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Post by the light works on May 4, 2017 1:03:43 GMT
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Post by silverdragon on May 4, 2017 7:27:32 GMT
Open a new thread in show ideas, and we can have the full discussion...?.. I think its worth the investigation?. However, to start, The fuel.Its a LOT more volatile than Petrol/disease-oil. Its stored in the wings that may/are/mostly designed to tear off on [heavy] impact to get them away from the passenger compartment. The fuel inside if it starts spilling near the hot exhaust of a jet engine WILL ignite rather than let you even see it, its camera shy, it likes to disappear quickly in a cloud of smoke. Its better that way. If a wing breaks off and instantly ignites and burns off the fuel before the plane stops moving, the passengers are not liable to be soaked in fuel or have a potential bonfire go whoomph as they escape the wreckage?.. the passengers compartment is sort of insulated against such fires. It gets rid of un-burnt fuel that way. A Plane crash is a lot more volatile than a car crash, you are liable to have hot metal in contact with the ground at speed, lots more sparks, lots more ignition points, for a lot longer time, I would say that any plane that crashes and doesnt burst into flames is a bloody lucky swine. Any that crash in a controlled way and stay under control of the pilot until they stop... they still say "Any landing you walk away from is a good oneSo if a cash is considered as the infamous one where the nose gear didnt fully deploy and was facing sideways, or no gear at all and a "Bellyflop", the walking away from that, Karma, you must have pleased some god somewhere?..
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Post by GTCGreg on May 4, 2017 12:52:29 GMT
However, to start, The fuel. It's a LOT more volatile than Petrol/disease-oil... I agree with everything you say except for aircraft fuel being a LOT more volatile than Petrol/diesel. General aviation fuel is pretty much the same gasoline fuel you would put in your car. Jet aircraft fuel is basically kerosene. Less volatile than gasoline but more so than diesel. In fact, they have played around with additives to make jet fuel a lot less volatile, but I don't think that has ever worked out. I have never seen an aircraft that runs on diesel, but I'm sure someone has built one at some point. It's the other things that you mention that make an aircraft more likely to catch fire after a crash, not that the fuel is any more volatile.
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Post by the light works on May 4, 2017 14:37:31 GMT
Open a new thread in show ideas, and we can have the full discussion...?.. I think its worth the investigation?. However, to start, The fuel.Its a LOT more volatile than Petrol/disease-oil. Its stored in the wings that may/are/mostly designed to tear off on [heavy] impact to get them away from the passenger compartment. The fuel inside if it starts spilling near the hot exhaust of a jet engine WILL ignite rather than let you even see it, its camera shy, it likes to disappear quickly in a cloud of smoke. Its better that way. If a wing breaks off and instantly ignites and burns off the fuel before the plane stops moving, the passengers are not liable to be soaked in fuel or have a potential bonfire go whoomph as they escape the wreckage?.. the passengers compartment is sort of insulated against such fires. It gets rid of un-burnt fuel that way. A Plane crash is a lot more volatile than a car crash, you are liable to have hot metal in contact with the ground at speed, lots more sparks, lots more ignition points, for a lot longer time, I would say that any plane that crashes and doesnt burst into flames is a bloody lucky swine. Any that crash in a controlled way and stay under control of the pilot until they stop... they still say "Any landing you walk away from is a good oneSo if a cash is considered as the infamous one where the nose gear didnt fully deploy and was facing sideways, or no gear at all and a "Bellyflop", the walking away from that, Karma, you must have pleased some god somewhere?.. doesn't need its own thread. that was just a good header for it. the pilot did a hell of a good job. lost engine power at under 500 feet, put it BETWEEN the power lines, and didn't actually slam anything on the way down. it was just good fortune that something breached his tanks when he clipped the lines and the traffic signal and ignited the fuel spill, so it burned off in a fireball instead of splashing on the ground.
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Post by the light works on May 4, 2017 14:40:43 GMT
However, to start, The fuel. It's a LOT more volatile than Petrol/disease-oil... I agree with everything you say except for aircraft fuel being a LOT more volatile than Petrol/diesel. General aviation fuel is pretty much the same gasoline fuel you would put in your car. Jet aircraft fuel is basically kerosene. Less volatile than gasoline but more so than diesel. In fact, they have played around with additives to make jet fuel a lot less volatile, but I don't think that has ever worked out. I have never seen an aircraft that runs on diesel, but I'm sure someone has built one at some point. It's the other things that you mention that make an aircraft more likely to catch fire after a crash, not that the fuel is any more volatile. around here, light planes run on 115 octane gasoline. drag racers buy it in 5 gallon cans for their race cars. I think I saw something about somebody making an aviation engine that runs on diesel, but of course, it has the totally expected disadvantage: no fuel pumps for it at the airport.
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Post by GTCGreg on May 4, 2017 15:10:45 GMT
I agree with everything you say except for aircraft fuel being a LOT more volatile than Petrol/diesel. General aviation fuel is pretty much the same gasoline fuel you would put in your car. Jet aircraft fuel is basically kerosene. Less volatile than gasoline but more so than diesel. In fact, they have played around with additives to make jet fuel a lot less volatile, but I don't think that has ever worked out. I have never seen an aircraft that runs on diesel, but I'm sure someone has built one at some point. It's the other things that you mention that make an aircraft more likely to catch fire after a crash, not that the fuel is any more volatile. around here, light planes run on 115 octane gasoline. drag racers buy it in 5 gallon cans for their race cars. I think I saw something about somebody making an aviation engine that runs on diesel, but of course, it has the totally expected disadvantage: no fuel pumps for it at the airport. Higher octane gasoline is actually slightly less volatile than lower octane fuel. It is used in high compression engines because it burns slower and doesn't "explode" in the cylinders like lower octane fuel does.
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Post by the light works on May 4, 2017 15:36:06 GMT
around here, light planes run on 115 octane gasoline. drag racers buy it in 5 gallon cans for their race cars. I think I saw something about somebody making an aviation engine that runs on diesel, but of course, it has the totally expected disadvantage: no fuel pumps for it at the airport. Higher octane gasoline is actually slightly less volatile than lower octane fuel. It is used in high compression engines because it burns slower and doesn't "explode" in the cylinders like lower octane fuel does. yep. what lets you get more horsepower is the ability to stuff more in without it going bang on you.
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Post by silverdragon on May 5, 2017 6:27:32 GMT
Can we check on the ignition needs of the different fuels. Will aviation fuel auto-ignite at lower temp, will it be more susceptible to stray sparks, does it create more gas at lower temp in the tank etc... Has it always been that way. I kinda remember being told in the RAF that Av-Gas is a lot easier to burn that "normal" gas... Or is it that we had mostly Disease-oil vehicles and the petrol/kerosene/other types of av-gas is quicker to burn than that and I got confuzzed?.. and why do I still think its so?.. or is it just me?..
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Post by the light works on May 5, 2017 15:46:19 GMT
Can we check on the ignition needs of the different fuels. Will aviation fuel auto-ignite at lower temp, will it be more susceptible to stray sparks, does it create more gas at lower temp in the tank etc... Has it always been that way. I kinda remember being told in the RAF that Av-Gas is a lot easier to burn that "normal" gas... Or is it that we had mostly Disease-oil vehicles and the petrol/kerosene/other types of av-gas is quicker to burn than that and I got confuzzed?.. and why do I still think its so?.. or is it just me?.. well, in that crash it aerosolized very well. I would guess, considering open wick kerosene lamps used to be a thing, that gasoline is more volatile than kerosene. the perception may come from the fact that you have to use a lot more safety precautions in fueling aircraft than fueling cars. it may also come just from the idea that fuel that makes things go in the air must be more potent than fuel that moves things on the ground. kerosene: autoignites at 410F/210C, flash point 38-52C, lower flammable limit .7% upper 5% Gasoline: autoignites at 536F/280C for automotive grade (50-100 octane) , up to 880F/471C for high octave Aviation grade (115-145 octane) flash point -45F/-43C to -50F/-46C for the same grade split. LFM 1.4-1.2% upper 7.8-7.1, same grade split. Diesel: autoignites at 494F/257C, flash point 126-204F, no flammable limits listed. so it looks like avgas does vaporize more readily than automotive grades, which would make accidental ignition easier, as long as you had a hot enough ignition source.
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Post by silverdragon on May 6, 2017 7:47:16 GMT
Can we check on the ignition needs of the different fuels. Will aviation fuel auto-ignite at lower temp, will it be more susceptible to stray sparks, does it create more gas at lower temp in the tank etc... Has it always been that way. I kinda remember being told in the RAF that Av-Gas is a lot easier to burn that "normal" gas... Or is it that we had mostly Disease-oil vehicles and the petrol/kerosene/other types of av-gas is quicker to burn than that and I got confuzzed?.. and why do I still think its so?.. or is it just me?.. well, in that crash it aerosolized very well. I would guess, considering open wick kerosene lamps used to be a thing, that gasoline is more volatile than kerosene. the perception may come from the fact that you have to use a lot more safety precautions in fueling aircraft than fueling cars. it may also come just from the idea that fuel that makes things go in the air must be more potent than fuel that moves things on the ground. kerosene: autoignites at 410F/210C, flash point 38-52C, lower flammable limit .7% upper 5% Gasoline: autoignites at 536F/280C for automotive grade (50-100 octane) , up to 880F/471C for high octave Aviation grade (115-145 octane) flash point -45F/-43C to -50F/-46C for the same grade split. LFM 1.4-1.2% upper 7.8-7.1, same grade split. Diesel: autoignites at 494F/257C, flash point 126-204F, no flammable limits listed. so it looks like avgas does vaporize more readily than automotive grades, which would make accidental ignition easier, as long as you had a hot enough ignition source. So my training was more correct in the sense that being auto-ignition is much higher, than the Kerosene grade, but higher than petrol, you expect it to be "safer", but as it vaporises earlier, and as it vaporises much quicker, not counting how fast it goes whoooof, it goes whoof a hell of a lot easier than petrol, so in the sense of what reacts first to outside ignition sources, Av-Gas IS a lot more volatile....?.. the definition of volatile changes with its intended use here?.. It vaporises quicker and the gas has a total separate care requirement than the liquid. I am still unsure of this, correct me as needed.... the fact that it vaporises at lower temps and that vapour is therefore liable to ignite quicker, Yes?. No?. BTW, Stoichiometry... yep, breaking out the 100 dollar words here, and thanks MB for that education, is Av-Gas 14:1 air:gas the same as petrol? or is there a difference the higher the octane rating?.. I am asking because of possibility that if its a much lower saturation needs, as in one part Av-gas to 20 parts air, a stray spark may ignite the gas with less of it about?.. Also, this I know from racing, it burns with an invisible flame. A Lot of the top fuel race cars use Av-Gas type petroleum, Formula 1 etc use that type of fuel, because its a cleaner burn, and a more complete burn, in that they are throwing a lot less unburnt fuel up the exhaust pipe, they like to get as much bang for the buck as they can these days when you get no in-fight refuling in F1, the less weight the better. Trying to fight an invisible fire, trust me, this I know from Aviation AND the ADR dangerous goods training, is bloody impossible... spray the air why dont you?.. as long as your facing the "HOT" you are not doing anything wrong?.. but whilst your doing that plan to retire quick, you never know when its going to get suddenly a lot warmer there... If a Wagon of Fuel starts on fire, even if I am carrying the 12lbs of dry powder, my job starts to become traffic warden to keep other traffic away, at a distance, a passing car catching fire, insurance wise, is a greater expense than the truck?.. especially if its blown 200yds up the fields at the side when it all goes BLEVE inside that tank. Anyone else, TLW, about that type of fire, I am sure you knows a few dont you?.. I aint that type of "fireman", I will put out small flames, if its a big one, I am outa here, rather than reach for the powder, I may try pulling the pin on the fifth wheel if I can, and dump that trailer if the cab hasnt caught yet?.. I aint winding legs down, aint nobody got time for dat, pull pin set handbrake on trailer, I am snatch-and-run outa here... No one around here does tanker Av-Gas... no need. The place that does the refining is a few miles away from the airport, but its still cheaper to pipe it all the way underground to the airport than try and carry it in tankers. And a LOT safer as well. And therefore less insurance risk. As far as having it away on my toes from suck risks?.. As I keep saying, if the driver is on the run, Do try to keep up.
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Post by the light works on May 6, 2017 8:19:26 GMT
that's 1.2 parts per HUNDRED is the lowest concentration that will burn.
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Post by silverdragon on May 6, 2017 9:29:43 GMT
that's 1.2 parts per HUNDRED is the lowest concentration that will burn. So educate me... for which?.. and is it less parts per hundred for either?.. so will a stray spark ignite Petrol gas faster than Av-Gas-Gas... Or what is it you call Av-Gas in gas form...?.. All I know is if you can smell it already, you should be worried. Brass tools to shut the valve tight and inspect for leaks [with a not naked flame source?... ] whilst sounding an alarm for spillage, get the kitty litter [Absorb] out and deal with something?..
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Post by the light works on May 6, 2017 9:54:25 GMT
that's 1.2 parts per HUNDRED is the lowest concentration that will burn. So educate me... for which?.. and is it less parts per hundred for either?.. so will a stray spark ignite Petrol gas faster than Av-Gas-Gas... Or what is it you call Av-Gas in gas form...?.. All I know is if you can smell it already, you should be worried. Brass tools to shut the valve tight and inspect for leaks [with a not naked flame source?... ] whilst sounding an alarm for spillage, get the kitty litter [Absorb] out and deal with something?.. avgas vaporizes slightly easier, and burns slightly leaner than gasoline.
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Post by silverdragon on May 7, 2017 6:37:57 GMT
So educate me... for which?.. and is it less parts per hundred for either?.. so will a stray spark ignite Petrol gas faster than Av-Gas-Gas... Or what is it you call Av-Gas in gas form...?.. All I know is if you can smell it already, you should be worried. Brass tools to shut the valve tight and inspect for leaks [with a not naked flame source?... ] whilst sounding an alarm for spillage, get the kitty litter [Absorb] out and deal with something?.. avgas vaporizes slightly easier, and burns slightly leaner than gasoline. So in terms of trying to prevent it going bang, Av-gas is more dangerous than Petrol... Thank Dog for that, I thought I had been wrong "For all those years"...
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Post by Lokifan on May 7, 2017 14:08:03 GMT
I saw "Die Hard 2" last night. I was reminded of this conversation when I saw the ending, in which a trail of fuel leaking from a 747 taking off was lit on the ground, destroying the plane just as it lifted up. Turns out this was one of Adam's most desired myths to bust during the old show that they couldn't manage: ew.com/article/2014/12/19/mythbusters-interview/
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Post by the light works on May 7, 2017 14:08:59 GMT
avgas vaporizes slightly easier, and burns slightly leaner than gasoline. So in terms of trying to prevent it going bang, Av-gas is more dangerous than Petrol... Thank Dog for that, I thought I had been wrong "For all those years"... I think it still averages out pretty much the same. especially when you compare it to some of the other products out there that are basically an explosion looking for an excuse. and then, there's liquid oxygen. in a 100% oxygen environment, the autoignition temperature of motor oil drops to around a hundred degrees F (38 Celsius) asphalt becomes explosive in free air (or free oxygen, as it were) so in comparing avgas to automotive petrol, you are comparing leopards to panthers. is one more dangerous? yes. is it a significant difference? only if leopards and panthers are the only animals you are comparing. does it depend on how you measure it? yes.
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Post by the light works on May 7, 2017 14:23:19 GMT
I saw "Die Hard 2" last night. I was reminded of this conversation when I saw the ending, in which a trail of fuel leaking from a 747 taking off was lit on the ground, destroying the plane just as it lifted up. Turns out this was one of Adam's most desired myths to bust during the old show that they couldn't manage: ew.com/article/2014/12/19/mythbusters-interview/I thought I remembered seeing it mentioned in context with the show, but it might have been in the old forums.
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Post by the light works on May 7, 2017 15:54:33 GMT
it came up in the video to share thread from a video of a plane crash causing a fireball that aviation fuel is commonly viewed as being more powerful/explosive than other forms of fuel, and it occurs to me that this is something that would possibly be good material for a show, having the potential for both science and fireballs. I immediately think of heat output for a free burning volume and ease of ignition as being two measurable properties. but lets see what we can come up with.
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Post by the light works on May 7, 2017 15:55:13 GMT
I started a thread in the myths section for aviation fuel.
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Post by silverdragon on May 8, 2017 6:01:06 GMT
I started a thread in the myths section for aviation fuel. Can we get a mod to tidy up in here and move posts across?... [Edit, and behold, it is done... thanks to probably Loki who is lurking about at the time of this edit and probably responsible for the tidy up, if not, thanks to whoever it was anyway?..]
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