Randy,
I am new to tuned pipes. I just got a Katana with a PA 61 and CF pipe. If my measurements are right, the pipe is 16 and 1/2" from the needle to the wider baffle dimension. I have a very accurate tach as well as your great chart. The PA is running a 12" 3 bladed prop. Here is my question. When run below 11,000, the smoke trail is blue and the engine runs only 5 minutes on the 6 oz tank. With higher rpm, 11,300 the running time of course increases but the smoke trail is now white and the motor is pretty hot. On a pipe, does the motor basically run a strong run or is it expected to do a 2/4 break? I am using 25% oil, 11% synthetic and 14% castor and 10% nitro. Your recommendations please.
Thank you
Mark Weiss
Hi Mark
you are doing something very differant, and much higher RPMs than most use with a 61, yours is more like a 49 setup.
I would reset it all, set pipe from the center of the chamber..or the glow plug, to the first baffle in the pipe at 17.3/4 inch
Use the prop pitched at 4.3 to 4.5 inches
Launch RPM will be near the 10,000 range, much power than your using.
You should set the needle at the fastest 4 stoke it will run in, then turn it in untill it is bouncing from 4/2
The fuel should be 20% oil, not 25, and should be mostly synthetic oil. 10% nitro is OK
this should yield about a 5.25 lap and should cycle slightly up and downhill
let me know what you think
Randy