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, entry-level personal helicopter, 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 systemGreenspun, Philip. "2005 Robinson R22 - owner's review " March 2010. Accessed: 20 September 2014. 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. SFAR 73 includes discussion and training on energy management, mast bumping, low rotor RPM (blade stall), low G hazards and rotor RPM decay. Tip weights were added to the R22 to increase rotor inertia, but the small rotor limits weight.Borrows, David A. Rotor RPM Flight Training, March 1998. Accessed: February 2011.
The first R22 sold, October, 1979, S/N 003, N1010WR, was purchased by Pacific Wing and Rotor, Inc., represented by Tim Tucker who later became a test pilot and chief instructor for Robinson. S/N 001 was crashed in the ocean during certification testing due to a failure of the casting that mates the tail rotor gearbox and stabilizing fins to the conical monocoque aluminum tail boom and S/N 002 was used to complete the FAA certification. S/N 002, N32AD, is still owned by Robinson and is now preserved in the collection of the Smithsonian Air and Space Museum.
By 2019, 4800 R22 had been made.
R22 cost Initially, Robinson projected the sale price in 1977 to be US$18-19,000. However, 3 months prior to initial deliveries starting in 1979, the price was raised to US$33,850. Per Tim Tucker, the sale price for S/N 003 including options was US$48,000, .
As of 15 January 2024, the R22 Beta II has a suggested retail price of US$375,000 (ex-factory price, USA) and the value on the second-hand market is dependent on component time in service. The estimated operating cost of a R22 Beta II, per the factory, including insurance, reserve for overhaul, and direct operating cost (fuel, oil, inspections, unscheduled maintenance) is US$189.87/hr when flown 500 hours per year.
Depreciation on a Robinson R22 is negligible, as freshly overhauled R22s typically sell for more than the original cost. However, a provision per flown hour must be made for a "reserve for overhaul" cost, currently estimated at US$90.42 per hour.
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 landing-gear mounting points, giving it a slightly nose-down attitude on the ground and better matching of the skids to the ground in a low-altitude hover with two people on board. The R22 Beta added an engine speed governor (optional), rotor brake, and auxiliary fuel tank (optional). The battery was moved from below the instrument cluster to the engine compartment for better balance. The R22 has been offered as an instrument trainer version, with optional fixed floats as the R22 Mariner, and other special configurations for police work, electronic news gathering, and so on. The R22 Beta II received a larger Lycoming O-360 engine derated for sea-level operation. It allows greater altitudes for hovering in and out of ground effect (HIGE/HOGE). The R22 Beta II also made the engine speed governor standard and included a carburetor heat assist, which correlates adding carburetor heat with a decrease in collective control. Only the basic skid style is currently being sold.
Controls
Instead of floor-mounted cyclic sticks between the pilot's knees, the R22 uses a unique teetering "T-Bar" control connected to a stick that emerges from the console between the seats. This makes it easier for occupants to enter and exit the cabin and reduces chances for injury in the event of a hard landing. The teetering bar has a hand grip on both sides that hangs down between the pilots' legs. Thus, if teetered to the right, the right-side pilot would be flying and the left grip would be about 12 inches above the left pilot's lap. R22 flight instructors learn to fly with their hand in the air. The left part of the bar, left collective control, and left tail-rotor pedals can be removed if the left-seat occupant is not going to pilot the aircraft. A floor-mounted, foot-activated push-to-talk switch facilitates intercom communications for the left-seat occupant, although some later models may be equipped with a voice-activated intercom system.
The helicopter rotor system consists of a two-bladed main rotor and two-bladed antitorque rotor on the tail, each equipped with a teetering hinge. The main rotor rotates counterclockwise when viewed from above, i.e. with the right-side blade moving forward. The main rotor is also equipped with a coning hinge for each blade. Collective and cyclic pitch inputs to the main rotor are transmitted through pushrods and a conventional swashplate mechanism. Control inputs to the tail rotor are transmitted through a single pushrod inside the aluminum tail cone.
To ease the pilot's workload, a mechanical throttle correlator adjusts the throttle as the collective pitch control is raised or lowered. The pilot needs to make only small adjustments by twisting the throttle grip on the collective throughout the flight regime. Later models are also equipped with an electronic governor, which works to maintain engine speed within normal operating limits (between 97 and 104%); the governor is active when the engine is running only above 80% and is most effective in normal flight conditions. Robinson introduced the governor to ease pilot workload and to reduce instances of main rotor stall due to low rotor RPM. The governor can be switched on or off with a toggle switch located at the end of the pilot's collective pitch control. When the governor is not engaged, a yellow caution light glows on the instrument panel.
Powerplant
The R22 uses a horizontally mounted Lycoming O-320 (O-360-J2A on the Beta II), flat-four, air-cooled, naturally aspirated, carburetor-equipped, reciprocating engine. It is fueled with 100LL grade aviation gasoline. JTI Air Holdings, Inc., offers an STC allowing use of 91+ octane non-ethanol automotive gasoline. Cooling is provided through a direct-drive, squirrel-cage cooling fan. At sea level, it is derated, or operated at less than maximum power, which has been attributed to the company wishing for the power unit to maintain the same performance at sea level as it does at altitude. As the air becomes thinner with increasing altitude, maximum available horsepower decreases, reaching a point where the throttle can be completely open and rotor speed is controlled by collective lever position. By derating the engine at sea level, the R22 achieves acceptable high-altitude performance without use of supercharging or turbocharging, thus saving the weight, cost, complexity, unreliability, and shortened engine life of a forced induction system.
A carburetor is used to provide the air-fuel mixture. Carbureted engines are susceptible to carburetor icing, a condition most likely to occur in conditions of a low 11 °C (20 °F) difference between the outside air temperature and dew point (the "dew point spread"), as well as visible signs of moisture in the atmosphere. Icing can lead to loss of engine power, and if not corrected, total shutdown of the engine. A carburetor heat control is used to supply heated air to the carburetor; this can prevent or cure icing, but also causes a reduction in engine power output because hot air is less dense, enriching the fuel-air mixture. The carburetor heat control is a simple plunger-type control mounted on the center console near the collective pitch control lever. Pulling the control up slides a gate valve near the carburetor that admits warm air from a scoop on the exhaust system. The R22 employs a carburetor air temperature gauge, marked to indicate temperatures conducive to icing. The Beta II version of the R22 also includes a "carburetor heat assist", which automatically applies carburetor heat when the collective lever is lowered below a certain point. When icing conditions are present, carburetor heat is required to prevent icing around the butterfly valve from the pressure drop at that point. As the carburetor air temperature (CAT) indicator does not read correctly below 18 in Hg (457 mm Hg) of intake manifold air pressure, icing conditions require applying full carburetor heat below 18 in Hg of manifold pressure. A placard indicating this requirement is located on the CAT indicator and in the pilot's operating handbook.