Air Tractor AT 301
The Air Tractor AT-300 is a family of agricultural aircraft that first flew in the United States on September 1973. Type certification was awarded to Air Tractor in November the same year, and serial production commenced in 1976. Of low-wing monoplane taildragger configuration, they carry a chemical hopper between the engine firewall and the cockpit.
• Country of origin: U.S.A
• Cockpit: 1 occupant
• Wingspan: 1375cm
• Empty weight: 1656kg
• Max take Off Weight: 2268kg
• Take-off distance: 400 metres
• Landing distance: 380 metres
• Max speed: 135kts
• Range: 470nm
An iconic ‘Agplane’.
Short field landing capability.
The Air Tractor AT-301 is an iconic symbol of American ingenuity and functionality. It has been exported world wide as a reliable ‘go to’ for aerial delivery solutions. Since its conception in 1973 the AT-300 series, or as most people know it, simply ‘the Air Tractor’, has been subject to continuous development to enable it to give continuous service in its primary role. It is considered to be one of the first ever purpose designed agricultural aeroplanes.
The Air Tractor AT-301 was the end result of over 20 years of modification and innovation by it’s creator and company founder Leland Snow. Snow developed his first custom built agricultural aircraft at the age of 23. Through careful review and change he was able to design an aircraft that has remained relatively unchanged in concept ever since. The only difference in the AT-300 and AT-301 is the size of the engine. In fact, such was the success of the initial build that later generations differed very little in their basic design, the main change being bigger payload capacity, or different types of engine.
The Air Tractor AT-301 is a low winged, single engined monoplane. The aircraft has a single seat for the pilot. It’s primary use, as the name would suggest is as an agricultural aircraft. With an excellent hopper capacity, around 1200 litres, and the ability to land almost anywhere, it presents an ideal solution for seeding or treating large areas of land. It has been employed in other roles as a quick and dynamic firefighting aircraft, and has even seen military service as a budget precision strike aircraft.
The aircraft is of hybrid construction. The majority of the structure is constructed of lightweight alloy, the tail plane is fabric covered. It is fitted with a wide and rugged spring-type landing gear assembly and a tail wheel, allowing it to make approaches into relatively rough and restricted terrain. The aircraft boasts a large wing span, the extra lift generated, helped in part by huge trailing edge Fowler-flaps, enables the aircraft to get airborne in a short distance. The same performance is demonstrated when landing. When fitted with a more powerful engine it displays a fierce rate of climb. It can reach rates of up to 1600 feet per minute.
From a construction point of view the airframe has some clever concepts inherent in its design. As the aircraft was originally designed to carry liquids, some of which would be corrosive, its panels are mounted away from the tube structure of the aircraft. This prevents the pooling of any fluid, including water, from resting in contact with structural fixtures. The net result of this ingenuity is that there is a reduction in corrosion of the airframe. Another clever feature is that the aircraft has removable panels, allowing easy access for maintenance and cleaning without the requirement for specialised tools.
The cockpit is fully sealed with a dedicated ventilation system. The aim of this is to avoid health risks due to exposure of dangerous or poisonous chemicals, which the pilot may otherwise come into contact with whilst performing spraying missions.
The aircraft was designed to be aerodynamically efficient, and offers a very respectable range, even when flying with a full payload. When discussing versatility and flexibility, it is interesting to note that the manufacturer is able to approve the carrying of excessive payloads often bringing the aircraft weight above the demonstrated maximum takeoff weight.
The Types of Air Tractor Models
Air Tractor AT-300: (1973) single-seat low-wing monoplane aerial application aircraft with a Pratt & Whitney R-1340-S3H1 Wasp radial engine.
Air Tractor AT-301: -300 variant with larger piston engine.
Air Tractor AT-302: -300 variant with turboprop engine.
Air Tractor AT-400: (1979) development of -300, with a Pratt & Whitney R-1340 radial engine.
Air Tractor AT-401: -400 variant with greater wingspan powered by a Pratt & Whitney Canada PT6A-15 engine.
Air Tractor AT-402: -401 variant with a P&W PT6A-15AG engine. With the AT-402B, Air Tractor’s goal was to combine turbine power with affordability. You get both, and more. It’s quiet, powerful, and fun to fly, even at the end of a long day.
Air Tractor AT-501: (1986) development of -400 with larger fuselage and hopper, greater wingspan, and seat for an observer. Uses a Pratt & Whitney R-1340 radial engine.
Air Tractor AT-502: Single-seat version of -501 with a PT6A-15AG engine.
Air Tractor AT-502B: Introduced in 1987, the 502B is the world’s most popular Ag Plane…and for good reasons. For many ag operators, the AT-502B is the ideal combination of payload and performance. It’s got every airframe and engine advantage to put you ahead at day’s end. Powered by the P&W PT6A-34AG engine.
Key features and sources for further reading