Robinson R44 Raven

The Robinson R44 is a four-seat single-engine light helicopter produced by the Robinson Helicopter Company of Torrance, California, since 1992. Derived from the two-seat R22, it is used for private flying, flight training, law enforcement, aerial news gathering and utility work, with military and paramilitary operators in around a dozen countries. It has been the world's best-selling general aviation helicopter every year since 1999, with 5,941 delivered between 2001 and 2020.

Development

Frank Robinson and his engineering staff designed the R44 during the 1980s as a larger, hydraulically assisted development of the R22. The prototype first flew on 31 March 1990, and the R44 Astro received an FAA type certificate in December 1992, with first deliveries in early 1993. The Newscopter, fitted with electronic news gathering equipment, was delivered from 1998. The Raven, introduced in January 2000, added hydraulically assisted controls and adjustable pedals; the Raven II followed in July 2002 with a fuel-injected engine, wider blades, higher gross weight and improved altitude performance. Robinson announced the Cadet in November 2015 and has ground-run a diesel engine intended to replace the Lycoming IO-540, reducing fuel burn from 16 to 12 US gal per hour. In 2023 Rotor Technologies developed the R550X, an unmanned helicopter based on the Raven II.

Design

The R44 uses a semi-rigid two-bladed main rotor of 33 ft (10 m) diameter, a two-bladed tail rotor and skid landing gear, with an enclosed cabin seating a pilot and three passengers in two rows. Tail rotor rotation is reversed relative to the R22, placing the advancing blade at the bottom for greater yaw control authority. The Raven II is powered by a 245 hp (183 kW) Lycoming IO-540-AE1A5 six-cylinder air-cooled piston engine, giving a maximum speed of 130 kn (240 km/h), a cruise of 109 kn and a range of 300 nmi (560 km) without reserve. Empty weight is 1,505 lb (683 kg) and gross weight 2,500 lb (1,134 kg). Following findings on post-crash fuel leaks, Robinson fitted bladder-type fuel tanks to new aircraft from 2009 and issued Service Bulletin SB-78 in December 2010 mandating retrofit of aluminium-tanked aircraft; Australia's CASA grounded non-compliant aircraft on 30 April 2013.

Operational History

In 1997 Jennifer Murray flew an R44 on the first helicopter circumnavigation of the world by a woman, covering 36,000 miles in 97 days. As of 2014 an R44 held the piston helicopter speed record of 123 kn (228 km/h). Military and government operators include the Bolivian Air Force, Dominican Republic Army, Royal Jordanian Air Force, Lebanese Air Force, Mexican Navy, Nicaraguan Air Force, Peruvian Army, Royal Thai Army, the Philippine Army, Navy and National Police, the South African Police Service Air Wing, the Alaska State Troopers and the Police of Uruguay.

Variants

• R44 Astro: Initial production model, certificated December 1992 with non-hydraulic controls.
• R44 Raven: Introduced January 2000 with hydraulically assisted controls and adjustable pedals.
• R44 Raven II: 2002 model with fuel-injected engine, wider blades, higher gross weight and better altitude performance.
• R44 Newscopter: Electronic news gathering variant delivered from 1998.
• R44 Cadet: Announced November 2015; Raven I with rear seats replaced by a cargo area and a derated engine.