In response to a question in another thread, I thought I'd give an update on my electric Partner.

I now have 126 flights on the model. It is flying great and I continue to be very pleased with the whole thing. I have had some learning curve issues and I'll go over them now.

Astro Flite makes a little device called a Whattmeter. You plug it in between the motor controller and a battery pack and it will tell you the volts, amps, watts and amp/hours you are consuming. It's a very useful device, but I never measured the Partner until just recently. This was a mistake as I will describe.

At around 50 flights I tried flying with an APC 24-12E prop. This is quite a bit larger prop then the 22-12E I had been flying with. I new it would pull more amps, but I never did install the Whattmeter and measure things. I did notice that the motor temps were getting higher, as I measured that with a little IR thermometer I got at Radio Shack. I had just assumed the higher temps were due mostly to the higher outside air temps we were having, since winter was ending. After about 6 or 7 flights with this bigger prop, during a flight the controller shut-off and I had to deadstick in. The controller has a protection circuit that will shut it off if the temps get too high. So I put the 22-12 prop back on and continued to fly.

My temps were still running a bit high, but they were still within what seemed to be OK numbers, but during flight 68, the controller fried itself. It burnt up completely, with smoke coming out of the model during the glide in. Hacker sent me another controller to install, but again I didn't measure the current consumption with the Whattmeter. The controller I was using was the Master 77, which is rated at 77 amps continuous. Remember that # for later.

Right after flight 107, when practicing on the Friday before the Riverside contest, the second controller burnt up. It happened on the ground right after I started the motor. This time Hacker express shipped me one of the new 90 amp controllers. I installed that in the model, it worked great, and I flew the contest. The power during all these problems was still great. Excellent performance at all times. But I did notice the higher temps of the motor and batteries.

So after the contest I decided to install the meter and measure the system. It was pulling 89 amps! No wonder I was blowing controllers. This set-up should have been pulling 65-67 amps at full power. I installed a new motor and the current draw went down to the expected 65 amps. Flying the model with the new motor showed much cooler temps on everything and still the excellent performance.

Turns out running that big 24-12 cause some high current draws with resulting high temps that partially demagnetized the motor. In this state, the motor will still put out good power, it will just pull a lot more current out of the batteries. This is what burnt up the two Master 77 controllers.

Lesson learned, use the Whattmeter from time to time to check the system performance. Use it when the system is new, and then use it whenever you make a change, like a different prop.

Controllers burning up is a bad thing. After the first time the controller went, all the servos in the model began to act up, then fail. Seems that when the controller went ballisitic, it sent a voltage spike through the throttle lead into the R/C system that damaged the amps in the servos. I had to replace all of them within 5 flights. So monitor that current draw and keep it at a safe level. And I would recommend the new 90 amp controller. It has a much better design and is now barely warm after a flight.

With this lesson learned, I am still very happy with this whole set-up. I now have the new Thunderpower 10c cells in the plane with a 10s3p pack and now the model is just under 11 pounds. It flies extremely well and I couldn't be happier. The no vibration, no oil, ease of operation has really made pattern flying a lot more fun for me. I will stay with electric.

Hope this helps!