Convair XC-99
Encyclopedia
The Convair XC-99, 43-52436, was 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 B-36
bomber, sharing the wings and some other structures with it. The first flight was on 23 November 1947 in San Diego, California
, and after testing it was delivered to the Air Force on 23 November 1949.
in San Antonio, Texas
, a record it would later break when it lifted 104000 lb (47,173.6 kg) from an airfield at 5000 ft (1,524 m) elevation. In August 1953, the XC-99 would make its longest flight, 12000 mi (19,312.1 km), to Rhein-Main Air Base
, Germany
, by way of Bermuda
and the Azores
. It carried more than 60000 lb (27,215.5 kg) each way. It attracted much attention everywhere it flew.
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 60,000,000 lbs 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 United States Air Force Museum 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.
near San Antonio, Texas
. During the 1960s, it was considered for restoration by the San Antonio Air Logistics Center at Kelly AFB, but the deterioration of the airframe due to the high magnesium
content led to the abandonment of that plan. The aircraft was later moved to a grassy field near the base. In 1993, the USAF moved it back to the Kelly AFB tarmac
(29°22'27.37" N 98°35'13.74" W). It was planned to move the XC-99 via road to the National Museum of the United States Air Force
at Wright-Patterson Air Force Base
, Ohio, restore and reassemble it, and put it on display in the USAF Museum's collection of experimental aircraft. Ultimately, transporting the massive aircraft by ground proved impractical and too expensive.
Base Realignment and Closure
(BRAC) action in 1995 resulted in the partial closure and realignment of Kelly AFB, with most of the former San Antonio Air Logistics Center becoming civilianized and renamed Kelly USA, while the runway and those flight line areas supporting C-5 and F-16 flight operations of the Air Force Reserve Command
's 433d Airlift Wing
and the Texas Air National Guard
's 149th Fighter Wing
reverted to adjacent Lackland AFB and was renamed Lackland AFB/Kelly Field Annex.
Disassembly of the aircraft began at Kelly Field in April 2004. Portions of the airframe were then airlifted from Kelly to Wright-Patterson Air Force Base
near Dayton, Ohio. Upon arrival at Wright-Patterson's active base, the parts had to be further moved by truck several miles to the museum side of the base. Transporting the XC-99 components taxed the C-5A's cargo capacity, as the largest piece moved intact was over 75 feet by 13 ft. By the summer of 2008, the XC-99 had been completely transferred to Dayton and was lying on the ramp outside the museum's restoration facility.
Upon examination, the aircraft was found to have suffered from considerable corrosion, which was not unexpected considering it had remained outside for over 50 years. The wing spar was found to be too badly corroded to restore, and a new replacement would need to be fabricated. A full restoration is being performed by the restoration crew of the Air Force Museum
, although no timetable exists at this time. As of May 2011, the corrosion control of the center wing boxes was nearing completion. Once this portion of the project is finished, the XC-99 will be reassembled and the restoration work started.
Following restoration, the aircraft was expected to be displayed inside in one of the museum's new hangars. Like its relative the B-36, it is expected to become a showpiece of the museum. Once all aircraft have been moved from the Museum's current "Research and Development Hangar" or "Presidential Hangar" to a new display hangar planned to be added onto the main Museum buildings, the XC-99 restoration project will move into the vacated hangar, where visitors will be able to watch the restoration in progress. Upon completion, the XC-99 will remain on display in either the former R&D hangar, or Presidential Hangar.
Pending the restoration and display of the XC-99, in an effort to educate visitors about the aircraft the Air Force Museum
has placed a model of the XC-99 on display in its Post-Cold War Gallery. The model, in approximately 1/72 scale, was constructed by a member of the museum's restoration staff. An explanation of the Museum's plans for the restoration and display of the XC-99 is located in the case with the model.
. The XC-99 will remain at Davis–Monthan Air Force Base, in an area containing other aircraft belonging to the Museum, until the restoration staff has the time and resources to perform a full restoration.
Fifteen aircraft were ordered by Pan American
for transatlantic service. However, the fuel and oil consumption of the six 3500 hp 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.
Cargo aircraft
A cargo aircraft is a fixed-wing aircraft designed or converted for the carriage of goods, rather than passengers. They are usually devoid of passenger amenities, and generally feature one or more large doors for the loading and unloading of cargo...
built by Convair
Convair
Convair was an American aircraft manufacturing company which later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Vultee Aircraft and Consolidated Aircraft, and went on to produce a number of pioneering aircraft, such as the Convair B-36 bomber, and the F-102...
for the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
. It was the largest piston-engined land-based transport aircraft ever built, and was developed from the B-36
Convair B-36
The Convair B-36 "Peacemaker" was a strategic bomber built by Convair and operated solely by the United States Air Force from 1949 to 1959. The B-36 was the largest mass-produced piston engine aircraft ever made. It had the longest wingspan of any combat aircraft ever built , although there have...
bomber, sharing the wings and some other structures with it. The first flight was on 23 November 1947 in San Diego, California
San Diego, California
San Diego is the eighth-largest city in the United States and second-largest city in California. The city is located on the coast of the Pacific Ocean in Southern California, immediately adjacent to the Mexican border. The birthplace of California, San Diego is known for its mild year-round...
, and after testing it was delivered to the Air Force on 23 November 1949.
Design and development
Design capacity of the XC-99 was 100000 lb (45,359.2 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.Operational history
In July 1950 the XC-99 flew its first cargo mission, "Operation Elephant." It transported 101266 pounds (45,933.5 kg) of cargo, including engines and propellers for the B-36, from San Diego to Kelly Air Force BaseKelly Air Force Base
Kelly Field Annex and is a former United States Air Force facility located in San Antonio, Texas. In 2001, the runway and land west of the runway became "Kelly Field Annex" and control of it was transferred to the adjacent Lackland Air Force Base, part of Joint Base San Antonio...
in San Antonio, Texas
San Antonio, Texas
San Antonio is the seventh-largest city in the United States of America and the second-largest city within the state of Texas, with a population of 1.33 million. Located in the American Southwest and the south–central part of Texas, the city serves as the seat of Bexar County. In 2011,...
, a record it would later break when it lifted 104000 lb (47,173.6 kg) from an airfield at 5000 ft (1,524 m) elevation. In August 1953, the XC-99 would make its longest flight, 12000 mi (19,312.1 km), to Rhein-Main Air Base
Rhein-Main Air Base
Rhein-Main Air Base was a U.S. Air Force / NATO military airbase near the city of Frankfurt am Main, Germany. It occupied the south side of Frankfurt International Airport. Its airport codes are discontinued....
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, by way of Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
and the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
. It carried more than 60000 lb (27,215.5 kg) each way. It attracted much attention everywhere it flew.
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
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
. It made twice weekly trips from Kelly AFB to the aircraft depot at McClellan AFB
McClellan Air Force Base
McClellan Air Force Base is a former United States Air Force base located in the North Highlands area of Sacramento County, northeast of Sacramento, California...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, 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 60,000,000 lbs of cargo. The aircraft made its last flight on 19 March 1957, landing at Kelly Air Force Base
Kelly Air Force Base
Kelly Field Annex and is a former United States Air Force facility located in San Antonio, Texas. In 2001, the runway and land west of the runway became "Kelly Field Annex" and control of it was transferred to the adjacent Lackland Air Force Base, part of Joint Base San Antonio...
, where it would remain for the next 47 years. The United States Air Force Museum in Dayton, Ohio
Dayton, Ohio
Dayton is the 6th largest city in the U.S. state of Ohio and the county seat of Montgomery County, the fifth most populous county in the state. The population was 141,527 at the 2010 census. The Dayton Metropolitan Statistical Area had a population of 841,502 in the 2010 census...
, 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
The aircraft was put on display at Kelly Air Force BaseKelly Air Force Base
Kelly Field Annex and is a former United States Air Force facility located in San Antonio, Texas. In 2001, the runway and land west of the runway became "Kelly Field Annex" and control of it was transferred to the adjacent Lackland Air Force Base, part of Joint Base San Antonio...
near San Antonio, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
. During the 1960s, it was considered for restoration by the San Antonio Air Logistics Center at Kelly AFB, but the deterioration of the airframe due to the high magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
content led to the abandonment of that plan. The aircraft was later moved to a grassy field near the base. In 1993, the USAF moved it back to the Kelly AFB tarmac
Tarmac
Tarmac is a type of road surface. Tarmac refers to a material patented by Edgar Purnell Hooley in 1901...
(29°22'27.37" N 98°35'13.74" W). It was planned to move the XC-99 via road to the National Museum of the United States Air Force
National Museum of the United States Air Force
The National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...
at Wright-Patterson Air Force Base
Wright-Patterson Air Force Base
Wright-Patterson Air Force Base is a United States Air Force base in Greene and Montgomery counties in the state of Ohio. It includes both Wright and Patterson Fields, which were originally Wilbur Wright Field and Fairfield Aviation General Supply Depot. Patterson Field is located approximately...
, Ohio, restore and reassemble it, and put it on display in the USAF Museum's collection of experimental aircraft. Ultimately, transporting the massive aircraft by ground proved impractical and too expensive.
Base Realignment and Closure
Base Realignment and Closure
Base Realignment and Closure is a process of the United States federal government directed at the administration and operation of the Armed Forces, used by the United States Department of Defense and Congress to close excess military installations and realign the total asset inventory to reduce...
(BRAC) action in 1995 resulted in the partial closure and realignment of Kelly AFB, with most of the former San Antonio Air Logistics Center becoming civilianized and renamed Kelly USA, while the runway and those flight line areas supporting C-5 and F-16 flight operations of the Air Force Reserve Command
Air Force Reserve Command
The Air Force Reserve Command is a major command of the U.S. Air Force with its headquarters at Robins AFB, Georgia.It stood up as a major command of the Air Force on 17 February 1997....
's 433d Airlift Wing
433d Airlift Wing
The 433d Airlift Wing is a unit of the United States Air Force Reserve assigned to Fourth Air Force. It is stationed at Lackland Air Force Base, Texas...
and the Texas Air National Guard
Texas Air National Guard
The Texas Air National Guard is the air force militia of the U.S. state of Texas and a component of the Texas Military Forces...
's 149th Fighter Wing
149th Fighter Wing
The United States Air Force's 149th Fighter Wing is a Texas Air National Guard unit located at Kelly Field Annex, Lackland AFB, in San Antonio, Texas.-Mission:...
reverted to adjacent Lackland AFB and was renamed Lackland AFB/Kelly Field Annex.
Disassembly of the aircraft began at Kelly Field in April 2004. Portions of the airframe were then airlifted from Kelly to Wright-Patterson Air Force Base
Wright-Patterson Air Force Base
Wright-Patterson Air Force Base is a United States Air Force base in Greene and Montgomery counties in the state of Ohio. It includes both Wright and Patterson Fields, which were originally Wilbur Wright Field and Fairfield Aviation General Supply Depot. Patterson Field is located approximately...
near Dayton, Ohio. Upon arrival at Wright-Patterson's active base, the parts had to be further moved by truck several miles to the museum side of the base. Transporting the XC-99 components taxed the C-5A's cargo capacity, as the largest piece moved intact was over 75 feet by 13 ft. By the summer of 2008, the XC-99 had been completely transferred to Dayton and was lying on the ramp outside the museum's restoration facility.
Upon examination, the aircraft was found to have suffered from considerable corrosion, which was not unexpected considering it had remained outside for over 50 years. The wing spar was found to be too badly corroded to restore, and a new replacement would need to be fabricated. A full restoration is being performed by the restoration crew of the Air Force Museum
National Museum of the United States Air Force
The National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...
, although no timetable exists at this time. As of May 2011, the corrosion control of the center wing boxes was nearing completion. Once this portion of the project is finished, the XC-99 will be reassembled and the restoration work started.
Following restoration, the aircraft was expected to be displayed inside in one of the museum's new hangars. Like its relative the B-36, it is expected to become a showpiece of the museum. Once all aircraft have been moved from the Museum's current "Research and Development Hangar" or "Presidential Hangar" to a new display hangar planned to be added onto the main Museum buildings, the XC-99 restoration project will move into the vacated hangar, where visitors will be able to watch the restoration in progress. Upon completion, the XC-99 will remain on display in either the former R&D hangar, or Presidential Hangar.
Pending the restoration and display of the XC-99, in an effort to educate visitors about the aircraft the Air Force Museum
National Museum of the United States Air Force
The National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...
has placed a model of the XC-99 on display in its Post-Cold War Gallery. The model, in approximately 1/72 scale, was constructed by a member of the museum's restoration staff. An explanation of the Museum's plans for the restoration and display of the XC-99 is located in the case with the model.
Recent developments
Because the XC-99 arrived in worse condition than had been expected the magnitude of the restoration was greater than the restoration staff was able to quickly accommodate. The fuselage was placed in pieces along the flight line in front of the restoration facility while plans were developed for the aircraft's restoration. The aircraft will be transported to the base in pieces by C-5 Galaxy transport aircraft as opportunities become available. During the seven years the aircraft has remained exposed to the elements, it has continued to deteriorate. In an effort to protect the aircraft, in the summer of 2011, a decision was made by the restoration staff to move the disassembled XC-99 to the Military Air Transport Service storage facility at Davis–Monthan Air Force Base, near Tucson, ArizonaTucson, Arizona
Tucson is a city in and the county seat of Pima County, Arizona, United States. The city is located 118 miles southeast of Phoenix and 60 miles north of the U.S.-Mexico border. The 2010 United States Census puts the city's population at 520,116 with a metropolitan area population at 1,020,200...
. The XC-99 will remain at Davis–Monthan Air Force Base, in an area containing other aircraft belonging to the Museum, until the restoration staff has the time and resources to perform a full restoration.
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 in 6 in (55.63 m) length, 230 ft (70.1 m) wingspan, and a high-capacity, double-deck fuselage. The projected passenger load was to be 204, and the effective range 4200 mi (6,759.2 km).Fifteen aircraft were ordered by Pan American
Pan American World Airways
Pan American World Airways, commonly known as Pan Am, was the principal and largest international air carrier in the United States from 1927 until its collapse on December 4, 1991...
for transatlantic service. However, the fuel and oil consumption of the six 3500 hp Wasp Major radials powering the XC-99 and B-36 meant that the design was not economically viable, and the hoped-for turboprop
Turboprop
A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
powerplants did not materialize fast enough. The low number of orders were not sufficient to initiate production, and the project was abandoned.
Survivors
- 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, OhioDayton, OhioDayton is the 6th largest city in the U.S. state of Ohio and the county seat of Montgomery County, the fifth most populous county in the state. The population was 141,527 at the 2010 census. The Dayton Metropolitan Statistical Area had a population of 841,502 in the 2010 census...
. The aircraft is disassembled, and is stored at the Davis–Monthan Air Force Base restoration facility.