gade600sdi

OK, during initial break-in in my back yard, and now at the flying field for my Maiden flight on Hangar 9 SU26 MM SE, the Evolution engine started and ran backwards on me for about 2 seconds of Horror. A real surprise and shocker, but it did. I am hand flipping it and have not experienced this before but it is scary. After it did it I had a guy hold my plane but most times it started in the right direction, just that 1 in 10 times it seems to run backwards for 1-3 seconds then die.

Is there anything I am doing that may contribute to this condition? I expect and hope to see a comment from PE on this one as he seems to the be resident expert on these engines.

I also must comment, the engine is very strong. Not broken in yet but the power is unbelievable and the smoothness of the transition and the lack of vibration for such a big single is impressing me. Very high quality engine. I expect to get many great years of high performance from this unit.

Tony Hallo

Check the timing, sounds like it is retarded, I don't know what ignition the MVVS uses but expect that it is a Valach similar to ZDZ. If that is the case 5 degrees before would be close.

gade600sdi

It is a different ignition than Rxcel and CH etc. It has a two magnet pickup system, so it is probably more accurate than using a single magnet. Its definately more tight of a setup than other ignition setups I have seen. Thanks for the post, but I doubt that is a contributor to this issue but I will keep it in mind and check it later if nobody else comes up with anythign.

I was wondering if too much choke excess fuel or not enough choke etc. would be a factor.

Kema

Too much choke in my experience. Mine has auto-choke servo installed and it does it sometimes.

MVVS ICU ignitions have auto shutdown in case of running backwards, so there is nothing to be scared of.

gade600sdi

Well that is very comforting to know, I did not know that but it explains why it stops after about a second each time. I may recall having read that in the manual a long time ago when I built the plane. Thanks I feel better now. I will take advice above and crack the throttle a little more so it doesnt happen as much.

THanks much.

init4fun

[8D] One other small point ..........

When hand starting an engine , the speed and strength with which you flip the prop are important !

I'll not get into the whole debate over wether it's best to flip it in the normal running direction or to bump it backwards against the compression , as some recommend . But I know that the more "smartly" or "strongly" you flip the prop , the more likely it is to start in the proper direction .

earlwb

You know, I never tried starting a spark ignition gas engine in reverse to get it going forward like I do with my bigger glow engines. But it might be worth a try. I have a couple of big glow engines that like doing that, and flipping them in reverse solves the problem.  But yeah a little too much choke can cause it too.

gade600sdi

Update its happening less now that I am used to it more getting more broken in and opening the throttle a little bit more on starting. Thanks guys. And this engine......unbelievable power its sick. Pulling my 24 pound Sukhoi vertical like a rocket. The vertical performance is sick.