Firewall fire protection

[Dorfie]

I need some advice about this process. I have likely spend more time on this project than most others and frustration levels are high!! I have read what I believe is everything about this topic but still have a few practical issues.
I am installing the firewall fire protection on the engine side as suggested by many. It consist of stainless steel 0.002" foil (which is very tough) and 1/4" ceramic blanket from McMaster Carr. Here are my problems and questions.

1. How do I get a clean hole through the SS foil? Larger holes (>1/2") I simply cut out with a knife using the hole in the firewall as my guide. It is the smaller holes I battle with. So far I have made a small cut in the SS foil with a knife in the center of the smaller holes (like for AN3) then used a tapered grinding stone in the Dremel to grind the SS foil to the size of hole, using the hole in the firewall as my guide. It works OK. My concern is how will I get a new hole through the SS foil AND firewall AFTER all is installed? It does not seem that I will be able to drill the hole from the engine side since a drill tends to tear the foil. Access from the cabin side is more difficult. I think a drill will also grab the ceramic fibers and twist it, ripping it out?? Hope someone has figured out a way to do this.

2. When bolting items (like pressure manifold and Air-Oil Separator) to firewall, is it OK to compress the ceramic blanket between the SS foil and firewall? Does it stay in place without frequent need for re-tightening?

3. I know that Dan Horton proposed fasteners for keeping SS foil and ceramic in place. Stainless steel pop rivets with large washer OK? Are the things bolted to the firewall insufficient support to keep the SS/blanket in place? (It will be sealed along the perimeter with Fire barrier 2000+).

4. Did you guys install the SS and ceramic BEFORE hanging engine? (I would guess so. Reason I'm asking is forgetting some penetrations at initial intall)

5. What did you do to the belly of the a/c at the cowl outlet for fire protection? (I read that fire has burned through the underside of the fuselage). I was contemplating using Fire Barrier 2000+ as a way to attach a piece of SS to the forward fuselage underside for about 2 feet behind cowl outlet. The fire Barrier will then function as heat insulation as well as adhesive. Will that work? Need SS pop rivets as well? What did you put between the SS and the aluminum of belly to prevent heat conduction if not fire barrier?

6. Here is a list of the firewall penetrations I have catered for: Brake master cyl. AOS. Pressure Manifold. Front and rear heat. Starter wire. 2 x fire-sleeved penetrations for other electrical wires. Engine control cables (3). Cables for heat (2), alt air(1), oil cooler air(1). Screw holes to mount cables to firewall per plans. Starter contactor. Any others you would advise or that I missed

Thanks.
Johan

[Andy Hill]

6. Here is a list of the firewall penetrations I have catered for: Brake master cyl. AOS. Pressure Manifold. Front and rear heat. Starter wire. 2 x fire-sleeved penetrations for other electrical wires. Engine control cables (3). Cables for heat (2), alt air(1), oil cooler air(1). Screw holes to mount cables to firewall per plans. Starter contactor. Any others you would advise or that I missed

What is AOS? Fuel seems missing... Earth point?

We use a corny phrase in Airline Flying of "Avoid, Trap, Mitigate". All the protection you detail is really the final, "Mitigation", stage i.e. the fire has started undetected, and burning so well your life / the airframe is threatened.

I am sure you are giving equal if not greater priority to the first 2 i.e. stop the fire in the first place (e.g. best practice FF, fittings, inspection intervals), and if one occurs, minimise the effect (detect the fire, put the fire out before it is a threat).

[Dorfie]

Originally Posted by Andy Hill

What is AOS? Fuel seems missing... Earth point?

We use a corny phrase in Airline Flying of "Avoid, Trap, Mitigate". All the protection you detail is really the final, "Mitigation", stage i.e. the fire has started undetected, and burning so well your life / the airframe is threatened.

I am sure you are giving equal if not greater priority to the first 2 i.e. stop the fire in the first place (e.g. best practice FF, fittings, inspection intervals), and if one occurs, minimise the effect (detect the fire, put the fire out before it is a threat).

Andy,
AOS = Air-oil Separator (I learned it on this website!!)
All hoses will be flexible and fire sleeve protected and I agree and abide by the rest of your prevention strategies. At present I have no "detection". I guess cowl outlet temp might be an option.
Was thinking of using the engine mounts as ground/earth. Battery will be grounded to the fuselage at the battery location. I am still pondering placing "forest of tabs" on engine side of firewall as well. I forgot to mention the fuel line penetration.
Thanks for your input.
Johan