The main problem with the Ivo is extreme vibration - not the power
limitation. I never heard ANY inflight adjustable prop that would
reduce cruise from 213 down to 170 - inconceivable. Its usually the
other way around.
H-U-G-E four bangers like the Lyc. IO-360 need very ridgid props
because they induce oposing "bang" vibration and can shake the prop
out of alignment. Ivo will not sell a prop for Lyc IO-360. There is no
problem with 6's because they are MUCH smoother - about 120 degrees
out of phase compared to 180 degrees of a four banger. Just compare
any 4 cylinder car and 6 cylinder of similar size for smoothnes.
Smaller engines like 0-320 do not produce as much vibration because of
their smaller size. IVO props really like the 220HP Franklin because,
in addition to being a 6, it has a fluid vibration damper system built
into the flywheel - very smooth engine. Thats what I have in my plane.
A smoother engine has important benefits - longer parts life due to
less vibration. A lot of parts failures can be traced to vibration.
Here are a couple of Velocities with the Franklin 220HP and
IVO props:
http://www.ida.net/biz/arlfrd/ (sold)
http://www.lavoiegraphics.com/velocityrg/
If you don't fancy Franklin, the Continental IO-360 is also a 6
- but a little heavier.
----------------------------------------------------
Paul Lee, SQ2000 canard project:
www.abri.com/sq2000
Dave S wrote in message link.net...
I am involved with the building of a velocity, and questions are flying
around about propeller choice. For in-flight adjustable, we are limited
at this time to an electric control, such as MT or IVO. Cost is pushing
our options in this area towards the IVO.
I have heard of some vibration/resonance probs with certified engines (i
believe it was a lycoming, but dont know specifics)..
And one emailer has mentioned when they used the engine on a mazda
powered a/c they were limited to 170 mph with the IVO but got 213 mph
with a cruise wood prop.
I am looking for any other experiences.. good bad or otherwise regarding
the IVO inflight adjustable props (particularly in the 200 hp range).
Experiences with any other electrically controlled props that can handle
200-220 hp would be welcome too.. but the MT is probably outside my
price range..
Dave