UK Ag Work
My old firm of Spooner Aviation, (Shoreham Airport, 1974 to 1980) ran a spraying business using the Enstrom 28C. (in the UK we didn't call it 'dusting')
We had several good contracts, Boots, ICI (Plant Protection) alongside dozns of 500 acre plus farmers. The turbo charged 28C was certificated to carry 600lbs (max auw being 2,600lbs) using the Agrinautics 36 foot boom spray gear for both the wet and dry application. For the dry spreading, we fitted a Vicon Hopper, the same container the farmer's used behind their tractors.
I recall spending more than a few hours calibrating the dispersal gear to produce the proper application rates. Several separate passes over a couple of dozen glass collection tubes which were subsequently measured and the spray nozzles or spreading impellors adjusted as necessary.
Our Ops Manager was a Paul Manning and none other than Brian Izzard was our Chief Ag pilot. Brian ... to those who knew him, was one of the Caledonian link pilots flying the S61 LHR - LGW route (G-LINK I seem to remember) until transport minister, Nicholas Ridley got the scheduled service cancelled. Brian Izzard was also a real live Bishop !
Spoonair Ag Services employed two other specialist ag pilots (Chris Cook and Derek Alexander both from NZ) and I found myself doing the simpler jobs, such as the Maneb on Potatoes and of course the treatment of Rinkosporium & Septoria. At one time we used some pretty fierce stuff to kill off Bracken, similar to the defoliant in Vietnam.
I recall managing around 100 acres an hour on insecticide work, which at that time we charged out at £4 an acre. So we werew doing good business)
The operation was flown under the CAA's Aerial Application permission ... (not an AOC) I still have the publicity video we made at the time showing how wonderful we were at saving the farmer's tons of money.
But mostly true as I recall the occasion when a Sussex farmer (Brian Harris) turned up with a brand new Rally 325, and was pleased to tell me that having saved his crop from the disastrous plague of Aphids that happened in 1976 ... the profit from his 1000 acres funded the purchase of the aircraft. He even had a Ladybird painted on the nose.
We mostly used human markers and it was important that we didn't spray them at the end of each spray run ! I can't remember why we didn't use the automatic flagmen.
I suppose it all came to an end with the increasing environmental awareness and associated costs, as one of the CAA requirements was to personally notify every adjacent property by a visit. As we often commenced spraying at 05.00 hrs, you can imagine the problem.
Anyway, I enjoyed the work, but as has been said, we did lose two aircraft ... One attempting to lift with the reloading hose still attached. The second due to a 'flashover' from a 33kv power which was being flown under. But thankfully no casualties, and we were spraying the next day. .
I know most farmer's preferred the helicopter for chemical application, since a good ag pilot gets the skids close enough to the crop to give it a good shaking which allows the chemical to reach the underside of the leaf. (Where the Aphids would settle) We used to double spray the headlands too just to keep the farmer happy !
Later in the work, we commenced the ULV and CDA system, (Ultra Low Volume & Controlled Droplet Application) where application rates of one pint per acre was the norm ... good for the R22 of course.
Typical spraying or spreading speed was 40 to 50 knots at around six feet so you didn't need to lose an engine ! At the end of each run, the heli is torque turned rapidly through 180 degrees to commence the return spraying run in the opposite direction. The trick here was to keep a good eye on the booms to keep them clear of the surface ... at the same time switching on and off the spray pump so you didn't do a spray job on the adjacent properties. A max wind spped was usually 5 to 6 knots to minimise spray drift.
So all in all, it was interesting and rewarding work and of course much of it was due to a successful team working well together. I suppose it was those steep torque turns that got me into the display flying.
If any prpruners have a specific interest in the subject I'll be happy to chat further.
Dennis Kenyon.