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Hi David,
I started out with the standard Van's 500 wheels and
brakes as provided in the kit for the RV-6A. After my brake failure
incident, I did some research about an upgrade kit I heard about on the RV
list. The Cleveland folks indicate the upgrade increases the stopping
power (energy dissipation by 30-40%). I found out that Aircraft
Spruce offers a upgrade kit for Approx $300.
The standard brake system is undoubtedly OK when the
aircraft weights in at/under Van's recommendation - but when the aircraft is
heavier and lands a bit faster, I feel the standard brakes leave very little
reserve. A couple of hard stops and you will find the brakes beginning to
slip. In any case, I wanted a bit of a reserve in stopping
power.
Well, I did further research and found that the upgrade
consisted of:
1. Thicker rotors (twice as thick as the one that
comes with the kit) - this is the key component as it absorbs and dissipates the
heat better.
2. A 1/8" thick spacer/shim for the
calipers
3. Two longer bolts to accommodate the additional
thickness of the spacer.
4. The standard brake pads continue to be
used.
As an aside, I found that the standard brake fluid has a
flash point of only 240F, so I went to a 450F flash point brake fluid -
compatible with the old fluid and seals.
I also replace the kit brake lines with -3 (1/8")
brakelines with ss braid and Teflon lining inside, they give a much firmer feel
to the brakes. Again, this is not necessary - just my personal
preference.
I found FAA approved rotors for approx $75.00 each for a
total of $150, so I decided to save $150 over the cost of the Kit from Spruce
and ordered them.
When I got the rotors, I realized I needed the
spacer/shim for the caliper to accommodate the thicker rotor. So
I figured how much can a 1/8" thick piece of aluminum with two bolt holes
in it cost? Well, they cost $84.00 each!!!!!. So, I made
my own out of a 1/8" thick piece of 6061T6 aluminum plate saving
$160. I could not believe this shim cost more than the rotors but they
did. I anodized the plate for corrosion protection. You can make
your own with a drill press, a hacksaw and a file. A bandsaw makes it a
piece of cake.
If you retrofit you will find that the thicker rotor will
more than likely require you to space the wheel pant bracket out further with
longer tube spacers on the bolts holding the bracket - else the rotor will rub
against the bracket. While I was at it, I remade the wheel pant brackets
out of 0.05 SS.
Here are the part numbers of interest.
If you want to buy Aircraft Spruce's Complete upgrade kit,
their part number is
#199-93 UPGRADE KIT - For
#199-102 standard wheels and brakes. Upgrades current 40-78B/ 30-9 to new
40-230/30-181 specs. Consists of #66-106 linings, discs, shims, bolts, rivets
and nameplates for two wheels and brakes. $295.65. This kit
has everything you need.
This kit is for the type wheels brakes on the RV series
there are two other kits for Long EZ and Cozy but they are much more expensive
as they include the wheels as well.
Now if you want to roll your own upgrade here are the part
numbers you will need.
2 - Brake Rotors (RAPCO) from Chief Aircraft Part
number RA 164-09900 $79.95
Each
4 - Longer bolts (2 for each wheel) to accommodate
shim thickness
Part Number AN4H-16A (This has the bolt head drilled for safety
wire)
2 - 1/8" thick 6061T6 plate. approx 3"x1" (I used a
brake pad to give me the curve needed to match the edge of the rotor) in which
you will need to drill two 3/16" holes to capture the two AN4H-16A
bolts.
As I mentioned you will probably need to use
longer spacers for the wheel pant brackets, I think I went from 1/2" to 3/4" but
you will need to do it so there is approx 1/8" Min between the rotor and wheel
pant bracket when installed.
You can find the rotors at other sources, but Chief had
the best price and I had deal with them before.
Here are a few links to websites with discussion on the
higher energy brake system
Cleveland brakes - the 199-93 upgrade kit
description starts on page 9 - top of page
Here is the best write up on the upgrade even though its
in context of the FALCO aircraft
Any question, just shoot me a line.
Ed A
----- Original Message -----
Sent: Monday, October 31, 2005 10:04
PM
Subject: [FlyRotary] Brake size (was Re:
Shady Bend Report
Ed, I've missed what kind of "brake upgrade" you
did. If the original Van's/Cleveland? brakes didn't have enough energy
absorption "power", what did you replace them with? Are you still using
the stock Van's size wheels and tires or something bigger in dia to allow for
bigger brake disc and pads?
What kind of options do we have for "size" of
brakes?
David
----- Original Message -----
Sent: Monday, October 31, 2005 9:26
AM
Subject: [FlyRotary] Re: Shady Bend
Report
Hope to see you there next year, Mark.
<snip> Sounds like you are making good progress
(when visitors are not present I was wondering about
your brake size, I am real happy with my brake up-grade, just feels like I
have more authority over where the aircraft goes. I calculated the
ft-lbs of energy required to stop my RV-6A from 60 MPH and decided that the
old brakes were marginal - especially with my somewhat heavier
aircraft.
<snip>.
Ed A
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