# Speed of Fire **URL:** \ **Category:** Factual Questions\ **Created:** [November 27, 2000, 5:01am UTC](https://boards.straightdope.com/t/speed-of-fire/42829 "2000-11-27T05:01:59Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [November 27, 2000, 5:01am UTC](https://boards.straightdope.com/t/speed-of-fire/42829/1 "2000-11-27T05:01:59Z")
I got into a discussion with a bunch of friends about how fast fire will travel, and in what conditions. In the movie Air Force One, when the refueling tanker breaks away, there is jet fuel running down the tube which supplies fuel to the airliner. This tube grates against the airliner and a spark ignites the fuel which, as the flames run up the outside of the tube to the tanker, causes the really cool eruption of the tanker into a huge fireball. Could this actually happen? They specifically state that the planes are moving at 200 knots at 15,000 feet. Would the flame be able to travel up the outside of the tube in such conditions? More generally, how fast would one need to propel a fluid fuel that is burning to prevent the flame from traveling up the trail of fuel and causing the fuel depository to explode. ---
**Author:** ![lesa](https://avatars.discourse-cdn.com/v4/letter/l/34f0e0/32.png) [@lesa](https://boards.straightdope.com/u/lesa)\ **Post date:** [November 27, 2000, 12:50pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/2 "2000-11-27T12:50:00Z")
Sorry I can’t answer your question. I just wanted to say I love your walrus symbols (:3= ---
**Author:** ![bizerta](https://avatars.discourse-cdn.com/v4/letter/b/3be4f8/32.png) [@bizerta](https://boards.straightdope.com/u/bizerta)\ **Post date:** [November 27, 2000, 12:53pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/3 "2000-11-27T12:53:24Z")
Not likely. Have you ever seen a fire go upwind? And it would have to go upwind when the wind was 200 MPH. At 15000 feet, there’s about 35% less air. And how could the fire go up the outside of the tube when the fuel is on the inside. This seems about as plausable as Mission Impossible when the helicopter flew into the train tunnel without hitting the sides of the tunnel and crashing. ---
**Author:** ![mrblue92](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@mrblue92](https://boards.straightdope.com/u/mrblue92)\ **Post date:** [November 27, 2000, 4:03pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/4 "2000-11-27T16:03:24Z")
> [@](#): > > This seems about as plausable as Mission Impossible when the helicopter flew into the train tunnel without hitting the sides of the tunnel and crashing. They did say Mission **Impossible** … Were you expecting Mission Plausible? Did you see the helicopter sequence in _Tomorrow Never Dies_ where the helicopter moves slowly forward a few feet off the ground nose down at, what, a 60 degree angle? ---
**Author:** ![c\_goat](https://avatars.discourse-cdn.com/v4/letter/c/f4b2a3/32.png) [@c\_goat](https://boards.straightdope.com/u/c_goat)\ **Post date:** [November 27, 2000, 4:15pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/5 "2000-11-27T16:15:27Z")
> [@](#): > > \*Originally posted by mrblue92 \* > \*\*Did you see the helicopter sequence in _Tomorrow Never Dies_ where the helicopter moves slowly forward a few feet off the ground nose down at, what, a 60 degree angle? \*\* You know, the helicopter blades were drawn into the frames later. They filmed that with no blades on the chopper. As far as the OP, I don’t think the fire would be able to do that. As a general rule, don’t believe everything you see in the movies. Air Force One was a good movie though, I like how the guy is standing at the door of the plane as it crashes (also impossible I think). ---
**Author:** ![Shiva](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shiva](https://boards.straightdope.com/u/Shiva)\ **Post date:** [November 27, 2000, 4:17pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/6 "2000-11-27T16:17:01Z")
And furthermore… Jet fuel has a flash point similar to kerosene. It’s not likely to burst into flame from a spark. Vapors or atomized fuel maybe, but not liquid. Further, furthermore… Fuel has to be mixed with air to burn. A solid stream of liquid fuel flowing out of a pipe is highly unlikely to allow flame propagation _upstream_. ---
**Author:** ![c\_goat](https://avatars.discourse-cdn.com/v4/letter/c/f4b2a3/32.png) [@c\_goat](https://boards.straightdope.com/u/c_goat)\ **Post date:** [November 27, 2000, 4:27pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/7 "2000-11-27T16:27:59Z")
Plus, when you spray lighter fluid on a barbeque fire, the fire doesn’t go up the stream and explode the can/bottle in your hand. ---
**Author:** ![SSgtBaloo](https://avatars.discourse-cdn.com/v4/letter/s/ac91a4/32.png) [@SSgtBaloo](https://boards.straightdope.com/u/SSgtBaloo)\ **Post date:** [November 27, 2000, 4:51pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/8 "2000-11-27T16:51:10Z")
> [@](#): > > \*Originally posted by c\_goat \* > \*\*Plus, when you spray lighter fluid on a barbeque fire, the fire doesn’t go up the stream and explode the can/bottle in your hand. \*\* Apples and oranges. When was the last time you lit a barbecue grill at 15,000 feet altitude while travelling at 200 mph? When you squeeze a can of lighter fluid, you eventually have to stop and let air back into the container to equalize the pressure. If a flame has travelled up the fuel stream to the nozzle just as you stop squeezing, the air rushing back into the container could draw the flame inside it, causing an explosion (not likely, but it does happen). Airborne tankers don’t work on the “squeeze, release, squeeze” method. Instead, pumps aboard the aircraft draw fuel from the tanks and send it down the refuelling probe to the other aircraft. As fuel displaces air in the recieving aircraft’s tanks, the excess pressure is vented through valves designed for the purpose. As the air pressure above the fuel in the tanker drops, other valves aboard the tanker allow air in to prevent the tank from developing a vacuum. The whole process is designed to avoid causing explosions, fire, or damage to either aircraft. I would guess that the materials used to make the boom itself would be of the non-sparking variety in any case. If there are any boom jockeys here at SDMB, I’m sure they can explain it better than I (and correct any technical mistakes I may have introduced). However, I am certain that my description of the above process is essentially correct. ~~Baloo ---
**Author:** ![mrblue92](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@mrblue92](https://boards.straightdope.com/u/mrblue92)\ **Post date:** [November 27, 2000, 6:42pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/9 "2000-11-27T18:42:40Z")
> [@](#): > > You know, the helicopter blades were drawn into the frames later. They filmed that with no blades on the chopper. Yes, I know. They show it in the DVD. I enjoy Bond movies for the style, not the substance–unbelievable plots are par for the course. That particular scene did bug me, though. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [November 27, 2000, 10:36pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/10 "2000-11-27T22:36:41Z")
> [@](#): > > \*Originally posted by Shiva \* > **A solid stream of liquid …** _Blinking_ I think I need a nap. ---
**Author:** ![\_D](https://avatars.discourse-cdn.com/v4/letter/_/71c47a/32.png) [@\_D](https://boards.straightdope.com/u/_D)\ **Post date:** [November 27, 2000, 11:54pm UTC](https://boards.straightdope.com/t/speed-of-fire/42829/11 "2000-11-27T23:54:46Z")
> [@](#): > > \*Originally posted by lesa \* > \*\*Sorry I can’t answer your question. I just wanted to say I love your walrus symbols (:3= \*\* **I loved it first! If this looks familiar, it was iberii’s sig line at one time. [What’s your favorite smiley? :\*\*D](http://boards.straightdope.com/sdmb/showthread.php?postid=670512#post670512) [What is the word for…](http://boards.straightdope.com/sdmb/showthread.php?postid=695553#post695553)** (iberii retired on 9/1 and iamthewalrus(:3= started on 9/25, so I’m sure there’s no conflict.)