Hi Dennis,
As always..........you did a great job of electrifying something new! I played with this last year, but have not had a chance to pursue it much more. I have a vertigo issue and get rather disorientated when attempting combat! I had an old Baliev wing to play with and tried quite a few motors, props and batteries. The most success that I had was with a 1250 Kv motor running on 4 cells with an APC 7 x 6 E prop. I tried 8 x 6 as well but it slowed down the turn rate a lot and used more power. The motor I used is a MVVS 2,5/1250 that is basically a .15 (2,5 cc) size motor with a 1250 Kv. It is an IN/OUT runner that has the spinning drum inside a casing. This is really well suited to harsh combat conditions, BUT..........it comes with a high price tag. I had a few from when I was the local MVVS agent and they are gems! You may want to try my motor mounting method which I simply made to fit the existing combat wing engine mount. This protects the motor in a prang quite well, and I think that it could be better shaped to protect the motor even more. Its made from some 1/8" aluminum and simple to make. I hit the deck doing a Fig. 9 into hard ground while flying against a proper combat pilot, and the motor just got dirty and broke the prop. The wing has had its days!
I used 2 x 1300 mAh 2-cell lipo's instead of one 4 cell. It is a bit of a schlepp, but this way I balanced the weight evenly. I stick them into the foam leading edges. I still found the wing to be tail heavy and if you look at the pics, I taped some lead weights around the motor mounts. I've already drawn a plan to make a narrower wing with a higher aspect ratio, but other projects got in the way, and I'm no combat flier anyway. I'm getting a lap time of 3.5 seconds and a 4 minute flight but we are up at 5800 ft. so that helps a bit. I can get the speed to 3.0 secs/lap but then it obviously flies a shorter time. I agree with others that 4 minutes is actually a bit long. Three minutes or even 2.5 minutes would be good for a decent bout. The other thing I tried was to use the Hobby King APC "look-alike" props. They are dirt cheap and more flexible than APC. You do need some more rpm but they work just fine. I do have a video of one of my test flights so I'll try to post it on Youtube.
I used my own KR governor timer (obviously!) and it keeps the speed better in sharp turns than an esc without a governor. I hit the deck a lot if I fly combat and as you all know my system shuts down if the rpm drops suddenly. It does not have to wait for the current to go up suddenly. This saves burning out esc's for sure. These days with much better batteries with lower internal resistance, this is not too bad without a governor.............as you have found out. I would think that the way forward for e-combat is to use no timer at all, and just use a simple 2.4 GHz R/C system with a kill switch for prangs and fly-away's. You can get fairly cheap esc's with heli governor's in them and you don't need to have the motor brake work either. If you try one without and then directly afterwards try with governor, you can feel the difference, so I believe that it is worth it.
I'm building myself a cnc foam cutter right now (well.....trying to!) and then I need to make some simple stunt trainers for our club that has had a lot of interest in C/L since last year. When this is all going, I'll get back to the combat wings. I did in the meantime make an electric Hellcat for some WW 2 combat and that is working very well. I'll post something on that later.
Keith R