Tips for firewall insulation on a flying airplane?

Hi, all... I've read the numerous threads discussing firewall insulation strategies (materials, front vs back, etc). I'm curious if anyone has experience adding insulation to a flying airplane, and if so, what advice you have. My main objective is to reduce heat in the cabin.

Thanks...

-Rob

p.s. yes, before anyone points it out, I should probably land the airplane and shut down the engine rather than try to add insulation to a flying airplane.

what I did..

Rob, lots of good threads on here, especially older ones where Dan H. blowtorch tests a bunch of stuff....and shows that very common 'firewall' insulation is not really even fire-resistant'...just insulation!
I have a -9, but much of this is general enough.

I did a sketch of my interior, and coloured with crayons the firewall and floor red, the sides and cowl pink, and the rest up to my butt, yellow.
the red zone got 2000 degree stuff, the pink zone 1000 degree stuff, etc.
for instance, I used fibrefrax on the floor, encapsulated in foil, then a mat of the automotive flexible stuff, then the lousy black foam insulation, (also foil-enclosed) just to build up to carpet level. The carpet & all upholstery I soaked with fire retardant, even tho it was pretty much self-extinguishing anyway.
There are still serious holes in the protection envelope, but I think I bought a few seconds of protection...not kidding myself there...but I think I reduced the risk exposure a few degrees.

I'm interested as well.

I'm not flying yet, but am closing in on it and haven't done anything with the firewall insulation wise. With lots of stuff poking through it, doing a full blown Dan Horton style, this is the best way possible treatment isn't really that realistic.

Having read through all the threads till I'm dizzy, I'm wondering if there is something that is "relatively" easy to apply that won't outgas and kill me under anything other than normal temps.

I know a lot of folks have just gone bareback, but it would be nice to get at least something in there, (on the cabin side so it won't soak up oil like a sponge or look hideous in the engine compartment) that will offer some level of insulation during normal ops and not be worse than nothing in a fire. My feet feel like they're on fire when the wife just turns up the floor heat in the car!

Thanks guys. Since there are already *plenty* of threads discussing what to use, I started a new thread specific to tips on retrofitting something on an existing airplane.

-Rob

The only difference are the gymnastics you got to play to get the insulation on the firewall. As long as you don't mind laying on your back under the panel, shouldn't be a problem.

The stuff that I used that was sandwiched between the sheets of aluminum and stainless, was a bear to work with. The stainless foil can do a nice job on your fingers if you don't wear gloves.

I installed mine at First Annual

On my 8a when I had all the baggage floors and sides out for inspection I install the self sticking foam type with aluminum layers against the firewall and on the floor back to the rudder peddle bar. The way I did it was to take old cardboard folders and cut them to fit each panel space then cut to fit. Once I installed them I tool strong aluminum AC tape and covered the joints. Made a world of difference in noise and heat reduction. Pain in the butt doing the work through the baggage door hole and under the panel! It was worth the trouble. Bought a sheet of the material from ACS. Best of luck, Bill RV-8A Bluebird

I just did the full blown "Dan Horton" method on the hot side of the firewall of my RV-8a that has been flying for 4 years and 400 hours. It's not hard, it just takes work. Much like building the airplane in the first place. Here was my process.

1. Remove all Adel clamps, pressure transducers, heat box, etc from the firewall. I removed anything that didn't penetrate completely. The motor mount and penetrating cables were left in place. I left all of these items dangling from their associated wires or hoses, tying to a motor mount where needed.

2. Washed firewall with dilute aviation simple green, followed by an Acetone wipedown.

3. I made a couple of stainless steel shields for some penetrations to improve on work done in the past. These were backfilled with intumescent caulking (3m Firebarrier 2000+) during install.

4. I used grid printed posterboard from Staples to make full sized templates of the firewall with penetrations. For my 8a, I had two templates, one left one right.

5. I used the template to cut fiberfrax and .003" stainless steel.

6. Installed the fiberfrax and stainless steel. The SS overlapped in the center. I sealed the overlap and edges with high quality aluminum tape to keep oil out and temporarily secure.

7. Sealed the perimeter, penetrations, and the edges with intumescent caulk.

8. Pushed the tail end of a pop rivet from the inside out to puncture the fiberfrax and dent the foil at screw locations. I then hammered the same rivet tail outside to in at those locations to puncture the foil. The holes were easily enlarged at that point by wallowing the rivet tail around.

9. Re-secured all firewall mounted items.

10. Drilled and added pop rivets with washers to secure the sandwich to the firewall where needed.

11. Touched up the caulking.

Other tidbits. I have 3 (aluminum) eyeballs for control cables that penetrate my firewall. I caulked over and around these, let the insulation overlap with no ability for the SS to touch the actual cables, and then caulked over that whole mess. I should have used SS eyeballs originally, but it would be a big deal to change now. Maybe a project for another time.

Except for my heater bowden cable, which I made a SS shield for this time, my other penetrations were pretty good. I have a SS heat box (a must in my opinion) and SafeAir1 cable pass-throughs for electrical.

I suggest wearing rubber gloves while handling fiberfrax. It's rough on the skin.

Best,
Guy

templates

Guy, Is there any chance you still have your templates and would think about selling them. I would like to do that approach to my 8A. Thanks Ron

868RM said:

Guy, Is there any chance you still have your templates and would think about selling them. I would like to do that approach to my 8A. Thanks Ron

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I did not keep them. They probably wouldn't help much due to differences in firewall penetrations anyway. They were not works of art; I just cut bits to the approximate shape and then used other bits and lots of tape to get the whole shape. It went much faster once I quit trying to make the template out of one piece. It was lots of little pieces taped together. I cut it in half, still on the firewall, with a centered vertical cut after it was complete

Firewall Insulation

Guy ( & Dan H. )

Would you have any pictures of your firewall that you wouldn't mind sharing. I will need to do the same in the spring and would like to have a look at how you did it.

Thanks

Bruno
[email protected]

49clipper

Is there any reason not to use fiberfax on back of firewall and then sandwiched with a sheet of AL on back side? My firewall is SS, but am looking for a good method to add fire protection and noise abatement. New build. I could use .010" SS on back, but just harder to work with.

49clipper said:

Is there any reason not to use fiberfax on back of firewall and then sandwiched with a sheet of AL on back side? My firewall is SS, but am looking for a good method to add fire protection and noise abatement. New build. I could use .010" SS on back, but just harder to work with.

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Fiberfrax inside the cockpit would be a BIG no no. It off gases when heated. Almost anything inside the cockpit for fireproofing would we be a no no for the same reason as well as some materials will actually transfer the fire.

jcarne said:

Fiberfrax inside the cockpit would be a BIG no no. It off gases when heated. Almost anything inside the cockpit for fireproofing would we be a no no for the same reason as well as some materials will actually transfer the fire.

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Fiberfrax felt has an organic binder (think "glue") to tie all the fibers together. Burn a piece of it with a torch. The binder will smoke and may burn. When it's gone, the fibers will be loose and the piece will fall apart.