The Air Force has some 500 KC-135s, airborne refuelling tankers, some of them should be modified to fight forest fires. At the end of the boom, a rotary sprinkler head could be fitted for wide area dispersal. It's already scorching is the western U.S.-- ty6, Jun 19 2003 Similar to this. http://www.edwards....e-icing_tanker.htmlDampen things down a bit. [ty6, Oct 05 2004, last modified Oct 21 2004] Commerce Business Daily - June 11,1999 issue http://www.fbodaily...n-1999/54sol001.htm"Edwards AFB, CA, is seeking sources for an anticipated requirement for water tank(s) to carry water as cargo aboard a KC-135 Stratotanker...The water will be drained from the tank(s) and expelled from the aircraft during flight." [phoenix, Oct 05 2004, last modified Oct 21 2004] Martin Mars water bombers http://www.martinmars.com/ [rapid transit, Oct 05 2004, last modified Oct 21 2004] As close as need be http://www.airliner...pen.file/0860344/L/They apparently didn't care whether I believed it [lurch, Jun 09 2007] Evergreen Aviation http://www.evergree...hoto_pg/drop_01.jpgis another outfit that doesn't care that they're making me look bad [lurch, Dec 22 2007] Alternative approach Borate_20Bouncing_20Bettys [normzone, Dec 27 2007] Boston Molasses Disaster http://en.wikipedia...n_Molasses_DisasterIt would be almost be enough to make you swear off molasses! [bungston, Dec 27 2007] see "virga"
Water dumped out of an airplane tends to evaporate. Particularly so over a hot updraft such as produced by a forest fire. If you watch fire-fighting aircraft, you'll see them actually getting down into canyons, as close to treetop level as possible, to attempt to dump water with the best accuracy and least evaporative loss.
The water needs to get out of the plane at a very high rate. The actual rate depends greatly on airspeed. A helicopter can dump a 50 gallon bucket at one spot with good effect, where a C-130 might have to throw 500 gallons in two seconds just to get any to hit the ground.
Air tankers used in fire suppression are usually prop-jobs, as jets tend to have higher stall speeds and are less forgiving of flying into hot drafts in tight spaces.-- lurch, Jun 19 2003 Most any cargo plane or bomber could be converted for use as an airborne tanker to fight fires. As they already come with large doors for the quick movement of goods/dropping of bombs, water could easily be dropped out the same. The reason why you don't see more conversions is because land-based aircraft are always limited on the availiable infrastructure on the ground.
There needs to be an airport nearby that can handle the weight of a few dozen tons of water. There also needs to be a method of filling the tanker as quickly as possible. Fire hyrdants could probably do this, and so could industrial pumps from a nearby water source. But this requires quite a bit of taxiing. Even if you get the process down to a science, you're still only going to get maybe 2 drops in an hour.
The solution to this is to use a flying boat. Two prime examples of this are based not even 20 minutes from my house (link). After every drop, all the Mars have to do is to find a body of water. They then drop down to it, skim across its surface, and the hold is filled with water within seconds. Flight to the fire then ensues, followed by a drop, then the process repeats. When used in tandem, they can get a drop in every 7 minutes.
I believe Bombardier has designed an aircraft exclusively for this purpose using the same methods. However, their birds are rather small compared to the Martin Mars.
The bombers are truly an awe-inspiring sight. I still run outside to watch them fly a few hundred feet overhead, even after 20 years of living here.-- rapid transit, Jun 19 2003 I'd prefer a KC-135 Wine tanker, perhaps equipped with a special bladder to keep the wine fresh.-- waugsqueke, Jun 19 2003 <news>There was a terrible accident today as a 500 gallon KC-135 wine tanker accidentally dropped it's cargo on a wedding dress manufacturing plant.</news>-- Worldgineer, Jun 19 2003 "Ladies and Gentleme, WaugsCo is proud to unveil its latest product, the 'Bag-In-Bomb' precision guided wine delivery munition, capable of delivering 500 litres of Sauvignon Blanc from 35,000 feet with stunning accuracy....."-- 8th of 7, Jun 19 2003 KC-135's are not the quickest-handling birds around; more like steering a yacht than flying a plane. They're made for you to come to them, rather than for them to go deliver by pinpoint. So accuracy would be extremely difficult, especially in the 135's preferred cruising altitude.
A friend of mine flies the KC's sister ship: the RC-135 Rivet Joint, which handles marginally better.-- RayfordSteele, Jun 19 2003 We keep the plane on ice before take-off.-- waugsqueke, Jun 19 2003 What, even for Chateau Mouton Rothschild '68 ?
<Slaps Waug's face with gauntlet>
Swords, or pistols, Sir ? My second, Mr. UnaBubba, will make the necessary arrangements for out next meeting.-- 8th of 7, Jun 19 2003 Sorry, that one's not available in 500 gallon quantities.-- waugsqueke, Jun 19 2003 Don't I know it ... I cry myself to sleep every night .....-- 8th of 7, Jun 19 2003 a couple problems. The KC-135 is a modified Boeing 717. It is incredibly ineffeint at low altitudes it has a cieling of 45,000 ft. It would need to be able to suck water up over a lake which it would be unable to due since it has a cruise speed 856km per hour 532 miles for you mercans. I agree that this machine has an incredible payload but this is not a feasible idea in any shape . Buy a CANADIAN 415 water bomber and save youir time anyway this thing was first put in to production in the late 50`s-- scott199, Feb 04 2004 Scene 1: a USAF base, somewhere, sometime...
OK, listen up! Chuck, you're on flight refuelling for today's big exercise. Take the KC-135 on the left. Bill - helping out the firefighters with that big blaze up the coast. Yours is the KC-135 on the right...
Scene 2: the evening news...
USAF investigators are puzzled by the loss of 12 military aircraft earlier today. Six simply fell out of the sky shortly after having refuelled in flight, the remainder were destroyed by a huge explosion which occurred as water was being dropped on a forest fire near their flightpath.-- Steve Adams, Feb 05 2004 What would happen if instead of droping buckets of water they dropped giant water ballons, then all of the water would make it to the ground.-- SystemAdmin, Feb 05 2004 But think of the time required to load huge water balloons into an aircraft compared to the time required to pour water into an aircraft.-- GenYus, Feb 05 2004 I gotta fishbone it. A KC-135 is to big to fly at the altitude and airspeeds needed for the job, they just can't manuver well enough either.-- KLRico, Feb 05 2004 Let's go back to the water balloon idea. I think this may work well if set up right. [Sys], I'm completely stealing it and posting it as my own - let me know if this isn't ok.-- Worldgineer, Feb 05 2004 OK, I just got slapped around again by reality. Evergreen Aviation has a 747 "Supertanker", 24,000 gallon capacity (that's a seven-fold increase over the previous big fire-tanker), 400 ft. drop altitude, and 140kt drop speed. Plus it operates 150,000lb *under* MTOW (max take-off weight) so it has lots of spare get-away power from tight spots.
It would definitely be one to go watch.-- lurch, Dec 22 2007 Another way to get the water to the ground despite hot updrafts is to raise the boiling point. Increased solute should do the trick. One could add salt but the salt would remain in the soil. Sugar would be better. The sugar could be added to the reservoir after it was filled, to be mixed en route. After the fire the sugar would be decomposed by bacteria, so no harm done.-- bungston, Dec 27 2007 Adding sugar to the water... hmmm. Let's give it a go. Suppose we put in equal masses - a ton of sugar for every ton of water. The water will need to be fairly warm (not extreme) to dissolve the sugar, but since we're flying to a fire, I'm assuming warm weather. The molality of the mixture (I'm using sucrose, 342.3g/mol) will be (1000/342.3)mol/liter, or 2.92 molal. The constant of ebullioscopy (boiling point elevation) for water is 0.52K/molal, so we end up with the boiling point of the water raised by 1.5 degrees C, or, not much.
We could caramelize the fire, rather than extinguishing it; but on a positive note, any game animals that were unable to escape the flames would end up with a very nice glaze.-- lurch, Dec 27 2007 Note, good lurch, that as steam boils away from the discharged water, the molar concentration of the remaining sugar solution increases and it becomes more difficult for additional water to boil away.
On reading about this, it looks like salt might be better after all - you can achieve a higher molarity with the same weight of solute, and thus improved weight for weight boiling resistance.-- bungston, Dec 27 2007 // salt might be better after all //
If you're that keen to kill all the vegetation, why not spray the whole area with defoliant, thus removing the risk of fire ?
Forest fires are a natural phenomenon, although there are the usual idiot humans who start them too. Fires become a problem when they aren't allowed to burn naturally, because humans build their residences in wooded areas. If you interfere with a natural cycle, sooner or later it will cause problems; this is just a palliative.-- 8th of 7, Dec 27 2007 Or a seasoning.-- lurch, Dec 27 2007 Can't it be both?-- bungston, Dec 27 2007 // On reading about this, it looks like salt might be better after all. // - I'd have to agree. In the early '60s I got to see (and smell) the clean-up of a train wreck near Bowie, Arizona which involved, among other things, several tank cars of sulfured molasses. When enough of the water boils out of the molasses, the sugar becomes flammable; it smells horrible, oozes into everything, and is very hard to put out.-- lurch, Dec 27 2007 That story reminded me of the Boston Molasses Disaster. I have linked it up for your molasses reminiscing pleasure, lurch.-- bungston, Dec 27 2007 random, halfbakery