talk about some long bolts sticking out of that motor mount[8D]

Thanks for the info and pics! Is there a reason for having the prop at least 2 inches form the cowl? Also what type of wood are you using for the stand-offs?

The bolts are hardened 10-32 x 4". They have to go from the engine, through the mounts, through the firewall, and through a 1/8" x 1-1/4" ply donut that will be inside the firewall. I prefer the long bolts to having a short one at each end of a threaded aluminum tube. Now if the middle structure (the standoffs) were a solid combined structure then I would go for it. Manufacturers can make a tube stock aluminum standoff REAL cheap, but not one milled from a solid block, and with longer standoffs a solid structure would be much, much better than individual tubes.

The mount material is a hardwood, oak, I believe in this case. It was obtained from the dumpster behind a custom cabinet shop. They throw all kinds of neat wood away. You should see some of the finish grade thin plywood scraps they toss. Usuable size pieces, too!

The primary reason for the forward positioning is to improve efficiency. Placing the prop up against a big round cowl sorta wipes out what the prop is supposed to do at the area against the cowl. Lot's of turbulence between the prop and the engine. Moving it forward an inch or more cleans up the air a little and improves thrust a bit. For the purists, yes, I'm aware that a propeller does not create thrust, but lift relative to the face of the propeller blades.

Secondary reason is that the 2.6 Yak 55 can end up tail heavy real easy. Using a light engine helps make that happen unless you plane for the lighter weight by positioning equipment more forward. In this case the additional forward distance will almost offset the lower engine weight and still look relatively scale. Anyone ever see the propeller of a full scale Yak or Sukhoi up tight against the cowl? They are not.

Again, thanks for the detailed info. That's what I thought. I was thinking of using 1"-1.5"(diameter) hardwood dowels wrapped in fiberglass and epoxy or wrapped in Kevlar string and epoxy then drilling them through.

Well I can give another great report for Keith's service. I sent in my 115 for a carb issue. Two days later the engine is on its way back to me with an new carb and a new reed cage.

What is the thing with the shortened riser? It sounds like something I could use on the application I am considering, since I antcipate having limited vertical clearance for the carburetor.

Is it supposed to affect the way the engine runs? About how much shorter is it?

Thanks for any information.

AmpAce

"

what does the reed cage do?

The reason for the shorter insulator block is because people did not like or want the carb hanging out the bottom of the cowl. Can't say I blame them. The new shorter one makes no change in performance. I presume that was what was meant by "reed cage".

Krayzc,

A reed cage keeps all the reeds from getting out and lost at night. Buggers are the devil to find once they get out. You see all the reeds in the cages are usually adolescent male reeds, and you can imagine how their hormones must be raging to make that 115 run so strong. If you have one female reed in the cage the engine misses a lot because all the males will be fighting over her. They will always go looking for female reeds if given the opportunity.

You need to go back to the sand box

Soon, I think.

Yes forgive me I meant insolator block. It was late at night and I could not think of what to call it. It did bring about your amusing definition of a reed cage though.

Thanks! It gave me the opportunity to have some fun with it

I'd like to get some outside input regarding the cooling vents on my Yak.

The ignition is mounted on the engine box above the engine, placing it in a warmer enviornment than I would normally like. I'm thinking of turning the top two vents around to face into the relative wind and prop blast in order to direct some cooler air over the ignition. I'm thinking it may also assist the hot air to better exhaust out the sides as well.

Anyone agree or have reason to disagree with that concept?

SS, you might end up pushing air out of the inverted vents. This may all depend on the type of baffling you are going to use also. With no baffling it seems that the pressure inside the cowl maybe greater than the ram-air effect from the two inverted vents, especially when the prop unloads in the air. I may be totally wrong here, but it is something to think about.

Well, I finally recieved it...Here are some pics, notice the updated carb, with the shorter velocity stack. I also went with the tapped carb plate.

Looks nice, what are you putting it in??

Thanks for the pics Pontiac. The engine looks much better. Keep us informed on the performance please.

Here is mine that arrive yesterday its a BME-111 its my old 100 that has been converted to this deal. New rings on old piston and old jugs the rest is all new BME-115 parts, last year i had it converted over to falcon ignition. I am in the gargae working on mounting it back in the BG Ultimate. I hope to be ready to do a test in the back yard before the little bit of sun that is out stays with us. Having to move the throttle servo to smoother location over the old deal along with adding about 5/8 to 3/4 more for the motor not having that spacer on it (shorter deal now).

Cool, let us know how it runs.
One of the things that I like about Keith is that he is willing (time permitting) to do custom work for people. No other manufacturer will do that, I have asked all of them.

bummer i am only getting spark from one side of the ignition is this letting me know i have a bad ignition?

More than likely

Silversurfer, it looks to me like that monster cowl and the ram-air effect from the prop and the plane's forward motion will far overcome any air you might get in through those louvers. I would leave them like they are, and they will serve as air exits. After all, it's hard to get too much exit area. That big blast of cool air from the front of the cowl should get back to your ingnition to provide plenty of cooling, and having those exits right above it might even help.

My $.02.

AmpAce

RTK, Steve,
The Motor is going in the Comp arf 2.6 Yak. I will post performance numbers as soon as I can, hopefully they are as good as promised...can't wait.