The Nagler NH-160 was an experimental single seat helicopter with counter-rotating blades.^[1]

Design and development

Bruno Nagler began wind tunnel experiments into helicopter design in 1926 and developed the first practical swash plate. The Nagler NH-120 was developed to test the idea of counteracting rotor torque with a small separate rotor. The engine was mounted above the main rotor on a shaft, and the anti-torque rotor was mounted above both. The NH-160 had a conventional helicopter engine and rotor layout, with the exception of the smaller anti-torque rotor mounted under the fuselage between the landing skids.^[2] Yaw control on both was effected through changing the difference in rotational speed between the two rotors, using a series of disc brakes. A small tail surface provided directional stability in forward flight. The smaller rotor would spin at a higher rpm, with about 60 percent of the load,. the main rotor being adjustable for lift control.

The NH-160 proved to be much more stable in tests than the NH-120 which had a higher center of gravity.

Variants

NH-120

Helicopter with engine mounted above rotor with a counter-torque rotor mounted above the engine.^[3]

NH-170

An enclosed two-seat side-by-side design with a shrouded lower counter-torque rotor.

Specifications (Nagler NH-160)

Data from Sport Aviation

General characteristics

• Capacity: one
• Gross weight: 700 lb (318 kg)
• Powerplant: 1 × McCullough Model 4318 , 72 hp (54 kW)
• Main rotor diameter: 2 × 20 ft (6.1 m)
• Main rotor area: 314 sq ft (29.2 m²) Lower rotor 8ft 3 blades

Performance

• Cruise speed: 104 kn (119 mph, 192 km/h)