Posted by ken on February 10, 2003 at 18:27:17:
In Reply to: Tunnel posted by Larry Credle on February 04, 2003 at 06:56:05:
: Need info on constructing fiberglass tunnels for inboard conversision or anyone know a web site that might have info?
The pocket/tunnel should be straight no taper for a minimum of 1 prop diameter forward of the prop. When the taper starts there, run the taper for 7 times the depth of the pocket. Use sufficient prop tip clearance at least 20% prop diameter. Do not allow two prop tips to line up with the pocket corners at the same time, this can start vibration.
Example, a 4 blade prop tucked up halfway. This allows two prop tips to line up with pocket corners at the same time. This is a cause of vibration.