REFLECTOR: IVO Props

[Hiroo Umeno]

I have flown IVO + Franklin combo for about 35 hours and over-all, I do like the setup.  I do like its simplicity and the failure mode (not the blade shedding kind) where the prop will "stick" to where you set it last and you can continue flying like a fixed pitch prop.  The pitch variation does work and the rpm / MP / seat of the pants will tell you that.

Like Chuck mentioned, checking the crush-plate torque is a MUST for first several hours.  Mine stopped moving after 10 or so hours but I still do torque it just to be sure before every flight.

One minor annoyance is that there is no limit switch on the thing so CB popping is the indication that you have reached the end of travel in either direction.  I haven't reached this in my fling (I can tell before the motor seizes that the prop is no longer twisting).  Also, in its default installation, it is not a true CS prop but is an "adjustable pitch" prop.  It's a bit more baby-sitting than a real CS prop.  You can get a control unit that will turn it into a CS setup, though.

Hiroo


-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Chuck
Sent: Wednesday, February 06, 2008 8:01 PM
To: reflector at tvbf.org
Subject: REFLECTOR: IVO Props

I know Ivo will sell you a prop for Lyc 6's because I have one, and recently
bought parts for it. I'm not aware of any insurance problem with an IVO prop
when I've renewed my policy.

He won't sell you parts for a Lyc 4 cylinder because of a V crash several
years ago. The owner who had lots of "help" building his plane later had a
problem with the pitch motor, so he dismantled the prop enroute. Instead of
following the tightening sequence (4 retightenings over a couple hours)
which is absolutely critical (and well known), he was in a hurry and took
off with his family onboard. Shortly afterward he started getting a
vibration and advised the tower that he would see if it would go away
instead of landing imediately. The blades separated from the hub and all
perished. There was speculation that the powerful firing pulses every 180
degrees of the 4 cyl. causes too much load for the clamping strength of the
IVO, but there are other V's that have successfully used an IVO on their Lyc
4's for a long time.

An Ivo is a less expensive (< $4K) in-flight adjustable pitch prop that
works on twisting the carbon fiber reinforced blades to change pitch. Some
people have said that this is not an efficient way to change pitch, but it
does work. The blades are very strong and seem to work well in a pusher
configuration. He has been making props for a long time particularly for
ultralights.

I'm sure some of the Franklin guys can tell us what they think of their
IVO's.




> HYTEC45 at aol.com wrote:
>
> ?
> ?
> Ivo had such a problem with the Lyc 4's that he just "gave up",
> understandable.? However, with the right R&D the Ivo (or Ivo design) could
> probably work on the Lyc 6's.? The Ivo have worked on the Franklins which
> are 6 cylinders.?
> I suspect it's an insurance issue.? I raised the question of 6 cyl Lyc and
> they said would refuse to sell the IVO for any Lyc.
> John

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