Bell H-12 - Helicopter - avia.wikisort.org

avia.wikisort.org - Helicopter

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]

R-12/H-12

YH-12B
Role	Military utility helicopter Type of aircraft
Manufacturer	Bell Aircraft
First flight	1946
Status	Pre-production
Primary user	United States Air Force
Number built	13[1]

Design and development

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

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

Variants

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]

Operators

United States

United States Air Force[3]

Specifications (XR-12B)

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)

References

Notes

Pelletier 1992, p. 92.
Pelletier 1992, p. 91.
"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.

External links

Wikimedia Commons has media related to Bell 48.

Copter Ferry Hops To The Front – Popular Science (December 1950)

v t e Bell Aircraft and Bell Helicopter/Bell Textron aircraft
Manufacturer designations	1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31¹ 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 J 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70–100¹ 101 102 103 104 105 106 107¹ 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131–199¹ 200 201 202¹ 203¹ 204 205 206 207 208 209 210 211 212 213¹ 214 214ST 215¹ 216 217¹ 218¹ 219¹ 220¹ 221¹ 222 223–229¹ 230 231–248¹ 249 250–300¹ 301 302–308¹ 309 310–359¹ 360 361–399¹ 400 401–405¹ 406 407 408¹ 409 410¹ 411¹ 412 413¹ 414¹ 415¹ 416¹ 417 418–426¹ 427 428¹ 429 430 431–439¹ 440 441¹ 442¹ 443¹ 444¹ 445 446¹ 447¹ 448¹ 449 550–504¹ 505 506–524¹ 525 526–532¹ 533 534–539¹ 540 541–547¹ 548 549–575¹ 576 577–582¹ 583 846–598¹ 599 600–608¹ 609 610–645¹ 646 647–679¹ 680 681–917¹ 918 D-188 D-255 D-292
Fighter aircraft	YFM-1 P-39 XFL P-59 P-63 P-76 XP-77 XP-83
Target drones	PQM-56
Attack helicopters	207 Bell AH-1 Singles Twins AH-1Z 309 YAH-63 360
Observation and utility helicopters	H-13 H-13J UH-1 UH-1N UH-1Y TH-57 OH-58 TH-67 ARH-70
Commercial helicopters	47 47J 204 205 206 210 212 214 214ST 222 230 407 412 427 429 430 505 525
Tiltrotors	V-22 V-247 V-280 AW609 TR918 QTR
UAVs	MQ-8C
Non-production helicopters	400 417 440
Experimental aircraft	ATV 201 533 D-188 D-255 D-292 FCX-001 L-39 LLRV/LLTV X-1 X-2 X-5 X-14 X-16 X-22 XF-109 XP-52 XV-3 XV-15
Names	Airabonita Airacobra Airacomet Airacuda Arapaho BigLifter Cobra Creek Eagle Eye Fire Scout GlobalRanger Huey HueyCobra Invictus Iroquois JetRanger Jet Ranger X Kingcobra KingCobra Kiowa LongRanger Osprey Quad TiltRotor Ranger Sea Cobra Sea Ranger Sioux Sioux Scout SuperCobra Super Huey Super Transporter Twin Huey TwinRanger Valor Venom Vigilant Viper Zulu Cobra
¹ Unknown/not assigned

United States helicopter designations, Army/Air Force and Tri-Service systems

Numerical sequence used by USAAC/USAAF/USAF 1941–present; U.S. Army 1948–1956 and 1962–present; U.S. Navy 1962–present

Army/Air Force sequence
(1941–1962)

Prefix R-, 1941–1948	R-1 R-2 R-3 R-4 R-5 R-6 R-7 R-8 R-9 R-10 R-11 R-12 R-13 R-14 R-15 R-16
Prefix H-, 1948–1962	H-5 H-6 H-9 H-10 H-11 H-12 H-13 J H-15 H-16 H-17 H-18 H-19 H-20 H-21 H-22 H-23 H-24 H-25 H-26 H-27 H-28 H-29 H-30 H-31 H-32 H-33 H-34 H-35 H-36¹ H-37 H-38¹ H-39 H-40 H-41 H-42 H-43 H-44¹ H-45¹

Tri-service sequence
(1962–present)

1962 redesignations	H-13 F J H-19 H-21 H-23 H-25 H-34 H-37 H-43
New designations	H-46 H-47 H-48 H-49 H-50 H-51 H-52 H-53 CH-53/E/K HH-53/MH-53 H-54 H-55 H-56 H-57 H-58 H-59 H-60 UH-60 SH-60 HH-60 MH-60 H-61 H-62 H-63 H-64 H-65 H-66 H-67 H-68 H-69¹ H-70 H-71 H-72 H-73
Alternate sequence	H-1 AH-1/J/T/W/Z UH-1/N/Y H-2 G H-3 CH-3/HH-3 SH-3 H-4 H-5 H-6 AH-6 MH-6 OH-6
Non-sequential	H-90 H-92 CH-92/VH-92 H-139

¹ Not assigned

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