just warming up after a 15 mins flight. With your ESC onthe outside you have one less worry. Enjoy her mate!