Bell HSL
{{Infobox aircraft
|name = HSL (Bell Model 61)
|image = File:U.S. Navy HSL-1 61.jpg
|caption = The U.S. Navy Bell XHSL-1 prototype in flight.
|type = Tandem-rotor ASW helicopter
|manufacturer = Bell Helicopter
|national_origin = United States
|designer =
|first_flight = 3 March 1953
|introduction = 1957
|retired = 1960
|status = Retired
|primary_user = United States Navy
|more_users =
|produced =
|number_built = 53 including one static test article
|unit cost =
|developed_from =
|variants =
}}
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. It had its first flight in 1953 and entered service with the U.S. Navy in 1957. Over 50 models were produced but it was out of service by 1960 - such was the pace of helicopter development in this period.
The helicopter had two main rotors at either end of the fuselage tube, linked by a transmission but powered by a single Pratt & Whitney R-2800-50m, which was an 18-cylinder air-cooled radial engine. The front rotor shaft was actually slightly ahead of pilots in the front cockpit.
Design and development
File:Bell XHSL-1 prototype in flight c1953.jpg
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.{{cite magazine|magazine=Popular Mechanics|author=Hearst Magazines|title=Navy's Most Powerful Helicopter to Hunt Submarines|url=https://books.google.com/books?id=8NsDAAAAMBAJ&pg=PA121|date=August 1953|publisher=Hearst Magazines|page=121}}
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
File:Bell HSL-1 towing tests 1956.jpg
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
Specifications (HSL-1)
File:Bell HSL-1 3-view line drawing.png
{{Aircraft specs
|ref=NAVAER-1519B - Bell HSL-1 :Characteristic Summary{{cite book |title=NAVAER-1519B - Bell HSL-1 :Characteristic Summary |date=30 August 1958 |publisher=Navaer |edition=Revision 10-51}} Bell Aircraft since 1935{{cite book|last=Pelletier|first=Alain J.|title=Bell Aircraft since 1935|publisher=Putnam & Company Ltd.|location=London|year=1992|edition=1st|pages=100–102|isbn=1-55750-056--8|oclc=25625769}}
|prime units?=imp
|crew=4 (search mission), 3 (attack mission)
|capacity=Hoist capacity {{cvt|800|lb|0}}
|length ft=39
|length in=11
|length note= (fuselage only)
|width m=3.5
|width note= (rotors folded)
|height ft=14
|height in=6
|height note=
|empty weight lb=13073
|empty weight note=
|gross weight lb=16958
|gross weight note=(search mission)
::::{{cvt|16853|lb|0}} (attack mission)
|max takeoff weight lb=26,500
|max takeoff weight note=
|fuel capacity={{cvt|450|USgal|impgal l|0}} maximum
|more general=
|eng1 number=1
|eng1 name=Pratt & Whitney R-2800-50
|eng1 type=18-cyl. two-row air-cooled radial piston engine
|eng1 hp=2100
|eng1 note=for sea level take-off at 2,600 rpm
::::normal power at sea level, {{cvt|1900|hp|0}} at 2,400 rpm
|rot number=2
|rot dia ft=51
|rot dia in=6
|rot area sqft=3840
|rot area note=
- Blade section: NACA 0015
|max speed mph=124
|max speed note=(search mission)
|cruise speed mph=96
|cruise speed note=at {{cvt|1500|ft|0}}
|never exceed speed kmh=
|never exceed speed mph=
|never exceed speed kts=
|never exceed speed note=
|range miles=350
|range note=
|combat range miles=140
|combat range note=
|ferry range km=
|ferry range miles=
|ferry range nmi=
|ferry range note=
|endurance=3 hours 30 minutes loiter on search mission
|ceiling ft=14400
|ceiling note=at take-off weight with normal power
- Absolute hover ceiling OGE: {{cvt|10750|ft|0}}
|climb rate ftmin=1475
|climb rate note=normal power, sea level, at take-off weight in forward flight
::::{{cvt|1200|ft/min|m/s|1}} in vertical flight with take-off power, sea level, at take-off weight in forward flight
|time to altitude=
|disk loading kg/m2=
|disk loading lb/sqft=
|disk loading note=
|fuel consumption kg/km=
|fuel consumption lb/mi=
|power/mass=
|more performance=
|guns=
|bombs= 2x Mark 43 torpedoes
|rockets=
|missiles=
|hardpoints=
|hardpoint capacity=
|hardpoint rockets=
|hardpoint missiles=
|hardpoint bombs=
|hardpoint other=
|avionics=
- Dipping Sonar
}}
See also
References
;Notes
{{reflist}}
;Bibliography
{{refbegin}}
- Andrade, John M. U.S.Military Aircraft Designation and Serials since 1909. Leicester, UK: Midland Counties Publications, 1979. {{ISBN|0-904597-22-9}}.
- The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985). London, Orbis Publishing, 1985.
- Thomason, Tommy H. The Forgotten Bell HSL. Simi Valley, CA: Ginter Books, 2005. {{ISBN|978-0-942612-70-7}}
{{refend}}
External links
{{commons category|Bell HSL}}
- [http://www.helis.com/timeline/bell.php helis.com: Helicopter history site]
{{Bell Aircraft}}
{{USN helicopters}}
Category:1950s United States anti-submarine aircraft
Category:Tandem rotor helicopters
Category:1950s United States helicopters
Category:Single-engined piston helicopters