Developed in 1958, the helicopter is powered by three turbo-compressors; the tip-jet aircraft can operate on two of its three engines, which can function independently.  The XV-1 Convertiplane rotor was used for the Model 120.  To steer, the engine exhaust was used [Ref Hirschberg. The American Helicopter. Page 62].


Data on design, manufacture and status

Design authority: McDonnell Aircraft Corporation

Primary manufacturer: McDonnell Aircraft Corporation

Parent type: No type defined

Aircraft status: No longer flying


Primary flight and mechanical characteristics

VTOL type: Helicopter

Lift configuration: Single main rotor

Crew required: 1

Crew seating: Single seater

Landing gear: Skids

Layout and Dimensions

Data on aircraft size

Overall Dimensions
Overall Height: 2.74 m 9.0 ft
Overall Length: 9.45 m 31.0 ft
Overall Width: 9.45 m 31.0 ft
Airframe Dimensions
Airframe Length: 6.10 m 20.0 ft
Airframe Width:  
Airframe Height: 2.74 m 9.0 ft
Landing Gear Dimensions
Landing Gear Base:  
Landing Gear Track: 2.79 m 9.2 ft
Cabin Dimensions
Cabin Internal Height:  
Cabin Internal Length:  
Cabin Internal Width:  

Weights and Performance

Data on aircraft weight and flight characteristics

Cruise Speed: 109 mph (175 km/h)

Max Gross Weight (ground): 2,858 kg 6,300 lb
Max Gross Weight (airborne):  
Max Take-off Weight: 2,858 kg 6,300 lb
Empty Weight: 1,111 kg 2,450 lb
Useful Load: 1,746 kg 3,850 lb
Empty Weight Fraction: 0.389
Climb Performance
Max Rate of Climb: 12 m/s 2,400 fpm
Hover Performance
Hover Ceiling IGE: 3,658 m 12,001 ft
Hover Ceiling OGE: 3,048 m 10,000 ft
Max Level Flight Speed: 222 km/h 120 kts
Never Exceed Speed:  
Service Ceiling:  
Range and Endurance
Max Range: 158 km 85 nm
Max Endurance: 1 hrs 1 hrs

Engine Details

Aircraft powerplant (lift and/or propulsion)

Provided powerplant data is for uninstalled, sea level, static operations.

Number of engines: 3
Designation: AiResearch GTC-85-35 turbine
Manufacturer: AiResearch
Normal Ratings
Max continuous:  
Take-off / rated: 63 kW 85 hp
OEI Ratings
OEI contingency:  
OEI continuous:  
OEI 30-second:  
OEI intermediate:  

Primary Lift Device

Data on primary lift devices such as main rotors

Main Rotor Characteristics
Diameter: 9.45 m 31.00 ft
RPM: 410.0 rpm 410.0 rpm
Direction of Rotation: Clockwise
Hub Type: Stiff inplane, bearingless, damperless
Main Rotor Blade Characteristics
Blade Construction:
Blade Chord:  
Blade Tip Geometry: Swept Tip-jet
Blade Twist:  
Number of Blades: 3
Main Rotor Derived Characteristics
Disc Area: 70.14 m² 755.0 ft²
Disc Loading: 40.74 kg/m² 8.345 lb/ft²
Main Rotor Blade Derived Characteristics
Blade area per blade:  
Tip Speed: 202.87 m/s 665.6 fps

Primary Control Device

Data on primary control devices such as tail rotors

Tail Rotor Characteristics
Configuration: Unknown
Direction of Rotation: Unknown
Tail Rotor Blade Characteristics
Number of Blades:  
Blade Construction: N/A
Blade Chord:  
Blade Twist:  
Tail Rotor Derived Characteristics
Disc Area:  
Tail Rotor Blade Derived Characteristics
Tip Speed:  
Blade Area (per blade):  

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