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another firewall insulated

A5555

Well Known Member
another firewall insulated and brakes installed but cannot remove air pocket from brake lines. any tips? air box stiffener made from alum tube.

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Fly or drive to PMH and borrow my bleeder pot(garden sprayer type from ACS). Bleed from bottom up and purchase 1 Qt of MIL-H-83282 from Sky Geek.
 
Just as an FYI, the stainless firewall is not what melts in an engine fire, it is the floor. Seen it.
 
Steve, I almost hate to comment, but.....

The insulator looks like Cereblanket or a similar aluminosilicate wool refractory fiber.

Cereblanket is an excellent insulator, and a good choice for the cabin side of a firewall for two reasons. It will not ignite when in contact with a red hot firewall, and it does not contain any significant quantity of binder material, meaning it will not generate much smoke.

However, loose refractory fibers in the air are considered a health risk (fibrosis, lung cancer and mesothelioma). So, if you install refractory fiber against a vibrating firewall, you really should do whatever is necessary to fully encapsulate the pads so that no loose fiber can escape into the cabin. Spending 1000 hours in a little box full of airborne ceramic fiber is a lot like the lab rats mentioned in the MSDS.

I don't see a fastening method. Remember, any glue or tape has the potential to negate the "no fire or smoke" advantages of refractory wool.

Much burn testing says insulating the engine side of the firewall is superior in every way. The inside of my own firewall is shiny unpainted stainless.
 
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Dan, you make a good point. Not sure if my method is better or not but on my 10 I installed the ceramic stainless wrapped blanket on the engine side of the firewall and fiberglass aluminum faced on the cabin side.

Pat

Steve, I almost hate to comment, but.....

The insulator looks like Cereblanket or a similar aluminosilicate wool refractory fiber.

Cereblanket is an excellent insulator, and a good choice for the cabin side of a firewall for two reasons. It will not ignite when in contact with a red hot firewall, and it does not contain any significant quantity of binder material, meaning it will not generate much smoke.

However, loose refractory fibers in the air are considered a health risk (fibrosis, lung cancer and mesothelioma). So, if you install refractory fiber against a vibrating firewall, you really should do whatever is necessary to fully encapsulate the pads so that no loose fiber can escape into the cabin. Spending 1000 hours in a little box full of airborne ceramic fiber is a lot like the lab rats mentioned in the MSDS.

I don't see a fastening method. Remember, any glue or tape has the potential to negate the "no fire or smoke" advantages of refractory wool.

Much burn testing says insulating the engine side of the firewall is superior in every way. The inside of my own firewall is shiny unpainted stainless.
 
Many of us have fiberglass ductboard duct work in our homes and businesses too. They typically run 2500 hours/year. I fly 75 hrs/year.
 
lab rat

the insulation doesn't burn or give off smoke. I put a butane flame on it and the surface fibers glowed but essentially no heat transferred to the opposite side because I could hold it in my hand. it is mechanically held in place the best I could behind tubes/cables/harnesses, no glue or velcro on the firewall but edges of insulation are alum tape and the tape has some glue. it is encapsulated with alum foil. the verdict is out on how well it will hold up. I suppose I'll be a lab rat for awhile.

I am not sure how best secure the small upper outer pieces where the firewall penetrations are. currently they are just sitting there.
 
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the insulation doesn't burn or give off smoke.

Yes, I know. Cerablanket was a test subject some time ago.

The stainless sheet is red hot on the other side of this blanket section:

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An aluminum cover sheet (like the aft-facing aluminum foil in your photo) improves performance by a factor of two. If you must insulate the cabin side, you're using the right stuff.

That said, overall performance remains poor compared to insulating the hot side. As you've noted, covering the cabin side is problematical. Labor is about the same, and the stainless foil cover sheet on the hot side wears well and looks good.

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Not to get too far off topic for this thread, but I'm still in favor of painting the engine side of the firewall with Contego. It's on my to-do list for the near short term.
 
Not to get too far off topic for this thread, but I'm still in favor of painting the engine side of the firewall with Contego. It's on my to-do list for the near short term.

Given the earlier comment, maybe a better place would be on the *exterior* of the floor pan.

(I'm only about 20% joking.)

Seriously, what does the stuff look like after it's applied, & is it UV/chemical proof?

Charlie
 
Contego works by forming a puffy char layer as an insulator. The char is very soft and fragile. Given 1~3 lbs/sec engine compartment airflow and sheet metal vibration the char will be destroyed as fast as it forms, meaning no insulation value.

Good stuff if you want to add fire resistance to your shop wall......
 


§ 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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Dan, step away from the computer and fabricate something cool with a stiff drink in your other hand :).
 
Contego works by forming a puffy char layer as an insulator. The char is very soft and fragile. Given 1~3 lbs/sec engine compartment airflow and sheet metal vibration the char will be destroyed as fast as it forms, meaning no insulation value.

Good stuff if you want to add fire resistance to your shop wall......

C'mon Dan, it can't be that bad. I'd ask you to simulate another test with a sheet of SS and a giant fan to simulate the airflow, but I'd get another funny picture of a bunny (?) beating his head against a wall. :D

There has to be some value in using it...even if it only buys you a minute or two. Of course, I'm just hoping...

Maybe I'll buy a quart and attempt to validate your hypothesis on my own. Also, I'm not sure that on the center of the firewall you would get that kind of air movement. Maybe at the very bottom...(where the fire is...I know, I know)...
 
Dan, step away from the computer and fabricate something cool with a stiff drink in your other hand :).

No, please don't step away. I find your tests extremely valuable, and while it might be inconvenient to hear for some, it is important that you share your results. Thanks a lot for that!
 
I know Dan personally and you can take what he says to the bank.

It may not be what you wanna hear but isn't that really what this site is for?

Best,
 
Dan
I have read the extensive test reports that you did and I thank you for all your work. I am at the insulatitng stage for a 7. Is there any reasonable alternative for thermal insulation and sound proofing for the firewall cabin side and the cabin floor. I too have considered regular ductboard for both possibly with no adhesive but mechanical connection. or regular fiberglass for cabin walls.

Do you have any recommendation and what, if anything do you have on the cabin side of firewall, floor and cabin side walls.

I have read about vinyl nitrile closed foam 1/4 or 1/2" for sound and thermal for floor and side walls. Any suggestions would be greatly appreciated.
 
better to insulate on the engine side of firewall

Better to insulate on the engine side of firewall. I'll probably do this when the engine is removed at some point but for now it's Steve Melton, AKA Lab Rat.
 
In-flight fires are a bit like IRS audits, everyone's afraid of them, but only a small percentage actually gets the experience.

In addition to 1/8" fiberfrax on the inside of the firewall and tunnel bottom, I installed a cowl exit limit switch, connected to an LED on the panel. I set my fuel flow limit to 0.5 gallons over max at takeoff. I have smoke hoods, nomex gloves, halon extinguisher and water available. In case of an engine fire, I will shut off fuel and electrical and begin an emergency descent.

With proper installation and inspections, we can greatly reduce our chances of an in-flight fire. Our greatest risks are takeoff, landing, maneuvering and weather. I believe we are all lab rats when flying. Continue head banging if desired.
 
Assuming that I try and take all precautions to avoid engine fire and use my best efforts when installing and maintaining the firewal forward, is there a consensus of a good insulation material in terms of weight and reasonable cost that others have used. I understand that if an engine fire does occur that immediate use of proper emegengency procedures and divine intervention are of greatest importance but I would like to use some insulation for sound, vibration and thermal comfort so I was hoping to get some imput on the safest and most cost effective material and installation.

I have received comments from several RV owners about drumming vibration on the floor and front cabin side walls and coolnest at the elbow areas
 
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