REFLECTOR: Aerocomposite Prop

Wed Apr 5 08:29:15 CDT 2006

TEC,

If the shooting every starts, I'm not standing next to you---you not the
good-luck man!  I have a bit different experience with the MT.  With
about 130 hours (IO-540), I've had it off twice, both times for blade
repair; one for an apparent stone and one that I've never figured
out-looked more like a bullet hole in the trailing edge of the prop than
anything, but hey, that's just stupid...nobody would every shot at
airplanes.

The first time, I wasn't too happy about the service and got hit with
the 'we won't work on the prop unless we put in the new grease seals to
replace the ones in the prop-that aren't leaking---and you get to pay
for it'.  The work was done and for the price agreed.  A few weeks later
I thought I noticed a grease leak evident on the hub from the new seals
but it turned out to be one of those tricky ones from the engine that
finally showed up on the hub.

The second fix, which must have been a 'big' stone that almost made it
through the prop (but still looked more like a bullet tear) was fixed,
painted up and delivered by the end of the second day-as promised and at
the agreed price.

So yes, I initially thought the MT was too darn expensive until finding
out the possible substitute CS aren't any cheaper.  Overall, I would
give the prop an A- grade.  The '-' comes from the lack of durability of
a composite prop on a pusher, but that's not really MT's fault, that's
just the way it is.

Chuck Jensen

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of HYTEC45 at aol.com
Sent: Tuesday, April 04, 2006 5:35 PM
To: reflector at tvbf.org
Subject: Re: REFLECTOR: Aerocomposite Prop

In a message dated 4/4/2006 11:10:53 A.M. Pacific Standard Time,
ajlz72756 at yahoo.com writes:

	haven't purchased my prop yet and am interested in hearing more
about your problems with your MT prop. I thought this was the best prop
that you could buy and know that this is the suggested prop to use by
Velocity. If others are having the same problems that you are, I sure
don't want to invest 11K on a piece of crap. Please tell us what kind of
problems that you are having.

After I purchased my prop in 2000, I developed a fatigue crack in one of
the blades.  mt said that there is now a AD that restricts the operating
RPM on non-counterweighted engines like mine between 2250/2550.  Even
though mt never sent the AD out to owners on file, I had to fight tooth
and nail for them to repair the crack.  After that, even though I
operated the propeller out of the "restricted" range, I developed
massive grease leaks.  American propeller who services mt told me that
mt has a big problem with grease leaks, and now has a another
modification that is needed to be done to address that.  I had that mod.
done, and continued to have grease leaks, along with bearing wear
requiring the replacement of bearings twice.  My average operation of
the prop between "return for repair" is around 44 hours.  I have under
290 hours of operation on the prop, and it has been off five times.  mt
admitted that the blade design as shipped on mine in 2000 is not
applicable to my four banger, so I have to PURCHASE new blades otherwise
I will continue to have bearing/seal/cracking problems.  This cost me
5K, as I had to pay for installation, along with of course new bearings,
and a pitch change yoke even though the prop was just overhauled 45
hours prior.  After I ran those blades for a little over one hour, they
developed almond like blisters on 2 of the three blade tips.  These were
decided by mt caused by sap trapped within the wood core.  The fix was
to drill holes in the blisters, fly it a while to sling the sap out,
then seal with 5 min. epoxie.  This still left these blisters (de
lamination areas) on the top side of the airfoil where the airfoil is
critical.  Even though the prop only operated for a little over one
hour, they will not pay to remove the blades, but will fix them if I pay
to have the prop once again disassembled ($700.00) to send the blades
back.  This of course does nothing for my time of installation and
removal of the prop, or the down time on the plane.

My prop is also an electric controllable pitch, and probably 75% of my
additional problems are due to the electrical mechanism.  This includes
three pitch change motors replaced, three RPM sensor replaced, plus my
time troubleshooting and installing these items.

As I sit, I am developing grease seal leaks again with the "new and
improved" blades, along with RPM sensor problems which I was assured
world not happen with the new blade design.

mt now tells me the problems are related to either that I am running 10
to 1 pistons, and or I am running a light speed electronic ignition.
They only tested the prop on a "standard" lycomming and since mine is
not standard, I'm on my own.

The reason that Velocity recommends the mt is because it's the ONLY
constant speed prop that will fit due to weight.  With the standard
Velocities, you could get away with a fixed pitch prop.  With the XL and
/-5 a constant speed is a must, and they (Velocity) would not have a
viable/safe product in the XL line without one.

I know that Velocity is very interested in the aerocomposite, and
another option may be soon available.  I hope so.

TEC

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