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{|{{Infobox Aircraft Begin
{{Infobox aircraft
|name = R-12 (Model 48)
|name= R-12/H-12
|image = Image:Bell_48.jpg
|image= File:Bell-48-Helicopter- H-12 -US-Air-Force-Bu-No.-6222.jpg
|caption = YR-12B / YH-12B
|caption= YH-12B
|type= Military utility helicopter
}}{{Infobox Aircraft Type
|manufacturer= [[Bell Aircraft]]
|type = five/eight seat utility helicopter
|designer=
|manufacturer = [[Bell Helicopter]]
|first_flight= [[1946 in aviation|1946]]
|designer =
|introduction=
|first flight = [[1946 in aviation|1946]]
|introduced =
|retired=
|status= Pre-production
|retired =
|primary_user= [[United States Air Force]]
|status =pre-series
|more_users=
|primary user = [[United States Air Force]]
|more users =
|produced=
|number_built= 13<ref name="Pelletier">Pelletier 1992, p. 92.</ref>
|produced =
|unit cost= (YR-12) $175,000<ref name="Pelletier"/>
|number built = 13
|unit cost =
|developed_from=
|variants=
|developed from = [[Bell 47]]
|variants with their own articles =
}}
}}
|}
The '''Bell R-12 (Model 48)''' was an [[United States|American]] 1940s military utility helicopter built by [[Bell Helicopter]] company.


The '''Bell R-12''' (later redesignated '''H-12'''; company '''Model 48''') was an American 1940s military utility helicopter built by the [[Bell Helicopter]] company.<ref>Pelletier 1992, p. 91.</ref> The design did not go into full production, but over a dozen prototypes were used for various tests and projects.
==Development==

During [[1946 in aviation|1946]] Bell Helicopter began development of a new helicopter, much larger, that [[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 a main rotor, and none were ordered.
==Design and development==
During 1946, Bell Helicopter began development of a new utility helicopter, the Model 42, much larger than the [[Bell 47|Model 47]], which utilized a scaled-up version of the Model 47's rotor system. Three prototypes were built, but serious rotor problems and complexity of mechanical systems precluded production. The initial Model 42 variant was civilian, but the [[United States Air Force]] ordered the development of its military variant, the '''Model 48'''. Two prototypes were ordered as the '''XR-12''', powered by a single {{convert|540|hp|kW|abbr=on|0}} [[Pratt & Whitney R-1340-AN-1]] [[radial engine]] and featuring seating for five. Of very similar construction to the Model 42, the Model 48 had a shorter rotor mast. A production batch of 34 helicopters was ordered, under the designation R-12A, but cancelled in 1947.<ref name="Pelletier"/>

Another enlarged prototype (the XR-12B, Model 48A) with seats for eight plus two pilots and a more powerful {{convert|600|hp|kW|abbr=on|0}} Pratt & Whitney R-1340-55 engine was also ordered, followed by ten pre-series YR-12B helicopters, with a glazed nose, instead of the car-like nose of the Model 42 and XR-12. While under flight test the helicopter was redesignated the '''H-12''', but the results were not satisfactory, as there were major problems with the main rotor due to blade weaving and poor rotor governor performance.<ref name="Pelletier"/>

==Operational history==
[[File:NNSA-NSO-913.jpg|thumb|Journalists and news reported examine a Model 12, which was used to survey the area after a nuclear test in Nevada. April 21, 1952.]]
No production H-12 aircraft were built but the prototypes and preproduction aircraft were used for various test and development programs.<ref name="Pelletier"/>

It was unofficially known as the "Fat Boy".<ref>{{cite book |title=Helicopter History and Aerodynamics |date=4 January 1961 |publisher=Headquarters, Air Training Command, United States Air Force |location=Randolph Air Force Base, Texas |page=15 |url=http://catalog.hathitrust.org/Record/100844426 |access-date=27 December 2024}}</ref>


==Variants==
==Variants==
;Model 42
;'''XR-12''':prototype, redesignated XH-12, two built.
:Bell's initial foray into the civilian luxury helicopter market, seating five. Three prototypes were built but serious problems precluded production.
;'''R-12A''':production version, 34 on order cancelled.
;Model 48
;'''XR-12B''':prototype with more powerful engine and increased seating, re-designated XH-12B, one built.
:Company designation for the military version of the Model 42, given the designation R-12. Two built as XR-12s and a production contract for 34 was cancelled in 1947.
;'''YR-12B''':as XR-12B but with R-1340-55 engines, re-designated YH-12B, ten built.
;Model 48A
;'''XH-12''':XR-12 re-designated in 1947.
:The more powerful derivative of the Model 48 with a 600 hp engine and ten seats. One XR-12B/XH-12B prototype was produced and a preproduction batch of ten were also built as YR-12B/YH-12Bs
;'''XH-12B''':XR-12B re-designated in 1947.
;XR-12
;'''YH-12B''':YR-12B re-designated in 1947.
:Prototype, redesignated XH-12, two built.
;R-12A
:Production version, 34 on order canceled.
;XR-12B
:Prototype with more powerful engine and increased seating, redesignated XH-12B, one built.
;YR-12B
:As XR-12B but with R-1340-55 engines, redesignated YH-12B, ten built.
;XH-12
:XR-12 redesignated in 1947.
;XH-12B
:XR-12B redesignated in 1947.
;YH-12B
:YR-12B redesignated in 1947.<ref name="Pelletier"/>
[[File:Bell YH-12B.jpg|thumb|A YH-12B]]


==Operators==
==Operators==
;{{USA}}
;{{USA}}
*[[United States Air Force]]<ref>{{cite web |url= http://www.aer.ita.br/~bmattos/mundo/helic/bell48.htm |title= Bell Model 48 |publisher= aer.ita.br |access-date= 18 October 2014 |url-status= dead |archive-url= https://web.archive.org/web/20121224014002/http://www.aer.ita.br/~bmattos/mundo/helic/bell48.htm |archive-date= 24 December 2012 }}</ref>
*[[United States Air Force]]


==Specifications (XR-12B) ==
==Specifications (XR-12B) ==
{{Aero specs missing}}
{{Aircraft specs
|ref=''Bell Aircraft since 1935''<ref name="Pelletier"/><!-- reference, you do need page numbers here -->
{{aircraft specifications
|prime units?=imp<!-- imp or kts first for US aircraft, and UK aircraft pre-metrification,
|plane or copter?=copter<!-- options: plane/copter -->
met(ric) first for all others. You MUST choose a format, or no specifications will show -->
|jet or prop?=prop
<!--
<!-- Now, fill out the specs. Please include units where appropriate (main comes first, alt in parentheses).
General characteristics
If an item doesn't apply, like capacity, leave it blank. For additional lines, end your
-->
alt units with )</li> and start a new, fully-formatted line with <li> -->
|crew=2
|crew=one
|capacity=8
|capacity=nine
|length main= ft
|length ft=56
|length alt= 12.06 m )(fuselage
|length in=9
|height ft=11
|span main= 47 ft 6 in
|height in=3.25
|span alt= 14.48 m
|gross weight lb=6286
|height main= ft
<!--
|height alt= 3.43 m
Powerplant
|area main= 1,772 ft²
-->
|area alt= 164.62 m²
|eng1 number=1
|airfoil=
|eng1 name=[[Pratt & Whitney R-1340-55 Wasp]]
|empty weight main=
|eng1 type=9-cyl. air-cooled radial piston engine
|empty weight alt=
|eng1 hp=600<!-- prop engines -->
|loaded weight main= lb
|rot number=1
|loaded weight alt= 2854 kg
|rot dia m=14.48<!-- helicopters -->
|useful load main=
|rot area sqft=1,772<!-- helicopters -->
|useful load alt=
|max takeoff weight main= 6,286 lb
|max takeoff weight alt= 2851 kg
|engine (prop)=[[Pratt & Whitney R-1340]]-55 Wasp
|type of prop=radial piston
|number of props=1
|power main= 600 hp
|power alt= 447 kW
|propeller or rotor?=rotor
|propellers=1
|number of propellers per engine=1
|propeller diameter main=
|propeller diameter alt=


<!--
Performance
|max speed main= 105 mph
-->
|max speed alt= 169 km/h
|cruise speed main= 90 mph
|max speed mph=105
|cruise speed alt= 145 km/h
|cruise speed mph=90
|range miles=300
|never exceed speed main=
|ceiling ft=12,800
|never exceed speed alt=
|ceiling note=Service ceiling<br/>
|stall speed main=
**''' Absolute ceiling:''' {{convert|15,000|ft|m|abbr=on|0}}
|stall speed alt=
**'''Hover ceiling:''' {{convert|4,350|ft|m|abbr=on|0}}
|range main= 300 miles
|range alt= 483 km
|ceiling main= ft
|ceiling alt= 3960 m
|climb rate main= ft/s
|climb rate alt= 2.28 m/s
|loading main=
|loading alt=
|more performance=
|armament=
}}
}}


Line 102: Line 102:
|related=<!-- related developments -->
|related=<!-- related developments -->
*[[Bell 47|Bell Model 47]]
*[[Bell 47|Bell Model 47]]
*[[Bell Model 42]]
*[[Agusta-Bell AB.102]]
*[[Agusta-Bell AB.102]]
|similar aircraft=<!-- similar or comparable aircraft -->
|similar aircraft=<!-- similar or comparable aircraft -->
*[[Sikorsky H-19]]
*[[Sikorsky H-19 Chickasaw]]
|lists=<!-- related lists -->
|lists=<!-- related lists -->
|see also=<!-- other relevant information -->
|see also=<!-- other relevant information -->

}}
}}

==References==
==References==
;Notes
{{reflist}}
{{Reflist}}
* Andrade, John M. ''U.S.Military Aircraft Designation and Serials since 1909''. Leicester, UK: Midland Counties Publications, 1979. ISBN 0-904597-22-9.
;Bibliography
* The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985). London, Orbis Publishing.
{{Refbegin}}
*[http://www.aviastar.org/helicopters_eng/bell_48.php Bell Model 48] retrieved 2-6-2008
* 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}}.
{{Refend}}


==External links==
==External links==
{{Commons category|Bell 48}}
* [http://www.aviastar.org/helicopters_eng/bell_48.php Bell Model 48] - description, photos and drawings
* [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
* [https://books.google.com/books?id=yywDAAAAMBAJ&pg=PA136 Copter Ferry Hops To The Front] – ''Popular Science'' (December 1950)
* [http://www.verticalmag.com/features/the-unknown-helicopter The Unknown Helicopter – Vertical]


{{Bell Aircraft}}
{{Bell Aircraft}}
{{USAF helicopters}}
{{USAF helicopters}}
{{aviation lists}}

[[Category:United States military utility aircraft 1940-1949]]
[[Category:Helicopters]]


[[mk:Bell 48]]
[[Category:Bell aircraft|H-012]]
[[Category:1940s United States military utility aircraft]]
[[Category:1940s United States helicopters]]
[[Category:Single-engined piston helicopters]]
[[Category:Aircraft first flown in 1946]]
[[Category:Single-rotor helicopters]]
[[Category:Aircraft with fixed quad landing gear]]

Latest revision as of 02:53, 27 December 2024

R-12/H-12
YH-12B
General information
TypeMilitary utility helicopter
ManufacturerBell Aircraft
StatusPre-production
Primary userUnited States Air Force
Number built13[1]
History
First flight1946

The Bell R-12 (later redesignated H-12; company Model 48) was an American 1940s military utility helicopter built by the Bell Helicopter company.[2] The design did not go into full production, but over a dozen prototypes were used for various tests and projects.

Design and development

[edit]

During 1946, Bell Helicopter began development of a new utility helicopter, the Model 42, much larger than the Model 47, which utilized a scaled-up version of the Model 47's rotor system. Three prototypes were built, but serious rotor problems and complexity of mechanical systems precluded production. The initial Model 42 variant was civilian, but the United States Air Force ordered the development of its military variant, the Model 48. Two prototypes were ordered as the XR-12, powered by a single 540 hp (403 kW) Pratt & Whitney R-1340-AN-1 radial engine and featuring seating for five. Of very similar construction to the Model 42, the Model 48 had a shorter rotor mast. A production batch of 34 helicopters was ordered, under the designation R-12A, but cancelled in 1947.[1]

Another enlarged prototype (the XR-12B, Model 48A) with seats for eight plus two pilots and a more powerful 600 hp (447 kW) Pratt & Whitney R-1340-55 engine was also ordered, followed by ten pre-series YR-12B helicopters, with a glazed nose, instead of the car-like nose of the Model 42 and XR-12. While under flight test the helicopter was redesignated the H-12, but the results were not satisfactory, as there were major problems with the main rotor due to blade weaving and poor rotor governor performance.[1]

Operational history

[edit]
Journalists and news reported examine a Model 12, which was used to survey the area after a nuclear test in Nevada. April 21, 1952.

No production H-12 aircraft were built but the prototypes and preproduction aircraft were used for various test and development programs.[1]

It was unofficially known as the "Fat Boy".[3]

Variants

[edit]
Model 42
Bell's initial foray into the civilian luxury helicopter market, seating five. Three prototypes were built but serious problems precluded production.
Model 48
Company designation for the military version of the Model 42, given the designation R-12. Two built as XR-12s and a production contract for 34 was cancelled in 1947.
Model 48A
The more powerful derivative of the Model 48 with a 600 hp engine and ten seats. One XR-12B/XH-12B prototype was produced and a preproduction batch of ten were also built as YR-12B/YH-12Bs
XR-12
Prototype, redesignated XH-12, two built.
R-12A
Production version, 34 on order canceled.
XR-12B
Prototype with more powerful engine and increased seating, redesignated XH-12B, one built.
YR-12B
As XR-12B but with R-1340-55 engines, redesignated YH-12B, ten built.
XH-12
XR-12 redesignated in 1947.
XH-12B
XR-12B redesignated in 1947.
YH-12B
YR-12B redesignated in 1947.[1]
A YH-12B

Operators

[edit]
 United States

Specifications (XR-12B)

[edit]

Data from Bell Aircraft since 1935[1]

General characteristics

  • Crew: one
  • Capacity: nine
  • 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

[edit]

Related development

Aircraft of comparable role, configuration, and era

References

[edit]
Notes
  1. ^ a b c d e f Pelletier 1992, p. 92.
  2. ^ Pelletier 1992, p. 91.
  3. ^ Helicopter History and Aerodynamics. Randolph Air Force Base, Texas: Headquarters, Air Training Command, United States Air Force. 4 January 1961. p. 15. Retrieved 27 December 2024.
  4. ^ "Bell Model 48". aer.ita.br. Archived from the original on 24 December 2012. Retrieved 18 October 2014.
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.
[edit]
Wikimedia Commons has media related to Bell 48.
Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=Bell_H-12&oldid=1265469063"