Hughes500E

My Feedback: (16)

I have two of these .49 engines mounted in my twin. I have five tanks of 5% XP Sport fuel ran through each engine on the bench.
XP is 75% synthetic 25% Castor and 20% oil It was a really good beginning to a break in, very impressive. Both engines were primed and started on the first flip. I installed a counter rotating crank in one of the engines and it runs the best. Went to the field for the maiden flight and had all kinds of trouble. The counter rotating engine ran great, I mean excellent. The normal rotation engine would not start. Here's the deal,
The prime burned off then the engine would just quit so, I opened the low needle 1 extra full turn, prime burned off engine would quit, I opened the needle another full turn and the engine ran. I advanced the throttle slowly to wide open and it took a minute to unload and reach the 11k RPM. Brought the engine back down to idle and it would load up almost right away and quit. Repeated this process about 6 times 'till I finally managed to obtain a rich needle half descent transition. Started the counter rotating engine (first flip) and ran them both up. One was running 11.026 the other was running 11,046 very nice. Back down to idle and then back up, the counter rotating engine reacted awesome, the normal rotating engine struggled through the mid range till it hit RPM and they both sounded awesome again. Very nice stall turns could be achieved with this setup I actually performed the maiden flight here and landed with one engine out. The counter rotating engine brought her home.
I started to lean the bottom end out somemore to match and managed to get it quite close. Filled both tanks got ready to go again and the dang thing burned its prime and quit again. Started to open up the needle again and basically repeated above.
I'm at a loss ! What could change?
The clunks in the tanks are closer to center mounted in the fuse then they were on the test stand
The tanks are the same ones that I used on the test stand
I swapped glow plugs
I blew fuel through thinking it was debris
????
Any idea?
The counter rotating engine is running awesome, quite possibly the best break in and best transition that I have ever experienced. Very nice!

David_Moen

Swap the glow plugs and see if the behaviour changes engines??

Make sure there are no obstructions (debris) in either the LS or HS needle?

Hughes500E

My Feedback: (16)

Been there done that!
One thing I forgot to mention, before running this engine I turned the cylinder around. The exhaust is now on the other side.
The ports are all lined up!

David_Moen

Sorry Steve, I didn't read your post thouroughly enough!

I have replacement LS needle assemblies in stock we can swap it out and see if that cures it. You can come pick it up or I'l bring one down to Vernon on Saturday, I suspect however, that you will want to have it sorted out by then!

DarZeelon

Steve,


The first stage would be to isolate the problem.
Try exchanging the carburettors between the engines, to see if the normal rotation engine keeps being 'less normal' than the counter-rotating engine.

This way we can know if your it is the carburettor, or something different.

What's next...

Hughes500E

My Feedback: (16)

Well, I swapped out the carbs (good thinking) and both engines are top notch. I'm thinking there must have been some sort of blockage in the low speed needle. Everything is just fine now, thanks guys. That counter rotating engine sure runs real good though. I richened her up just a little to match the other. Probably the nicest break in I have ever done
Running APC 11x6 props I am within 50 RPM, this is considered awesome by many!
Great engines!

DarZeelon

Great, Steve.

Enjoy your engines and plane.