Developed in 1952, the HTK-1 (US Navy designation) is a continuation of the K-225; the aircraft is modified with an added closed fuselage and cockpit.  Production of the 3-place trainer helicopter ended in 1953.


Data on design, manufacture and status

Design authority: Kaman Aircraft Corporation

Primary manufacturer: Kaman Aircraft Corporation

Parent type: Kaman K-225

Aircraft status: No longer flying


Primary flight and mechanical characteristics

VTOL type: Helicopter

Lift configuration: Synchropter (x2)

Crew required: 1-2

Crew seating: Side-by-side

Landing gear: Wheels (non-retractable)

Layout and Dimensions

Data on aircraft size

Overall Dimensions
Overall Height: 5.18 m 17.0 ft
Overall Length: 12.50 m 41.0 ft
Overall Width:  
Airframe Dimensions
Airframe Length:  
Airframe Width:  
Airframe Height:  
Landing Gear Dimensions
Landing Gear Base:  
Landing Gear Track:  
Cabin Dimensions
Cabin Internal Height:  
Cabin Internal Length:  
Cabin Internal Width:  

Weights and Performance

Data on aircraft weight and flight characteristics

Cruise Speed: 70 mph (112.654 km/h)

Max Gross Weight (ground): 1,134 kg 2,500 lb
Max Gross Weight (airborne):  
Max Take-off Weight: 1,134 kg 2,500 lb
Empty Weight: 1,032 kg 2,275 lb
Useful Load: 102 kg 225 lb
Empty Weight Fraction: 0.910
Climb Performance
Max Rate of Climb: 4 m/s 699 fpm
Hover Performance
Hover Ceiling IGE: 2,042 m 6,699 ft
Hover Ceiling OGE:  
Max Level Flight Speed:  
Never Exceed Speed:  
Service Ceiling: 5,182 m 17,001 ft
Range and Endurance
Max Range: 312 km 168 nm
Max Endurance:  

Engine Details

Aircraft powerplant (lift and/or propulsion)

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

Number of engines: 1
Designation: Lycoming O-435-4 reciprocating
Manufacturer: Lycoming Engines
Normal Ratings
Max continuous:  
Take-off / rated: 175 kW 235 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: 12.50 m 41.01 ft
Direction of Rotation: Counter-rotating
Hub Type:
Main Rotor Blade Characteristics
Blade Construction: Solid Wood
Blade Chord:  
Blade Tip Geometry:
Blade Twist:  
Number of Blades: 2
Main Rotor Derived Characteristics
Disc Area: 122.72 m² 1321.0 ft²
Disc Loading: 4.62 kg/m² 0.946 lb/ft²
Main Rotor Blade Derived Characteristics
Blade area per blade:  
Tip Speed:  

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):  

Related VFS Resources

Resources related to the K-240 / TH-43E (HTK-1), provided by the Vertical Flight Society.
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Related Public Resources

Resources related to the K-240 / TH-43E (HTK-1), provided by public sources across the internet.