Hello Again:

         If you are using only synthetic oil in your fuel kindly tell us the % and the reason that do.

         How much additional heat and back pressure is generated via muffler use?

         While flying yesterday, the rear of my muffler departed for parts unknown.  The engine picked quite a bit of speed as it leaned out.  This prompted me to rethink the negative effects of mufflers.  However, since we run our stunt engines slow, rich and cool, perhaps heat and back pressure are not an issue.  The engine in question was not using muffler pressure.  I believe that it leaned out due to the loss os back pressure.  If so, our mufflers need to be redesigned to minimize this power robbing feature.  Perhaps we need rethink sound suppression.

       Suggestions/Comments

                                                                                              Frank McCune

   Frank,'
   Around 1999 Paul Walker was using a Saito .56 so I tried one myself when Paul switched to Powermaster YS/20-20 I tried it. Then I tried it in my other piped engines . I found the All Synthetic fuel allowed the engine to rev higher , run cooler and didnt break or charge as hard as a 50-50 syn ,castor would .I've used 10,15 & mostly 20% nitro Heli low viscosity oil  fuels. Some guys say all Syn wont allow their engine to run correct & it overheats,, . I wont debate what I have found so if Joe Bellcrank can't get things to work... he needs help in that area.
  I like Byrons Heli , Powermaster YS-20/20 , Torco 20/20 Heli, Riches Brew Heli 20/20 low viscosity . I run the stuff in My piped ABCs, Stalkers , Double Star ringed , K&B .61 ,Merco .61 Tiger .60s. The only damage I've inflicked to my engines was from using an electric starter.  I do however toss in a bit of castor  when running my Mercos & Tigers.








    John L.