The Robinson R22 is a two-seat, two-bladed, single-engined, light utility helicopter manufactured by Robinson Helicopter Company. It was designed in 1973 by Frank D. Robinson, and has been in production since 1979. Development The majority of flight testing was performed at Zamperini Field in Torrance, California. Flight testing and certification were performed in the late 1970s by test pilot Joseph John "Tym" Tymczyszyn, and the R22 received FAA certification in March 1979. Due to relatively low acquisition and operating costs, the R22 has been popular as a primary rotorcraft trainer around the world, and as a livestock-management tool on large ranches in North America and cattle stations in Australia. The R22 has a very low-inertia rotor system and the control inputs are operated directly by push rods with no hydraulic assistance. Thus, its flight controls are very sensitive and require a light touch to avoid overcorrection, and students who master an R22 are usually well prepared to transition to heavier helicopters. Due to the specific training required by the low-inertia rotor system and a teetering main rotor, operation of the Robinson R22 or R44 in the US requires a special endorsement by a certified flight instructor. Tip weights were added to the R22 to increase rotor inertia, but the small rotor limits weight. Design The R22 is a light, two-place, single reciprocating-engined helicopter, with a semirigid, two-bladed main rotor and a two-bladed tail rotor. The main rotor has a teetering hinge and two coning hinges. The tail rotor has only a teetering hinge. The normal production variant has skid landing gear. The Mariner version, no longer manufactured, provided floats. Wheeled gear is not available. The basic structure is welded chromoly steel tubing. The forward fuselage is made of fiberglass and aluminum with a Plexiglas canopy. The tailcone and vertical and horizontal stabilizers are aluminum. It has an enclosed cabin with side-by-side seating for a pilot and passenger. The doors may be removed for flight, as is often done for photographic flights, interior cooling in high temperatures, or a 10.4 lb weight saving. The first version was produced as the R22, followed by the R22 HP, R22 Alpha, R22 Beta, and R22 Beta II. Superficially, the aircraft appear similar. The R22 HP was fitted with a 160 bhp Lycoming O-320-B2C engine, an increase of over the original R22. The steel-tube frame on the R22 Alpha was modified by extending the aft