REFLECTOR: Aerocomposite Prop

Tue Apr 4 20:33:20 CDT 2006

TEC,

I flew an IO-360A1A for 14 years on a 1964 Mooney M20E, it had the red line on the tach from a SB from 2000 to 2250 to protect the prop. Its hard for me to believe that MT would ask you to restrict your operation at an RPM that is typically where you would be needing to cruse at. It is true that the older IO-360 engines were considered very rough running. I thought that Lycoming solved this problem on later models of the IO-360. I never cruised below 2400 RPM for 14 years on the same Hartzel prop. 

Has anyone on the reflector had a problem with the MT on the IO-540 engines?

Andy
  ----- Original Message ----- 
  From: HYTEC45 at aol.com 
  To: reflector at tvbf.org 
  Sent: Tuesday, April 04, 2006 4:35 PM
  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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