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10-30-2006, 04:24 AM
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Join Date: Apr 2006
Location: Lantz,Nova Scotia ,Canada
Posts: 556
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Having been in the Aircraft firefighting business for the last 26 years as well as a recreational pilot, I have come to the conclusion that prevention is the key. Even if the integrity of the firewall is not compromised the surrounding aluminum would fail in seconds in the event of a wind driven, fuel fed fire.
The industry standard for aircraft skin burn through is three minutes on an airliner (thick stuff) but from what I've seen that appears to be a little optimistic. The thin materials we use wouldn't last very long. I would say that the general trend of the responses are on the right track , use the proper material as correctly as possible and check it often.
RV 8 Fuselage
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10-30-2006, 08:06 PM
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Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
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Quote:
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Originally Posted by Paul Tuttle
Having been in the Aircraft firefighting business for the last 26 years as well as a recreational pilot, I have come to the conclusion that prevention is the key. Even if the integrity of the firewall is not compromised the surrounding aluminum would fail in seconds in the event of a wind driven, fuel fed fire.
The industry standard for aircraft skin burn through is three minutes on an airliner (thick stuff) but from what I've seen that appears to be a little optimistic. The thin materials we use wouldn't last very long. I would say that the general trend of the responses are on the right track , use the proper material as correctly as possible and check it often.
RV 8 Fuselage
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Amen to all of that!
Rv6ejguy reported some very interesting test results at 1500 degrees but the bloody reality is if there is 1500 degree fire roaring up front, you can kiss your butt good bye (if you can reach it) no mattery how encased everything is foreward of the firewall. Your best chance is to turn off the fuel valve, zip up the nomex flight suit and hope to land before things melt completely. For sure the fiber glass cowling will be gone quick.
The only thing that gives me a warm and fuzzy feeling doing what we do are decent fuel lines that are not likey to break and a good quality electric system. (I had not considered a nomex flight suit but am thinking about it.)
Some may think the high pressure fuel lines with the Subaru are not acceptable in an aircraft, but look at it from this perspective. When was the last time you heard of one rupturing in a car or airplane? They are used in millions of installations everywhere on the planet. The OETIKER clamps that hold them in place are about as bullet proof as anything can be. (never use screw clamps!)
Aeroquip is "aircraft" quality plumbing. But don't rest your laurels on it. Years ago, I had a Long EZ with a troublesome primer and when testing the system with the cowl off, notice the little 4-7 psi Facet pump was pushing fuel through the Aeroquip hose like a sieve. The entire line was wet with 100LL. It turned out to be a bad batch of rubber, fuel was desolving it and I'd been flying the airplane for some time in that condition. With the pump off, the hose dried quickly and a visual inspection revealed nothing. Most everyone switched to 666 teflon after that fiasco. There was an AD on that batch of hose.
There should be a federal law prohibiting copper primer lines. I had them on a 0360 and they broke.
Ignition source concerns me a lot. A fuel leak is a relevant non event unless something lights it off. Exhaust systems must be checked regularly. Also electric leads to the starter and altenator must be secure. I believe most car fires are electrical due to battery failure and/or alternator failure. I have my batteries mounted on the cabin floor just forward of the fuel valve. If they act up - like get hot - I will know it right now.
All this, just my 2 cents worth. We all face the same risk and deal with it in our own way. So far, so good. 
dd
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10-31-2006, 12:51 AM
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Join Date: Feb 2005
Location: Torquay, Victoria, Australia
Posts: 826
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Put it out!
Lots of fire fighters on this forum and they will all tell you what you need for a fire. Fuel, Oxy, Ignition.
Whilst prevention is the Holy grail, puting it out comes next.
Not to comment on the fire discussed here (which is reported to have burnt for "few minutes") as the full details have not been printed, but if fire is evident, airborne or on the ground, TURN THE FUEL OFF.
With a fuel injection system there is not much fuel in the lines to burn and only a little more if a carby bowl releases its contents, so turning the FUEL OFF should extinguish the fire. It will certainly stop a torching type fire continuing whilst being supplied with high pressure fuel.
We would all love to have an engine bay fire system, if it weighed nothing and was free. If you do install one and you have a fire; ensure you turn the fuel off and give the fire time to die down before dumping you precious extinguishent. 30 sec delay is the airline standard.
Pete.
Gee George. Never thought I would write more than you. Dunder Pete.
__________________
Peter James.
Australia Down Under.
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10-31-2006, 04:53 AM
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Join Date: Nov 2005
Location: Asheville, NC
Posts: 2,692
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Although the report that began this thread (of the RV-6) indicated the cabin was not penetrated, I did see the after effects of a similar failure on an RV-4 last year. The fuel pressure sense line failed on crosswind approach and the fire melted the aluminum floorboards under the rudder pedals before the pilot got out. This event will cause me to improve the cabin protection over and above what is provided in the kit.
__________________
Bill Pendergrass
ME/AE '82
RV-7A: Flying since April 15, 2012. 850 hrs
YIO-360-M1B, mags, CS, GRT EX and WS H1s & A/P, Navworx
Unpainted, polished....kinda'... Eyeballin' vinyl really hard.
Yeah. The boss got a Silhouette Cameo 4 Xmas 2019.
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10-31-2006, 04:20 PM
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Join Date: Feb 2005
Location: Torquay, Victoria, Australia
Posts: 826
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Alarming
This is pretty alarming. I'm thinking like Bill.
I know one of the Vans boys had an exhaust pipe fail, but the exhaust gases though impinging on the cowl -at low power drift down- did not burn through the cowl, which has fire resistant impreg.
So I assume these fires exits the engine bay via the cowl outlet.
If this is the case, would it be sufficient to cover the lower Al. skin in this area with SS?
If so, how far back?
Pete.
It also highlights the point in my last post. It may be better to close the throttle, pull the mixture lean, turn of the fuel, turn the fuel pump off and maybe the master and dead stick it.
Pete.
__________________
Peter James.
Australia Down Under.
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10-31-2006, 07:57 PM
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Join Date: Jan 2005
Location: Mtns of N.E. Georgia
Posts: 1,322
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Fire
Whilst (down under for "while", gotta love it!) we're fighting this fire; thought I'd throw my $.02 in.
Before shutting down after my last flight a couple of weeks ago, I briefly smelled raw av-gas. Last week I had the cowl off, finally getting around to installing the cabin heat on my -8 when I read Vern's post about the fire.
I thought I would pressurize the fuel system to look for a leak. When I did, I found fuel leaking out around the mixture shaft on the FI Servo Unit. Only happened at the middle of the mixture range, not at ICO or full rich. Wasn't much, but enough to scare the Bejesus outa me and think Crispy Critter.
Needless to say, the Servo and Flow Divider is now with Don Reviera at Airflow Performance in Spartenberg, SC. being overhauled.
Mannan Thomason Msgt USAF (Ret)
RV-8 N161RL (No. One Girl)
Almost 50 hrs Saving For Paint
(Gonna take longer now with this setback)
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03-24-2007, 05:06 PM
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Join Date: Mar 2007
Location: Upper ny
Posts: 78
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fire...all-stainless fuel lines?
I occasionally ask aero parts places, and auto stores about all stainless fuel hard tubing and fittings. I never get a good lead. It seems that correctly mounted and designed, stainless would be worth the pound or so it adds to the plane. Lots of posts prase steel, but never stainless? I'm not interested in decorating with shiny braid. Wool is a low toxic fire resistant barrier. It's used in some heavy duty welding uniforms.
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03-24-2007, 05:23 PM
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Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,147
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Stainless is (relatively) cheap and easy to work - I use a large amount of 1/4" OD 316 stainless for high pressure air work, rated for 10,000 psi, .180" ID, that should flow enough fuel for our purposes. I also occasionally use 3/8" OD with a .290 ID rated for 7500 psi, that would work as well with less pressure drop. Easily formed by hand, but a real tubing bender makes it look professional. I buy the stuff for about $1.50-$2 (depends on size of order) per foot. Flareless compression fittings for the ends average around $3 each. It is absolutely tops in my book, and I will use it for all fuel and oil lines. Speaking of which - I also have 1/8" OD stainless for oil and fuel pressure gauges. I'll still put fireproofing wrap on it, just to avoid heat transfer with vapor lock in mind.
PM me if you need a chunk, I buy it in 20' sticks and have LOTS of scrap laying around.
__________________
Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2020 dues paid 
N16GN flying 700 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, 430W
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
Last edited by airguy : 03-24-2007 at 05:27 PM.
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03-24-2007, 05:56 PM
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Join Date: Mar 2007
Location: Upper ny
Posts: 78
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[quote=airguy]Stainless is (relatively) cheap and easy to work - I use a large amount of 1/4" OD 316 stainless for high pressure air work, rated for 10,000 psi, .180" ID, that should flow enough fuel for our purposes. I also occasionally use 3/8" OD with a .290 ID rated for 7500 psi, that would work as well with less pressure drop. Easily formed by hand, but a real tubing bender makes it look professional. I buy the stuff for about $1.50-$2 (depends on size of order) per foot. Flareless compression fittings for the ends average around $3 each. It is absolutely tops in my book, and I will use it for all fuel and oil lines. Speaking of which - I also have 1/8" OD stainless for oil and fuel pressure gauges. I'll still put fireproofing wrap on it, just to avoid heat transfer with vapor lock in mind..........................What I'm still hurting for is the fittings, valves, and tools. Is there a catalog that will satisfy all-stainless fuel handling? I know to use flexible hose to the carburetor.
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03-24-2007, 06:35 PM
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Banned
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Join Date: May 2006
Location: Phoenix, Az
Posts: 920
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Flex hose only!
I can't be sure from some of the posts........so I want to post a clarification of what I understand to be the facts in this accident. Rigid metal tubing running between the moving engine (because of rubber motor mounts) and the stationary firewall was the cause. Van's clearly calls for flexible hose on all of these connections, but people don't seem to understand how much the motor moves around, especially during start and shutdown, and many people have made this compromise.
Fire sleeve wouldn't/couldn't keep a rigid tube from failing in this location.
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