Stearman PT-17 Kaydet

[Jure Miljevic]

Hi everybody

Does someone has a drawing or a good photo of Stearman with early pest control/crop dusting equipment? I'm talking about WWII vintage equipment with small box and dispenser under the nose and without spraying bars below the wings. On Fold3 I found some photos of PT-17s spraying swamps to suppress mosquitos in Italy in 1945 and I have a Revell 1/72 Stearman just dying to be converted. Regards

Jure

[sanmigmike]

I've never seen the picture (I would love to see it) but I have seen pictures of other military aircraft (not Stearmans) being used for mosquito abatement using the military smoke equipment. That I think was liquid based spraying. The very early dusting equipment I've seen looked almost homemade. A sheet metal rectangular venturi box looking thing with a small usually four bladed prop driving a device to agitate the dust down from the hopper that was where the front seat used to be. Soo, depending upon what way you wanted to go you could look up aerial smoke equipment or put a small rectangular box below the front pit with a tiny prop (looking like a test club) on something that looks like a tiny generator on the side of the dust equipment. Not too many years after that you got into R-985 engines (and a few R-1340s) and various wing conversions...Squared tips, four ailerons, extending wingspan and at last in some of them some roll over protection for the pilot. The dusting unit became more aerodynamic, looking a bit like a wing. Not much out there on the net but there are some videos of early (post WW II) dusting and spraying and some pictures. Not much pre-WW II and pre-WW II would not be PT-13 and on Stearmans. Might try some of the fire bombing modeling sites or Ag Aviation (real) sites for help. There is at least one Ag Aviation museum in the US that might have a site...didn't find it in my first quick look. Sorry this isn't much help.

[Jure Miljevic]

Hi sanmigmike

I'm fairly nervous about copyright issues so to see some of the photos I talked about go to Fold3 and put the following into their advance search browser:

342-FH-3A23308-3A23308

342-FH-3A26016-60249AC

The first photo shows Stearman dusting swamps in Italy and the second one is war-weary A-20B getting ready for dusting in France (Corsica) both in 1945. No doubt venturi boxes had been used on Stearmans and dust was a mix of 75% of Fuller's earth (I don't have a slightest idea what that was) and 25% Paris green (which is arsenic). Imagine someone tries to dust with something like this these days!

I hope somebody else has more information. Otherwise it would have to be yet undefined boxlike structure under the Stearman's belly but only as a last resort. Thanks anyway and regards

Jure

[famvburg]

The "box" under a Stearman, or any other ag plane is called a spreader. It's used for dispensing dry checmicals or seed. also, just because it isn't under a Stearman doesn't mean anything, most are fairly standard and in the early days, there was a lot of homemade equipment anyway.

Edited November 18, 2012 by famvburg

[famvburg]

http://www.amazon.com/Low-slow-insiders-agricultural-aviation/dp/0936815000/ref=sr_1_1?s=books&ie=UTF8&qid=1353272124&sr=1-1&keywords=mabry+anderson

[Jure Miljevic]

Hi famvburg

Thanks for the information about the book, I ordered myself one. About home-made spreaders ... Do you thing AAF would also resort to this improvise equipment? Especially as it appears that three AAF PT-17B had been converted for dusting. Regards

Jure

[famvburg]

Since cropdusting was still in its infancy then, I wouldn't be surprised if the AAF did have to make their own spreaders.

[Jure Miljevic]

OK, we'll see what can be found in the book. Regards

Jure

[famvburg]

http://translandllc.com/pdf/spreaders.pdf

[Jure Miljevic]

Yes, I've already found that one and several other spreader catalogues but those all look far too advanced for the WWII period. There's a description of Stearman' spray unit from 1943 or 1944 in Air war against pests article. Unfortunately I can't remember where on the web I found it. It seems Stearman's equipment has been developed from Piper Cub unit from 1943. However the article only talks about spraying liquid DDT so I guess different equipment must have been used for dusting. Regards

Jure

[famvburg]

Liquid dispersal uses booms and nozzles and also a usually fan driven pump, in the early days modified auto water pumps were used. The bottom hatch (gate) of the hopper was used as an emergency dump in case of an emergency. That same gate is where the dry materials came out, into the spreader.

[sanmigmike]

You are right, the same gate for the spreader and for an emergency dump. A real kick to practice an dump of a whole load in something like a Thrush or Agcat.

I looked at some of those pictures. I think the A-20 was also spreading the same dry mixture as the Stearman (I found pictures of them dumping the mixture into the A-20). For the Stearman I'd put a rectangular hopper hatch in the area of the front seat opening. A tiny rectangular gate going into a small spreader...more of a rectangular open ended box with some effort to get a venturi effect rather than the more wing (if you wanted to put that kind of effort into 1:72) looking things that the spreaders turned into. I'd bet money (but not much since I don't have much) that the whole mess on the Stearman and the A-20 were field built...homemade contraptions...but they certainly seemed to have worked.

Thanks for sharing those pictures...rather fascinating.

Edited November 24, 2012 by sanmigmike