My testing of the RC Timer 40A ESC continues. I have about 10 flights with it now paired with a 2212/6 2700 Kv motor and 6x3 EMP prop combo. This would be the primary motor I would pair this ESC with if it works to my satisfaction. However, thus far it is not performing to my requirements.
For the first couple flights, I flew fairly aggressively, lots of bursts of full throttle for 3-4 seconds at a time, lots of acceleration and deceleration for aerobatics, etc. Battery used was the Zippy Flightmax 2200 3S 40C discharge from Hobby King. Testing with the wattmeter before the first flight this motor (which has been well used in other planes, prop is new and balanced)
- 50% throttle - 16A/178W;
- full throttle - 37A/428W.
As a refresher, according to the RC Timer info on this ESC, it should be capable of handling 40A continuous and 45A at a burst. Since I didn't have a wattmeter connected during the flight, I am not sure what sort of amps it pulled during the flight, but after landing from these aggressive flights, the ESC was quite hot. I don't have anything to test for temperature other than my trusty fingers, but the ESC was so hot after these flights, I couldn't keep my finger on it for more than 3 seconds before it felt like my finger was going to get burned. Not a good result in my book.
The ambient air temperature at the field today was 22 C/72 F, so moderate, but I will be flying in temperatures much warmer than this over the summer, so this overheating has me concerned.
So, I decided to test it under slight more docile conditions to see what difference there might be. I decided to launch at 60% throttle and keep it pinned there until I was ready to land, but kept a good aerobatic routine of turns, loops, rolls, split S, etc to keep the built in BEC under load as well.
Before launch, I tested the setup again with the wattmeter at 60% throttle and got 21A/253W.
After landing, again the trusty finger test and I lasted 4 seconds this time before it got too hot.
Of note, the motor was running at fairly normal temperatures, warm, but not too hot to touch, the battery never got warmer than ambient air temperature during any of the tests.
So there could be a few things going on
- this particular ESC could be a dud, I have second one that I will test to see if there is a difference;
- this motor while in the air could be drawing far more than 37A, I will fly with a lighter battery and with the wattmeter aboard to see what the max amp draw might be;
- perhaps the heat sink is too small, although it seems to be about the same size as the Turnigy Plush 40A ESC which I currently use in most of my planes which never get as hot as this RC Timer one did today;
- perhaps the burst overhead is not enough compared to the Turnigy Plush for this motor and prop setup. The Turnigy Plush 40A ESC is capable of handling bursts of 55A according to the Hobby King data, so if I do a bit of math, at 37A, I am pushing the RC Timer ESC (max burst of 45A) to 82% of it's max, but only pushing the Turnigy Plush 40A ESC to 67% of it's max. I am certainly a bit out of my depth in how ESCs work exactly, but looking at these numbers and feeling how hot the RC Timer ESC got, perhaps it makes sense.
So just for fun and the sake of testing, I will try out the second RC Timer ESC I bought and also take along a Turnigy Plush 40A ESC so that I can swap them out at the field and test with the same motor/prop setup and see how the heat build up compares under the same field conditions.
The ESC I was using today is certainly not living up to my expectations with the 2212/6 2700 Kv motor setup, but again, more options to be explored and more testing to follow before making my final judgement/decision on the RC Timer 40A ESC.