stunthanger.com

Engine basics => Engine set up tips => Topic started by: frank mccune on January 29, 2021, 10:16:52 AM

Title: Hop up tips for Cub .049A engine?
Post by: frank mccune on January 29, 2021, 10:16:52 AM

     Hello:

     Does anybody have any information re. improving the power of these engines?  If so, kindly share.

      Tia,

     Frank

   

 

     

Title: Re: Hop up tips for Cub .049A engine?
Post by: kenneth cook on January 29, 2021, 04:10:08 PM

http://www.flyfreeflight.com/Site/Home.html

Title: Re: Hop up tips for Cub .049A engine?
Post by: Dan Berry on January 29, 2021, 06:51:02 PM

Quote from: kenneth cook on January 29, 2021, 04:10:08 PM

http://www.flyfreeflight.com/Site/Home.html

He can make them real zippy. Until the crank breaks or it just wears out the piston/cylinder.
There is a reason everyone flew TDs for so many years.

Title: Re: Hop up tips for Cub .049A engine?
Post by: Larry Renger on February 03, 2021, 09:24:26 PM

Forget the extra head gaskets, Cubs have low compression. Substitute a Cox RTF needle assembly for the Cub one, clean up the crankshaft port and bypass entry holes and there you are. I have used up to 60%+P fuel with good results on small props and no failures with these mods. Oh yes, I also did a bit of grinding to improve crankshaft balance, chamfered the venturi entry a bit and rounded the exit hole from the crankshaft. Just touch up stuff, probably not much of importance.

After dealing with the hideous needle valve design, cleaning up the flow and balance seem to be the key to Cub performance. Followed by the fact that it has low compression. Hmm, unless you can’t get Nitro, is this a problem? 😜