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 aircraft into an amphibious floatplane with the capability to not only land on water, but to its also able to scoop up and then drop it onto a fire. This capability allows the aircraft to stay out on a fire without needing to return each time to an airport to refill the water tank and has been purchased by several government authorities.
Helicopters are a very useful platform for agricultural work, as their maneuverability means they are often purchased to undertake application work that requires highly detailed and accurate flying. Spot spraying for weeds over large areas of land is often done this way, and this involves the pilot flying along and identifying a problem area, hovering over it while the chemical is sprayed, and then moving on to locate the next area. This type of spraying is simply not possible with a fixed wing aircraft. Another unique application for helicopters in agriculture is frost prevention, and this is where small piston helicopters are hovered over fruit crops on nights where damaging frost is likely, and in doing so air is kept moving preventing the frost from occurring.
The two main tasks for ag planes is the spraying of chemicals and the spreading of fertilizers. As insects and weeds reduce crop outputs significantly, Agricultural Aircraft for sale are purchased to spray specialized chemicals designed to kill or inhibit the growth of pests. Spray booms are fitted that span nearly with full width of the ag plane’s wings and these are used to disperse the chemical that is carried in the aircraft. Spreading or ‘topdressing’ as it is sometimes referred to, is the process of distributing fertilizers by air in order to encourage the growth of cr