McCulloch J-2

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The McCulloch J-2 was a small, two-seat autogyro with an enclosed cabin, one of only three designs of this type of aircraft to receive a type certificate in the United States. It was built by McCulloch Aircraft Corporation.

Design and development

It was designed by Drago Jovanovich and first flew in June 1962. McCulloch acquired the design in 1969 and put it into production, building 83 aircraft over the next three years. They were reported to sell for US$15,900.

The design featured a belt clutch and a transmission which could be engaged to spin the rotor blades to high speed before take-off to produce short takeoff runs. A lever on the rear cockpit wall would select the drive position for the transmission. A single "spin-up lever" on the cockpit left side would then be pressed downward, operating as a collective pitch control to put the blades into flat pitch while simultaneously tensioning the belt clutch. The rotor could be spun to over 500 rpm before takeoff, well above the normal flight range (typically 425 rpm). Release of the spin-up lever would disengage both the clutch and the transmission, while placing the blades into flight pitch. After a very brief takeoff run (typically 25 to 200 feet, depending upon load and winds) adequate flight airspeed would be attained, while the rotor speed decayed to the normal flight range. The rotor was not engine-driven in flight. A strong spring resisted accidental depressing of the spin-up lever while airborne. Dual controls were provided for all functions except the spin-up lever, which was accessible only from the left seat. The aircraft enjoyed nimble handling with light control forces, but suffered from a shallow climb gradient.

Early versions were equipped with a two-bladed wooden Sensenich propeller. A later "Super J-2" variant employed a three-bladed Hartzell controllable-pitch propeller, accompanied by an increase in allowable gross weight. Baggage of up to 95 pounds, to the extent permitted by gross weight considerations, could be carried in a large bay under the seat. Fuel was carried in tanks in the stub wings. A total of 24 U.S. gallons could be carried, 12 on each side, but only 20 were usable through normal flight attitudes. At a typical fuel burn rate of about eight gallons per hour and economy cruise at about 85 mph, with a need for a safety reserve, this limited the aircraft's range.

The rotor system (hub and blades) is very similar to that found on the early versions of the Hughes 269 / Schweizer 300 series helicopters. The primary difference is in the twist of the blades (or lack thereof), optimized for autorotation in the case of the J-2.

Most examples of the J-2 were sold to pilot owners in the United States but at least one example was exported to the United Kingdom.UK Register of Civil Aircraft - register entry for G-AZWZ (pictured)
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In 1974, the rights were bought by Aero Resources, who planned to return the Super J-2 to production, but could not find a market for the aircraft and no more were built.

Variants

;Jovanovich Jov-2
:The initial prototype as designed by Drago Jovanovich.
;McCulloch J-2 and Super J-2
:Production versions built by McCulloch from 1971 to 1974. 83 built.
;Aero Resources Super J-2
:Further planned production by Aero resources, powered by a Lycoming O-360-A2D. None built.

Specifications (Super J-2)

See also

* Robert P. McCulloch
* Twin-boom aircraft

References

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Aerofiles
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{{McCulloch aircraft
http://www.gyroplane.co/gyro_article_2003.html

1960s United States civil utility aircraft
Single-engined pusher autogyros
Aircraft first flown in 1962
Twin-boom aircraft