The development model for the H-21 series. It is distinguishable from the later models by the forks holding the main wheels.


Data on design, manufacture and status

Design authority: Piasecki Helicopter Corporation

Primary manufacturer: Piasecki Helicopter Corporation

Parent type: Piasecki H-21

Aircraft status: No longer flying


Primary flight and mechanical characteristics

VTOL type: Helicopter

Lift configuration: Tandem (Fore/aft) (x2)

Crew required: 2

Crew seating: Side-by-side

Landing gear: Wheels (non-retractable)

Layout and Dimensions

Data on aircraft size

Overall Dimensions
Overall Height: 4.86 m 15.9 ft
Overall Length: 26.31 m 86.3 ft
Overall Width: 13.41 m 44.0 ft
Airframe Dimensions
Airframe Length: 16.02 m 52.6 ft
Airframe Width: 3.97 m 13.0 ft
Airframe Height:  
Landing Gear Dimensions
Landing Gear Base: 7.51 m 24.6 ft
Landing Gear Track: 4.48 m 14.7 ft
Cabin Dimensions
Cabin Internal Height:  
Cabin Internal Length:  
Cabin Internal Width:  

Weights and Performance

Data on aircraft weight and flight characteristics

Cruise Speed: 180 mph (160.934 km/h)

Max Gross Weight (ground): 5,000 kg 11,022 lb
Max Gross Weight (airborne):  
Max Take-off Weight:  
Empty Weight:  
Useful Load:  
Empty Weight Fraction:  
Climb Performance
Max Rate of Climb: 8 m/s 1,600 fpm
Hover Performance
Hover Ceiling IGE:  
Hover Ceiling OGE:  
Max Level Flight Speed:  
Never Exceed Speed:  
Service Ceiling: 5,182 m 17,000 ft
Range and Endurance
Max Range: 805 km 434 nm
Max Endurance:  

Engine Details

Aircraft powerplant (lift and/or propulsion)

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

Normal Ratings
Max continuous: 951 kW 1275 hp
Take-off / rated: 1063 kW 1425 hp
OEI Ratings
OEI contingency:  
OEI continuous:  
OEI 30-second:  
OEI intermediate:  

Primary Lift Device

Data on primary lift devices such as main rotors

Fwd rotor rotates ant-clockwise, aft rotor rotates clockwise

Main Rotor Characteristics
Diameter: 13.41 m 44.00 ft
RPM: 255.0 rpm 255.0 rpm
Direction of Rotation: Not applicable
Hub Type: Fully articulated
Main Rotor Blade Characteristics
Blade Construction: Wooden blades with steel spar and plywood covering
Blade Chord: 0.457 m 1.50 ft
Blade Tip Geometry: Conventional
Blade Twist: -0.122 rad -7.000 deg
Number of Blades: 3
Main Rotor Derived Characteristics
Disc Area: 141.26 m² 1520.6 ft²
Disc Loading: 17.70 kg/m² 3.624 lb/ft²
Solidity: 0.0651
Main Rotor Blade Derived Characteristics
Blade area per blade: 3.07 m² 33.0 ft²
Tip Speed: 179.06 m/s 587.5 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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Related Public Resources

Resources related to the YH-21 Work-Horse, provided by public sources across the internet.