I have a brand new DL-50 on a Hangar 9 Yak. I'm using a Mejzlik 23x8 prop. I ran about half a tank through it on the ground using a 40:1 mixture. The next day I'm flying my maiden flight and about a minute in I go dead stick. My batteries were fine but I checked my spark plug and it was very corroded. What do you guys think went wrong? Running to hot maybe?

I think you're over propping a new engine. Start with a 22x8 and tune the needles. Good luck.
sam

Thanks for your help!

The OP posted this twice. I deleted one but there was a reply in it

As Rick said; get a NGK-plug. The supplied plug is pure junk.
I think you do abuse the engine a bit; should run more oil for the first gallions. And not a synthetic for breaking in either.

Its weird you call a simple thing - the spark plug as; "junk. Its not a very complicated thing..

I'll have you know, Ive burned over 40 liters of fuel thru my spark plug since I first started it for breakin - and its still going strong. Yes, its the original..

and happily outrunning two DA50's in the field..

Apparently a lot of them are junk. Some might be good but many people are having problems. For what you spend in a plane in money and time, $3 is a drop in the bucket for an NGK CM-6. That's what I use. The stock ones go in the trash.

Some of the off-brand plugs are "hit-And -Miss" as one person has one that is as good as any plug made and the next guy has a useless one.

The OP noted that the plug looked "very corroded" after running a tank at 40-1. If the engine was not tuned prior to running he could have carbon fouled the plug. I'd suggest replacing the plug, set the needles at 1-1/2 turns out from fully closed, and tune the engine for the best performance before flying. Correctly tuned, the 23-8 prop will not be a problem.

I agree with T.O.M. Mine swings the 23X8 fine. Also, the plug that came with mine was "junk". When I pulled it out of the bag the center electrode was almost touching on one side with a big gap on the other. I didn't have a CM-6 on hand so I tried to break it in with the stocker. It did run but not too good so I went and bought a couple of new CM-6's and put one in and it ran much better. We've had a number of folks at our field have bad experiences with the stock plug although one gentleman had a good one so I think it's "hit or miss" like w8ye said above.

thanks for the input guys!