Message-ID: <001401bfafc7$8595c140$b66b1b3f@oemcomputer>
Reply-To: "dfs" <dfs@gateway.net>
From: "dfs" <dfs@gateway.net>
To: "Lancair List" <lancair.list@olsusa.com>
Subject: Auto conversions and constant speed props
Date: Wed, 26 Apr 2000 14:36:44 -0700
Mime-Version: 1.0

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Re: Greig Huggins questions about IVO Props.

There was some lively input on this subject in LML not too long ago (some by
me, since I had had some experience with them). Rather than reiterate, take
a look - I believe the thread was "IVO Props" - for one person's experience
and opinion. Of course, always remembering that my experience was with a
specific airplane and engine. things could be different with different
components. I've heard tell of a guy running a big V-8 conversion on an
Ag-plane who swears by his IVO Magnum. Unfortunately, I tried and can't use
one on my O-235-L2C.

Dan Schaefer


[There is someone successfully flying an ES with an IvoProp, unfortunately
I don't remember exactly who it is or what engine he's got in his
airplane.

I contacted Ivo right after Sun'n'Fun to try and discover the names of
anyone that the factory could recommend I talk to who was successfully
operating the Magnum at speeds in excess of 200mph... they referred me to
a Mr. Bill Dunbar, right here in Fort Myers, who's flying an Ivo Magnum
on his Glasair SuperII RG.  I visited with him at his hangar and saw the
prop in operation, unfortunately only during ground operations as he
was having some voltage regulator problems and didn't want to go flying
that day... at least not until his electrical system was back to 100%.

We discussed his installation and I learned that he had the prop attached
to an IO360, and in the 3-blade configuration the original 74" diameter was
too much prop for the engine.  He cut it back 2", reducing the prop disc
to 70" and was getting full power without problem and seeing some pretty
impressive speeds.  He reported the during a full power low-level pass
his airspeed was 245 indicated, and no, that wasn't after a dive to pick up
speed.  The run started at a level cruise of 185mph to which full power was
added and pitch dialed in until there was just no faster to go and no power
left to add.  (I don't know if I believe him as that seems like real
fast for a SuperII RG, but what do I know... even if he was exagerating
by 20 mph, that's still some impressive performance.)

The Magnum has undergone some significant changes over the last year and
I understand that they are doing more to it yet to better suit it to
the high performance kitplane market.  There is little resemblance to
the blade shape seen on their smaller props, as these "new" props have a
considerable amount of twist near the hub and are airfoiled in shape... a
far cry from the more oval shape of their ultralight prop or the middle
power range prop which was actually the forerunner to the Magnum.  (The 
"oval" shape extends from the prop hub outboard to about 1/3 of the overall
blade length on those other props, and that's where the speed problem
seemed to have been on the earliest Magnums.  That has been cured.)

Do your own due diligence in this regard, call the factory, ask for the
names of people who are flying examples near your home base that you can
talk to... they apparently have lots of these props flying and are
delivering more every day.  They obviously aren't for everyone, nor
am I suggesting that they are an exact replacement for an MT.  However,
they do seem to be a viable alternative to a fixed pitch wood prop with
the ability to provide inflight pitch adjustability at
a fraction of
the cost of a Hartzell or an MT, and for some of us that might be the
only way we'll be able to install that capability on our airplanes. 

An interesting side note... three 3-blade Ivo Magnums not only cost as
much as a single Hartzell, but they also weigh as much.  The 3-blade Magnum
tips the scales at just under 23 pounds, costs $2100.  Pretty interesting
stuff.........

   <Marv>          ]


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