Bell HSL
# Bell HSL

The Bell HSL (Model 61) was an American 1950s anti-submarine warfare (ASW) helicopter built by the Bell Helicopter company, the only tandem rotor type designed by Bell.

## Design and development

The prototype Bell Model 61 first flew on 3 March 1953; it had been designed to meet a United States Navy requirement for an anti-submarine warfare helicopter. In June 1950, the Model 61 was announced as the winner of the competition, and three XHSL-1 evaluation aircraft were ordered. The Model 61 had a rectangular-section fuselage structure and four-leg, six-wheel landing gear. It was powered by a Pratt & Whitney R-2800 radial engine mounted in the aft fuselage. Crew included two pilots and two sonar operators.

Because of the urgency of the requirement, low-rate production was ordered almost immediately after Bell received a contract for three XHSL-1s. The Navy eventually contracted for at least 160 production aircraft, including 18 intended for the British Royal Navy. Bureau Numbers were assigned for a total of 234. Because of development problems that resulted in poor schedule performance to the contract, only 50 were built. Although all were delivered, after service test and acceptance only a handful were used, for the development of airborne mine sweeping. The rest were delivered directly into storage and were subsequently struck off.

## Operational history

The HSLs were not used operationally. Approximately seven were assigned to the U.S. Naval Air Mine Defense Unit at Panama City, Florida, for the development of airborne mine-sweeping, the first arriving in September 1956 and the last being struck off in early 1960.

## Variants

### XHSL-1

    two experimental flight test and one static test article

### HSL-1

    production version, 50 built.

### Bell Model 61

    Company designation for the HSL

### Bell D-116

    A proposed civil variant of the Model 61, not proceeded with.

### Bell D-216

    A proposed variant of the HSL, not proceeded with.

### Bell D-238

    A proposed variant of the HSL, not proceeded with.

## Operators

### United States

* United States Navy

## Specifications (HSL-1)

Data from NAVAER-1519B - Bell HSL-1 :Characteristic Summary Bell Aircraft since 1935<

General characteristics

* Crew: 4 (search mission), 3 (attack mission)
* Capacity: Hoist capacity 800 lb (363 kg)
* Length: 39 ft 11 in (12.17 m) (fuselage only)
* Width: 11 ft 6 in (3.5 m) (rotors folded)
* Height: 14 ft 6 in (4.42 m)
* Empty weight: 13,073 lb (5,930 kg)
* Gross weight: 16,958 lb (7,692 kg) (search mission)

             16,853 lb (7,644 kg) (attack mission)
* Max takeoff weight: 26,500 lb (12,020 kg)
* Fuel capacity: 450 US gal (375 imp gal; 1,703 L) maximum
* Powerplant: 1 × Pratt & Whitney R-2800-50 18-cyl. two-row air-cooled radial piston engine, 2,100 hp (1,600 kW) for sea level take-off at 2,600 rpm

             normal power at sea level, 1,900 hp (1,417 kW) at 2,400 rpm
* Main rotor diameter: 2 × 51 ft 6 in (15.70 m)
* Main rotor area: 3,840 sq ft (357 $m^2)$
* Blade section: NACA 0015

Performance

* Maximum speed: 124 mph (200 km/h, 108 kn) (search mission)
* Cruise speed: 96 mph (154 km/h, 83 kn) at 1,500 ft (457 m)
* Range: 350 mi (560 km, 300 nmi)
* Combat range: 140 mi (230 km, 120 nmi)
* Endurance: 3 hours 30 minutes loiter on search mission
* Service ceiling: 14,400 ft (4,400 m) at take-off weight with normal power
* Absolute hover ceiling OGE: 10,750 ft (3,277 m)
* Rate of climb: 1,475 ft/min (7.49 m/s) normal power, sea level, at take-off weight in forward flight

             1,200 ft/min (6.1 m/s) in vertical flight with take-off power, sea level, at take-off weight in forward flight

Armament

* Bombs: 2x Mark 43 torpedoes

Avionics

* Dipping Sonar
