Crashing and Burning
Guest
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Crashing and Burning
Re SQ 006 at TPE, another long-haul T/O crash - another catastrophic fire.
Is it not time for the industry to revisit the wire-mesh fuel tank 'stuffing' that has been proven to inhibit (I believe 'prevent' is not too strong a word) the propogation of a fuel fire in the event of the tank(s) being structurally breached?
I believe the material used is fine enough that tank capacity is not greatly reduced.
Anyone heard more of this?
Is it not time for the industry to revisit the wire-mesh fuel tank 'stuffing' that has been proven to inhibit (I believe 'prevent' is not too strong a word) the propogation of a fuel fire in the event of the tank(s) being structurally breached?
I believe the material used is fine enough that tank capacity is not greatly reduced.
Anyone heard more of this?
Guest
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The mesh does its job by absorbing / dissipating heat in order to prevent local temperatures being high enough for flame front propagation inside the tank.
However I don't think it can actually have an effect once the fuel leaves the tank because there is then a discontinuation of fuel / mesh contact.
Racing cars commonly use this system.
However I don't think it can actually have an effect once the fuel leaves the tank because there is then a discontinuation of fuel / mesh contact.
Racing cars commonly use this system.
Guest
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I recall several years ago the Americans were working on "Anti-Misting Kerosene" and I still have a videotape of a remotely-controlled 707 being deliberately crashed onto a salt lake bed with steel cutters positioned to slice into the wing-tanks shortly after impact. The AMK was thicker and refused to turn into an aerosol when violently agitated (such as in a rupturing fuel-tank) but had to be converted back into less-viscous jet fuel by a "degrader" located in the wing-pod before being fed to the engine.
It seemed to be a successful test, in spite of the aircraft impacting slightly off the planned aiming-point and one engine and degrader being ruptured, spilling ordinary kerosene into the hot engine parts and causing a very spectacular fire. The AMK in the tanks burnt for a shortish period of time and instrumentation inside the fuselage showed the interior conditions to be survivable (for temperature) for several minutes (ignoring issues such as smoke, toxic fumes etc).
Of course, AMK costs more because of the special additive required to produce it, as well as the degraders necessary on each engine to convert it. In an industry as price-sensitive as airline travel, it comes as no surprise it hasn't been adopted. Perhaps there have been undisclosed developmental problems as well. Someone with more knowledge may care to augment/update this posting.
It seemed to be a successful test, in spite of the aircraft impacting slightly off the planned aiming-point and one engine and degrader being ruptured, spilling ordinary kerosene into the hot engine parts and causing a very spectacular fire. The AMK in the tanks burnt for a shortish period of time and instrumentation inside the fuselage showed the interior conditions to be survivable (for temperature) for several minutes (ignoring issues such as smoke, toxic fumes etc).
Of course, AMK costs more because of the special additive required to produce it, as well as the degraders necessary on each engine to convert it. In an industry as price-sensitive as airline travel, it comes as no surprise it hasn't been adopted. Perhaps there have been undisclosed developmental problems as well. Someone with more knowledge may care to augment/update this posting.
Guest
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Explosafe is the product name. Used in motor racing.
I believe the problem is after the fuel leaves the aircraft at speed it atomises and becomes explosive. Petrol based fuels are explosive in their contained environment.
[This message has been edited by buck-rogers (edited 04 November 2000).]
I believe the problem is after the fuel leaves the aircraft at speed it atomises and becomes explosive. Petrol based fuels are explosive in their contained environment.
[This message has been edited by buck-rogers (edited 04 November 2000).]
Guest
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I believe the additive used in the test was Poly Iso Butylene. For a short time back in the 70s I was marketing this material as a anti smoke additive. Garrett Airesearch used it to eliminate smoke when they were running off mixture tests. When they ran the test without the additive the smoke blew across the San Diego Freeway and the California Air Quality Board would slap them with a fine of several thousand dollars.
Because of this, they had to run the tests at night which involved premium pay. They used it until my supply ran out. I also contacted the engine manufacturers and they turned it down because they were working on smoke free engines. The navy used it on their diesel driven mine sweepers. It totally eliminated the smoke. I contacted several large oil companies asking if they could add it to their diesel and gasoline supplies and I provided samples. Some were interested and I started counting the dollars
that is, until I got a letter from Texaco.
They owned the patent on the additive and told me if I were to market it to other refineries I would be sued as would the other refineries. I stopped at that point and the product was never put on the market. Texaco however, never added the material to their fuel and until I heard of the test described above involving the 707 I thought everyone had given up on it.
What surprised me the most when I saw the test on TV the announcer said they were using Poly Iso Butylene as a means of preventing misting. The reason it worked so well as a smoke reducer is that it allowed the fuel to atomize into smaller particles
thus, burning cleaner.
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The Cat
[This message has been edited by Lu Zuckerman (edited 04 November 2000).]
[This message has been edited by Lu Zuckerman (edited 04 November 2000).]
Because of this, they had to run the tests at night which involved premium pay. They used it until my supply ran out. I also contacted the engine manufacturers and they turned it down because they were working on smoke free engines. The navy used it on their diesel driven mine sweepers. It totally eliminated the smoke. I contacted several large oil companies asking if they could add it to their diesel and gasoline supplies and I provided samples. Some were interested and I started counting the dollars
that is, until I got a letter from Texaco.
They owned the patent on the additive and told me if I were to market it to other refineries I would be sued as would the other refineries. I stopped at that point and the product was never put on the market. Texaco however, never added the material to their fuel and until I heard of the test described above involving the 707 I thought everyone had given up on it.
What surprised me the most when I saw the test on TV the announcer said they were using Poly Iso Butylene as a means of preventing misting. The reason it worked so well as a smoke reducer is that it allowed the fuel to atomize into smaller particles
thus, burning cleaner.
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The Cat
[This message has been edited by Lu Zuckerman (edited 04 November 2000).]
[This message has been edited by Lu Zuckerman (edited 04 November 2000).]
Guest
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LU,
your chemical may well have been the additive to make AMK (the identity of the additive was never mentioned in the video footage), but how would the degrader convert the thickened fuel back to a free-flowing kerosene? The voice-over was notably silent on this process as well, merely mentioning the degrader hardware which was mounted above the engine just behind the leading-edge of the pylon.
It always comes down to dollars, doesn't it?
your chemical may well have been the additive to make AMK (the identity of the additive was never mentioned in the video footage), but how would the degrader convert the thickened fuel back to a free-flowing kerosene? The voice-over was notably silent on this process as well, merely mentioning the degrader hardware which was mounted above the engine just behind the leading-edge of the pylon.
It always comes down to dollars, doesn't it?
Guest
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If they had only added Poly Iso Butylene to the fuel there would be no need to have some device added to the engine. Poly Iso Butylene mixes completely in hydrocarbon fuel. I used it in my car, the US Navy used it in their Diesel engines and Garrett AiResearch used in their jet engines.
Regarding the mentioning of the additive it was mentioned on one TV bit that I saw. I have seen this same crash demonstrated on many different TV segments and the only one that mentioned the additive was the one referenced above.
Is it possible that there was no device added to the engine?
It would seem that the additive described in the original posts would get thicker due to cold soaking at high altitude and would not flow freely to the engines making it difficult to pass through the degrading device and thus cause fuel starvation. Just a thought.
NASA has tried other developmental tests with out complete investigations into the ramifications of unseen problems.
One other thought. If the material was stripped out of the fuel what happened to it. Was it recirculated back into the tanks where it would serve to increase the viscosity of the fuel making it increasingly difficult to flow to the engines? Or, was it dumped overboard. It makes one think if the test were a valid demonstration of a commercial aircraft in revenue service.
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The Cat
[This message has been edited by Lu Zuckerman (edited 10 November 2000).]
Regarding the mentioning of the additive it was mentioned on one TV bit that I saw. I have seen this same crash demonstrated on many different TV segments and the only one that mentioned the additive was the one referenced above.
Is it possible that there was no device added to the engine?
It would seem that the additive described in the original posts would get thicker due to cold soaking at high altitude and would not flow freely to the engines making it difficult to pass through the degrading device and thus cause fuel starvation. Just a thought.
NASA has tried other developmental tests with out complete investigations into the ramifications of unseen problems.
One other thought. If the material was stripped out of the fuel what happened to it. Was it recirculated back into the tanks where it would serve to increase the viscosity of the fuel making it increasingly difficult to flow to the engines? Or, was it dumped overboard. It makes one think if the test were a valid demonstration of a commercial aircraft in revenue service.
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The Cat
[This message has been edited by Lu Zuckerman (edited 10 November 2000).]
Guest
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Lu,
My impression from the voice-over was the degrader altered the AMK additive rather than stripping it out. Presumably after degrading it simply went through with the fuel and burnt in the usual manner.
If this was the case then a catalytic conversion process would seem to suggest itself, rather than one involving the addition of yet another chemical and a subsequent reaction. Adding another chemical would require a storage tank etc, pumps, valves, and none were mentioned.
Just did a search using Altavista and came up with a reference at the following URL:
http://www.dfrc.nasa.gov/gallery/movie/CID/index.html
[This message has been edited by criticalmass (edited 10 November 2000).]
My impression from the voice-over was the degrader altered the AMK additive rather than stripping it out. Presumably after degrading it simply went through with the fuel and burnt in the usual manner.
If this was the case then a catalytic conversion process would seem to suggest itself, rather than one involving the addition of yet another chemical and a subsequent reaction. Adding another chemical would require a storage tank etc, pumps, valves, and none were mentioned.
Just did a search using Altavista and came up with a reference at the following URL:
http://www.dfrc.nasa.gov/gallery/movie/CID/index.html
[This message has been edited by criticalmass (edited 10 November 2000).]
Guest
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To: Criticalmass
What you say about a catalytic converter may be true. If the material were Poly Iso Butylene there would be no need for such a device as the Poly Iso Butylene actually improves the combustion process. That's why I was confused when I heard that it was the additive. To settle this whole mess, I sent an email to the NASA test director asking him what the additive was. I also asked him if it was Poly Iso Butylene. Hopefully, I 'll have an answer early next week.
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The Cat
[This message has been edited by Lu Zuckerman (edited 10 November 2000).]
What you say about a catalytic converter may be true. If the material were Poly Iso Butylene there would be no need for such a device as the Poly Iso Butylene actually improves the combustion process. That's why I was confused when I heard that it was the additive. To settle this whole mess, I sent an email to the NASA test director asking him what the additive was. I also asked him if it was Poly Iso Butylene. Hopefully, I 'll have an answer early next week.
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The Cat
[This message has been edited by Lu Zuckerman (edited 10 November 2000).]
