This is from two excellent books which details the NZ Topdressing industry from the very start in 1949 through until 1990, the first book covers up until 1981. Some great photos and stories from someone who did a great detail of research to write these two books. They are both out of print and sell for reasonable money when they sometimes come on the market. All of the pilots history is included in the books and I have included a typical sample page. NZ is a small country but aviation is quite big here, nothing like the U.S. of coarse.

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It wasn't a game for the faint hearted and they reckon only probably two out of ten pilots would be suitable for Agwork. DC-3 was single pilot 5 ton load.Used for jobs where it was difficult to get fertiliser close. Operated mainly out of fixed base airport, about 20/30 min turn around time rather than the usual 4/5 min.

Been having trouble getting photos right way up!

All the older planes here, Cub, Stearman, Snow, Pawnee, CallAir, Ag Cat, and Thrush were slow and had to work off spray strips, pastures, dikes, and secondary roads to make a profit. In the 80s Lealand Snow (Snow, Thrush early, and Air Tractor) started lightening empty weight, using R-1340, and then turboprops, and slicked up the fuselage and dispersal systems. Six Pawnee operations became one Air Tractor operations and increased range from 15 miles to fifty miles.

600s must have made some of the extra power by tightening things up. Needed wobble pump to put a lot of start fuel in and quite a bit of starter crank.

My Dad hand propped his once. I drove the water truck to an airport closer to the fields needing to be sprayed. Dad was to get there about the same time but I waited and waited. This was in 1974 and no phone close but eventually he arrived with his left hand all bandaged up. The master was on and the battery was dead so he got Danny "the Greek" who flew the Ag Cat to sit in the cockpit. When she fired the prop got the meat of his left had and Dad never found his wrist watch that went flying. He was fortunate that he healed up without problems but the bandage looked like a small cast and had to make running the throttle etc more difficult.

Ack!

The only copy of "The Topdressers" I could find for sale was $495!


I'd like to read it....but not that much!

A mechanic at Ag Flight taught me the easiest way to start the Pratt and Whitney R-1340 600hp on Billy Howell's Air Tractor. I forget the number of pumps on the wabble pump, several. Engage starter until prop had made full rotation. Wait one minute for fuel in cylinders to atomise. Engage throttle till enough cylinders keep the prop moving.

The 235 HP O-540 on the Pawnee was a loose engine as well as the 450 HP R-985, but didn't have that heavy Hamilton Standard prop. With lots of prime or accelerator pump fuel cold or three quick throttle pumps hot, it would prop. It wasn't fun but certainly easier than what your Dad did.

It's nice to see the old crop duster thread alive and kicking. Returning from my early summer travels north found me looking at instant and dramatic life changes.... The kind that disrupt so many things that you just don't know where to start picking up...Never being one to sit and think to much, the answer came quick to me. Borrow an airplane and go to work

Made a sudden and unplanned run to Marty's neck of the woods for a few weeks in a very nice Air Tractor, and although I am a Thrush guy at heart and had been offered up a sweet TPE331-10 powered Thrush for the corn run, I elected to mix it up a little. My apologies in advance for the incredibly poor photography, I really hadn't taken any of these with the thought of posting them on the http://www...


A pair of -34 powered 502's, a -45 602 and a -60 602.

The one I spent the bulk of a few weeks in may not have been the 'latest greatest' but it was exceptionally clean, and definitely modern enough to have earned the moniker the prior pilot set up for it in the SatLoc. Seen here at the center top of the screen


This photo puzzles me because not only is a multi back to back one of my favorite SatLoc patterns to fly (and I clearly didn't here) but it probably would have saved me 10 or 11 minutes had I done so.... perhaps they were in a windmill farm? The other thing weird is you can see a couple more fields under the 'quick keys' that didn't get tied in to the ones already sprayed, and such long and drawn out turns? ...

A more zoomed out pic to show the typical AT dash


I have absolutely no idea why we're carrying so much power with only 450 gallons on? That's the problem with snap shots after the fact... pretty hard to determine exactly what was going on

Another ho hum screen shot for inquiring minds;


Things I notice looking at it... Well, obviously we sprayed field # 1 first. It's apparent that I trimmed it out prior to spraying (probably similar crop adjacent so trimming it out first 'paints' a nice start/stop reminder) Then I moved on to field # 4 and started to trim it out and set it up with the 'remaining' 15 gallons. It appears that the computer believed it had 15 left, but in all actuality it must have run short ... probably loaded a little long on the next load to make up... a day spraying is a day of constantly calibrating on the fly... even with the most modern equipment

Also obvious is the north wind as evident by the drawn out south turns on field 1 and the set up direction on field 4. You can see I identified the first field a half mile +/- out and was comfortable enough with it that I just went right to work as opposed to having a look around Maybe I was working next to it on the prior load and scoped it out?

A prior poster was asking about the extensive time training prior to actually sitting in the seat... My normal gig has me flying over what we term 'critical crop' (can go from field to table with no processing) and mostly at night... so probably easy to understand why in that scenario, but this shot (spraying very benign fungicides over hard to hurt field crop) shows a very common speed to see on some of the faster AT's.... At a typical spray height of 8' - 16', with nothing but a little glass separating you and 4000-7000 lbs. of economical poison, would you really feel comfortable traveling through obstacles at this speed with lighter training? If the answer is yes, you are probably not the right person for this job


All in all it's a good gig, which I believe can be as safe as working in an office. You just need to treat it as a career, both in how you pursue it, and how you function once you get there.... and as stuffy as that sounds, there's no reason the entire ride can't be fun filled... on that note, I thought renaming the wonderful FlapTractor prior to returning her to her rightful owner was appropriate



Take care, Rob

Rob:

-LMAO
-why do you like the Thrush so much? Granted, I'm a confirmed Air Tractor guy (flaps are useful, ya know). Limited time in a Thrush, but to me it felt....weird.
-personally love an 802.


I enjoy your pics, and your notes....please keep on posting.

contactflying wrote:….450s were loose and easy to prop. 600s must have made some of the extra power by tightening things up....

Those extra 355 cubic inches might have had something to do with it also.

Good to hear from you, Rob. I had to fly whatever crooked tail Pawnee was available. Hope your mount gets OK.

Contact, it's been over 40 years since Dad let me start the 1340 but this is the way I remember. After pulling it through a bunch to make sure no oil in the cylinders. Wobble pump until needle in fuel pressure gauge came up. Then engage starter and after she started turning, switch the mags on and run the throttle ahead and back and she'd be running. This was first start of the day.

Great posts Rob. I to am curious why you like the thrush so much? I've had 2 502s and a 402 spraying off my strip all summer, and a brand new 510 thrush flew a few loads off it. The ATs had no problem pulling full loads off it and the thrush only pulled around 400 gallons off. I know the thrush is heavier, and it's a 2 seat plane, but not pulling full loads sure gives it a disadvantage around here. The hutterites like 3 gallon rates which means 400 gallons won't do a 1/4 section. More trips is less profit as you well know. Just curious if you have any insight. If I had just spent that kind of coin on a brand new plane I'd sure be disappointed that it can't pull full loads and ATs are doing it all day long no problem...

180Marty, I remember the fuel pressure gauge now. I only sprayed with the AT 402 a few times because they wanted me to be familiar with the faster planes the students would be flying. I owned or leased Pawnees and CallAirs. I was a bit scared of the high speed AT. I had always worked six inches or so and used nurse rig and whatever field for distant work. Longer wing and faster speed didn't go well with the places I loaded.

sb and David,

I have to back peddle just a little bit. I really enjoy the flight characteristics of a good Thrush, but my favorite airplane to work is the one that fits the mission best...

As David pointed out, if you have to make 2 trips out to a field that could have been done in one, you're flying the wrong machine. Likewise, if you're in my neighborhood where every field is a 40 acre wired up block (or parts of it) and no two mixes alike, and you're in an 802.... you probably need to review your fuel bill....

Having said that, I guess the real reason I like a Thrush so much is because I'm a lazy pilot I mean, I really enjoy an airplane that you can give it's head and it minds it's business....

A good Thrush can be turned loose, and it will go where you last pointed it until it runs out of gas or you tell it otherwise... A good Thrush flies so much like a good cub that I am of the opinion that a good cub guy with zero Thrush time could probably hope on in and safely fly on a way...Notice I did not say go to work (different skill sets there). A good Thrush has no bad habits, and will let you really be stupid before it gets uptight.

The small bodied AT's are kind like a husky, that got together with an Extra 300... They're nice on the controls and flick around really really well... They are a blast to fly in the morning dead flat air. But for that maneuverability you pay a price once the air goes to pot... They will still haul the load just fine, but working them (in other words making it go exactly where and when you want it to) becomes work... and give a run of the mill small AT it's head, and just like that Extra 300, it'll be anyones guess which wing is going to drop or which way it's going to pitch... which will eventually turn into an oscillation.... When's a guy supposed to eat lunch in them things for pete's sake?

All things equal the AT is quite a bit faster, but my experience has been that you really need to be running far for that to come in to play much. A good thrush guy will turn inside of a good AT every time...

The big bodied AT's mellow out quite a bit which is probably why you like the 8 (sb), and the 6 is actually one of my favorite airplanes, it just doesn't fit my area at all.

Of course all of this is painted with a pretty broad brush, and what flight characteristics one man likes, may not mean anything to the next.

Take care, Rob

David,

Unfortunately, comparing a 510 to a 502 randomly over the net is like polling crosswind capabilities or landing preferences..... There are just too many variables ...

I have a fair amount of time in 500 gallon machines alone, and have flown examples that were 400 gallon machines on a good day, and others that were un-overloadable. In either flavor...

I sold a good Thrush a few months ago to a really nice young man who promptly put 450 gallons in it and tried to work it at a field elevation of 4500'...
I'm guessing over a mile of DA, almost zero ag time. Needless to say he needlessly fell out of the sky. He's still with us, but it was an expensive lesson

I actually prefer 'Diet Thrushs' (S2R's that have been converted) because they are generally quite a bit lighter than new or late model ones.
the 2 hole variant isn't all that much heavier than a standard cockpit, but a late model 2 hole compared to a light early one is a fair amount heavier.

Any of the machines in a 500 with 750hp or less swinging a three blade prop, is not going to be a stellar performer. the good ones will do it, but a weaker or less than perfectly rigged one will require cool days and a cool headed driver. Add a loadmaster prop, or another 50 hp, and they become childs play to work. Put a -10, (ewww ... scratch that... noisy buggers...) a -45 or better on the nose, and they become pocket rockets.

I guess I like all of them, I just really like working a Thrush.

Take care, Rob

Thanks for taking the time for a great explanation Rob. I grew up 9n a farm with a 600 radial thrush on it and loved that plane. Was just a bit surprised to see the performance difference between the AT and thrush working from my place and thought I'd ask.
Theres also a 402 flying around here with a -34 Nd that thing is a heck of a performer. But still suffer a bit from the smaller tank. Up here most of our fields are big. 1/4 is small, lots of halve sections and even 2 mile long runs that are 2 full sections. An 802 would be nice for some work, but the 502 is a great all around plane and seems to he the preferred model for around here.

Yep, either flavor in a 400 gallon machine, with a -34 is a pocket rocket. Again the speed nod going to the AT, and the over all good manners to the Thrush.

'Stock' Tanks in either are marginal for most places, but if I had a machine that never left my area, (where ferries are 7 miles at most) I would prefer them. It is just so much easier to know exactly how much fuel you have. The long range tanks in either become so long across the wing that a good fuel computer becomes a must, as an inch across the bottom could be an hour of fuel.Either way, stock tanks haul 2 hrs. of gas. Even with 2gpa work getting a full load out shouldn't be a problem unless the ferries are long.

I *think* the 502 is not only the preferred in your area, but probably the most popular ag plane ever built.

A real pocket rocket would be the no longer made AT-400 with a -34. Which was really a short winged , light framed predecessor to the 402.

Some other random thoughts,

Either flavor has good crash survivability, but when you've seen both naked, the heavier Thrush seems to shine. Light doesn't come free.
Both copies have life limited wings (except the latest Thrush) but there are many flavors of after market spar list for the Thrush, some extending the wing life to as much as 60,000 hrs.
AT has been a pretty solid company. Thrush has been traded and in bankruptcy more times than the Indian motorcycle company.
I know far more owners of older Thrush who love them than owners of the late model ones... That doesn't speak well for the present (who are now again restructuring) team.

Take care, Rob