Agricultural aircraft (‘ag planes’) are used for the aerial delivery of agents beneficial to primary industries. The sale of agricultural aircraft is tied closely to the cycle of primary industries, especially crop production, and is cyclical in nature. Buyers of agplanes are typically purchasing USA made aircraft, chiefly Air Tractor and Ayres / Thrush Aircraft, but an increasing number of agricultural aircraft for sale are coming from Brazil (Embraer), New Zealand (Pacific Aerospace) and Poland (PZL Mielec). Helicopters are also used as agricultural aircraft, and are ideally suited to small area work and where accuracy is crucial. Agricultural aircraft are often purchased for use in firefighting and are well suited to water and retardant dropping, and are even modified to operate on amphibious floats. A large number of Agricultural aircraft for sale were originally manufactured with piston engines and have been modified to fit turbine engines.
The earliest agricultural aircraft were all piston powered, as turbine engines were still yet to be developed. Small in-line and opposed engines were first adopted for ag planes, but their limitation in terms of power was quickly reached in mainstream applications. The more powerful radial engines soon became popular with buyers post World War Two and remained so until recently. Piston engines are still in use for small ag planes, as their cheaper cost is well suited to the needs of those looking to purchase entry level aircraft.
As the demands of agricultural flying increased, and it became commercially vital to increase both the amount of chemical carried and the time spent on the job, piston engines became increasingly unsuited for the task. The only obvious alternative was the use of a turbine engines that had significantly more power than a piston and a much better power to weight ratio. Originally popular piston aircraft – like the Grumman Ag Cat and the PZL Dromader – were modified by owners by having the original piston engine removed and an aftermarket turbine engine installed. Eventually the manufacturers responded and began producing turbine versions of their aircraft to satisfy the demand from buyers for aircraft with more horsepower. An early example of a factory built turbine aircraft was the Air Tractor AT-302, first delivered in 1977.
As the dropping of chemical and water are very similar, an agricultural aircraft can be easily modified for firefighting applications in less than a day. Some agricultural aircraft manufacturers are now selling dedicated firefighting versions of their aircraft as the demand for this type of flying grows. Firefighting authorities will sign up operators during the summer months to be on stand-by in the event of a fire and once needed, the aircraft are filled up with water and often a foam or retardant additive is included to enhance the effectiveness of the water. A recent innovation in this area is the Fire Boss aircraft, developed from a joint venture between Air Tractor and Wipaire. The Fire Boss is a AT-802 Air Tractor married up to a set of special Wipaire Wipline 10000 floats, turning the air