For several reasons use of helicopters by South African aerial applicators fell out of fashion some years ago. However, the discovery of some Enstrom airframes and spray gear in a dusty Ghanaian hangar may lead to a revival of rotary wing crop spraying
Those in aviation who are plugged in to African politics will know that every so often a leadership change presents new opportunities. This applies to rotary wing aircraft as much as fixed wing and it's amazing what can appear from the dusty shadows of an old hangar.
When Flight Lieutenant Gerry Rawlings came to power in a military Coup in 1981 local government was obliged to mark time until the new administration found its feet. The changes also had a similar effect on aid programs, many of which languished until eventually cancelled. Before the Coup, the country was in turmoil anyway and one casualty was a crop spraying operation allegedly financed by one of many Non-government-organisations involved in Ghanaian development. The program was to use Two Enstrom F28Cs delivered to Kotoka International Airport, Accra, in the late seventies.
Concerned that political upheaval in Ghana would lead to two of their helicopters being maintained in a haphazard fashion, Enstrom kept track of their whereabouts. The company contacted South Africa's distributor, Wonderboom-based Salelease and asked their CEO, Keith Smith, to take a look at them. Keith subsequently flew to Accra in 1989 and indeed found the two helicopters at the back of a hangar, one of which had crashed and was in pieces. Alongside them were two complete sets of spray gear, specially manufactured for the F28C.
Successfully negotiating their purchase, Keith packed the two complete airframes into a container and liberated them to South Africa. One of the two 1977 model Enstroms, ZS-RJT, is still flying in private ownership today. The spray gear was stored in Keith's hangar and was recently dusted off and attached to F28C ZS-HMC, an Enstrom Keith originally sold new in 1981.
The use of helicopters for aerial applicators in South Africa is not new. Using turbocharged Bell 47GBs and Hiller UH-12L4s as their preferred delivery vehicles, helicopters were ideally suited to spraying small areas and undulating terrain. Initially, rotary wing sprayers proved somewhat more expensive than their fixed wing counterparts. Aerial spraying was carried out using dedicated but inexpensive Piper Pawnees, Cessna Ag-Wagons and various other aircraft. Over the years there has been a trend towards larger farms and consequently bigger aircraft. As airframes grew, so too did the need for more power, leading to the almost universal adoption of turbine engines. Predictably, costs skyrocketed to a point today where a new crop duster is several times the cost of a sixties or seventies-manufactured piston helicopter.
A high attrition rate and parts scarcity has rendered 30-year old Hillers and Bells obsolete resulting in a scarcity of suitably-powered helicopters and Keith has decided to fill the niche market that still remains. Amongst traditional helicopter users have been Cape wineries, banana farms and sugar farms. The South African Police makes extensive use of rotary wing sprayers in the battle to destroy dagga plantations. Main rotor downwash tends to allow spray particles to form a swirl, which wineries like as it gives a measure of coverage to the underside of its grape bushes. Banana and cane sugar farms are often located in hilly areas, especially along Natal's south coast where helicopters are the only method of spraying plantations.
Helicopters have a number of other advantages apart from accuracy. Fluids can be placed immediately adjacent to the field so there is virtually no ferry time for reloading. Speeds are more easily controlled over upward and downward slopes and penetration is often better as a consequence of the helicopter's slower speed - about 60mph for most applications. Some operators also maintain that the swathe is more even as there is no propwash to dissipate the spray released under the fuselage.
From a piloting point of view, turns are tighter and hence reduce spray time. A helicopter can make a 180 degree turn at the end of its spray run in 9-14 seconds compared to a fixed wing aircraft that can take between 30 and 45 seconds to turn around. Moreover, the turns can be completed at a far lower speed without the risk of stalling - an area fixed wing pilots are at risk.
If Keith is able to fill his niche, he will have placed himself in a unique position. Although a current model Enstrom F28F can be bought new for US$330K plus an additional US$20k for spray gear, older models, like ZS-HMC can be purchased for R1.5 million in a zero-timed condition. Enstrom quote R900 per hour direct operating cost for a new F28F advising an extra 12 percent for older models. The company currently manufacture two models - the 225hp Lycoming engined F28F and similarly-engined 280FX. The last F28C was delivered in 1980.