ORIGINAL: glennb2006
330 to 340 mm works for me. As Believe It said, adjust to suit the boat / prop / conditions on the day for best compromise.
Has anyone ever thought of trying to make a variable length pipe for a Zenoah? IE shortens as the revs rise and lengthens to get some low down power through and out of the turns as the load goes up?
I kind of thought of something connected to throttle position but then think something related to engine revs might work better.
Any thoughts?
Glenn.
Theres a guy name Pat down in FL that i do believe has a sliding pipe setup that can be used on a 3rd channel for quick adjustments..not sure how much testing hes done with it. My grandfather (a current control-line plane recold holder) was wanting to do something similar for my nitro motor.
You can also do it easier with a fixed length by having a controled water injection into the system. Injecting water into the tuned pipe hurts RPM but increases torque, so if you could regulate the injection good enough, you could have a boat that sings comin down the straight and doesnt lose much in the turns.