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Old Jul 04, 2012, 03:22 AM
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I would be very leery about trying to replicate the physical qualities of Phos-chek. What you see coming out of the bellies of air-tankers looks like a fine mist, but in actuality the stuff has about the same constistency as tomato sauce. Or snot, if you want to be really accurate in your description. The "misting" effect is a result of the retardant hitting the air stream at 130-140 Kts...the individual droplets are still quite large. Bottom-line is, I don't think you're going to get the scale effect you want by dropping a heavy, viscuous liquid from your model at 30-40 mph. There's a wealth of accumulated knowledge here on RCG...listen to what these guys are telling you.

Other fun-facts about fire retardant - Regardless of what you may have seen in the movie "Always," retardant is never dropped "on" a fire, the goal being to build a fire suppressing perimeter around the fire. One of the main constituents in retardant is sheep's blood, although that's not what gives it it's red color. The color is a dye, and is intended to leave a "witness mark" of sorts to indicate where a previous drop started and ended in order to aid in "building the line." The dye fades in about a year, so as not to leave permanent scars on the forest. Retardant is also quite heavy...about 9 pounds per gallon, if memory serves. (water is around 8) Spill some on the ground, and it doesn't flow out. Rather, due to it's high viscosity, it stacks" about a half-inch high. It was actually engineered to be viscuous like that so that when air dropped it would blast through tree-tops and lay down good coverage on the ground (fires spread in shrubs and ground cover, too)

Ground crewmen have been seriously injured and large vehicles knocked completely over by ill-timed air drops...I remember hearing a story about a fire truck being destroyed in such a manner. Look at the physics...9+ pounds per gallon times 2,000 gallons, traveling at 150 mph. The energy being dissipated is about the same as that of a large truck traveling at that speed.

Speaking of ground crewmen...in California, in the 70's and 80's, it was common to use inmates (both male and female) from the work camps dotted around the forests to man the tanker bases and assist in dragging the heavy hoses to and from the planes working the fires. You never saw a harder-working group of individuals in your life! They considered such duty to be a privilege, and wanted to be used again whenever the California Division of Forestry was actively working a fire.

Good luck on your project!
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Last edited by Ojimy; Jul 04, 2012 at 03:37 AM.
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