FuzzyDice

My Feedback: (6)

Initial run on BME 50. Engine likes to be very wet before starting. Once warmed up, starts first flip. 3 or 4 flips when cold. Running a 22-8 Bolly prop. Tached 7300 and engine is not near to being broken in yet. Pulls like crazy!!! Very impressed with engine, but, it does seem to vibrate more than I thought it would. Running a Dubro rubber mounted engine mount. Test stand solid, from 2X4. Carbon fiber Bolly prop factory balanced. I checked it and it seems okay. Wide open vibration seems normal, but mid-range seems rough. Ran a couple of 24 oz. tanks through it then opened it wide open and engine cut out, just a little. Retarded timing 2-3 degrees and it ran smoother. Also stopped the engine misfire. Will check it with a degree wheel to see where timing is. A guy at our field has a US 41 and it seems smoother than the BME but no near the power, of course. Took the engine to our field and ran it for the guys. They were very impressed with the thrust and power and told me that they thought that the vibration was normal. Am I expecting too much? By the way, putting the engine on a Wendell Hostettler GeeBee Z. Any input will be helpful. :spinnyeye

DGrant

My Feedback: (4)

I have the same engine and also am very impressed with it. Although my initial runs only yielded 6400 R's after 10minutes or so, and now in the plane with almost 5gallons through it, I'm getting 7000 with a 22x10 Pro-Zinger. It runs very strong, with no hesitations. The only adjustment I made was leaning out the low-end almost 1/4turn. That cleaned it up considerably, so the slow flight is much smoother, with instant transition(which it had good transition before), it made it very crisp though.

Mine is solid mounted in a GreatPlanes mount. With the mount being plastic(or whatever it is) it does absorb some of the vibes while still retaining a solid connection to the plane. The engine does shake slightly, but no more then my Moki.

I've questioned the idea of rubber mounting a large gasser, and for reasons of the vibes amplifying with the rubber. I would question the rubber mounts being firm enough to dampen vibes without the amplification. I don't know enough about the larger Dubro's though to comment further though, just something you might want to check into, or maybe already have.

With the R's being up that high too, I might wonder if the high-end is to lean. Especially if you say when you opened her up, it cut out. Not to say they don't run up there, I know they will with the right prop, and yours being a Bolly22x8 may just put it up there. Again, just something to think about. I get totally unlimited vert with my Midwest Extra(15lbs), and running like it does, it's got gobs of torque to pull it out of a hover at will. This is again with the Pro-Zinger prop. I've not yet experimented with other props, but this spring I do plan alot of flying, so will get the opportunity.

I guess what I'm thinking too, is adjusting your timing might camoflauge the prob of a carb setting being off slightly. When you change the timing it might aleviate one problem while possibly creating another slight one. Just keep an eye on the temp, and keep a check on your plug too.

The vibes are very normal though, mine does it to some degree...I just take as I can "FEEL THE POWER"!!!
Glad you like your BME...I can relate.