REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable

[aminetech at bluefrog.com]

Sid,

Can you explain the mechanism that caused the fire?

Thank,

John

--- sbjknox at earthlink.net wrote:

From: "sbjknox" <sbjknox at earthlink.net>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Subject: Re: REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable
Date: Wed, 9 Nov 2011 22:15:28 -0600

From: "Scott Derrick"

Subject: Re: REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable


> Shielding of the exhaust manifold is recommended where the aileron cables
> come in close proximity to the exhaust stack.

In the past I have had two experiences with siezed aileron cable.  The first 
was from a broken exhaust pipe that sprayed hot gas on the cable (also 
melted aileron servo housing).
The pipe broke at the point of 'strengthened weld' in the photo "Exhaust 
mod.jpg". The original pipe was designed by monkeys as that long sweeping 
curved portion was un-braced and just waiting to vibrate and break... which 
it did.
Couldn't move the ailerons but with rudders and  little wind, landing was 
non-event.

I modded the pipe to have a 'vibration damper' (see photo) and added a 
second safety cable.
I also added a SS heat shield on both sides.

The second time was from a gas-fed engine fire during climb-out.  I had no 
clue something bad was happening back there until the engine started 
missing,  I called the tower and turned back not much concerned at that 
point because I knew I could make the field but when the ailerons started 
getting stiff I knew I had a fire and the pucker-factor jumped an order of 
magnitude!  I made it back with no further problem other than a very rough 
engine from the burned ignition wires (see photo "Burn Damage.jpg").  The 
fire was out by then and the ailerons were locked solid.

Originally  there was no fire sleeve on the cables but of course there is 
now!
And a "sniffle valve" (spelling?) was installed.  Had one been installed 
before, that fire would not have happened.

Sid Knox
Oklahoma

Velocity  173 RG  N199RS
Starduster  N666SK
KR2         N24TC
W7QJQ


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