Fire resistant firewall??

[Bluboyz]

Aircraft - Active Fire Extinguishing - (thread drift, from passive fire control, perhaps)

 

To Launch A Light Sport by the late Bob Fritz's, of Kitplanes magazine fame, builder's log of his Jabiru J250 build from 2008 - 2010 where he installed / plumbed in a Halon fire system - In the Line Of Fire-

To Launch a Light Sport

 

Fire In The Hole - Is an extinguisher just extra weight or an essential part of your aircraft systems? By Bob Fritz (pp 47-51 Kitplane mag Aug 2008)

https://s28490.pcdn.co/wp-content/uploads/2019/05/Kitplanes_2008_08.pdf

 

A Life Saved - Kitplane's Letters -

Letters

 

IIRC Halon is no longer legal in Au..

[kgwilson]

Halon works well by removing the oxygen. If we didn't need that to breathe it would be great. With the right petrol/oxygen mix you only need about a cup full to blow your house up.

[Old Koreelah]

...Does the exhaust header shine a dull red for a engine at 100% in climb out ?...

Glen I tried to come with a smart-alec response to this, but will leave it your imagination.

[M61A1]

Halon works well by removing the oxygen. If we didn't need that to breathe it would be great.

https://www.h3rcleanagents.com/support_faq_2.htm

[Bluboyz]

Kgwilson If we didn't need that to breathe it would be great.

I hear what you're saying kg - No one would chose to be exposed to it in any strong concentration for any period of time.. similar to installing a BRS perhaps active fire control would be yet another item in the pilot's tool box..

 

Further to M61A1 reference(s)

FAQs Clean Agent Fire Protection & Halon

CDC - Immediately Dangerous to Life or Health Concentrations (IDLH): Trifluorobromomethane - NIOSH Publications and Products

 

CASA,FAA, ICOA, etc have developed policies post Halon

https://www.casa.gov.au/sites/default/files/_assets/main/airworth/awb/26/002.pdf?acsf_files_redirect

 

Fire resistant clothing together with all the passive fire retardants measures that can be built into any recreational aircraft is likely the best way to proceed.. and maybe a couple of these masks/hoods in the door pockets as well as leather rigger/safety gloves would not be a bad idea if one was to be found in such an unfortunate situation

https://www.aircraft spruce.com/catalog/pspages/provitasmokehood.php

POCKET SMOKE MASK | Aircraft Spruce

[kgwilson]

https://www.h3rcleanagents.com/support_faq_2.htm

Well there you go. I'd never researched it, having been told numerous times that it removed Oxygen. It was always used in our Computer rooms as it didn't leave residues that would attack electronics & the advice was to not try to breathe & get out immediately if it was activated. Now I know it is a CFC so that's what is bad about it.

[facthunter]

I would reckon ALL exhaust pipes glow red at high engine power. Turbo charged ones are often near white hot. You won't see it in sunlight. It has to be night time..

Fuel lines pulling off connections was/is fairly common. You need to rely on more than a worm drive clip. Lube oil will ignite easily on a hot exhaust pipe.. The more external oil pipes you have makes it riskier but if the engine chucks a piece out you will usually get plenty of oil about. Wheel fires are not uncommon either but not in most U/L types where landing speeds are moderate and planes are low mass Halon is a good fire suppressant but is a CFC so ruins the ozone layer. CO 2 is pretty safe if you don't freeze your hand to the nozzle. 2 Cups of petrol properly mixed with air will blow up a house. A lot of engines throw sparks out. Again you only see this at night. Some types of fuel injected engines can flood on starting if not done correctly and easily start a grass fire.. Nev.

[RFguy]

Thanks Nev, et al.

In broadcast transmitters, they all used to have the Halon. Vesda aspirating smoke detectors hooked up to the Halon via entry control interlocks. Couldnt be tripped with alarm deactivated. Now they just let em burn.

 

Fuel lines coming off is a worry. How much pressure is in those fuel lines on a low wing (with pump) ? I guess 100kPa ?

 

Dull red, mild steel... what's that about 450-500C. Good point about the oil. I actually never saw oil catch fire in my Datsun, only billow enormous amounts of white smoke when it hit the exhaust headers. Once from overfilling and it came out a crank case breather.

 

I ALWAYS wear full cottons when I fly, even in RPT. I often tell the passenger next to me it's so my skin doesnt melt when I have to climb through the burning fuselage. ...

[Yenn]

The Bing carbie used by Jabiru has push on hose fuel lines with Jubilee clips. Not the best but I have lived with it for 18 years. Better is screwed fittings, such as the AN stuff and only have flexible hose where it is needed. There is a difference between an oil fire and a fuel fire. I had the thread on the rocker cover give way on my original Jab 1600 engine. Result a lot of whitish, grey smoke, just after I turned crosswind, which quickly reduced in volume. I had time to work out what was causing the smoke and was easily able to make a safe landing. That was flight No 3 on my test flying program and the decider to overhaul the second hand engine.

[Downunder]

Fuel lines coming off is a worry. How much pressure is in those fuel lines on a low wing (with pump) ? I guess 100kPa ?

A bit under half that for a carby.......

 

Hose barbs and worm screw clamps (or similar) are common in rec aircraft, including factory built.

There doesn't seem to be a mass of fires resulting from their use....... lets not panic.

[Old Koreelah]

...I ALWAYS wear full cottons when I fly, even in RPT. I often tell the passenger next to me it's so my skin doesnt melt when I have to climb through the burning fuselage. ...

...and only woollen jumpers; plus (on the advice of an old Ag pilot mate) leather gloves with two fingertips missing for touchscreens.

And elastic -side leather boots- easy to slip out of if tangled in wreckage.

Plus beacon on my belt.

[RFguy]

On worm drive clamps- often using for antenna afixing. Always torqued to xx.

I have a screw handle 1/4 drive low-torque wrench that the end of the driver it changes from WHITE to RED instead of click- because up a tower you cannot feel the click in gloves or hear the click.

 

I am guessing when climbing through the burning 737max fuselage, putting cottons aside, seeing where you are going and having your eyes open is the biggest issue. some sort of eye only googles like advanced swimming eye goggles required ?

[skippydiesel]

Dan Horton also did some practical tests on fire retardant sealants that were written up on VAF. His conclusion was that 3M Fire Barrier 2000+ performed best.

 

Not expensive either. https://www.3m.com.au/3M/en_AU/company-au/all-3m-products/~/3M-Fire-Barrier-Silicone-Sealant-2000-/?N=5002385+3293123941&rt=rud

don't worry about it, just build it and go fly langted

 

do you know of intumescent paints - don't know how they would peform in aviation and as a top coat on your fire wall - see link below ?

 

Intumescent Paint Information | Nullifire | Permax

Great information gentlemen. Hope to start a renovation within the next few weeks and I will be applying your advice (when I get to the firewall in many months)

[onetrack]

Remember, there are hose clamps, and hose clamps, too. Some hose clamp designs are pretty poor.

My preference is for the designs that have rolled edges (to eliminate cutting into the hose), the maximum number of teeth in the screw grip, and band perforations that don't weaken the ban, nor do they strip out under maximum torque.

If you want maximum strength in the design, you go for hose clamps that don't have band perforations.

 

https://www.normagroup.com/corp/en/aba-constant-torque-std/

[skippydiesel]

Remember, there are hose clamps, and hose clamps, too. Some hose clamp designs are pretty poor.

My preference is for the designs that have rolled edges (to eliminate cutting into the hose), the maximum number of teeth in the screw grip, and band perforations that don't weaken the ban, nor do they strip out under maximum torque.

If you want maximum strength in the design, you go for hose clamps that don't have band perforations.

 

https://www.normagroup.com/corp/en/aba-constant-torque-std/

You forgot the hose clamps designed specially for high [pressure applications - variose designs (many sizes) all intended to provide even 360 degree pressure without "pinching"

[onetrack]

Skippy, I didn't mention them specifically, because many of those designs are "heavy duty", involving bolts for fastening - and the accent is on "heavy". As a result, the weight penalty would be against them, to use on aircraft.

I've had hose clamps - even stainless hose clamps - that stripped out the threads in the band, or stripped the threads on the screw, when tightened to a satisfactory level.

Not all hose clamps are the same quality, many are obviously built to a price, not for a job.

[Geoff_H]

Let us assume the wiring doesnt catch fire. All teflon, or silicone right ? AND encased in a braid or other armour. Although the gas from burning Teflon is bad

Actually aircraft wiring is not Teflon, similar in properties but with less toxicity when burning.

[RFguy]

Geoff you are right.. it is not PTFE, and I did not mention all the possibilities - FEP, crosslinked-polyalkine etc.

 

All my reel stock is "MIL22759/16"

which is described as ETFE which for others reading is :

 

"ethylene tetrafluoroethylene copolymer". not far away from teflon in name, anyway.

 

releases hydroflouric acid when burned. can be bonded with FRP. useful.

 

I use it regularly in high power radio work. Just been reading "AC 21-99 Aircraft Wiring and Bonding"

I have come across genuine PTFE in some aircraft intercom wiring very small gauge (32) wiring as I remember holding it for stripping was a bugger. -glen

[onetrack]

Pure Teflon insulation is no longer used in new aircraft builds, Tefzel is the preferred insulation, but there are insulation types still produced with a level of Teflon in them.

 

https://www.flight-mechanic.com/wiring-installation-wire-types/

[Bruce Tuncks]

Getting back to the first posting, I like langted's idea and it is what I would do now with the Jabiru. I would use a 3mm layer of fibrefax and a thin sheet of stainless over the top of the fibrefax. This would be better and lighter I reckon that the galv iron sheet that was supplied in the kit.

[skippydiesel]

Skippy, I didn't mention them specifically, because many of those designs are "heavy duty", involving bolts for fastening - and the accent is on "heavy". As a result, the weight penalty would be against them, to use on aircraft.

I've had hose clamps - even stainless hose clamps - that stripped out the threads in the band, or stripped the threads on the screw, when tightened to a satisfactory level.

Not all hose clamps are the same quality, many are obviously built to a price, not for a job.

You might have to look again Onetrack - with the exception of my radiator hose clamps (too big) all my hoses are secured using fuel injector type clamps. I havnt purchased any for a long time (have all I need) but when I was refreshing my Zephyr I purchased by the box (mainly Gates brand) mostly from my local Repco. By the box is by far the most cost effective way to purchase hose clamps.

[Geoff_H]

Geoff you are right.. it is not PTFE, and I did not mention all the possibilities - FEP, crosslinked-polyalkine etc.

 

All my reel stock is "MIL22759/16"

which is described as ETFE which for others reading is :

 

"ethylene tetrafluoroethylene copolymer". not far away from teflon in name, anyway.

 

releases hydroflouric acid when burned. can be bonded with FRP. useful.

 

I use it regularly in high power radio work. Just been reading "AC 21-99 Aircraft Wiring and Bonding"

I have come across genuine PTFE in some aircraft intercom wiring very small gauge (32) wiring as I remember holding it for stripping was a bugger. -glen

Yes all the Teflon style of wiring is hard to skin, even with a skinning tool. In the 70's we used lots of Teflon wire for control cabling in very large control installations. Packaging density very high but the gas given off is really bad. When Torrens Island power station had a fire in their computer control room the fumes subtly destroyed most control cards in the system. The insurance company paid out for a complete refit control system. Hans I would replace all wiring in an aircaft if I ever had a small fire anywhere in that aircraft.

[danny_galaga]

Meh, the firewall on my kit plane is aluminium covered fibreglass cloth. I figure it prolly buys me 20-30 seconds if there was a fire. I've decided it's best if I just don't have a fire ?

[kgwilson]

You might have to look again Onetrack - with the exception of my radiator hose clamps (too big) all my hoses are secured using fuel injector type clamps. I havnt purchased any for a long time (have all I need) but when I was refreshing my Zephyr I purchased by the box (mainly Gates brand) mostly from my local Repco. By the box is by far the most cost effective way to purchase hose clamps.

The best hose clips to use for fuel and oil lines are Cobra Clips. They are SS & made for each size of hose & have a special installation tool but you don't need it as a pair of good pliers will do the trick. They can be removed and used again as well. The best things about them is they are very low profile so don't catch on things and provide the correct amount of clamping force as they are specifically made for each hose size. Available from Pirtek. I have them on all fuel & oil lines.

[skippydiesel]

The best hose clips to use for fuel and oil lines are Cobra Clips. They are SS & made for each size of hose & have a special installation tool but you don't need it as a pair of good pliers will do the trick. They can be removed and used again as well. The best things about them is they are very low profile so don't catch on things and provide the correct amount of clamping force as they are specifically made for each hose size. Available from Pirtek. I have them on all fuel & oil lines.

 

Yes ! I am familiar with this style of "spring" clamp - all newer cars have them and I have seen photos of Rotax 912 engines employing the same.

 

I have even purchased a tool to make it easier to remove/reinstall them (works so much better than pliers or similar).

 

There is one down side to them - mainly psychological - I have no control over the clamping force. After a lifetime of using hose clamps, of many different designs, all requiring "screwing" in some way the lack of this input leads to considerable unease. I guess time and familiarity might remedy this fault in myself.

 

One point - this style of hose clamp does not seem to be used on fuel injector systems