REFLECTOR: Matco brakes

Tue May 29 09:41:11 CDT 2007

Larry,

Your understanding is correct.  The concensus seems to be the upgrade to
Clevelands for the XL is warranted, almost required.  The Matcos don't
seem to handle the little bit higher landing speeds and heavier weight
of the XL, but they do fine on the standard fuselage.  

Chuck Jensen 

 -----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Lawrence Epstein,MD
Sent: Tuesday, May 29, 2007 10:27 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Matco brakes

My understanding is that the problem with the Matco is with the XL and
the standard fuselage doesn't need the upgrade?

Larry Epstein

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Scott Derrick
Sent: Tuesday, May 29, 2007 9:13 AM
To: Velocity Aircraft Owners and Builders list
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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