Well, if you have the AP already, give it some run time on the bench and see how you like it. Before doing that, open it up and rinse out the internals of the engine to get rid of dirt left inside it from machining.

If you don't already own it, then there are probably other engines that people would recommend for the Akromaster. Something like an OS 10FP or Enya 09-IV or Enya 15-V.

-Chris

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              The weight factor is certainly going to be a bit of a concern as it usually is on the Akro. The 15x unmuffled is what the plane was designed for. I know this was quite problematic with the Enya .15 I had on mine. I stated in a earlier thread with regards to the rear exhaust. I truthfully don't know how you can get around that aside from mounting your tank inboard. That just may be the solution. A standard wedge places the pickup of the tank too far outboard and through the flight about midway the engines I used would want to start leaning rapidly and fuel draw would suffer and you just couldn't control the run. I would have the plane dead rich on launch barely able to leap off of the ground and then it would go bananas. The short nose of the Akro doesn't allow for much in tank design and having the rear exhaust would certainly complicate that factor.

Many on here suggested to increase the wing length of the plane on the Akro. Although, I've never done this I certainly recommend it. I think the problem  the Akro is faced with is,  for the amount of squares it has, it's already taxiing the wing using  the lighter Fox.15. When you start using heavier engines, the plane now has to fly much faster which works well, but it doesn't  seem  to allow for the graceful flying of a larger stunter. Ideally, I would bet an engine such as the Cox Medallion .15 would be a terrific choice if unmuffled engines are an option. All of my Akromaster's were from kit built wood. I made no alterations to any of the Akro's I built,  so my best suggestion is to keep it light. I built 3 of them all using different engines. I've run the AP.09 and I wanted to try this engine on a plane, the rear exhaust however has me stumped. The engine just runs poorly with the factory muffler so I suppose the .15 Yellow Jacket wouldn't be any different seeing that it's the same muffler. Ken

              T.J., I would be very interested in hearing your experience using this engine as I own one myself. As for things from Hong Kong, it certainly could surprise you. Mine was an Ebay purchase some time back also from Hong Kong. I don't recall the wait but it didn't come with box or instructions. It was just factory sealed in a bag. I wasn't concerned with that issue as I'm quite familiar with the smaller brother the .09. I thought of making a adapter that threaded into the case but extended out the rear with a barb like fitting. I would think something like a tuned pipe like the R/C car group uses would be quite interesting. This style muffler/pipe could be attached to the adapter via a silicone coupler. A elbow for the header may also get things out of the way for the tank. Ken

The only thing that I found was that the venturi you could get from hobby people was a little to big. You had to block off the muffler to get pressure in the tank to get it to run. balance was good and the power was good. Try to put a spray bar in it, and now I need a new venturi.

Steve

Well my engine arrived today it weighs approx 4.75 oz the 15x weighs approx 2.75oz I am going to see how it runs and depending how that comes out see where I go from there . I bet I could drop 1/3 oz with a venturi instead of the carb . A lot of people used to fly these thins with McCoy 19's with no problems but that decision is a while away maybe an RSM Balloon tank might be in my future.

I think a profi 15 and a bladder tank would be a good match for the acromaster