MX-Bach 30cc Wrapping Up

Joe Nelson sent me a sweet deal on a RCGF 30cc gas engine! I have installed it in the MX-Bach. It wasn't quite plug and play,  but is wasn't as much trouble as it could have been,.

The four mount posts were not a perfect fit, from the fuselage side  (the hardpoints on the engine are fine). The top two were spot on, The bottom two were a bit further apart  (something they did with the design of the firewall). I used a large clamp and pulled them in a few mm and it works wonderfully.

I had to build a box for the throttle servo. It works well, but today the challenges of its position became evident when it stopped working and I had to remove it. I am not sure what happened with it. I ordered a replacement from Amazon and it will be here in a couple of days. I should be able to maiden it soon!

One of the problems with the engine is that it was particular about the fuel system set up. I have redone the plumbing from a two to a three pipe system, replaced the stopper with a gas proof one (had a black one on it becasue it's what I had, but it was breaking down), and moved the tank forward. Changing to a 3 pipe system allowed a single shorter uninterrupted line from fuel to engine. All possibly moot, as I just ordered a new fuel tank. I may just keep this one.

One of the "not plug and play" problems was that I learned that the ignition didn't like having the Spektrum RPM sensor attached. Through a series of trials and errors I figured out that when even a blank lead was connected to the RPM plug from the ignition, no spark. I pulled it from the reciever, no spark, pulled the extension from the ignition and spark. This doesn't make sense. Once I have it running well I will try it again and see what happens.

I had to tweak the needles. She was fussy, and the initial changes I made from what Joe had set made huge problems. Once I got the fuel system set up, the spark problem settled, and reset the needles to factory, a small tweak and it is running very nicely!

So... new throttle servo will be here the day after tomorrow. I suspect I will stay with the 14 oz tank for now. I will be putting the cowls on, finishing up repairs on the spinner (from a previous build the tip was melted by a starter). Maiden is in a few days!