Convair XC-99

XC-99

The sole XC-99 in its early days of operation, before a nose radome was fitted.
Role	Heavy transport
Manufacturer	Convair
First flight	24 November 1947
Introduction	26 May 1949
Retired	1957
Primary user	United States Air Force
Number built	1
Developed from	Convair B-36 Peacemaker
	Type	Prototype
Serial	43-52436
Total hours	7,400 hours
Preserved at	National Museum of the United States Air Force in Dayton, Ohio

The Convair XC-99, AF Ser. No. 43-52436, is a prototype heavy cargo aircraft built by Convair for the United States Air Force. It was the largest piston-engined land-based transport aircraft ever built, and was developed from the Convair B-36 bomber, sharing the wings and some other structures with it. The first flight was on 24 November 1947 in San Diego, California, and after testing it was delivered to the Air Force on 26 May 1949.^[1] The Convair Model 37 was a planned civil passenger variant based on the XC-99 but was not built.

Design and development

Design capacity of the XC-99 was 100,000 lb (45,000 kg) of cargo or 400 fully equipped troops on its double cargo decks. A cargo lift was installed for easier loading. The engines face rearward in a pusher configuration.

Planned civil variant

The Convair Model 37 was a large civil passenger design derived from the XC-99 but was never built. The Model 37 was to be of similar proportions to the XC-99; 182 ft 6 in (55.63 m) length, 230 ft (70 m) wingspan, and a high-capacity, double-deck fuselage. The projected passenger load was to be 204, and the effective range of 4,200 mi (6,800 km).

Fifteen aircraft were ordered by Pan American Airways for transatlantic service. However, the fuel and oil consumption of the six 3,500 hp (2,600 kW) Wasp Major radials powering the XC-99 and B-36 meant that the design was not economically viable, and the hoped-for turboprop powerplants did not materialize fast enough. The low number of orders were not sufficient to initiate production, and the project was abandoned.

Operational history

The XC-99 in flight with a B-36B

In July 1950, the XC-99 flew its first cargo mission, "Operation Elephant." It transported 101,266 pounds (45,933 kg) of cargo, including engines and propellers for the B-36, from San Diego to Kelly Air Force Base in San Antonio, Texas, a record it would later break when it lifted 104,000 lb (47,200 kg) from an airfield at 5,000 ft (1,500 m) elevation. In August 1953, the XC-99 would make its longest flight, 12,000 mi (19,000 km), to Rhein-Main Air Base, Germany, by way of Kindley Air Force Base, Bermuda and Lajes Field in the Azores. It carried more than 60,000 lb (27,000 kg) each way. It attracted much attention everywhere it flew.

The XC-99 landing during trials

The US Air Force determined that it had no need for such a large, long-range transport at that time, and no more were ordered. The sole XC-99 served until 1957, including much use during the Korean War. It made twice weekly trips from Kelly AFB to the aircraft depot at McClellan AFB, California, transporting supplies and parts for the B-36 bomber while returning by way of other bases or depots making pick-ups and deliveries along the way. During its operational life, the XC-99 logged over 7,400 hours total time, and transported more than 60 million pounds (27,000 tonnes) of cargo. The aircraft made its last flight on 19 March 1957, landing at Kelly Air Force Base, where it would remain for the next 47 years. The then-United States Air Force Museum at Wright-Patterson AFB in Dayton, Ohio, requested that the aircraft be flown there for display, but the Air Force refused due to the $7,400 cost of the flight.

Retirement and display

XC-99 at Kelly AFB, Texas while attached to the Military Air Transport Service 1700th Air Transport Group, 1954. Note San Antonio Air Materiel Area (SAAMA) tail marking, indicating the aircraft was assigned to the Air Materiel Command.

The aircraft was put on display at Kelly Air Force Base near San Antonio, Texas, in 1957. Deterioration of the airframe due to the high magnesium content was beyond local abilities to address. The aircraft was later moved to a grassy field near the base and 1993 the USAF moved it back to the Kelly AFB.

Disassembly of the aircraft began at Kelly Field in April 2004. and the airframe was moved in pieces from Kelly to the museum at Wright-Patterson Air Force Base near Dayton, Ohio.^[2] By the summer of 2008, the transfer was complete and the parts were lying outside the museum.^[3] The aircraft had continued to suffer corrosion and was found to be in worse condition than expected, with the restoration task being beyond the resources of the museum in a realistic time scale. Some major components such as the wing spar would need to be completely replaced.

The Museum's plans for the restoration and display of the XC-99 are displayed in a case with a 1:72 scale model made by Lt Col Howard T. Meek (USAF, Ret).^[4]

In an effort to preserve the aircraft it was later moved to the 309th Aerospace Maintenance and Regeneration Group (AMARG) storage facility at Davis–Monthan Air Force Base, in Tucson, Arizona, where it will remain, in an area containing other aircraft belonging to the Museum, until the museum is able to restore it.^[3] In 2014, Lieutenant General John L. Hudson, USAF (Ret), director of the National Museum of the United States Air Force said that there would be insufficient resources for restoration in the foreseeable future.^[5]

Surviving aircraft

XC-99 s/n 43-52436 is part of the National Museum of the United States Air Force collection at Wright-Patterson AFB in Dayton, Ohio. The aircraft was disassembled at Kelly Air Force Base and its sections transported to Ohio for anti-corrosion preservation and reassembly there.^[6] It was subsequently transported in the summer of 2012, to Davis-Monthan AFB and is stored in Area 20 of the AMARG, the so-called "Boneyard."

Specifications (XC-99)

Data from General Dynamics Aircraft and their Predecessors^[7]

General characteristics

Crew: Five duty + five reserve crew
Capacity: 400 troops
Payload: 100,000 lb (45,000 kg)
Length: 182 ft 6 in (55.64 m)
Wingspan: 230 ft 0 in (70.12 m)
Height: 57 ft 6 in (17.53 m)
Wing area: 4,772 ft² (443.5 m²)
Empty weight: 135,232 lb (61,469 kg)
Loaded weight: 265,000 lb (120,455 kg)
Max. takeoff weight: 320,000 lb (145,455 kg)
Powerplant: 6 × Pratt & Whitney R-4360-41 Wasp Major 28-cylinder air-cooled radial engine, 3,500 hp (2,611 kW) each

Performance

Maximum speed: 307 mph (267 knots, 494 km/h)
Range: 8,100 mi (7,043 nmi, 13,041 km)
Service ceiling: 30,000 ft (9,150 m)

References

Notes

↑ Jacobsen & Wagner 1980, p. 41.
↑ Hill, Bruce R. Jr. "XC-99 begins piece-by-piece trip to Air Force Museum". U.S. Air Force Official Website. Retrieved 21 April 2016.
1 2 "XC-99 Disassembled." Wikimapia. Retrieved: 2 November 2011.
↑ "Factsheet: Convair XC-99 Model." National Museum of the United States Air Force. Retrieved: 14 September 2011. (see subsection: Current situation)
↑ Dorr, "We’ll lose the XC-99 and it won’t be alone"
↑ Lockett, Brian. "Convair XC-99 and Model 37." Goleta Air and Space Museum via air-and-space.com, 19 February 2011. Retrieved: 2 November 2011.
↑ Wegg 1990, p. 98.

Bibliography

Dorr, Robert F. "Saving the XC-99." Air Force Times, 12 August 1998.
Dorr, Robert F. "XC-99 is a treasure." Air Force Times, 10 June 2000.
Jacobsen, Meyers K. Convair B-36: A Comprehensive History of America's "Big Stick". Atglen, Pennsylvania: Schiffer Military History, 1997. ISBN 0-7643-0974-9.
Jacobsen, Meyers K. Convair B-36: A Photo Chronicle. Atglen, Pennsylvania: Schiffer Military History, 1999. ISBN 0-7643-0974-9.
Jacobsen, Meyers K and Ray Wagner. B-36 in Action (Aircraft in Action Number 42). Carrollton, Texas: Squadron/Signal Publications Inc., 1980. ISBN 0-89747-101-6.
Jenkins, Dennis R. Convair B-36 Peacemaker. St. Paul, Minnesota: Specialty Press Publishers and Wholesalers, 1999. ISBN 1-58007-019-1.
Johnsen, Frederick A. Thundering Peacemaker, the B-36 Story in Words and Pictures. Tacoma, Washington: Bomber Books, 1978.
Miller, Jay and Roger Cripliver. "B-36: The Ponderous Peacemaker." Aviation Quarterly, Vol. 4, No. 4, 1978.
Wegg, John. General Dynamics Aircraft and their Predecessors. London: Putnam, 1990. ISBN 0-85177-833-X.

External links

Wikimedia Commons has media related to Convair XC-99.

Convair and General Dynamics aircraft

Manufacturer designations	(numbering continued from Vultee): 100 101 102 103 104 105 106 108 109 110 112 115 116 117 118 1 2 3 4 5 6 7 8/8-24 9 11 21 22 23 24 27 30 31 48 240 300 340 440 540 580 600 640

Bombers	B-36 XA-44 XB-46 XB-53 B-58 YB-60

Fighters and attack aircraft	XP-81 XF-92 F-102 F-106 XFY F2Y Charger

Civilian transports	37 58-9 110 240 300 340 440 540 580 600 640 880 990 5800

Military transports	XC-99 C-131 R3Y R4Y T-29

Experimental aircraft	Kingfish NB-36H X-6

General Dynamics	F-111 F-111B F-111C F-111K EF-111A F-16 F-16XL F-16 VISTA Model 1600 RB-57F

Aircraft produced by Consolidated Aircraft

Manufacturer designation	1 2 7 8 9 10 14 15 16 17 18 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 36 37 39 40

By role	Trainers NY PT-1 PT-2 PT-11 AT-22 Observation aircraft O-17 Fighter P-30 Patrol PY P2Y P3Y XP4Y-1/P4Y-2 PBY PB2Y XPB3Y PB4Y-1/-2 Bombers X/B-24 B-32 XB-41 B-36 BY XB2Y LB-30A/B Liberator B.I Liberator GR.I Transports C-11 C-22 C-87 XC-99 C-109 RY R2Y Liberator C.IX Reconnaissance F-7

United States military transport aircraft designations, Army/Air Force and Tri-Service systems

Army/Air Force sequence (1925-1962)	C-1 C-2 C-3 C-4 C-5 C-6 C-7 C-8 C-9 C-10 C-11 C-12 C-13¹ C-14 C-15 C-16 C-17 C-18 C-19 C-20 C-21 C-22 C-23 C-24 C-25 C-26 C-27 C-28 C-29 C-30 C-31 C-32 C-33 C-34 C-35 C-36 C-37 C-38 C-39 C-40 C-41/A C-42 C-43 C-44 C-45 C-46 C-47/T C-48 C-49 C-50 C-51 C-52 C-53 C-54 C-55 C-56 C-57 C-58 C-59 C-60 C-61 C-62 C-63 C-64 C-65 C-66 C-67 C-68 C-69 C-70/A/B/C/D C-71 C-72 C-73 C-74 C-75 C-76 C-77/B-D C-78 C-79 C-80 C-81 C-82 C-83 C-84 C-85 C-86 C-87 C-88 C-89 C-90 C-91 C-92 C-93 C-94 C-95 C-96 C-97/KC-97 C-98 C-99 C-100 C-101 C-102 C-103 C-104 C-105 C-106 C-107 C-108 C-109 C-110 C-111 C-112 C-113 C-114 C-115 C-116 C-117 C-118 C-119 C-120 C-121/F C-122 C-123/A C-124 C-125 C-126 C-127 (I) C-127 (II) C-128 C-129 C-130/J C-131 C-132 C-133 C-134 C-135/KC-135 C-136 C-137 C-138¹ C-139¹ C-140 C-141 C-142

Tri-service sequence (1962-present)	C-1 C-2 C-3 C-4 C-5 C-6 C-7/B C-8 C-9 C-10 C-11 C-12 C-13¹ C-14 C-15 C-16¹ C-17 C-18 C-19 C-20A-D/F-H C-21 C-22 C-23 C-24 C-25 C-26 C-27/J C-28 C-29 C-30¹ C-31 C-32 C-33 C-34¹ C-35 C-36 C-37A/B C-38 C-39¹ C-40 C-41 C-42¹ C-43¹ C-44¹ C-45 C-46

Revived original sequence (2005-present)	C-143 C-144 C-145 C-146

Non-sequential designations	C-767 C-880

¹ Not assigned See also: AC-47 • AC-119 • AC-130 • DC-130 • EC-130 • HC-130 • KC-130 • LC-130 • MC-130 • WC-130 • CT-39 • CT-43

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