Firewall Insulation

[DanH]

§ 23.1191 Firewalls.

(f) Compliance with the criteria for fireproof materials or components must be shown as follows:

(1) The flame to which the materials or components are subjected must be 2,000 ±150 °F.

(2) Sheet materials approximately 10 inches square must be subjected to the flame from a suitable burner.

(3) The flame must be large enough to maintain the required test temperature over an area approximately five inches square.

(g) Firewall materials and fittings must resist flame penetration for at least 15 minutes.

§ 23.1182 Nacelle areas behind firewalls.

Components, lines, and fittings, except those subject to the provisions of §23.1351(e), located behind the engine-compartment firewall must be constructed of such materials and located at such distances from the firewall that they will not suffer damage sufficient to endanger the airplane if a portion of the engine side of the firewall is subjected to a flame temperature of not less than 2000 °F for 15 minutes.

[Bill Wightman]

Great work, Dan.

There's some sensitivity to weight of course, esp added in the nose of an 8. About how much weight would the insulation kit add? How thick is the material? The metallic shield used - what's needed, what are you testing? Impressive results! Thanks...

[flyboy1963]

Dan,
a note to say how much we all appreciate your efforts to save us from ourselves.
I voted 'very interested' before seeing it was engine side...sorry.
I am not about to pull my FWF to do this, much as I'd like to.
I will have to be satisfied with my cabin side insulation, which is various layers of the least toxic stuff I could find.
....a side note, does anyone else find it strange that we have this little 'bomb', the brake reservoir, on the firewall, with a nice big hole thru to the cabin, so its plastic fittings can burst and spray flaming fluid on our legs when it reaches just a few hundred degrees??????????????

[JonJay]

... as discussed to infinitum before in other threads, the firewall itself is only part of the problem. I think most would be interested in a cost effective "system" rather than just the materials. You might get more interest with a system, methodology, or construction approach rather than just a material approach.

Also, some real statistics on engine fires, injuries, and/or fatalities would be appropriate. I think it is pretty presumptious statement that an engine fire "will" produce injury or death. Likely? perhaps....
Now, anything that prevents even one injury or death is worth pursuing so not arguing or putting down the time and efforts as not well spent.

[scsmith]

I put the individual reservoirs on my brake master cylinders.

I was afraid there would be interference with the firewall when the rudder pedals are all the way forward ( RV-8 flight-adjustable pedals) or that they would limit the range of adjustment of the pedals. I am 6'1". This turned out to be no problem at all for me.
So I am very happy with these.

It gets all the leak sources out of that part of the brake system, and gets the 'bomb' off the firewall.

[scsmith]

Dan, it sounds like you have constructed essentially a double-wall firewall by putting a second plate in front of the firewall on standoffs?

If that is the case, is there any reason why something similar could not be done on the cabin side? And in that case, could it be aluminum?

So, for example, on all the stiffening angles on the cabin side of the firewall, rivet on a second set of angles to form channels, and then a sheet of 0.032 aluminum pop-riveted or screwed to those channels. It would extend over as much of the cabin face of the firewall as possible, but not contact the side skins and longerons. So it would create an air gap and radiant heat barrier. Since it would not get direct conductive heating from the firewall, it could have a sound-proofing mat on its front face (in the space between the firewall and the shield). This mat would not pose the same smoke/toxic risk since it is on the shield piece, not the firewall, and would not get conductive heating (except through the mounting angles).

It would be difficult, but not horrible, to install this on a finished airplane.
What do you think?

[L.Adamson]

Originally Posted by flyboy1963

....a side note, does anyone else find it strange that we have this little 'bomb', the brake reservoir, on the firewall, with a nice big hole thru to the cabin, so its plastic fittings can burst and spray flaming fluid on our legs when it reaches just a few hundred degrees??????????????

No................. I figure that by that time; the top cowl will be completely melted away, and the canopy won't be doing too well either....

Of course I'll shut off the fuel, to eliminate the worst source.

L.Adamson ---- RV6A (flying)

[axlr8r]

Would also like to know about the weight.

Thanks for your efforts

Steve

[jlk]

I'm a new guy here, just been lurking until now. I just received preview plans for a 7A and I think I am going ahead with it.

Anyway, the reason I am writing (I am no expert) is there are some neat light materials that could be placed on the cabin side of the firewall.

http://www.infraredheaters.com/insulati.htm

http://www.mauritzononline.com/indus...a-fabrics.html

http://www.mauritzononline.com/indus...ca-1-side.html

The stainless steel firewall on the RV series should contain flame but not heat. Fireproof insulation on the inside of the cabin seems to be the most effective means of lenghtening survival time.

The first link above is spun ceramic blanket material and the third is a reflective high temp silica fabric. The second is a very high temp fabric that does not have the reflective surface. The ceramic would go against the firewall on the cabin side and the fabric on top of the ceramic with the aluminized side toward the ceramic to act as a heat reflector. I would estimate the weight of the combination at about six pounds and cost $150-200 in materials. There may be commercial blankets with this structure already available, I have not tried to source it. Some further research would be necessary to find the best combination of materials.

If you haven't seen the spun ceramic blanket, it is the same type of material that the space shuttle heat tiles are made of.

Just a thought. Keep cool.

Jordan

[jimgreen]

Hi Dan. Yes, I'd be interested. Do you have a sketch of how this would work? Seems firewall penetrations would be problematic.