Fuel Cell Foam and Fire Systems

I have two AFFF systems that were given to me by a friend. Back in the late 90's a gentleman I knew was actively developing these systems for aircraft use. Unfortunately he passed away from cancer before the product was marketed. He tested the system in a Pitts project and had actually set the airplane on fire to do a real world test. It worked.

This system was basically a rebranded SPA system shown here:
https://www.pegasusautoracing.com/productselection.asp?Product=2436

Rather than fighting the fire I'm thinking it may be more effective to point the nozzles at the wing area, particularly slightly forward of the fuel tanks by installing the nozzles in a recessed area on the sides of the fuselage. This way the fuel fire can be suppressed enough to allow escape.

The system is not very heavy but one drawback is that it cannot be allowed to freeze.

There would be a seperate system for firewall forward, probably a halon system. Thoughts?

Bob - great topic idea, so rather than get it mixed in with the thread on clothing, I moved your post over to start a new, dedicated thread. I'm looking forward to reading responses!

Paul

Do we have enough data--

Paul---Do we know enough about the causes of these fires to work on improving the root cause? And, is this something particular to the -10?
Naturally I am curious as to what is actually going on. With the thousands of RV's flying, the problems seem small. But any loss is not acceptable. Lets see what is causing the problems.
Tom

AFFF Fire Supression System

We have a FireCharger AFFF fire suppression system in our (non-RV) homebuilt. The bottle lives on the cold side of the firewall, with the actuator cable coming out right at the fuel shut-off valve. In case of fire the action would be to shut off the fuel, and pull the fire suppression handle. The system we have is two nozzles, with one going above the engine, and one below.

I have no idea if it will work at flight speed. I am confident that it will work on the ground.

As a fearless and stupid 18 year old I managed to have a gallon of model airplane fuel (methanol, nitromethane, and oil) explode in my hand. It produced a second and third degree burn on my leg from my ankle to my waist-line, and raised blisters on my hand that were over an inch thick. I have a healthy fear for fire now.

The system cannot be allowed to freeze, which is one drawback. Here in California, I don't really worry about that.

fire suppression weight

Kevin,

How much would you estimate you fire suppression system weighs?

Bevan
RV7A

Testing?

I must admit that I have ALWAYS wanted to have an engine compartment fire suppression system in an airplane - the installations in "big iron" work, and are effective in most cases, and getting th fire out (if it occurs) would be a huge step towards survival.

My biggest concern with installing a racing system in an airplane like an RV is the total lack of testing data that shows if it would be effective or not. As an operations engineer, I believe that unless you can prove something works, you haven't bought a thing by installing it. is carrying that lucky penny in my pocket making me lucky, or isn't it? I just don't know....

So I know that we've got an assortment of flight test folks that visit here - does anyone know the testing protocols that are used for fire suppression certification in aircraft? Could we possibly do some non-destructive testing that would give us a clue if these are worthwhile or not?

Fie in the air has got to be at the top of the "fear" list for most of us. It clearly doesn't happen very often, but if it did, it would be catastrophic in the most horrible way. I personally have always put a huge amount of effort into preventing the fire, since I am not sure I can count on an un-tested suppression system. (Clearly, the suppression systems will help with a ground fire, since the environment is similar to that of a race car.)

So maybe we can investigate a way to test effectiveness. Any input from the collective?

Paul

I have to wonder if this is a problem that really needs solving... By the time we add all the equipment to our airplanes to protect from every eventuality, we'll have BRS parachutes, airbags, ejection seats, fire supression, etc. We'll be back to the performance of a Cessna anyway due to all the extra weight.

Snowflake said:

I have to wonder if this is a problem that really needs solving... By the time we add all the equipment to our airplanes to protect from every eventuality, we'll have BRS parachutes, airbags, ejection seats, fire supression, etc. We'll be back to the performance of a Cessna anyway due to all the extra weight.

Click to expand...

I wonder too.

It's making sure all fittings are tight. Check fittings occasionally, especially after initial engine runs. And mark them, so you can see if they're rotating. Have a quick and easily accessible way to shut off the fuel supply. Most of our RVs do have an easy to get to... fuel tank knob. Cary some pliers to crimp in cockpit fuel lines if necessary. I can crimp mine, right where they come into the cockpit from the wings, if I had to. Do everything possible not to stall and knock the wings off.

As far as I'm concerned, we're not going to have a sustainable 2000 degree blast furnace ahead of the firewall, if the fuel source is quickly dealt with. Wings breaking off, and fuel tank rupture is another problem.
Like I said ........Don't stall! There has been two fatal airplane accidents very close to my house, in the last three weeks. I do live next to an airport. In both of these cases, there was no fire. But both airplanes did stall and breakup badly.

L.Adamson

Ironflight said:

My biggest concern with installing a racing system in an airplane like an RV is the total lack of testing data that shows if it would be effective or not. As an operations engineer, I believe that unless you can prove something works, you haven't bought a thing by installing it. is carrying that lucky penny in my pocket making me lucky, or isn't it? I just don't know....

So maybe we can investigate a way to test effectiveness. Any input from the collective?

Paul

Click to expand...

I am putting a system in my new 7. Despite the lack of any testing data in aircraft I am willing to spend the money and the time to install. Whether the vehicle is in the air or on the ground to me is not the issue. A Top Fueler traveling 275 MPH+ has this type of system installed for a reason and they work. I love watching racing and have seen the systems activated successfully in virtually every case. The only difference is when they get stopped they will have support if the fire continues.

In reality, how much of the extra equipment in our planes was actually tested and what were the results. We install stuff because that is what is in the plans and that is what others do. Several examples come to mind but I won't drift the thread.

The only real source for fire in our planes is fuel. (If oil is on fire, you've got additional problems) We check our lines continuously but they could break and then a fire is possible. From there, we have to cut the source and extinguish the existing fire.

My EP will be simple, Fuel cutoff, mags off, pull the fire handle, grab one of the two fire extinguishers in the cabin and be ready. With practice this will take 1-3 seconds.

We have people putting in dual alternators, dual batteries, back up instruments, two or more GPS units, etc. They may or may not save you. In reality, just how many failures of the above have occurred. Not many, but yet there seems to be a resistance to installing a 6 lb system that is under $500 that just might save your life. Trying to figure this one out!!!

I'm not sayig don't install one Darwin, i am simply pointing out that without testing, we don't know if it woudl be effective. dual electrical systems, moutliple GPS's, backup instruments? Of course they are easy to test (mine have all been), and why not?

It pays to base our decsions on data, not just on faith and/or a guess. I am pretty darn sure your fire system will work extremely well on the ground BTW (based on auto experience and testing) - and lots of fires start there, so it is worthwhile from that aspect!

Paul

Ironflight said:

I'm not sayig don't install one Darwin, i am simply pointing out that without testing, we don't know if it woudl be effective.

Paul

Click to expand...

Never implied that you said not to install one.

Why do think it would not work or be effective in an airplane? The dragsters are moving through air although lightly attached to the ground. They have a greater chance of fire (both fuel and oil) because of uncontained engine failures and the systems work there. In fact, they are required. The parallels to flight are very close and that data is sufficient for me to spend $500 to keep from burning. With the system, at least I know there is a calculated chance it will be effective.

I'm trying to learn. I'm extremely safety oriented although I don't see a need for much of the redundancy many put in especially with the reliability of our modern stuff. I kind of see it as seeking a solution for a problem that doesn't really exist.

The beauty of Experimental aviation. Put in whatever makes you feel good

foam extinguisher

You can get aqueous foam fire extinguishers at Home Depot and other places. There is no good excuse not to carry one in your plane since they are cheap, light, non-corrosive, non-toxic and the foam stays where you spray it... like on your burning feet, hands, face, chest, co-pilot, etc... !!!

You can use these things on any type of fire... even electrical... which still astounds me.

The only downside is that they will freeze. I've tested this. They will work again when thawed. So, carry it in your flightbag and store indoors.

If you happen to be ordering something from us, we have carried them for several years now. Firegone Extinguisher. If you're not ordering from us, save the shipping and just get one at Home Depot... I mean, who doesn't go there at least once a week. I know I do.

But let me reiterate... if you're in a bad spot, you can spray this on yourself to buy time. Try that with Halon or dry powder.

No, it's not a perfect plan, but it's certainly better than no plan at all.

Weight and Testing

Bevan said:

Kevin,
How much would you estimate you fire suppression system weighs?

Click to expand...

According to Pegasus Racing, where I purchased it, the system weight is 7.4 pounds.
https://www.pegasusautoracing.com/productdetails.asp?RecID=3431

Snowflake said:

I have to wonder if this is a problem that really needs solving... By the time we add all the equipment to our airplanes to protect from every eventuality, we'll have BRS parachutes, airbags, ejection seats, fire supression, etc. We'll be back to the performance of a Cessna anyway due to all the extra weight.

Click to expand...

I will happily trade 7.4 pounds for peace of mind from fire. Like I said, I've been on fire before. It scares the living **** out of me. I think without much trouble I could lose 7.4 pounds and it would do me a lot of good, and my plane will weigh the same.

Ironflight said:

My biggest concern with installing a racing system in an airplane like an RV is the total lack of testing data that shows if it would be effective or not. As an operations engineer, I believe that unless you can prove something works, you haven't bought a thing by installing it.

So maybe we can investigate a way to test effectiveness. Any input from the collective?

Paul

Click to expand...

I have the Firecharger AFFF 2.3L system. I have the brackets installed, but not the nozzles. A recharge kit costs $53. I will gladly ship the system to someone with the equipment and an agreed test protocol to mimic an engine install and fire. Dan H was doing some great firewall testing. Anyone have a Lycoming shell, a cowl, an big fan and a pint of fuel they want to press into service?

I like the peace of mind.

I would think the foam would work best if it doesn't get blown out of the engine cowling. To do this, the air supply must be cut off. Could this be done by closing a large valve at the cowl holes next to the spinner? I would think a butterfly style valve in the opening should be doable. This could be activated by the same cable that opens the fire bottle's valve.

Thoughts?

Bevan

Non-destructive test...

...would be measuring the oxygen concentration within the engine compartment.

That being said, I don't knowhow to do it in real time.

LarryT

I would think the foam would work best if it doesn't get blown out of the engine cowling. To do this, the air supply must be cut off.

Click to expand...

I'm having trouble with this:

1. We have an optimally designed "chamber" with inlets and outlets designed to maximise the throughput of air to enable cooling.
2. We have ~300lbs of hardware, hot, and relying on said cooling to minimise heating further.
3. We now have a fire, which can either be sourced from the engine oil, or more likely the fuel.
4. The fuel supply can be, and should be, shut off immediately. The oil supply is somewhat limited, albeit I would not like to be behind it.
5. Any of those fluids leaking, and not burning, is being driven out of the engine compartment by the cooling airflow.
6. You now want to block off that airflow that is both driving the fluids and flames away, and also cooling the engine.

I appreciate there are arguments both ways, at our amateur design level. If you are still interested I would tackle it in 3 ways:

1. Are there really a good % of (fatal) accidents caused by the "problem" across GA?
2. Are there any certified aircraft designs carrying something similar?
3. Get a qualified opinion and testing done (which will be very expensive) to see if it really works as desired.

It's been said before, but to minimise risk of fire (rather than deal with one that has started) seems the best bet to me. Sensible design, minimise joints, no fancy unknowns. Read NTSB reports closely and look at why the fires that did occur started? If you are still paranoid, reduce inspection interval to 10hrs.

Andy