The Elebee Project

The purpose of the elebee project is to make my Elebee (Santa's Little Helper) faster than a stryker C.

Phase one of the project is a bigger battery. This I've now done. Am using a 4s 2200mAh 15C LiPo, which should be able to generate aroudn 485Watts when teamed with the right engine.



The new battery just fits into the space in terms of width.



The battery is too high for the canopy to fit in palce, so I've cut the canopy to accomodate it. This should give the LiPo a little more cooling which wont be a bad thing when it is actually working (whereas at the moment it's a bit like Mike Tyson and Bambi squaring off with that poor little 380 class brushed motor at the back of the aircraft).

Bench Checking

Before flying I wanted to check the current flow etc. I could care less about that 380 motor at the back, but I wouldn't want to blow the speedie or even worse the battery by drawing too much current (as unlikely an outcome as that seems).

I did some testing (outside because the pitch of the engine was really annoying the other half) and ended up limiting the up throttle throw to 32% on the JR 2610 (above 32% the 380 started making really really unhappy noises). At that stage the engine was only pulling about 6 amps (so 6 x 14.4 = about 85 watts) on a 5x3 prop. What I found if I went past that point was amp draw suddenly jumped to 10amps, the motor made unhealthy noises (perhaps just cavitating).

Satisfied that neither the speedie (20A continuous/30A burst) or the battery (33A continous) were in any danger I decided to proceed to flying her.

Flying Test

Before flying the elebee this morning I took about 80 grams of washers off the nose of the plane, to allow for the extra weight of the new battery.

I put her up and gave her full throttle. She accelerated quite quickly and was flying quite well. Although I gave her bursts at full throttle, I was mostly using somewhere between 50% and 75% (I don't care about the 380, but I don't want it to start an onboard fire!).

Not really happy with result I pulled her down and decided that maybe the volts were just asking the engine to spin too quickly. I pulled of the 5x3 and stuck on a spare electrafun xp prop (its a spare electrafun xp motor so it seemed a reasonable match). Not having tested the amp draw on this combo I was a little cautious, but nudging her up to full throttle (32% of full throttle really) the engine sounded good, and I could feel the extra thrust.

I gave her a fly - she flew much much better. Very quick and aerobatic.

Liking what I saw I pulled her down and dialled the throttle up to 50% of maximum throw and did another quick flight. She handled the extra throttle with ease, although the speed 380 was still too hot to touch 5 minutes after landing. Maybe some sort of heat sink would be a good idea.

Anyway, back home now - will spend some time with the clamp metre and figure out how many amps she draws with that EF prop.

In other news, put up the RV4 for another flight today and did some inverted flying and loops. It is a beautiful plane to fly - still apprehensive about crashing it through.

PS - An elebee is an epp foam flying wing from Windrider. I bought mine from my lhs nitrodude.