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RV10 cabin side fire wall insulation pattern

flysrv10

Well Known Member
Looking for the pattern to cut firewall insulation for the cabin side of RV10? CAD drawing, dimensioned drawing or full size patten will all be great. Thanks.
 
Cabin side insulation has been discussed on here at great length, are you aware of the hazards with doing so? Perhaps a search on these forums would help.
 
I insulated the interior firewall on my RV-10 when I built it. I used a piece of cardboard and traced the firewall on it, then measured the approximate interior bracing and went from there cutting and fitting piece by piece. Turned out OK and kept the firewall heat at bay. I also was apprehensive of doing it but figured if Cessna put it on my C-152, good enough for me. This time around I decided to insulate and fire-stop on the engine side of the firewall using 1/8" fiberfrax and .005 SS sheeting on my 9-A. It took a lot of time since I had to remove the previously hung engine and mount,,,,,,Then strip the firewall of the PAINT the previous builder applied. :mad: I had already decided I would strip the paint when I purchased the project so engine and mount removal was going to get done anyway. There was some discussion on the forum around the same time about the firewall fire-stop so I decided to just go ahead and do it following DanH method.
 
Thanks Ron for your concern. Yes I have been researching it and will continue to do so. I came across this company http://www.pegasusaeromarine.com/aircraftSystems/rv10/index.html#firewall that sells acoustical fire wall. The guy seems to be very knowledgeable regarding aircraft insulation. Unfortunately, he no longer makes pre-cut panels. No enough biz.

Thankfully.

Quick review. The usual vendor claim is "Our materials all pass FAR 25.853(A) - 12 second vertical burn." or similar. That's the standard for upholstery and cabin sidewalls in passenger areas of Part 25 airliners. It means the material will self extinguish after the heat source is removed. The test is conducted with a small burner; think Little Johnny playing with his father's Zippo.

It is important to understand that an FAR 25.853 material is not fireproof. It can and will continue to burn if the external heat source is not removed. As such, FAR 25.853 is not a suitable standard suitable for a firewall, or the floor immediately aft of the cooling air exit.

First, per FAR Part 23 (see below), the typical "hot spot" is 25 sq inches of firewall metal at 2000F, meaning vastly more heat energy than the vertical burn test. Second, and perhaps more critical, is that the heat source cannot be removed. The pilot doesn't have any direct control of an engine compartment fire, or exhaust system failure.

As noted, there is plenty to read if you search VAF. Here's the quick version:

http://www.vansairforce.com/community/showpost.php?p=476353&postcount=20

Hands down, the best overall thermal performance for both ordinary comfort and fire protection to to place a reflector over an insulator on the engine side of the firewall. It probably also has some unmeasured effect on sound transmission. There is no safe sound insulation for the cabin side.

BTW, theses are the FAR's applicable to firewall insulation:

§ 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.

 
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Hands down, the best overall thermal performance for both ordinary comfort and fire protection to to place a reflector over an insulator on the engine side of the firewall. It probably also has some unmeasured effect on sound transmission. There is no safe sound insulation for the cabin side.
...

Dan, a request for clarification: Do you mean this as an absolute, meaning even if the engine side is treated according to your recommendations, that no acoustical insulation can be applied safely to the inside of the firewall; or that there is no safe sound insulation that can be applied to the inside absent proper engine side fire insulation?
 
Apples and oranges

Dan and I have discussed this in the past concerning my RV 10------

The qualities that make sound insulation work well are the issue. These materials tend to burn----or put out really nasty gases even below ignition temp.

The materials that stand up to the heat levels needed no not insulate sound very well.
 
On my 6, I used a foil+f/g+adhesive (search cool matt) on the engine side of the firewall to keep unwanted heat out of the cabin. It has worked well for me on the 6 and will do the same on the 10. Not as good as Dan's approach, but definately better than nothing and easy to install. While nothing but the adhesive can burn with fumes, it doesn't matter as it is on the engine side. This provides no acoustic improvement.

Larry
 
Thankfully.

Quick review. The usual vendor claim is "Our materials all pass FAR 25.853(A) - 12 second vertical burn." or similar. That's the standard for upholstery and cabin sidewalls in passenger areas of Part 25 airliners. It means the material will self extinguish after the heat source is removed. The test is conducted with a small burner; think Little Johnny playing with his father's Zippo.

It is important to understand that an FAR 25.853 material is not fireproof. It can and will continue to burn if the external heat source is not removed. As such, FAR 25.853 is not a suitable standard suitable for a firewall, or the floor immediately aft of the cooling air exit.

First, per FAR Part 23, the typical "hot spot" is 25 sq inches of firewall metal at 2000F, meaning vastly more heat energy than the vertical burn test. Second, and perhaps more critical, is that the heat source cannot be removed. The pilot doesn't have any direct control of an engine compartment fire, or exhaust system failure.

As noted, there is plenty to read if you search VAF. Here's the quick version:

http://www.vansairforce.com/community/showpost.php?p=476353&postcount=20

Hands down, the best overall thermal performance for both ordinary comfort and fire protection to to place a reflector over an insulator on the engine side of the firewall. It probably also has some unmeasured effect on sound transmission. There is no safe sound insulation for the cabin side.

BTW, theses are the FAR's applicable to firewall insulation:

? 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.


Thank you all for your comments.
 
Dan, a request for clarification: Do you mean this as an absolute, meaning even if the engine side is treated according to your recommendations, that no acoustical insulation can be applied safely to the inside of the firewall; or that there is no safe sound insulation that can be applied to the inside absent proper engine side fire insulation?

Some of my experiments looked at rate of heat rise and maximum heating for objects on the cabin side. I also looked at the possibility of point source ignition, and long term readers will recall a quick test of sealants for penetrations.

At five minutes into a burn, good engine side reflector/insulator combinations could hold structural temperatures to a ballpark of 300~350F (the aluminum angle, for example). That's probably high enough to generate cabin smoke with some of the plastic "firewall insulation". A flat black heat target intended to simulate the soles of a pilot's shoes was placed 6" from the hot firewall. Temperatures there would ballpark 200~250F, certainly uncomfortable, but flyable/survivable unless flying barefoot. A pilot would not need to have his feet on the pedals throughout an entire emergency.

Point heat sources were more tricky. An ordinary AN-3 bolt used to fasten something to the firewall is a good example. With the head exposed directly to the heat source on the engine side, the nut and bolt stub can reach near red temperatures on the cabin side. It can easily be an ignition source.

There are a great many firewall penetration methods. Many have through-fasteners as above. Some may leak hot gas in an extended burn, and the cable, wire, or fitting itself will get very hot.

So, no, I don't think it's a good idea to place sound insulation on the cabin side, even with the engine side well insulated. My own firewall is clean bare stainless in the cabin, with no plastic (brake tubing or tie wraps, for example) in contact.
 
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Dan, a request for clarification: Do you mean this as an absolute, meaning even if the engine side is treated according to your recommendations, that no acoustical insulation can be applied safely to the inside of the firewall; or that there is no safe sound insulation that can be applied to the inside absent proper engine side fire insulation?

Following up on this one... my certified Tiger has insulation on the cabin side of the firewall. It looks like a stitched fiber glass blanket, but doesn't really look like 2000 degree stuff...:) The engine side is bare metal.

I presume a lot of the certified manufacturers just use this bit of the FAA firewall definitions from 23.1191

(h) The following materials may be used in firewalls or shrouds without being tested as required by this section:
(1) Stainless steel sheet, 0.015 inch thick.
(2) Mild steel sheet (coated with aluminum or otherwise protected against corrosion) 0.018 inch thick.
(3) Terne plate, 0.018 inch thick.
(4) Monel metal, 0.018 inch thick.
(5) Steel or copper base alloy firewall fittings.
(6) Titanium sheet, 0.016 inch thick.


I realize the specs have probably changed since the 70's :) but what sort of woven material is used on these older planes?
 
Following up on this one... my certified Tiger has insulation on the cabin side of the firewall. It looks like a stitched fiber glass blanket, but doesn't really look like 2000 degree stuff...:) The engine side is bare metal.

Yep, there are plenty like it.

I realize the specs have probably changed since the 70's :) but what sort of woven material is used on these older planes?

The kind that burns.

Here is accident report LAX07LA263, a PA22-150 with failed muffler.

According to the pilot, he performed another run-up and, finding everything in order, he took off. During initial climb a "small amount of exhaust appeared." The pilot turned the airplane onto the downwind leg and advised the air traffic controller that he would be returning for landing. By the time the airplane progressed to midfield, the conditions had deteriorated and a small visible flame appeared forward of his left foot. The pilot reportedly immediately aimed for the runway, turned final, and landed as smoke was filling the cockpit.

The pilot stated that on approach it became difficult to see, and during the landing rollout he could see only inches ahead. So, he opened a window to look outside. The airplane's brakes became totally dysfunctional. As the smoke intensity further increased and the fire spread, the passenger exited the rolling airplane via the right cabin door. The pilot followed the passenger's exit from the airplane. The airplane came to rest and was consumed by fire.
 
Is that still the case for the more modern aluminum certified planes?

Are there any recent certified aluminum designs?

Ya'll do as you please. I've seen mylar coated plastic bubble wrap, and pink Dow Corning styrofoam sheet on the cabin side of firewalls.

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