REFLECTOR: Aluminum Tubing for Brakes

[Ron Brown]

The age of nyloflow has a lot to do with UV damage.  Since most of mine is 
hiding in conduit and fuselage, I don't think there will be a problem.

The nyloflow is tough and is good for 1000 psi, hydraulic pressure for the 
brakes is around 300 psi.  The brass fitting is tougher than either the nylo 
or aluminum tubing - not to worry about it.

Aircraft Spruce PN 03-39200 ($1.50 per foot) is a 3/16" aluminum tube that 
could be used (but isn't really necessary - but lots of folks had rather use 
it - Velocities and RV's).  Cessna uses a similar tube for its brakes with a 
loop at the bottom as it enters the caliper.  I didn't do the loop since the 
nyloflow gives some flexibility at the top.   You could also use Aeroquip 
but that gets expensive - about $6.50 per foot and it still has plastic 
(Teflon) hose on the inside and is good for about 1500 psi.

With an RG, you would have to put in some kind of flex tube at the top. 
But since you have an FG, then you could use aluminum tubing.  By the way, 
aluminum tubing is more subject to vibration wear than nyloflow.  I had one 
wear a hole through on my low time (1700 hours)172 - rubbing on the gear leg 
as I recall.

Happy Building!
Ron

----- Original Message ----- 
From: "Grigore Rosu" <grosu at cs.uiuc.edu>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Wednesday, March 08, 2006 8:42 AM
Subject: Re: REFLECTOR: Aluminum Tubing for Brakes


> Ronnie,
>
> Thanks for the picture.  So, if I understand correctly, you used the 
> standard nylaflow all the way as suggested in the manual, except that you 
> used the nylon conduit instead of the suggested drinking straws on the leg 
> down and except that you replaced the last 8" by an equivalent in size 
> aluminum tube.
>
> I'm not a mechanic and really don't know how much vibration one really 
> gets in the leg, but I feel it natural to ask whether the additional brass 
> tube fitting connecting the aluminum and the nylaflow may be affected by 
> the vibration provoked by the wheel during landing ... Wouldn't it be also 
> a possibility to use aluminum tubing all the way on the leg and put the 
> brass fitting closer to the fuselage?  Is it a matter of price?  I mean, 
> is this aluminum tubing expensive?  BTW, where can we get aluminum tubing 
> from to replace the nylaflow?
>
> Grigore
>
>
>
> On Wed, 8 Mar 2006, Ron Brown wrote:
>
>> Here's a picture.  The nylon conduit stops about 8" short of the caliper. 
>> Then aluminum tubing runs down to the caliper to minimize heat transfer 
>> to the nyloflow from hot brakes.
>>
>> Ronnie
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