• There seems to be an uptick in Political comments in recent months. Those of us who are long time members of the site know that Political and Religious content has been banned for years. Nothing has changed. Please leave all political and religious comments out of the forums.

    If you recently joined the forums you were not presented with this restriction in the terms of service. This was due to a conversion error when we went from vBulletin to Xenforo. We have updated our terms of service to reflect these corrections.

    Please note any post refering to a politician will be considered political even if it is intended to be humor. Our experience is these topics have a way of dividing the forums and causing deep resentment among members. It is a poison to the community. We appreciate compliance with the rules.

    The Staff of SOH

  • Server side Maintenance is done. We still have an update to the forum software to run but that one will have to wait for a better time.

F7F Tigercat SOH Project

there are several types of retardants but below is the most comman in california as far as i know



the components of long-term retardant are:

Fire retardant salts (alone or in combination)
Ammonium sulfate
Diammonium phosphate
Monoammonium phosphate
Ammonium polyphosphate
Preservative or spoilage inhibitor (found only in gum-thickened retardants)
Corrosion inhibitor(s)
Coloring agent
Thickening agent
Guar gum or clay

its stored in large tanks and premixed as its loaded onto the planes in a process done right at the time ( if that makes sense)
well im not sure about "drop rates" but they use a system in Calfire called "coverage level"

coverage level 1
coverage level 2
and so on to
coverage level 5
and that means how many doors to open ..one door..or all doors....the tanks are compartmentalised..they are not just open water tanks
the grumman S2T trackers can carry a full load of 1200 gallons..but they normally carry what they call a "combat load" of about 900-1000 gallons on most initial attack calls,and they make a minimum of two drops on the fire...UNLESS its "rippin and gettin",,say the fire activity is very heavy and theyve dispatched both grass valley tankers and the two from columbia,,and maybe a heavy (P3 or DC7) from Chico...they make..they may go
"full load ,coverage level 5" which means ofcourse to dump the whole tanks...but stagger the dropping so it extends the drop..stretches it out...not a big clump or mass...but a long thin line...the new tanks are also run by computer...you could look up tanker 910 online..its the DC10 and send them an email ..ask them about the computer tank controls..or how theres works..they are allways happy to answer..im going to drop a note on

www.airtanker.org
now and ask them
 
oops..cant ask at airtankers anymore..they have a 30 dollar join fee...ack

BTW the F7F had a 1000 US gallon capacity,but they flew 800 gallons for safety reasons,and could not land with any retardant in the tank.
 
thunder100 said:
Me and James among others are looking into it

May I ask the knowledgeable firefighters

What is water content of tank?
What is drop rate -->Liter/min or Liter/sec?Or Gallons or whatever
I asume its not stable as the doors dont open suddenly
How is the water dump operated?Open the doors by a lever?


All the best

Roland
Click to expand...

I wasn't sure what you meant by water content of the tank? are you asking what the retardant to water mix ratio is? The standard mix ratio is 5.5:1 but that does vary a bit by jurisdiction. Drop rate depends on the type of door (variable flow or doored tank, also known as a compartmentalized tank) and as Daveroo mention the coverage level. Coverage level one = 1 Gallon of retardant per 100 Square feet of ground, coverage level 2 = 2 Gallons of retardant per 100 Square feet of ground...coverage level 8 is about as high as most tanks can manage. With variable flow tanks the AAO will ask for a portion of the tank at a certain coverage level ie. 1/4 at coverage level 6. The doors on these tanks work on head pressure, the will actually flutter opened and closed very quickly limiting the amount of retardant that can come out of the tank. On a compartmentalized/doored tank the individual doors can be opened independently or in sequence to create a string drop (these doors open in one quick shot). The F6F most likely had a 4 door tank, the DC6 had a fantastic 8 door tank, we have an Electra L188 here in BC with a 12 door tank. You wouldn't call for a coverage level with a doored tank but you can increase or decrease the coverage level by spacing the opening of the doors. You could ask for a single door string, total of 4 at .5 you would get all 4 doors opening in sequence with a half second interval between them. 2 door salvo, 4 door salvo's etc are used when the load has to penetrate heavy canopy, all the doors open at once. The pilot has to arm the tank first and then its just a push button on the yoke that opens the doors. The door sequence or coverage level + drop quantity are set on a panel that is connected to the bomb tank computer. Let me know if you need any photos of this equipment, I'd be happy to help.
 
This is great information to have. Thank you all for contributing. I believe the question was about capacity of the tanks, one was wider, one was cylindrical, ... and we may provide both options. Thanks for all the interest and information.

My question is: ?Are these doors correct or were there four doors on these double wide tanks?"
 
hey slund?..when you say they "armed" the system and then dropped the mud with a push of a button on the yoke/stick(i know thats not word for word,ive forgoten what ya typed...lol)

how did/do they arm the system?....id love to see some pics myself....

Dave
 
if you look at that scale drawing on the site you (milton) posted for the airtankers it looks like there are 4 doors in two pairs on either side of a ceter band of the tank...look at the bottom drawing on either of the scale drawings...

Dave

IF...and thats a big IF...thats the case...it would make sense from waht i know about how the tankers work..slund can comment on this.but if the two sides are seperated with doors on both sides,then they could have spkit the drops so they could have a minumum of two drops per flight instead of just one,,,,, i know the F7F had a 1000 US gall capacity but only carried 800 US gallons so that would mean they dropped 400 per drop..im so temped to drive up to the Grass Valley ATB and ask Hoser if he was around for the F7Fs or if he knows any pilots who were...
 
Slund said:
The F6F most likely had a 4 door tank, the DC6 had a fantastic 8 door tank, we have an Electra L188 here in BC with a 12 door tank. You wouldn't call for a coverage level with a doored tank but you can increase or decrease the coverage level by spacing the opening of the doors. You could ask for a single door string, total of 4 at .5 you would get all 4 doors opening in sequence with a half second interval between them. 2 door salvo, 4 door salvo's etc are used when the load has to penetrate heavy canopy, all the doors open at once. The pilot has to arm the tank first and then its just a push button on the yoke that opens the doors. The door sequence or coverage level + drop quantity are set on a panel that is connected to the bomb tank computer. Let me know if you need any photos of this equipment, I'd be happy to help.
Click to expand...

Sorry to be so unspecific,and thanks for help

BUT

I only talk about F7F Firetanker-->the one in development

A.)
I need to know the max weight of the retardant.So far I have read it could hold up to 1000 gal but usually flown with 800 gal-->equals 3028 kg or approx 1081 Gal fuel(in FS9 we can only simualte the weight change ot the waterdrop by drop tanks(fuel) and would calculate the retardant drop weight-->to liters of fuel.I need this weight to define the weight release once you drop-->and the influence to the Flight dynamics

B.)Had the F7F a chambered tank?How much chmabers?
C.)If so(like I read here) then what would be the 3 most common waterdrops

Thanks for help

Roland
 
Daveroo said:
if you look at that scale drawing on the site you (milton) posted for the airtankers it looks like there are 4 doors in two pairs on either side of a ceter band of the tank...look at the bottom drawing on either of the scale drawings...

Dave

IF...and thats a big IF...thats the case...it would make sense from waht i know about how the tankers work..slund can comment on this.but if the two sides are seperated with doors on both sides,then they could have spkit the drops so they could have a minumum of two drops per flight instead of just one,,,,, i know the F7F had a 1000 US gall capacity but only carried 800 US gallons so that would mean they dropped 400 per drop..im so temped to drive up to the Grass Valley ATB and ask Hoser if he was around for the F7Fs or if he knows any pilots who were...
Click to expand...



Well, I used the drawing for the wider tank and it shows 2 doors. Now that could be left/right compartments, or fore/aft, not sure.
 
I suppose even with two doors, if the tanks were compartmentalized, there could be two drops.

Also, I am looking closely at all the pics for other "exhaust ports" besides doors or fill doors or connections. There seems to be some variations from the early Cal-Nat and Sis_Q to the later versions. Can anyone clarify?
 
i sent an email to "aero union corp" they fly P3/P2V/DC7 airtankers and asked what a gallon of retardant wieghs....lol....but imma guess the will say that with the chemicals they ad..being mostly powders...you should just calculate it as per a gallon of water...8 pounds something?
 
You must log in or register to reply here.
Back
Top