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|more users =
|more users =
|produced =
|produced =
|number built = 13<ref name="Pelletier">{{cite book|last=Pelletier|first=A.J.|title=Bell Aircraft since 1935|publisher=Putnam & Company Ltd.|location=London|date=1992|edition=1st|isbn=1-55750-056--8|oclc=91-66350}}</ref>
|number built = 13<ref name="Pelletier">Pelletier 1992</ref>
|unit cost = (YR-12) $175,000<ref name="Pelletier"/>
|unit cost = (YR-12) $175,000<ref name="Pelletier"/>
|developed from = [[Bell 42]]
|developed from = [[Bell 42]]
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The '''Bell R-12 (Model 48)''' was an [[United States|American]] 1940s military utility helicopter built by [[Bell Helicopter]] company.<ref name="Pelletier"/>
The '''Bell R-12 (Model 48)''' was an [[United States|American]] 1940s military utility helicopter built by [[Bell Helicopter]] company.<ref name="Pelletier"/>


==Design and development==
==Development==
During [[1946 in aviation|1946]] Bell Helicopter began development of a new helicopter, much larger, than [[Bell 47|Model 47]]. It was partly basing upon its construction, first of all, a rotor system, and was basically a scaled-up version of Model 47. The basic variant was civilian [[Bell Model 42|Model 42]], but the [[United States Air Force]] got interested in the design and ordered development of its military variant, '''Model 48'''. Two prototypes were ordered as the '''XR-12'''. It was powered by a 540&nbsp;hp [[Pratt & Whitney R-1340]]-AN-1 [[radial engine]] and seated five. A production batch of 34 helicopters was ordered, under a designation '''R-12A''', but it was cancelled afterwards. Another enlarged prototype (the '''XR-12B''', Model 48A) with seats for eight and a more powerful 600&nbsp;hp R-1340-55 engine was also ordered. It was followed by ten pre-series helicopters '''YR-12B''', with a redesigned cabin, with a glazed nose, instead of car-like nose<ref>[http://www.aviastar.org/helicopters_eng/bell_48.php Bell Model 48]</ref>. With a change in designation system the helicopter was re-designated the '''H-12'''. Test were not satisfactory, there were initially problems with the main rotor, and none were ordered.<ref name="Pelletier"/>
During 1946, Bell Helicopter began development of a new helicopter, much larger, than [[Bell 47|Model 47]]. It was partly basing upon its construction, first of all, a rotor system, and was basically a scaled-up version of Model 47. The basic variant was civilian [[Bell Model 42|Model 42]], but the [[United States Air Force]] got interested in the design and ordered development of its military variant, '''Model 48'''. Two prototypes were ordered as the '''XR-12'''. It was powered by a 540&nbsp;hp [[Pratt & Whitney R-1340]]-AN-1 [[radial engine]] and seated five.
A production batch of 34 helicopters was ordered, under a designation '''R-12A''', but it was cancelled afterwards. Another enlarged prototype (the '''XR-12B''', Model 48A) with seats for eight and a more powerful 600&nbsp;hp R-1340-55 engine was also ordered. It was followed by 10 pre-series helicopters '''YR-12B''', with a redesigned cabin, with a glazed nose, instead of car-like nose<ref>[http://www.aviastar.org/helicopters_eng/bell_48.php Bell Model 48]</ref>. With a change in designation system the helicopter was re-designated the '''H-12'''. Test were not satisfactory, there were initially problems with the main rotor, and none were ordered.<ref name="Pelletier"/>


==Variants==
==Variants==
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;'''R-12A''':production version, 34 on order cancelled.
;'''R-12A''':production version, 34 on order cancelled.
;'''XR-12B''':prototype with more powerful engine and increased seating, re-designated XH-12B, one built.
;'''XR-12B''':prototype with more powerful engine and increased seating, re-designated XH-12B, one built.
;'''YR-12B''':as XR-12B but with R-1340-55 engines, re-designated YH-12B, ten built.
;'''YR-12B''':as XR-12B but with R-1340-55 engines, re-designated YH-12B, 10 built.
;'''XH-12''':XR-12 re-designated in 1947.
;'''XH-12''':XR-12 re-designated in 1947.
;'''XH-12B''':XR-12B re-designated in 1947.
;'''XH-12B''':XR-12B re-designated in 1947.
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}}
}}
==References==
==References==
;Notes
{{reflist}}
{{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.
* 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.
* ''The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985)''. London, Orbis Publishing, 1985.
⚫
* Pelletier, A.J. ''Bell Aircraft since 1935.'' London: Putnam & Company Ltd., 1992. ISBN 1-55750-056-8.
⚫
*[http://www.aviastar.org/helicopters_eng/bell_48.php Bell Model 48] retrieved 2-6-2008
{{Refend}}
⚫
*{{cite book|last=Pelletier|first=A.J.|title=Bell Aircraft since 1935|publisher=Putnam & Company Ltd.|location=London|date=1992|edition=1st|isbn=1-55750-056--8|oclc=91-66350}}


==External links==
==External links==
{{commonscat|Bell 48}}
{{commonscat|Bell 48}}
* [http://books.google.com/books?id=yywDAAAAMBAJ&pg=RA1-PA36&dq=popular+science+1950+ferry+hops&hl=en&ei=nze9TNajH4SAnwe0_Y2KDg&sa=X&oi=book_result&ct=result&resnum=2&ved=0CDIQ6AEwAQ#v=onepage&q&f=true ''Copter Ferry Hops To The Front'', December 1950, Popular Science] large and detailed article with rare photos
* [http://books.google.com/books?id=yywDAAAAMBAJ&pg=RA1-PA36&dq=popular+science+1950+ferry+hops&hl=en&ei=nze9TNajH4SAnwe0_Y2KDg&sa=X&oi=book_result&ct=result&resnum=2&ved=0CDIQ6AEwAQ#v=onepage&q&f=true "Copter Ferry Hops To The Front.", Popular Science,'' December 1950, large and detailed article with rare photos]
⚫
*[http://www.aviastar.org/helicopters_eng/bell_48.php Bell Model 48]


{{Bell Aircraft}}
{{Bell Aircraft}}

Revision as of 00:00, 4 March 2012

R-12 (Model 48)
YH-12B
Role five/eight seat utility helicopter
Manufacturer Bell Helicopter
First flight 1946
Status pre-series
Primary user United States Air Force
Number built 13[1]
Developed from Bell 42

The Bell R-12 (Model 48) was an American 1940s military utility helicopter built by Bell Helicopter company.[1]

Design and development

During 1946, Bell Helicopter began development of a new helicopter, much larger, than Model 47. It was partly basing upon its construction, first of all, a rotor system, and was basically a scaled-up version of Model 47. The basic variant was civilian Model 42, but the United States Air Force got interested in the design and ordered development of its military variant, Model 48. Two prototypes were ordered as the XR-12. It was powered by a 540 hp Pratt & Whitney R-1340-AN-1 radial engine and seated five.

A production batch of 34 helicopters was ordered, under a designation R-12A, but it was cancelled afterwards. Another enlarged prototype (the XR-12B, Model 48A) with seats for eight and a more powerful 600 hp R-1340-55 engine was also ordered. It was followed by 10 pre-series helicopters YR-12B, with a redesigned cabin, with a glazed nose, instead of car-like nose[2]. With a change in designation system the helicopter was re-designated the H-12. Test were not satisfactory, there were initially problems with the main rotor, and none were ordered.[1]

Variants

Dats from:Bell Aircraft since 1935[1]

XR-12
prototype, redesignated XH-12, two built.
R-12A
production version, 34 on order cancelled.
XR-12B
prototype with more powerful engine and increased seating, re-designated XH-12B, one built.
YR-12B
as XR-12B but with R-1340-55 engines, re-designated YH-12B, 10 built.
XH-12
XR-12 re-designated in 1947.
XH-12B
XR-12B re-designated in 1947.
YH-12B
YR-12B re-designated in 1947.

Operators

 United States

Specifications (XR-12B)

Data from Bell Aircraft since 1935[1]

General characteristics

  • Crew: 1
  • Capacity: 9
  • Length: 56 ft 9 in (17.30 m)
  • Height: 11 ft 3.25 in (3.4354 m)
  • Gross weight: 6,286 lb (2,851 kg)
  • Powerplant: 1 × Pratt & Whitney R-1340-55 Wasp 9-cyl. air-cooled radial piston engine, 600 hp (450 kW)
  • Main rotor diameter: 47 ft 6 in (14.48 m)
  • Main rotor area: 1,772 sq ft (164.6 m2)

Performance

  • Maximum speed: 105 mph (169 km/h, 91 kn)
  • Cruise speed: 90 mph (140 km/h, 78 kn)
  • Range: 300 mi (480 km, 260 nmi)
  • Service ceiling: 12,800 ft (3,900 m) service ceiling
    • Absolute ceiling: 15,000 ft (4,572 m)
    • Hover ceiling: 4,350 ft (1,326 m)

See also

Related development

Aircraft of comparable role, configuration, and era

References

Notes
  1. ^ a b c d e Pelletier 1992
  2. ^ Bell Model 48
Bibliography
  • 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.
  • Pelletier, A.J. Bell Aircraft since 1935. London: Putnam & Company Ltd., 1992. ISBN 1-55750-056-8.
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