REFLECTOR: Matco brakes

Tue May 29 11:36:25 CDT 2007

MessageMe too.  1999 kit, XT upgrade by Matco, 350 hours.  NO PROBLEMS!  Doesn't even chatter while slowing down through 30 knots.  

(Whoops - I did have problems with a cocked pad opposite the caliper.  It was causing the pad not  to retract or ride close to the disk  The guide sleeves were dry - I cleaned and lubricated the sleeves and bolts.  No more problems.)

Ronnie
  ----- Original Message ----- 
  From: Scott Derrick 
  To: Velocity Aircraft Owners and Builders list 
  Sent: Tuesday, May 29, 2007 9:13 AM
  Subject: Re: REFLECTOR: Matco brakes

  I never had a problem with my Matcos with 450 hours of flying???  No interference what so ever, no gear leg heat problems.. 

  I guess I had a later version brake from Matco?  Kit bought in 96, built in 97.

  Scott

  gibbons wrote: 
    Yes the axle flange was hitting the weld on the tube. I had to repair both main gear legs with metal bootees.( cutting off about 6 inches of leg and replacing it with a metal leg, in with Velocity sells them.) I did tell Velocity about the problem so they would let other know about the problem. The plane steers good now with out a lot of braking.
    Barry
      -----Original Message-----
      From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Al Gietzen
      Sent: Monday, May 28, 2007 3:34 PM
      To: 'Velocity Aircraft Owners and Builders list'
      Subject: REFLECTOR: Matco brakes

      Subject: Re: REFLECTOR: [SPAM] Re: Matco to cleveland brakes

      Hello Folks

      I've been having problem with my steering on my plane and some brake problems. It turned out to be the Mattco brakes. The brake back plate was hitting the axle. You can see this problem if you remove the back plate and you will see it riding on the weld around the small pipe. This made my brakes drag all the time, creating too much heat

      Do you mean at the axle flange, or the tube the bolt goes through?  When installing my Matcos I recall noting that issue and chamfering the backing plate to make things work right.  Anyone installing the earlier version Matcos should inspect carefully.

      Here is the text of a memo I wrote to Velocity at the time, but never had a response nor saw any notice:

      To:      Duane/Scott Swing

      @Fax:   407, 589-1893

      From:    Al Gietzen

      Date:     7/22/97

      Re:        Matco Brakes and axle

      When installing the Matco assembly I found that the weld buildup where the lower guide tube for the cylinder bolt is welded into the torque plate, interferes with the axle flange.  They are very close at that lower corner and that weld prevents the torque plate from seating properly, causing the torque plate to get slightly bent when the mounting bolts are tightened; and results in binding on the bolts holding the cylinder.  This could cause the brakes not to hold properly; or more likely, cause them to not release completely when the peddle was released, hence, brake drag and continued heating of the rotor. 

      If this is common to the Matco assembly, a builder who did not notice and grind it off could have some problems.  A definite QA problem on these parts.

      Also, I recall a safety note in Velocity Views a few issues back about overheating of a gear leg, causing it to bend.  My quick analysis of the heat transfer paths indicates that a significant amount of heat would transfer across the small air gap between the rotor and the torque plate.  This could be as important as to the rim, through the bearing and the axle.

      The air gap heat transfer could be reduced significantly by simply reducing the size of the torque plate (increasing the gap).  A change from 1/16" to 1/4" would cut that flow by more than a factor of 4.  The path to the rim could be reduced by placing a spacer of insulating material of some type at the three rotor-to-rim attach points (I haven't looked into what that material might be).  This could also be important to protect the tire.  It seems to me that by the time the leg got hot enough to bend, the temperature of the rim would have to be scorching; enough to damage the tire at the bead.

      I think these fixes may be more effective than a heat dissipation plate between the axle flange and the leg.  Of course it may be that the designers intended the heat to transfer away from the rotor; which is fine if it's mounted on a metal leg.

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