Ken Moore Posted September 5, 2009 Share Posted September 5, 2009 I am fairly new to model flying and have just about completed assembling a Phoenix Rainbow, but am unclear about the battery mounting. The battery (3200 mAH) is too large to fit in the bay, and it looks as though it will need to be pushed through the firewall (towards the motor) a little to achieve the recommended balance point at 90mm from the wing l/e. Anyone one else have this problem? Thanks in advance for any advice. Ken Quote Link to comment Share on other sites More sharing options...
Pete B Posted September 6, 2009 Share Posted September 6, 2009 Hi Ken, Welcome to the forum. I'm fairly new too and have had a lot of help from the good people here. I have a Rainbow - lovely model to fly - and at present have been running it on a 2200mah pack. The battery bay just isn't the right shape for Li-Po's, is it? I've just bought some 3000mah Flightmax Li-Po's to extend the flight time. My balance point is reached with the front end of the battery about 4cm rearward of the bulkhead - seems quite a way back from yours - and I needed to remove some some material from the ply former just in front of where the instrument panel would be. I believe it would often be referred to as F2 on a plan. Quite difficult to explain as the model is in France and I'm currently in the UK! If you invert the fuselage and feed the battery in from the front, you'll see where you need to remove the ply to accomodate the pack. I used a circular sanding wheel on the Dremel, which removes ply quickly and efficiently. My pack is attached to the ply base with sticky velcro to set the fore-and-aft adjustment, with a velcro strap through the horizontal ply former inside the battery bay. The rear end of the pack then just rests on the cut-out part of the former. If your set-up needs the pack to go forwards into the engine bay, you may be able to open out the bulkhead inside the rectangle formed by the engine mount assembly. Incidentally, there are a number of build threads elsewhere such as this one which may be of assistance. I have beefed-up the cross-member at the top of the windscreen and down the side pillars to minimise the risk of squeezing. I've also run an extra brace diagonally downwards from the rear of the wing bay down to the next vertical brace - both as a result of other builders' recommendations. You'll find some good tips if you search the threads. I've also programmed flaperons to give me some very slow flight - no sign yet of tip-stalling as she has proved to be very docile. Good luck with your build and maiden! Pete Quote Link to comment Share on other sites More sharing options...
Ken Moore Posted September 7, 2009 Author Share Posted September 7, 2009 Hi Pete, Thanks very much for your reply, it is really helpful to get some practical advice. In fact I had almost decided to do what you suggest - to open up the motor mount bulkhead and move the battery forward a little, so now I will go ahead and do it. I am slightly concerned that I need to do it though as I can't see any obvious explanation for the tail heaviness. The motor I plan to use, a Hacker A30 12L, is about 10gm lighter than the AXI recommended but I doubt that would explain it. I had already noticed that the side pillars were a little weak and had beefed them up, both the front and back ones. Now I'll add the diagonal braces as you suggest. I looked at the threads you pointed me to, and they do provide some helpful comments, although no one mentions battery mounting problems! Maybe they are just par for the course with ARTFs? Anyway thanks for all your help, I hope to maiden next week as long as the wind stays fairly quiet. Ken Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.