Dennis,
It seems the both of us are on a similar quest to match our motors/rpm to our battery packs. Here are a few of my "givens".  ("given" simply means that I believe the principle is correct, but can't completely quantify the exact value)


1) A large diameter low-rpm prop is more efficient than a smaller lower diameter prop running at a higher rpm in providing the same thrust--or you need less power to make the same amount of thrust. Thrust is what your plane cares about. Also I believe a larger prop increases its thrust faster as airspeed drops (at constant motor rpm) which works out better in the overheads.
2) Running at a low throttle setting is punishing to your battery, and to some extent to your ESC. Basically we measure the average current the battery is putting out. If you are flying at half throttle (lets say), then the instantaneous amps are twice what you measure, with the net result that the heating in the battery (taking into account the current is flowing only 1/2 the time) is twice what you would have with the same current if the ESC was running at full throttle. This means that you are leaving watts in the battery that you could have been sending to the ESC. Of course we always have to run at less than full throttle to have the extra "oompf" when we pull the nose up.

So what you are suggesting is beating "given" 1 against "given" 2. The better, but more costly solution is to buy a motor with a lower kV (I am guessing that 1100 would be about right for you). However it is worth trying what you suggest, simply because I am not sure where your optimum spot is for your current motor/battery.

Dennis,
Actually the last few flights have been pulling out ~1600mAHr! However those electrons are being pushed by ~14-15V and so have more power than those coming out of your 10V setup. In the end it is the Watt-Minutes that matter (Watt-Minutes are more relevant than watt-hours in our application, but being FPL guy, I know you already know that!

Alan   I think that if you thought about it when using a pusher prop, the air effect on you rudder would also make it turn right, beside having the torque effect also..... humm    

Dennis,
I do agree that you want to match the kV, but my only comment is that close enough is good enough. I've been obsessing a bit too much about my 880kV motor, thinking that if it were 800kV or 775kV that my battery would be happier. I am just a bit surprised that it doesn't seem to matter as much as I thought it would.

Now your 1500kV is pretty high, and maybe it would make a difference.

Another thing to think about is your plane. I chose the TF ARF Nobler because 1) I had one!, 2) they are pretty darn light (experience from my Brodak 40 powered one), and 3) they have a relatively thin airfoil compared to today's stunt behemoths! I was hoping the thinner airfoil would translate into a good cruising efficiency.

If you go to my old motor test thread http://stunthanger.com/smf/index.php?topic=9256.0 , you can see that I tested (in the garage) the efficiency of my 3020-12 Stock motor (kV~1080) and my 3020-16 Hand wound motor (kV=880). The 880 kV was more efficient (~10%?) than the 1080 on a 4s pack at max power. Now this test does not account for the battery in the equation (I was only comparing how many average watts it took to run the ESC and motor at a fixed rpm with the same props. Taking the battery also into the equation should tilt the efficiency more towards the lower kV motor, but I haven't actually figured out how to do that--except by flying the plane. However you would need to fly in exactly the same weather to make a comparison (another way of saying that the differences are not gigantic). Maybe another way would be to run a test over a fixed period of time. Need to think about that one a bit.

By the way, the 775kV motor was just the 3014-16 mentioned in the above thread, but I re-terminated the windings from the original "Delta" configuration (which gave a kV=1250) to a "Wye" (or "Star") termination which gave a kV of 725. Too bad that was just a little too low a kV for the 4s battery. Because otherwise, it would have been a nice motor for the Nobler (and an ounce less weight than the 3020's!).