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Using a 747 to Fight Wildfires 276

RotJ writes "It's fire season again. And the government just grounded 33 aging air tankers on Monday due to safety issues. Looking for a modern solution, Evergreen Aviation has come up with a 747 supertanker with 24,000 gallons of tank space onboard, which allows it to cover seven times the area of today's largest existing airtanker. In addition to fighting fires, it will be able to contain oil spills and 'perform challenging homeland security missions' like neutralizing chemical or biological attacks. And think of how many John Goodmans you could cover with fire retardant. Be sure to watch the videos."
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Using a 747 to Fight Wildfires

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  • Speed (Score:5, Interesting)

    by JohnHegarty ( 453016 ) on Monday May 17, 2004 @08:04AM (#9172090) Homepage
    How much can you slow down a 747.... would it no make it hard to hit the target at 600mph
    • Re:Speed (Score:3, Insightful)

      by Anonymous Coward
      Well, ofcouse, I dont know if the guy is accurate or not.
      But he claims about 170mph for takeoff.
      I would see this as a lowest for flying speed at low altitude.
      But that's still pretty damn fast s. pdf
    • Re:Speed (Score:5, Informative)

      by AllUsernamesAreGone ( 688381 ) on Monday May 17, 2004 @08:14AM (#9172149)
      747s can go down to 250knots and be managable - heavy load turn stall speed is around 210knots IIRC.
      • Re:Speed (Score:5, Informative)

        by joemc91 ( 757436 ) on Monday May 17, 2004 @09:01AM (#9172408) Homepage
        A 747 can actually slow to around 120knots, about 140 mph. The standard approach speed for one of these behemoths is around 140-190 knots, depending on the weight. I don't think the proper question is "can the plane go slow enough?" but "can the plane maneuver at low-altitude among mountains?"

        Here's some more reading from a slightly more advanced aviation source: full.html#187301
    • Re:Speed (Score:5, Informative)

      by Analogy Man ( 601298 ) on Monday May 17, 2004 @08:16AM (#9172161)
      One would not need to be going at cruise speed, but you bring up a very important point. I would shudder to think of a 747 trying to deal with a low altitude drop in mountainous terrain.

      I am not sure a commercial airliner is the best recipe for this problem. In general they are designed to get up to Mach 0.78 - 0.84 and cruise along at 35,000 ft.

      A derivative of a military aircraft would be more appropriate. Problem is, by the time the National Guard has used them up (repair costs exceed operating value) there is not much left to the structural integrity.

      Bottom line, you get what you pay for. Hearing the dollars on NPR, it is amazing to me that companies were able to keep WWII vintage aircraft in the air for what they make.

      • Re:Speed (Score:5, Informative)

        by Anonymous Coward on Monday May 17, 2004 @08:28AM (#9172228)
        For years, commercial pilots had to essentially make the "low altitude drop in mountainous terrain" you are speaking of at Kai Tak in Hong Kong. The airport was essentially nestled up against a steep mountain, densely populated by tall apartment buildings and the ocean at the end of the runway. This called for some truly interesting descents and there were "incidents" on the runway but none major, if I recall, before the airport was eventually closed.

        Check out this photo: []
        • Re:Speed (Score:5, Informative)

          by Analogy Man ( 601298 ) on Monday May 17, 2004 @10:23AM (#9173096)
          I used to work at Boeing in the performance group working out how to do this. The approaches and procedures are all worked out with margins for all obstacles and provisions for engine out, performance adjustments for temperature etc. In the case of Hong Kong it is at sea level so the performance is much better than it would be at 8000 ft somewhere in the Sierras or Rockies

          In the case of dropping on a fire, it is an ad hoc mission, the pilots would have to eyeball the situation and think on their feet. Also, suppose they count on being rid of 150,000 lbs of water before they need to do a climbing turn at the end of a valley and a hydraulic valve sticks? The only good news as that 25,000 gallons of water would help extinguish the 30,000 gallons of jet fuel.

          The wind conditions around a forest fire are also dangerous. Fires create their own weather.

      • Re:Speed (Score:5, Insightful)

        by Jesrad ( 716567 ) on Monday May 17, 2004 @09:09AM (#9172435) Journal
        Exactly, and I would rather have a C130 do that work instead of a 747. Hercules can fly half as fast as those big commercial jets when needed. One even landed on a carrier [].
        • Re:Speed (Score:5, Funny)

          by steve_l ( 109732 ) on Monday May 17, 2004 @10:01AM (#9172862) Homepage
          they are very disconcerting to encounter in the mountains. I was driving up in scotland when this hercules crawled overhead at about 100' - it is a lot harder to avoid reacting badly to the sight of something that looks about to land on you, than it is it deal with a fighter plane going above you at that height -they are usually gone before you have time to notice.
        • Re:Speed (Score:5, Informative)

          by lunartik ( 94926 ) on Monday May 17, 2004 @10:17AM (#9173019) Homepage Journal
          Bombardier's 415 is an awesome plane and doesn't have the concern of decades-old surplus planes (remember that video from a couple years ago of a C-130 losing its wings during a drop?). From their site []:
          It takes only 12 seconds, travelling at 130 km/h (70 knots) to scoop up the 6137-litre (1621-US gallon) water load. This requires an on-water distance of only 410 metres (1350 feet). The Bombardier 415 can scoop water from sites as shallow as 2 metres (6.5 feet) and 90 metres (300 feet) wide. This means that a great number of water sites can be used to reload its tanks. The aircraft doesn't need a completely straight scooping path. Since it's still in "flying" mode while scooping, the pilots can maneuver the Bombardier 415 around river bends or avoid visible obstacles in the water. As well, if the water site is too small for a full pick-up, the Bombardier 415 can take a partial load and return to the fire.
        • Re:Speed (Score:2, Insightful)

          by smurf975 ( 632127 )
          I might also agree with you if I knew the details of these:

          1. How much does the maintance of a 747 cost? During operation and non operation (fuel, repairs, metal fatique, parts)
          2. How much would the maintance cost of a smaller plane? My guess is that it would be cheaper.
          3. If smaller planes maintance is cheaper then a 747 then maybe you can get a fleet of smaller planes compared to one big one.
          4. Are 747's ok to use in all terain types?

    • Re:Speed (Score:5, Informative)

      by neodymium ( 411811 ) on Monday May 17, 2004 @08:29AM (#9172232) Homepage
      a 747 in full flap configuration can be slowed down to 210kt (approx. 340km/h) IAS fully loaded, and close to 140kt (approx. 220km/h) IAS empty. the maneuverability is a little bit limited, i.e. bank angles over 25 are forbidden. no steep turns are possible, so it takes over 1 minute to do a 180 turn.
    • by mpe ( 36238 )
      How much can you slow down a 747.... would it no make it hard to hit the target at 600mph

      That is cruising speed for an airliner. Aircraft takeoff and land considerably slower than their cruising speed.
      A critical number for takeoff is V2, which is the minimum airspeed where lift excedes weight. A firefighting aircraft will tend to climb as it makes a drop, since lift remains the same whilst weight is reduced.
    • Re:Speed (Score:3, Interesting)

      by valiko ( 575930 )
      Check this thread [] well... read the first reply in this thread. US forestries banned the use of IL-76 firefighter, which is twice smaller than 747, how would 747 be any different??? Il-76 payload is 11,000 gallons, pretty good too
  • Refills? (Score:5, Interesting)

    by MrIrwin ( 761231 ) on Monday May 17, 2004 @08:05AM (#9172095) Journal
    I know one feature of firefighting planes such as the Canadair is the ability to refill by skimming the surface of a lake or the sea.

    Somehow I can't envisage this with a 747, and how many 747 sized airstrips do you find near forestry areas?

    • I'm no aerospace engineer.... But I thought 747's weren't particularly strong. How much does all that water weigh compared with what a 747 could carry?
      • Re:Refills? (Score:5, Informative)

        by CommandNotFound ( 571326 ) on Monday May 17, 2004 @08:21AM (#9172190)
        But I thought 747's weren't particularly strong.

        They were strong enough to carry the shuttles around on its back. According to the specs [], the 747-400ER has a maximum takoff weight of 910,000 lbs. A fully-loaded 18-wheeler dirt truck averages around 80,000 lbs, to put that into perspective. I don't see how it gets off the ground. 11 trucks are heavy.
      • Re:Refills? (Score:5, Informative)

        by twbecker ( 315312 ) on Monday May 17, 2004 @08:30AM (#9172233)
        24000 gallons of water weighs 99.96 tons.

        Load capacity of a 747 is just over 116 tons.

        But yeah, that sure is a lot of weight. Amazing aircraft.
      • Re:Refills? (Score:5, Informative)

        by general_re ( 8883 ) on Monday May 17, 2004 @08:32AM (#9172241) Homepage
        How much does all that water weigh compared with what a 747 could carry?

        24,000 gallons of water weighs just shy of 200,000 pounds. A quick glance at the technical specs for the 747 says that the maximum payload capacity of a 747-400 cargo freighter is 244,000 pounds.

        • So if I understand correctly... if one engine goes out the plane is pretty much screwed?

          Or does the "maximum payload" take that sort of thing into account?
          • Re:Refills? (Score:5, Insightful)

            by confused one ( 671304 ) on Monday May 17, 2004 @08:51AM (#9172344)
            The plane has no problems staying in the air with one engine out. Even if they lost two, it would be a simple matter to dump their payload: It's only water.

            Some people might get a little wet... and appropriately ticked off; but, it's better to get suddenly drenched than to have a 747 crash land on your head.

          • If I recall correctly, in order to be certified as airworthy, the 747 must be able to sustain an engine failure at or after V1 - i.e., even at its maximum weight, it must be able to take off, climb safely, and fly on only three engines.
    • I know one feature of firefighting planes such as the Canadair is the ability to refill by skimming the surface of a lake or the sea. Somehow I can't envisage this with a 747,

      It would need to be fitted with something which extended quite a distance below the fuselage. So as to keep the engines out of the water.

      and how many 747 sized airstrips do you find near forestry areas?

      Maybe the Antanov-124 would be a better option. This has shoulder mounted wings and can land of grass strips.
    • Re:Refills? (Score:5, Interesting)

      by Rolo Tomasi ( 538414 ) on Monday May 17, 2004 @09:14AM (#9172461) Homepage Journal
      Beriev [] makes amphibious planes, some of which are designed for firefighting. The Be-200 [] has about 1/7th of the water capacity of the 747 mentioned in the article, but it can scoop up water during touch-and-go on a lake or river. It can also land on a lake or river to refuel (you'd just have to get a fuel truck near to where the fire is, and the plane could operate there all day). The 747 would have to fly to a big airport (needs a long runway), and this airport would have to be situated next to a body of water, or have some other kind of huge water reservoir. IMHO this looks highly impractical vs. an amphibian plane.
  • Biological attacks (Score:2, Insightful)

    by Anonymous Coward
    How will it protect us from a biological attack? By drowning us in more harmful anti-bodies instead?
  • How Slow (Score:2, Interesting)

    by PingPongBoy ( 303994 )
    do you need to go if you want to water a forest, which is not large compared to the flight range of a 747?

    Then again, in a flight simulator I've flown the 747 straight up so you could approach the burn and then climb hard while dropping the water.

    What effect does this kind of dump do to the aerodynamics?
    • >What effect does this kind of dump do to the

      If you keep the center of gravity in the middle, the impact on aerodynamics is not so bad. But with lots of liquid on board, this can be quite difficult, as the liquid moves during flight. So either have lots of small cells containing the liquid, or make sure that all maneuvers are well coordinated. NO straight climb up then.
      • Re:How Slow (Score:3, Insightful)

        by eric76 ( 679787 )
        They could also use baffles to keep the water from sloshing around.

        When I was in high school, I routinely hauled water to cattle in an old truck with a thousand gallon water tank.

        The only time that it got dicey was if I used part of the water in one location and the rest in another.

        With the tank half empty, the sloshing was unbelievable. If you weren't careful, it was entirely possible to turn the truck over.
    • Re:How Slow (Score:5, Funny)

      by System.out.println() ( 755533 ) on Monday May 17, 2004 @08:15AM (#9172153) Journal
      Then again, in a flight simulator I've flown the 747 straight up so you could approach the burn and then climb hard while dropping the water.

      Do I even need to add anything to make you sound less credible? :)
    • Re:How Slow (Score:5, Informative)

      by mumblestheclown ( 569987 ) on Monday May 17, 2004 @08:33AM (#9172244)
      You know, I've been studying 747-400 systems for the last few months in preparation for some work i am going to do (I am an experienced pilot).

      "flown the 747 straight up" sounds about as dumb to a pilot as those tech support calls that ask what the cupholder is for to a computer company.

      Now, I can't speak for the -200, but as far as the -400 goes, if you fly the 747 straight up in real life, you will in all probability die.

    • Then again, in a flight simulator I've flown the 747 straight up so you could approach the burn and then climb hard while dropping the water.

      Dropping water will cause any plane to climb. Anyway how do you get a 747 to climb vertically? Even with full engine power you'd need quite a bit of airspeed. The thrust to weight ratio of an airliner is rather less than one.
  • by njh ( 24312 ) on Monday May 17, 2004 @08:06AM (#9172101) Homepage
    This "11,000-gallon tanker plane pours 'too much water,'" []. I guess 24,000 gallons (90000L) is not too much though...
    • "The faucet is pouring too much water."
      "Turn it down."

      /$2,000,000 investigation.
    • by Analogy Man ( 601298 ) on Monday May 17, 2004 @08:28AM (#9172226)
      One thing the Russians are good at is making things tough. Their design philosophy on military aircraft (including their fighters) is to make them robust to hostile environments including unimproved runways etc. On the surface this looks like a far more economical model using either the Russian or Canadian equipment than to retrofit some used up aircraft not designed for anything like this mission.
      • I couldn't agree with you more, however, the US seems to suffer from a major case of Not Invented Here Syndrome. At one point in time, the Alaskan legislature appropriated funds to purchase two Canadair fire bombers, and the state's top fire fighting official wouldn't let the purchase go through, claiming they would do no good in Alaska. Some progress is being made, Hawkins and Powers, one of the major contractors is in negotiations to buy several of the Russian Be-200's. The problem is, the US Forest Se
    • by sharrestom ( 531929 ) on Monday May 17, 2004 @08:41AM (#9172292)
      Back in the 80's, I worked 3 summers as a Smokejumper for the BLM out of Fairbanks, Alaska, and was detailed to the lower 48 on 2 occasions. Smokejumpers and air tanker are considered initial attack resources, so, getting to the fire while it was small and containable was the primary mission. Personally, I find that the aging A-10 aircraft would be more practical than the 747, as it can be forward positioned to the existing air tanker support facilities (Minden, NV being nearest to my neck of the woods/desert), and is fast and exceptionally maneuverable, a requirement for the mountainous terrain of much of the west.
    • by EinarH ( 583836 ) on Monday May 17, 2004 @08:50AM (#9172336) Journal
      A very interesting article indeed, I read something similar on USENET but this one is more extensive. As somone said; it's all about two things:
      1. The NIH, Not Invented Here-syndrome and
      2. Money.
      In addition to his work for BLM, Lamun heads the Interagency Airtanker Board that represents air tanker contractors and federal firefighting agencies. It is responsible for setting criteria for air tankers and overseeing the certification process.
      Am I the only one that can see a clear conflict of interest situation in this case? The same guy in both a "criteria role" and as representative for contractors (both private and federal)...

      Ten bucks that The Forest Service will abandon it's "too much water" policy when a US-company comes up with a US-built plane doing the exact same thing as these Ilyushins. And that despite the advantages of the Ilyushins like better maneuverability, reduced cost and shorter takeoff.

    • Go back and read the article and get a little bit more context. Too much water at an incorrect angle.
  • by t_allardyce ( 48447 ) on Monday May 17, 2004 @08:07AM (#9172109) Journal
    After watching a programme last night on a (mockup) terrorist attack on london (about 2000 people died when a chlorine tanker was blown up) i want one of these for stopping chemical attacks! apparently we have 1 air-ambulance for the whole city and a fraction of the police have chemical/biological training and equipment and the tube staff have nothing except some training that said "get everyone out of the nearest exit as fast as you can" wow i think i might become an emergency training consultant, i could make millions!
    • ...whisper it very quietly but...maybe there isn't a massive terrorist threat of this nature...

      I travel on the tube daily and know a couple of people who work at one of the busier stations. Anyone knows it's desperately easy for a suicide bomber to blow up a tube train. Carry a rucksack packed with the necessary equipment and off you go.

  • The 747 with a gross weight of the 747 of roughly 800,000 pounds is more than that of almost any other aircraft built. The 747 can carry a maximum payload of approximately 144,000 pounds for a distance of 6854 miles and has a cost-economical cruising speed of 564 miles per hour. That's a lot of water in with a short flight time (even if local). And for an airplane that's been around since the 1960's -- not bad either.
    • it is not very helpful to think of the cruising speed of jets in terms of "miles per hour." rather, it is helpful to think of it as a percentage of mach. big jets typically cruise at between .68 (quite old and slow ones) and .86 mach.

      what is mach? why, it's (rule of thumb) 38.94 * ((temp in K)^(1/2)). Given a jet standard atmosphere lapse rate of -2 deg c per 1000 feet, on a day where the surface temperature is at 30c, a .85 mach cruise at 36000 would be 589 knots (683 mph). on the same day, .85 mach

    • There is one aircraft with a greater gross weight - the Airbus 380A. It hasn't been flown yet, but the first one was unveiled sometime last month, so it has been built.
  • by shoppa ( 464619 ) on Monday May 17, 2004 @08:16AM (#9172158)
    Didn't early brochures for the 747 show a small swimming pool in first class?
  • Popular Science (Score:3, Interesting)

    by xplosiv ( 129880 ) on Monday May 17, 2004 @08:17AM (#9172164)
    One of the latest Popular Science articles talked about a new(?) type of plane which is a combination of a helicopter and a jet (so it has rotors and jet engines), so it can take off almost anywhere, but get up to almost mach 1 if I remember correctly. The hauling capacity is enormous, one of the scenarios they showed was for fire fighting. Unfortunately, I was unable to remember the url of the manufacture, or find the article on, I am sure someone else here knows the model name.
    • Re:Popular Science (Score:4, Interesting)

      by ericspinder ( 146776 ) on Monday May 17, 2004 @09:07AM (#9172428) Journal
      I love Popular Science as well, but almost all of their "forward-looking" inventions are vaporware. Sometimes, I think, their qualification for story submission is a good color drawing of the "product" and lots of hype about how the worlds going to change because of it in 2 to 6 years. For how many years now have they been saying "flying cars are right around the corner". I am not saying that they are always wrong (or every fraudulent), their coverage on new products and (working) prototypes is good, but just don't count on anything that needs an "artist rendering", like the fire-fighting plane you (apparently) saw in that mag.
    • Re:Popular Science (Score:3, Informative)

      by kidgenius ( 704962 )
      Are referring to this []? First, trying to get a prop plane to go the speed of sound is something I don't want to try anytime soon. IIRC, you start encoutering problems with the blades and shockwaves. No thank you. Also, that aircraft is fairly tiny. Lastly, it's amazing that the government keeps pushing that plane through testing considering how many accidents in testing that have occured and killed US soldiers. Not too mention the aircraft has had quite a lengthy development cycle.
      • No, the plane I am talking about has stationary engines just like a regular plane, but also has the rotors like a helicopter. If I remember correctly, the plane was manufactured by a company in the Netherlands (I remember seeing the .nl TLD).
  • A few Problems.... (Score:4, Insightful)

    by Graemee ( 524726 ) on Monday May 17, 2004 @08:19AM (#9172175)
    Cost - even the smaller water bomber's are expensive. Operating cost of a 747 would be even higher again.

    Accessability - a 747 doesn't operate from small dirt airfields or remote areas. I can see one of these trying to fly from a larger area to a remote area to drop water. (See costs)

    Speed - they'd be running a lot faster than most water bombers. I can here the STALL STALL warnings now.

    Accuracy - See Speed.

    They might be good for fast burning "California or OZ" fires but I not sure they would be much use for most medium size forest fires. IMHO

    • Insightful?????
      Speed -- The 747 may cruise at about 550 mph but there is nothing that says it can't fly slower. You ever seen an aircraft land? They are going pretty slow in comparison to cruise, and there is nothing that says they can't fly at speeds like that for a bit.

      Accuracry -- See Speed

      Accessibility -- If you can cruise at 550 mph, there is nothing to say you can't get more water further from the fire and still make trips that take just as long as a regular water bomber. Also, Sky Harbor Airpor

  • by tronicum ( 617382 ) * on Monday May 17, 2004 @08:20AM (#9172187)
    Imaging building suchs a tanker from a Airbus 380 [] Specs []

    Interesting is that it covers "7 times" of what a normal air tank covers. As amateur I would assume that it takes similar time to cover the burning area, it just takes makes re-fitting faster. It is probably harder to fly as whell.

    Beside that the chemical and biological "homeland" security aspect is ridiculous. You dont have such planes equipped in time fight such attacks.

  • There is old testimony relating CIA / Pacificorp with selling off Aircraft to the private sector to combat firefighting. Wonder if this is a cleanup operation to retire the "suspicious" planes re st_service_c130s.html
  • by Anonymous Coward on Monday May 17, 2004 @08:26AM (#9172215)
    And here's the thing, once a fire gets to the size that you start thinking about dropping 24,000 gallons of water on it, YOU'VE ALREADY LOST! Water sure as hell ain't stopping it, unless it happens to be in the form of a severe rainstorm, and even then fires can burn underground for months. There were fires in Yellowstone that started in late fall, got snowed on, smolderd the entire winter underground and then reemerged the next spring.

    What the Forest Service needs to do, and to their credit seem to at least be aware of on the ground (at least from my personal experience), is have quick response helicopters that can get to fires before they have blown up (read, still under 100 acres, give or take). Once a fire gets much bigger than say 1000 acres, it starts to create its own weather - at this point, the effort becomes more one of 'figure out where the wind will push the fire and get the hell out of the way!'

    The only possible use I see for this plane, and one in which it is probably well-suited for, is in protecting man made structures from large, fast moving fires. Let's say there was a fire bearing down on Denver and threatening a rather pricey subdivision. This plane would be perfect for that job - they could load it up with fire retardant and create a huge 'wet line' in front of the subdivision. Maybe make a couple drops and you would be golden. My guess is that's what they have in mind, but I could be wrong.
    • You do realize that 1000 acre fire is small right? There are about 640 acres in a square mile. And fighting fires of 1000 acres is nothing. It's relatively easy. Hell, if fires stayed to 1000 acres (about a mile and a half square) , the forest service would be fighting those without any trouble. You'd be amazed at how big fires get and they still get put out by human intervention.
      • by Anonymous Coward
        From my personal experience, 50 acres (give or take of course) is about the threshold between a small manageable fire, and a larger, 'project' type fire. Maybe you've never been on a real fire before? I don't know. The 50 acre fires that I have been on have involved large numbers of engine, multiple helicopters, and lots of support personell, not to mention the people digging line and dropping trees. Get to 1,000 acres and you can EASILY justify calling in smokejumpers or a shot team from NIFC. When I
  • by Molina the Bofh ( 99621 ) on Monday May 17, 2004 @08:36AM (#9172263) Homepage
    Jeff, you moron ! That was not the water release button !! That was the emergency fuel dump button !
  • by EulerX07 ( 314098 ) on Monday May 17, 2004 @08:38AM (#9172275)
    Bombardier CL415

    Check the description and FAQ here. []

    Retrofitting a 747 for firefighting? Why not buy a plane designed from the ground off for firefighting purposes? It can drop 32000 to 65000 gallons of water between refueling. In real life situation it has proven to be able to deliver up to 30 000 gallons per hour.

    Ever since I was a kid I'd seen videos of CL215 (the predecessor) fighting the big forest fires, and I was always wondering why the US used small choppers carrying minuscule payloads of water to fight the fires. Can anyone clear this up?
    • by Wacky_Wookie ( 683151 ) on Monday May 17, 2004 @09:29AM (#9172557) Homepage Journal
      I used to live on Vancouver Island, Canada. We get one or two big fires every year and these planes are called in when things get hairy.

      During a fire a few years back, the pilots were using are road as ref. point for heading back to the fire after scooping up a new load of water. These things were passing over our house not more then 100 ft from the top of our roof. With a full load of water then engines make one hell of a noise.

      Vancouver Island is home to two other interesting fire fighting planes: The Mars Water Bombers [].

      The Mars planes fight fires in the US all the time since they are privetly owned.

      • I live in the Yukon, Canada. We have forest fires here all summer long. We usually contract a squadron of Air Spray's B-26 Invaders [] for fire supression services. It's an awesome sight watching a dozen of these things take off from the base to head out to a fire. You can really imagine what it must have been like in WWII when these same aircraft would have been heading out on a bombing mission over Europe.
    • I was reading a case study about this for a class a while back. I don't remember which exact planes they were talking about, but I do remember that the fire jumpers had less problems and felt much safer using retrofitted military planes than newer ones designed for firefighting.

      The biggest thing was that the updrafts from the fires would cause alot more turbulence and strain on the wings being shaken up and down, and these newer ones couldn't handle the beating as well.

      Although I would think that a 747 wo
  • by Anonymous Coward on Monday May 17, 2004 @08:40AM (#9172288)
    (This is a post from a pilot forum by a tanker pilot with considerable experience.)

    All tanker delivery systems in use today, except the MAFFs systems (modular airborne firefighting system; military) are capable of multiple drops, split loads, and variable coverage level on every drop. It's part of the basic requirement to field a tank system for use over the fire.

    The Evergreen project is being tested at Marana (AZ) now through the middle of next month.

    I believe it holds a certain amount of promise, but also some challenges. Like every asset over the fire, it has advantages and drawbacks.

    The delivery system is reported to use water injection ahead of the retardant stream to break up the airflow; a fairly complex and weighty soloution to an otherwise simple problem.

    The aircraft is swept wing, which presents certain difficulties at low speeds in the fire environment. The concept is of a tanker that makes high retardant or water drops, rather than using it for directly fighting fire. The aircraft will be very limited in the fields from which it can operate, restricting it from being useable at most tanker bases. It also means the airplane will have to make longer ferry's to get to fires, which will give it longer turn around times, greater costs, and may negate any advantages to carrying a greater retardant payload.

    Large burning objects fly around over a fire, including trees or parts of trees. A turbofan engine is subject fo FOD contamination by smoke on the compressor blades, but also to direct strike damage from objects over the fire. It is also subject to flame-out, a greater liklihood than a piston engine that has continuous ignition

    Drops are typically best done slow; the faster the tanker is moving, the higher the drop needs to be in order to allow the retardant to stop it's forward motion and fall straight down. Retardant moving forward on contact with the fuels only coats one side, an effect known as 'shadowing.' This leaves one side of the fuel unprotected, and negates the value of dropping the retardant.

    A fast tanker may need to drop so high that the benifits of the retardant drop are muted. The higher the drop, the greater the drift isue, meaning reduced accuracy, and consequently reduced usefulness.

    A DC-4 can be supported by the flight crew; often mechanics who can work on the aircraft as well as fly it. Often a single additional mechanic is a luxury, or all that is necessary to keep the airplane flying. Not the case with a B747.

    Maneuverability close to the fire, in terrain with severe or extreme turbulence and reduced visibility may present a number of unique problems for the B747.

    If it's viable, the B747 concept (and the DC-10 being fielded by Omni) will present a useful and valueable tool over the fire. It's just one tool, however, and not a soloution of a panacea for other problems plaguing the industry right now. Each aircraft over the fire, heavy fixed wing, single engine fixed wing, light helicopters, heavy helicopters, lead aircraft, air attacks, jump ships, etc, all have important roles. No one aircraft can or should perform them all. Additional available resources such as a B747 only mean that additional tools are available from which to choose when deciding how to most effectively fight a fire.

    I fully support any developmental effort to enhance the industry. I tend to take a wait-and-see attitude; these aircraft were never intended to enter or operate in an environment such as the fire ground. Only time will tell what the success of these projects will be.

  • by coyote_oww ( 749758 ) on Monday May 17, 2004 @08:54AM (#9172361)
    Here's a little more general information about the industry [] For those who are too lazy to click, existing airtankers apparently run from 800-3000 gallons.

    AVWeb ran an article [] about "heavy airtankers" - used ex-Airforce/Navy C-130 and P-3s pressed into service as tankers. From this, we get a weight of 9.3lb/gallon for retardant, for those interested. For our 747, this would be 223,200lb, or 111.6 tons. The most interesting part of this paper is where they talk about the fatigue resulting from the rapid unloading of the aircraft. Apparently, this is the main cause of catastrophic wing failure. When you suddenly change the aircraft load by 15-20%, you get a definite bending action in the wings. Just like bending a paperclip, eventually this leads to failure.

    The paper also briefly mentions the super-tanker idea (747 or DC10 based).

    The other big concern is that the economic payback for larger aircraft is longer than for smaller aircraft. They were talking about the proposition being questionable with an $8 million acquistion cost. I don't think you could get an operation 747 for anything close to that...

    I've heard of proposals like this before. For a while there, the FUSSR was trying to get interest up in Western countries to buy/lease IL-76's for similar duty. FUSSR aircraft might make more sense, they are notoriously inexpensive.

    • Martin Mars [] is the world's current best, AFAIK. May not have the single-drop capacity of the 747 design, but can refill every 15 minutes by scooping water from a lake while in flight. That equates to a helluva lot more overall capacity.
    • by Goldenhawk ( 242867 ) on Monday May 17, 2004 @09:59AM (#9172840) Homepage
      Yes, I am an aerospace engineer.

      It's the turbulence that causes fatigue, not the action of unloading a lot of water at once. If you think about it, when you go flying in an airliner and you hit a bumpy patch of air, it's usually around clouds. The reason clouds usually form is that air (moist air) is rising, and carrying the water vapor up to a height where the temperature drops enough for the water to condense. The point is, the air is RISING. As the plane flies thru this rising air, the direction the wing is encountering the airflow suddenly changes slightly. Not a lot, but enough that the lift on the wings suddenly increases. The lift (the force that holds the plane up) is a function of angle of the airflow to the wing, as well as airspeed squared. So when you increase the angle of airflow, the lift increases. Now you have more lift than weight, so the plane bumps upwards. But the area of rising air is relatively small, so you get a short transient bump.

      Over a fire, you've got LOTS of bumpy air - the fire is superheating patches of air, and it's all bumpy and roiling around. All that mess is rising rapidly into the sky, and fresh cold air is rushing in around the edges (remember Backdraft, the movie?), moving downward.

      To be an effective air drop platform, you need to fly very low, so that the water doesn't disperse too much before it hits the target zone. So you're deliberately flying an airplane thru extremely unstable (rapidly rising and falling) patches of air, with very large vertical speeds (which means, larger changes in airflow direction, which means more severe turbulence).

      As any materials engineer knows, and as most of us geeks know, if you bend something often enough, it breaks. And the further you bend it each time, the faster it breaks. An airplane wing is designed for a certain "fatigue life" - a certain number of cycles of bending. With the above primer on turbulence, you can imagine how drastically different from the design you will be using the airplane when you fly it 500 ft over a forest fire, compared to relatively smooth air at 38,000 ft.

      So watch the amazing video from last year of a C130 losing its wings over a fire - it's a natural but hopefully rare consequence of abusing an airplane this way. The way the airplane owner SHOULD handle this is frequent and intensive inspections. That C130, as I recall, was NOT properly inspected and was well past its service life. You can read the NTSB report on that accident at f [] (PDF file). A particularly telling quote: "The rate that maneuver load factors between 2.0 and 2.4 were experienced by firefighting aircraft was almost 1,000 times that for aircraft flown as commercial transports." (Load factor is engineer-speak for "g-force" - 1g is normal gravity; most transports never exceed 1.4g except in severe turbulence.)

  • Let's use stealth bombers instead to drop water.
  • by ianscot ( 591483 ) on Monday May 17, 2004 @08:59AM (#9172399)
    A couple of years back, one of the old WWII-era planes that just got grounded crashed on Highway 36 east of Estes Park, Colorado. We're a couple of miles off the other highway into Estes Park, up a mountain, and between the fire and the crash we had to take a different route home that year.

    What happened in that 2002 crash was, one of the wings of the plane just sheared off in flight as it came out of a turn. It was structural fatigue, as this article says. The plane involved was just under 60 years old, IIRC.

    The pilots got profiled in the papers. Impressive people. Most pilots are flying for the love of it, they get paid next-to-nothing even for the airlines until they have tons of seniority, but these guys were what you'd call heroic characters.

    They're truly old planes; it was like seeing a B-24 Liberator at an airshow, only instead of being carefully eased along in their dotage they were still hauling massive loads of water at low altitudes and speed, flying risky in the mountains in this case, for decades after the war. Pretty hard use.

  • Just as much as you would need a large fast plane that frops a huge amount of water you also need planes that can pick up water locally and fly VERY slowly.

    My biggest concern with this system is turn around time.
  • Would the reduced oxygen from smoke filled air have a detrimental effect on the efficiency of the air intake / mixing in the jet engine? If the 747 would swoop down low to deliver its payload through a very thick wall of smoke, the jet engine intakes would undoubtedly have a very reduced amount of oxygen to mix with fuel to combust... This would put the heavily loaded 747 at risk, especially if it were fully loaded.

    Just my two cents...
    • Very doubtfull, dont forget those engines were built to operate at some 30k ft, at a higher speed granted, but check the partial pressure of o2 at that altitude and youll see its still lower than what would generally be encountered at near ground level even during a fire.
      • Good point.

        Would maintenance be harder for jet engine as opposed to turbo prop engines that see a lot of action in smoke and heat filled environments?

        Anybody see those old 747 test films where they purposely puncture the fuel tanks of taxiing 747s to see the ensuing explosions? I would not want to see a 747 get its fuel tank punctured by trees or debris while fighting a fire. It may just compound the problem...
  • Loosing weight ... (Score:4, Insightful)

    by wwwillem ( 253720 ) on Monday May 17, 2004 @09:39AM (#9172622) Homepage
    Besides all the discussions about flying a 747 at very low speed and about the manouvrability at low altitude, what happens to the plane when in a few seconds it becomes 100 tons lighter? Don't know the ratio between the empty and full weight of the plane, but loosing weight that fast doesn't seem to be a situation when I would like to be a pilot. And definitely not one when you are low speed, low altitude.
  • Taxidermy (Score:3, Funny)

    by cr@ckwhore ( 165454 ) on Monday May 17, 2004 @09:49AM (#9172743) Homepage
    Why does it seem like I'm the only one getting a taxidermy site when I click the link for Evergreen Aviation?

    Maybe they've gone to the other end of the spectrum ... an entire flock of radio controlled, stuffed birds converted to "tanker" use, able to carry 1 cup of water in a single drop.
  • Density Altitude (Score:3, Informative)

    by eutychus_awakes ( 607787 ) on Monday May 17, 2004 @10:46AM (#9173323)
    Forest fires typically occur in mountains. Mountains are usually between 1,000 feet and 13,000 feet tall (300 - 4000 meters). Forest fires usually occur in the summertime. Forest fires make a lot of hot, dry air. The net result of this is a substantial increase in the density altitude in the region around a forest fire.

    The density altitude is the altitude the airplane "sees" - taking into account air density, temperature, humidity, etc. Above a 5,000ft density altitude (~1,500m), most airplanes have a hard time just taking off with a full fuel load, much less performing high-g maneuvers close to the ground. At Las Cruces, New Mexico, the airport here is at about 4,500ft (1,370m) mean airfield elevation. Density altitudes above 7,000 feet (2,130m) are not uncommon - even early in the morning.

    To operate under these conditions, pilots simply reduce their passenger and fuel loads. I haven't done the math, but I suspect that to make a 747 light enough to operate safely "down low" at a high density altitude, it wouldn't be able to carry much more water than the C-130 tankers we already use. Plus, a loaded 747 would tend to perform like an elephant on ice skates - a consequence of its swept wing and turbine engines - which don't "spool up" as fast as props. There would be zero margin for error.
  • Los B52s (Score:4, Insightful)

    by n9fzx ( 128488 ) on Monday May 17, 2004 @11:30AM (#9173733) Homepage Journal
    Rather than cutting them up, why not cut a deal with the Russians and keep a few B52H bombers in water tanker service? With the appropriate firefighting gear in the bomb bay, it would be difficult if not impossible to revert back to a bomber; heck, give the Russians the contract for the firefighting mods.

    After all, the BUFF has a proven track record of being stressed properly for low-altitude flight; there are plenty of retired USAF pilots and navigators out there who have 1000+ Time-in-Type, as well as mechanics, spare parts, etc.

  • by KFury ( 19522 ) * on Monday May 17, 2004 @12:02PM (#9174011) Homepage
    Imagine a beowulf cluster...
  • by K-Man ( 4117 ) on Monday May 17, 2004 @01:15PM (#9174682)
    I came up with this idea [] a couple of years ago, after a few in-flight disintegrations of air tankers. The idea is that the JDAM kit can drop anything on a dime, costs less than $20k, and could probably cost a lot less in a non-military configuration.

    There are actually a lot of pros that I didn't think about initially. Besides the safety problem with diving into fire zones, there's also a fuel problem, since each climb out consumes almost as much as taking off. This constraint reduces the weight capacity of each mission -- many tankers seem to fly with only a fraction of their rated weight.

    The ability to load a plane up to its full capacity with retardant, fly to a fire area, and make repeated, accurate drops from high altitude, without running out of gas, seems like a major plus to me. There are also benefits in being able to make "quick response" drops, eg from Smoke Jumper aircraft, with less risk.

  • by Uberbot ( 729689 ) on Monday May 17, 2004 @01:20PM (#9174736)
    Airplanes just weren't meant to carry water.

    Try this gedanken experiment: Fill a bucket about half full of water. Now grab the bucket with both hands and run down the street. Once you get up to speed, try to stop or turn quickly without spilling any water. In fact, try to do it without letting the weight shift inside the bucket.

    You see, as soon as you try to quickly change speed or direction, the weight shifts. When 24,000 gallons of water shifts, you have a lead sinker on your hands.

    Watch the videos of those planes crashing. That is exactly what it looks like happened. The pilot tried to pull up, but the water shifted, and the plane lost it's wings under the intense weight shift.

    This reminds me of a friend in highschool who's dream car was a hearse with a waterbed in the back. Sounds like a good idea untill you try to turn a corner at any speed greather than 5 mph!

    By the way, Shane, if you are reading this, contact me.

    • Divide the bucket into two sealed compartments. Fill one compartment fully with water, while leaving the other one empty...

      Given that planes have been used in fighting fires for rather some time now, I'm guessing they have considered the problems.
  • by snStarter ( 212765 ) on Monday May 17, 2004 @02:05PM (#9175162)
    At least a military aircraft would be designed for the maneuvers required to fight forest fires.

    But really, these machines are VAST, and are turbojets the right engines for low-altitude use? I don't think so. You want an engine optimized for close-to-the-ground operation, that will spool up quickly so you have power when you need it.

    Fun image
  • by MtViewGuy ( 197597 ) on Monday May 17, 2004 @05:33PM (#9177433)
    Actually, who bother with a Boeing 747 is may not be structurally sound for low-altitude firebombing missions?

    Recently, Boeing proposed an idea of using C-17A Globemaster III transports dropping 2,800 beachball-sized containers filled with water or fire retardant in a wide pattern some 2,000 feet above the fire. This means you could deliver up 144,000 pounds of fire surpressant in a wide pattern, which means more of a fire can be quench with such a plane. And because it is dropped around 2,000 feet in the air, that means the plane will fly in far less hazard conditions than firebomber planes do now.

    If you check out the Popular Mechanics web site, the proposal is mentioned here:

    Another interesting proposal is to bombard a fire with artillery sheels filled with liquid nitrogen. Why liquid nitrogen? Because it has these advantages: 1) the extreme cold of liquid nitrogen will quickly slow down a fire, 2) the presence of that much nitrogen gas expansion will snuff out the oxygen needed to feed and fire and 3) liquid nitrogen quickly boils away, so you don't have an enviromental hazard like you do with some chemcial fire retardants.

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