I recently installed in a plane a MLD35 gas engine that I have had NIB for some time.

The ignition module said that it was good for up to 8.4 volts, so needing some weight I used a 2500mAh 5 cell NICAD that I had to hand.

Took the model out to do some tests, the engine started easily and ran well, however I was getting some interference.

When I got the plane back on the bench to investigate I found that there was no spark. Further investigation indicated that the problem was the ignition sensor (I had a spare that I was able to substitute, when I did the spark was back!)

This started me thinking that maybe the module itself was able to handle the higher voltage but not the sensor. As it all came together I didn't give it a thought when I first installer. As the sensor is just a hall device with maybe a transistor I would not have thought it was that sensitive, but who knows. Certainly before risking my spare I will be dropping back to a 4 cell pack.

Anyone any thoughts?


Terry