I haven't run my 67 on a pipe yet so I'm a little curious for settings for that also.  My current plans for the 67 is on a header muffler in my Collossus (classic).
  
My 76 runs at 18.25 inches at 9600 RPM at launch with a Randy PA 75 pipe, and uses 7.25 oz of 18% nitro and 18% oil (15% Klotz and 3% Castor).   I fly at 2300 ft altitude in Tucson AZ. (Hot sometimes).  Engine runs cool.  Glow plug is Enya #3,  prop is Mejlik 13-4.25 three blade (narrow blade), 68 ft 18 thou lines.

Randy Cuberly



  

   Thanks Randy.  Is the venturi  stock ?

Sorry... No it's not stock.  It's .006 larger than stock, but has one layer of panty hose over it!  I typically trim this way.  Keeps out the pebbles too!  It does not have a "spigot".  I tried that but found it temperamental to tune.  I realize a lot of the "big boys" use the spigot but it didn't seem to work on this particular engine for me.  It might have if I had spent more time fiddleing with it but I simply went back to the afore mentioned setup because it worked very well and was very easy to deal with.  I would imagine that at sea level things might be a bit different and a smaller venturi might work better.  I would mention that it regulates very well with this setup and a bit better than others that I tried without the pantyhose which probably indicates that a slightly smaller venturi coul be used even here!

Randy Cuberly

  Ron , this is the info I  recieved from the afore mentioned users,,, if I write something that is false I only wrote what info I recieved,   Joe sets his .76 up with a .205 venturi & the pipe is set to 19.25"  Dave has a .205 venturi & the pipe is set at 21.5".

 Ron , this is the info I  recieved from the afore mentioned users,,, if I write something that is false I only wrote what info I recieved,   Joe sets his .76 up with a .205 venturi & the pipe is set to 19.25"  Dave has a .205 venturi & the pipe is set at 21.5".

Hi John.  A little difference,  Joe uses the .67, and I the .76.  I get a two inch pipe difference between the .61 and the .76- using the same prop and roughly the same RPM.  The pipe for the .76 is also larger in diameter.

Dave