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Ok, not from the delta and have only seen a duster plane twice in my 26 years. Where are the chemicals held, how much chemical can one of these hold, and about how many acres can they do without having go reload.

Okay, you see the brown part in front of the cockpit? That is the top of the hopper. There is a hinged door that opens up if you are standing on the left wing. You open that door to put in the fertilizer, seed, other dry material. When putting out liquid, you hook a 2 or 3 inch hose up to a valve on the bottom (much like fuel truck plumbing) and pump it in that way. The first plane in my pics is an AT-401 I think, which means it has a 400 gallon hopper. If it were a 402, it would still have a 400 gallon hopper but the "2" designates that it is a turbine and not a radial engine.

I think the Thrush is a 660 (see 660 on the wingtip). I'm pretty sure it has a 600 gallon hopper, but I'm not certain.

Air Tractor makes an AT-802 and that thing is huge. 800 gallons of water weighs roughly 6400 pounds, so that thing has to have some power to fly around with 3 tons of liquid in the hopper.
You could put a couple of tons of dry fertilizer in the hopper which makes them really popular in the heavy rice producing areas like Arkansas. Fertilizer work means lots of trips back and forth from the airport, so anything that will cut down on the amount of trips (ferry time) is money saving. I'll never forget the time we were putting out Bulldog Soda, which is a type of fertilizer. It is just about the heaviest fertilizer out there. I loaded up the hopper too full and when the pilot got back, he said, "Son, if you ever put that much bulldog in my hopper again, my ghost will come back to haunt you." We were using a 1/2 mile grass strip out in the country and he liked to have never gotten off the ground on that load.

For fertilizer/seeding work, they take off the spray booms on the wings and put a spreader under the belly. The spreader is made of aluminum and is widest at the back with an open throat in th front. The wind blows through it and when the hopper door is opened, the fertilizer falls into the spreader and spreads out through several channels and out the back.

For spraying work, how long they can stay out depends on how many GPA (gallons per acre) they are putting in the field. Cotton poison work is usually done at 2 GPA, so he could cover 200 acres per 400 gallon load. Herbicide work is usually done at 5 GPA. This is for stuff like Roundup and any other jobs where you are spraying chemicals to kill weeds and need more coverage. 10 gallon work is pretty rare, but I have seen it done when putting out Stam on rice. Man, it looks like fog coming out the back. On some of the lower GPA jobs, you can barely see the spray exiting the plane. Boll Weevil work is some of the lowest GPA I know of, they only put out about 1/2 to 1 GPA and it is really difficult to see anything come out of the booms at all.

As far as how much chemical is in each load, that varies. Say you are spraying pyrethroids like Karate, Asana, Baythroid, or Ammo on budworms in cotton. When I was working at the flying service, we usually put out Karate at 1:60 or 1 gallon of pesticide to 60 acres of cotton. If you're doing 2 gallon work, then you know you can spray 200 acres with one full, 400-gallon hopper. You pour 3.33 gallons of Karate into the vat and pump it in the plane followed by roughly 397 gallons of water. It all mixes together and you spray the solution onto the field.

dang rob, I rode in em, loaded em, dug crashed ones out of the field etc, and did not know all that I just ain't never flown one

Good info!!!

I've never flown one either, just a whole lotta loading in high school and college.

The spreaders are made out of stainless steel, not aluminum. I put aluminum in the other post.

Jeff, why don't they run the booms all the way out to the end of the wingtips?

the only reason I can think is the wingtip vortices might mess up the flow of the spray. Other than that, I have no idea.

Correct, but it's not because they mess up the flow so much as it's to reduce drift. Spray caught in the vortices gets curled high in the air and is more likely to drift. Most booms only extend 3/4 of the wing length.

Ever noticed drop-nozzles underneath the plane and just to the side of the fuselage? Dropping the nozzles a foot or so in these areas keeps the spray out of the prop wash.

I was just toolin around on the air tractor site and it says the largest concentration of them in the world is in the Mississippi Delta. Kinda strange considering the delta is a relatively small piece of the american farm pie. The midwest i hear doesnt have much bug pressure, and they dont grow cotton or rice, so not much need for them out there? What about texas . . . they grow a $#!+ of cotton in texas, they must not have that many planes either. Kinda thinking out loud here . . .

I don't know why AT is so popular here, but it seems most all F/S have them with the exception of a few Thrush's, Dromader's, and the smaller guys might still be using Cessna's.

FYI, Leland Snow originally manufactured Thrush. He sold the company and founded Air Tractor. Thrush makes a dope plane that is equipped with armor plating and painted dark blue. They use them in Central and South America for spraying dope farms. I've heard tales from ag pilots that went down there for work about their loaders getting shot off of the wing while loading up another batch of chemical.

cool pics to everyone that posted some.
rob, arent those white 2 seaters called dromerdiers(sp)? we have a service over this way that has/had one,i have not seen it this year yet. talking about clipping wires......several years ago one of thier pilots clipped some cross country wires. from witnesses.....he was shot straight up for a bit and the engine stalled causing a nose dive straight to the ground. my dad had not yet retired from the vol.f.d. and made the scene. it was pretty gruesome from his account. the engine had to be dug out of the ground.....down to about 6'.

at one time we had a few duster that used helo's. one of dad's good friends from school was killed in one!!
i enjoy watching these guys work but, at the same time am scared as hell for them. their bravery level is far greater than mine!!

I never understood how they could just spray that stuff into the air...gotta have some kind of effect on the people and their health

I am all for agriculture and how it supports our great state but on the other hand dont wanna die of cancer either

baffles me how this day and age a mfg plant has to have their own water treatment system and go so far as to even buy environmental credits to offset pollution and yet our nations farmers can just spray it out into thin air...personally cant believe the EPA tolerates it, of course no one ever accused them of being completely unbiased in their rulings

the doc

Wingman, how often do they calibrate? I am just wondering b/c on golfcourses we do it daily/ or each time we go spray/spread any type of chemical or fertilizer. On the averrage golf course you spray 2-3 times weekly depending on types of grass and types of diseases that are current. Just wondering if they had to do it daily as well and also how do they calibrate, the spray booms would be easy b/c you could do them on the ground but the spinners seem like they would be difficult.


Ace there are a few crop dusters around Louisville

They have it down toa science. Drift is very minimal. Anti- drift agents make a bigger droplet causing it to fall with less drift. Most chemical today are weak as dish water compared to the ones that caused cancer. With the Sat-Loc and DelNorte systems, its hard to F up.

lets hear one for the ag-cat guys. love the sound of the old bi-wings.

duckkiller wrote:Wingman, how often do they calibrate? I am just wondering b/c on golfcourses we do it daily/ or each time we go spray/spread any type of chemical or fertilizer. On the averrage golf course you spray 2-3 times weekly depending on types of grass and types of diseases that are current. Just wondering if they had to do it daily as well and also how do they calibrate, the spray booms would be easy b/c you could do them on the ground but the spinners seem like they would be difficult.


Ace there are a few crop dusters around Louisville

There is an inline computer on most all planes called a flow meter. It measures how much liquid is flowing through the plumbing and this is pretty much self-calibrated. Tips are replaced every so often because they do wear out and throw off the calibration. Spreaders are calibrated usually when you buy them and most all of the pilots I know have a sheet telling how wide to open the bottom door for every material they put out dry. They will put paper cups on the ground and make a pass overhead to see if all of the product is being distributed evenly. Once it's all set, you pretty much don't have to change anything.

Marionfd708, Dromader are usually white. Huge planes made in Poland. When everyone started using them, all of the controls and instruments were in Polish. I think most now have english writing in the cockpit. Definitely a weird looking plane but a workhorse nonetheless.

ok, yeah we have something called a flow meter to but we are required by law to check them. I am currently studying up and getting ready to take my test to get my chemical license, and I swear I am so tired of doing calibrations and reading labels I want to pull my hair out

I used to sit on top of my tractor while I was waiting on parts & watch them... amazing what some of them can do with a plane. Old roommate and good friends Dad used to have a crop duster service in Belzoni (Wingman worked for him for a while). He said his Dad had to put a plane down just out of reach of the runway because he ran out of fuel and still had a partial load so he didn't quite coast all the way back and nosed over when he landed... My buddy drove down to the end of the runway, picked him up, and dropped him off at the hangar to get another plane and he went back to work. Said you just gotta get back up in the air before you have too much time to think about it or you may never get back up (he also flew helicopters in Nam for a couple of tours, though so I'm sure some of the things he's done in a crop duster, he's probably had to try to do in a helicopter as well to stay alive).
Seems like one of the Bell boys from Belzoni got hung up in a double tower somewhere a long time ago, didn't see it until it was too late and ended up upside down hanging by the wires - nobody was hurt, only pride.