REFLECTOR: Matco vs Cleveland

[Pat Shea]

The two main factors when evaluating overall braking
performance are braking power and braking capacity.
Yes, I made those term up.

More braking power provides greater deceleration and
the ability to hold the plane still at a higher power
setting during run-up. Braking power comes from the
caliper design (torque rating, poad area, etc) and the
coefficient of friction between the pads and disc.

Braking capacity is the amount of kinetic energy the
brakes can absorb before they fade out. Because
Velocities (especially XL's) are relatively fast and
heavy, this is of far greater concern to us than
braking power - just ask Rob Johnson. The primary
determination of braking capacity is the mass of the
brake disc. Metallic pads are supposed to work better
at higher temps so they also slightly improve
capacity.  

Upgrading the Matco's results in more braking power,
but no real improvement to the braking capacity. I've
done this upgrade on my XLRG and it increased my
braking power by about 30-40%. This enables me to keep
the wheels from rolling up to about 75% power during
run-up. Certainly an improvement, but no big deal in
my mind. On landing, I never used the full braking
power on my original Matco's as it seemed a little
abusive to pilot/plane. 

Here are the design specs for the standard Matco
brakes (from matcomfg.com): 

The WHLW600 is designed for the following standards:
Static Capacity 1860 LBS 
Load Limit 5580 LBS 
Maximum Accelerate/Stop Kinetic Energy 337932 ft-lb 
Torque Rating (@450 PSI) 4473 in-lb 

Here are the design specs for the upgraded Matco
brakes:

The WHLW600XT is designed for the following standards:
Static Capacity 1860 LBS 
Load Limit 5580 LBS 
Maximum Accelerate/Stop Kinetic Energy 337932 ft-lb 
Torque Rating (@450 PSI) 6441 in-lb 

Does anyone know the design specs for the Cleveland
brakes used on the Velocity? That would make for an
easy comparison.

Pat 

--- Chuck Jensen <cjensen at dts9000.com> wrote:

> Kurt,
> 
> You seem to have captured the essence of the
> situation.  I had Matcos on
> an XLRG 300 and I can say that the conversion to
> Clevelands was
> absolutely the right move but it gets consistently
> reported that the
> Matcos are more than adequate for the 173 Elite. 
> 200-300 extra pounds
> at another 5-7kts make all the difference in braking
> demand.  Now, if
> you intend to visit a lot of short fields that are
> high-and-hot, then
> you might reconsider, but since you already have the
> Matcos, it doesn't
> strike me as important that you convert to the
> Clevelands.  Others may
> have higher quality opinions to share.
> 
>  
> 
> Chuck Jensen


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