Colyn,

 

Note that 300 series Lancairs use aircraft plywood for the core of the firewall, one layer of glass on each side and many layers of glass in the engine mount and support gusset areas.  That glass has not been cured in an oven and will soften at a temperature well below 280F.  The wood remains rigid until it chars.

 

Turbines aside, Engine compartment fires may be oil or gas or, possibly both after a while.  Oil from a significant "leak" will be blown overboard rather quickly until the engine seizes.  Fuel can be shut off from reaching the engine compartment, thus one would want easy access to the shutoff valve leading to the engine compartment (unfortunately, the 200/300 series puts the header tank shutoff deep into the passenger foot well).  A high speed dive has the possibility to snuff the fire by screwing up the A/F ratio.

 

All flexible fluid lines in the engine compartment should be the best (like auto racers, I believe that only steel-ended fire-sleeved teflon-SS covered lines meet that requirement).

 

Engine fuel fittings should be steel.

 

It is common aviation practice to use aluminum fittings for oil since they are beefier when larger than the -4 size.

 

Now, all that is left to worry about is that maintenance assembly problem where a connection was left finger-tightened or a small exhaust leak that becomes focused on some flammable fluid carrying part.

 

Crashes with the engine running are a different problem.

 

Cockpit fires are a different problem (open air vents and extending the gear may allow more air to enter the cockpit and feed the fire).

 

Finally, Lancairs without cabin pressurization will have the cockpit pressure less than the engine compartment pressure whilst joyfully operating at high speed and at any elevation.  There must be NO firewall openings that would allow passage of any engine compartment gasses into the human occupied cockpit, thus eliminating flames or flame by-products (like CO) to pass.  Review the security of the heating system for the same reason.

 

Uh, in case of fire you may want to shut down air vents where the intakes are located just aft of the cowling.  Just saying.

 

Scott Krueger

 

PS No, I don't wear a smoke hood or a nomex fire suit. No stinking parachute either.  Risk is manageable. The perfect outcome may not always be economically possible (think of Fed death panels).

 

The data on the blanket may be available from HI-Temp INsulation Company in Camarillo, CA.

...and it may be available from Lancair.

I remember that:

- it passed a 2000 dF/15 minute burner test to establish compliance with AC 20-135

- backside temp after 4 minutes was over 300 dF

- backside temp after 9 minutes was over 500 dF and slowly rising after that.

I would be interested in any data on the SS/Fiberfrax approach.

Things that concern me about the LIV-P firewall:

- I'm told that pre-preg loses structural integrity around 280 dF.   That would give you 3 minutes to get it on the ground by above numbers.

- The engine mount will conduct heat directly into the firewall

- The cabin air valve includes plastic components

- The rubber grommet approach for through holes I'm told will convey smoke into the cockpit.

- At 3000 fpm it takes 8 minutes to get down from FL240

It seems to me SS might to some degree mitigate the above issues. If I had it to do over again maybe:

- Blanket over SS

- Fully SS air valve

- Improved through holes with connectors fastened to the SS

- What does FiberFrax do?

In the meantime I have temp sensors around the engine compartment and a Halon canister in the back plumbed to the engine compartment. (To be used after fuel shutoff, prop stopped-to stop pumping oil, electrical off, airspeed reduced - to reduce Halon dilution)

It is true that vigilant maintenance is the most effective strategy.   On the other hand it got my attention when my "brand new" exhaust system leaked enough to burn through a blanket near the gascolator. (exhaust system since replaced).

On Jun 29, 2012, at 3:28 PM, Steve Colwell wrote:

Is there someone out there that would like to make a comparison (cost, utility, performance et al) between the blanket and the stainless/fiberfrax installation?
Jim

 

I was stressing out over the best possible fire protection by looking at fire resistant: Paint, Firewall Penetrations, Sealants, etc..  My conclusion was to do the best job I could on fire prevention (fuel lines, anti-chafe, heat shielding, exhaust pipes, fire sleeves) and have a procedure for getting it on the ground as quickly as possible with fuel and ignition off.

Why?  A local Aerobatic Performer flying a Harmon Rocket had a FWF fire in the pattern.  He got it on the runway asap, but not before a hole was burned in the belly.  He died of smoke inhalation.  The odds are not good on a in-flight FWF fire, has anyone heard of a successful conclusion? 

 

Steve Colwell  Legacy

 

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