AKA Bell 209. Retired US Army AH-1Fs have been converted into US Forest Service Firewatch Cobras with infrared and low-light sensors for real-time fire monitoring, GIS mapping, real-time color video, geo-referenced infrared, and infrared downlink. In addition to intelligence gathering, they are also used as a platform for an Air Attack Group Supervisor (ATGS) or a Helicopter Coordinator (HLCO).

Overview

Data on design, manufacture and status

Design authority: Bell Helicopter Textron, Inc.

Primary manufacturer: Bell Helicopter Textron, Inc.

Parent type: Bell Model 209/AH-1 Cobra

Aircraft status: Operational

Configuration

Primary flight and mechanical characteristics

VTOL type: Helicopter

Lift configuration: Single main rotor

Dedicated control device: Tail rotor

Crew required: 2

Crew seating: Tandem

Landing gear: Skids

Layout and Dimensions

Data on aircraft size

Airframe width includes stub wings. While there is some variation among Cobra variants, most fuselage widths without stub wings are .914 m (3 ft).

Overall Dimensions
Overall Height: 4.10 m 13.5 ft
Overall Length: 16.14 m 53.0 ft
Overall Width: 13.41 m 44.0 ft
Airframe Dimensions
Airframe Length: 13.77 m 45.2 ft
Airframe Width: 3.15 m 10.3 ft
Airframe Height: 3.11 m 10.2 ft
Landing Gear Dimensions
Landing Gear Base: 3.27 m 10.7 ft
Landing Gear Track: 2.13 m 7.0 ft
Cabin Dimensions
Cabin Internal Height:  
Cabin Internal Length:  
Cabin Internal Width:  

Weights and Performance

Data on aircraft weight and flight characteristics

Weights
Max Gross Weight (ground):  
Max Gross Weight (airborne):  
Max Take-off Weight:  
Empty Weight:  
Useful Load:  
Empty Weight Fraction:  
Climb Performance
Max Rate of Climb: 8 m/s 1,620 fpm
Hover Performance
Hover Ceiling IGE: 3,719 m 12,200 ft
Hover Ceiling OGE:  
Limitations
Max Level Flight Speed: 237 km/h 128 kts
Never Exceed Speed: 315 km/h 170 kts
Service Ceiling: 3,780 m 12,400 ft
Range and Endurance
Max Range: 519 km 280 nm
Max Endurance:  

Engine Details

Aircraft powerplant (lift and/or propulsion)

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

Powerplant
Number of engines: 1
Designation: Lycoming T53-L-703 turbine
Manufacturer: Lycoming Engines
Normal Ratings
Max continuous:  
Take-off / rated:  
Intermediate:  
Maximum: 1343 kW 1800 hp
OEI Ratings
OEI contingency:  
OEI continuous:  
OEI 30-second:  
OEI intermediate:  

Primary Lift Device

Data on primary lift devices such as main rotors

The Kaman K747 blade was designed to improve upon the B540's hover performance, maintainability and reliability, while also reducing ballistic vulnerability. Aircraft using the K747 blades used the same general hub as the B540, but added other improvements such as strengthened swash plates, scissors and other control system elements designed to account for the K747's higher loads.

Main Rotor Characteristics
Diameter: 13.40 m 43.96 ft
RPM: 324.0 rpm 324.0 rpm
Direction of Rotation: Counterclockwise
Hub Type: Flex-beam, stiff-in-plane teetering hub
Main Rotor Blade Characteristics
Blade Construction: Multi-cell filament wound spar, Nomex core, fiberglass skin and Kevlar trailing edge
Blade Chord: 0.762 m 2.50 ft
Blade Tip Geometry: Trapezoidal planform tip taper
Blade Twist: -0.209 rad -12.000 deg
Number of Blades: 2
Main Rotor Derived Characteristics
Disc Area: 141.03 m² 1518.0 ft²
Disc Loading:  
Solidity: 0.0724
Main Rotor Blade Derived Characteristics
Blade area per blade: 5.11 m² 55.0 ft²
Tip Speed: 227.33 m/s 745.8 fps

Primary Control Device

Data on primary control devices such as tail rotors

Tail Rotor Characteristics
Diameter: 2.59 m 8.50 ft
Configuration: Tractor
Direction of Rotation: Top blade aft
RPM: 1654 rpm 1654 rpm
Tail Rotor Blade Characteristics
Number of Blades: 2
Blade Construction: Bonded aluminum skin with abrasion strip
Blade Chord: 0.292 m 0.96 ft
Blade Twist:  
Tail Rotor Derived Characteristics
Disc Area: 5.27 m² 56.7 ft²
Solidity: 0.1436
Tail Rotor Blade Derived Characteristics
Tip Speed: 224.37 m/s 736.1 fps
Blade Area (per blade): 0.378 m² 4.07 ft²

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Related Public Resources

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