RV-12 Exhaust Tip Cutoff Angle

[Geico266]

What is the most efficient angle to cut off the exhaust pipe? (or worded another way) What is the best angle to "help" or allow the exhaust gasses to leave the pipe to increase efficiency?

The plans call for trimming the exhaust pipe 4" from the bottom of the cowling. Okay, is there an angle that is more efficient than others?

The pipe comes out of the bottom cowling at an angle, so do I measure from the bottom of the hole or the top of the hole?



The pipe definitely needs to be trimmed so you can get the cowel on & off easier.

 

[steve wyman]

Larry- On my RANS S-7S, the exaust pipe is trimmed off at a 45 degree angle, with the angle facing aft. This is the factory setup, as indicated in the RANS plans. Hope this helps- it seems to work just fine on the 912, in my airplane. Steve

 

[Geico266]

Thanks Steve.

I wonder if having more of an angle (more area for the exhaust to escape) is a good thing. Less / no back pressure?