REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable

[John Tvedte]

Mark,

You’ll end up with a slot in the bottom of the cowl rather than 3 openings – using the factory solution.  Looking at Custom Aircraft’s solution – it may not be obvious – but the pipe sizing is enlarged for the bottom pipe section – which the other two pipes feed into.

If I remember correctly those pictures are of Pat Shay ‘s velocity – which is a very nice flying example of a Velocity.  I have more pictures of his engine installation if you are interested.

I’m with Ruben on the oil cooling issue – Vernatherm – need to also check the case for uniform seating.

On the pinhole potential – I would suggest you examine closely the EGT sensors – and location of the holes for these relative to the aileron cable(s) , any cracked welds and even signs of leakage around the exhaust gasket.

John

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Mark Magee
Sent: Thursday, November 10, 2011 11:14 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable

Scott,
I really like that exhaust header. Do you believe it is as efficient as 3 straight pipes? The thing I like about the 3 straight pipes is possible cooling benefits from efficient extraction and the three holes per side on the bottom cowl could evacuate some additional cooling in the downflow from the engine baffling. Any thoughts?

Mark B. Magee
Sent from IPhone

On Nov 10, 2011, at 9:22 AM, Scott Derrick <scott at tnstaafl.net<mailto:scott at tnstaafl.net>> wrote:
Mark,

Custom Aircraft might be the best exhaust fabricators in the business.

http://www.customaircraft.com

Here is a picture of what my exhaust looks like.  This is of a Lycoming and mines a Continental but looks very similar.

http://www.customaircraft.com/images/33912A.JPG

Scott

-------- Original Message --------
Subject: Re: REFLECTOR: XL FG Hi Temps/ Siezed Aileron Cable
From: Mark Magee <edjonesbrady at gmail.com><mailto:edjonesbrady at gmail.com>
To: sbjknox <sbjknox at earthlink.net><mailto:sbjknox at earthlink.net>, Velocity Aircraft Owners and Builders list <reflector at tvbf.org><mailto:reflector at tvbf.org>
Date: 11/10/2011 05:46 AM

Sid,
Your pic labeled "Burned Cable" looks eerily like my first seized cable and the damage it had. I believe I need to begin confirming a pin-hole leak in the stbd side exhaust manifold. I wonder if this is not a good time to consider going to 3 straight down pipes per side? Certainly the straight down pipes have far fewer welds. No?

Mark
On Wed, Nov 9, 2011 at 10:15 PM, sbjknox <sbjknox at earthlink.net<mailto:sbjknox at earthlink.net>> wrote:
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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While I see many hoof marks going in, I see none coming out. It is easier to get into the enemy's toils than out again.

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