I have just been flying with a Cub .049 that has been carressed, cared for, tweaked and optimised.  A Babe Bee could steal it's lunch money!  Sorry gang, I tried.  With less than 50% Nitro and Propyline oxide, the babys just don't put out.

This particular engine is the Cub X which has the 2 bolt mounting that matches the Atwoods and Hollands.  I cleaned up the crank port, balance and all the bypass entries.  I pulled the head and after trial and error, ended up with a Hot, long reach plug with 3 gaskets ( best match to the cylinder head ).  The needle system was replaced by a Texas Timers fine thread needle unit.  (The Cub system is about the worst concievable!!!)

For a Cub, it is really good.  Otherwise, it is, at best, a trainer or sport FF ( Dakota? ) engine.  I managed figure eights with difficulty on a plane that an Atwood Shriek will haul around with authority.  I can also sub a Holland Hornet   

Many, many years ago when I didn't know any better, the OK Cub .049A was the engine I had.  I literally wore it out flying in my back yard(folks had 5 acre place).  But, before it wore out an older club member kept razzing me that his Babe Bee would fly circles around the  Cub.  So the race was on, 100 laps.  Can't remember who flew for me as I wanted to pit my own airplane.  Needless to say I won by a cosiderable margin as he couldn't get the Babe Bee restarted.  He also had it leaned out as he was passing me.  The old Cub usually took a few flips to start, even hot.  Even after I got a Babe Bee the Cub was still my favorite engine.  To me it is one of the better sport engines like the old Fox .35 Stunt.  With care they were great for sport flying.

About 1969  one one of those lazy days when you have nothing to do and you really shouldn't be idle because your a 20 something ,a few of us decided to try an experiment.In the late 40's a fellow by the name of Leo Yobb had rigged up a small cylinder of Oxygen to his model and had rigged it to inject the 02 when the model got airborne. He probably wasn't the first one to do this.
We decided to repeat this experiment but not wanting to waste a perfectly good engine a lowly Cub 074 was selected for the experiment.
We rigged a small dribble tube to the stand and had it close to the venturi and fired it up after adjustment to proper rpm we cracked the cylinder open. Now I'm not going to say how much better that cub ran because it still remains the only small cub engine that ran fast enough and built up enough pressure to actually rupture the cylinder. It made 50% nitro look like flat soda. Needless to say we then knew why there is a provision in the aMA rules against gasseous boost to model engines.

Dennis