wrote:
On Apr 5, 12:31 pm, wrote:
I have 140 hours on IVO in my homebuilt with 200hp Franklin. The prop
plates are knurled and I have never seen any blade shifting - make
sure to follow IVO instructions and for proper bolt torque and check
the torque once in a while. I have some vibration but not excessive.

The prop we had was an earlier mode; no knurling on the
plates. No matter how snug we got the bolts we still had some
fretting. And because the bolts have clearance in the blade bushings,
you can't get the blades aligned axactly opposite each other with any
accuract, and the chordwise balance is off. You could pay for dynamic
balancing but it would be off again the next time the prop was apart.

I have heard that IVO does not tolerate Lyc and other four bangers
especially big ones. The torsional pulses are too great for the
blades. A smooth six or auto adaption is not such problem. Ivo will
not sell you a prop for a Lyc four banger.

Which goes to show how weak they are. I'd rather find a prop
with a lot more margin and would settle for a fixed-pitch wooden prop
before I'd use an IVO again. They did have a "Magnum" version that was
supposed to be OK for the direct-drive applications, but maybe they've
taken it out of those applications.

I've often thought it would be interesting to adapt a larger
helicopter tail rotor to a homebuilt propeller application.
Mechanical, manual pitch control that has fewer gyroscopic issues,
with its teetering action and automatic pitch differentiation to keep
it aligned with the shaft. I think I'd want to try it on an airboat
for a while, first. There are almost always unforseen issues. Maybe
someone has already tried it?

Dan

Tail rotors are symmetrical airfoils. I thought about it myself
when I was working on helicopters. I suppose you could do it, but I
don't think it would be very efficient. If you want to play with some
blades they show up on e-bay occasionally.

Dan, U.S. Air Force, retired