The Convair B-36 Peacemaker.

1. The Convair B-36 "Peacemaker" was a strategic bomber built by Convair and operated solely by the United States Air Force (USAF) from 1949 to 1959. The B-36 is the largest mass-produced piston-engined aircraft ever built. It had the longest wingspan of any combat aircraft ever built, at 230 ft (70.1 m). The B-36 was the first bomber capable of delivering any of the nuclear weapons in the U.S. arsenal from inside its four bomb bays without aircraft modifications. With a range of 10,000 mi (16,000 km) and a maximum payload of 87,200 lb (39,600 kg), the B-36 was capable of intercontinental flight without refuelling.

Entering service in 1948, the B-36 was the primary nuclear weapons delivery vehicle of the Strategic Air Command (SAC) until it was replaced by the jet-powered Boeing B-52 Stratofortress from 1955. All but five examples were scrapped.

The B-36 set the standard for range and payload for subsequent U.S. intercontinental bombers.

2. The aftermath of a Blitz attack on Livepool.

The genesis of the B-36 can be traced to early 1941, prior to the entry of the United States into World War II. At the time it appeared there was a very real chance that Britain might fall to the Nazi "Blitz", making a strategic bombing effort by the United States Army Air Corps (USAAC) against Germany impossible with the aircraft of the time.

The United States would need a new class of bomber which would reach Europe and return to bases in North America, necessitating a combat range of at least 5,700 miles (9,200 km), and hence, the B-36 project was born.

3. An XB-36 next to a B-29, showing its massive size.

Due to various factors, the aircraft was delayed and was unveiled on 20 August 1945, and flew for the first time on 8 August 1946.

4. A B-36 gun turret.

After the establishment of an independent United States Air Force in 1947, the beginning in earnest of the Cold War with the 1948 Berlin Airlift, and the 1949 atmospheric test of the first Soviet atomic bomb, American military planners sought bombers capable of delivering the very large and heavy first-generation atomic bombs. The B-36 was the only American aircraft with the range and payload to carry such bombs from airfields on American soil to targets in the USSR. The modification to allow the use of larger atomic weapons on the B-36 was called the "Grand Slam Installation."

5. XB-36 on it's first flight.

The B-36 was arguably obsolete from the outset, being piston-powered, coupled with the widespread introduction of first generation jet fighters in potential enemy air forces. But its jet rival, the Boeing B-47 Stratojet, which did not become fully operational until 1953, lacked the range to attack the Soviet homeland from North America without aerial refueling and could not carry the huge first-generation Mark 16 hydrogen bomb. The other American piston bombers of the day, the B-29 and B-50, were also too limited in range and nuclear arsenal. Intercontinental ballistic missiles (ICBMs) did not become sufficiently reliable until the early 1960s. Until the Boeing B-52 Stratofortress became operational in 1955, the B-36, as the only truly intercontinental bomber, continued to be the primary nuclear weapons delivery vehicle of the Strategic Air Command (SAC).

6. B-36 fuselage undergoing structural testing.

Convair touted the B-36 as the "aluminum overcast", a so-called "long rifle" giving SAC truly global reach. While General Curtis LeMay headed SAC (1949–57), he turned the B-36 arm, through intense training and development, into an effective nuclear delivery force, forming the heart of the Strategic Air Command. Its maximum payload was more than four times that of the B-29, and exceeded that of the B-52. The B-36 was slow and could not refuel in midair, but could fly missions to targets 3,400 mi (5,500 km) away and stay aloft as long as 40 hours. Moreover, the B-36 was believed to have "an ace up its sleeve": a phenomenal cruising altitude for a piston-driven aircraft, made possible by its huge wing area and six 28-cylinder engines, putting it out of range of most of the interceptors of the day, as well as ground-based anti aircraft guns.

7. The huge landing gear of the XB-36. At the time it had enough rubber for 60 automobile tires.

The tricycle landing gear system's initial main gear design, with huge single wheels found to cause significant ground pressure problems, limited the B-36 to operating from just three air bases in the United States: Carswell Field (former Carswell AFB, now NAS JRB Fort Worth/Carswell Field), adjacent to the Consolidated factory in Fort Worth, Texas; Eglin Field (now Eglin AFB), Florida; and Fairfield-Suisun Field (now Travis AFB) in California). As a result, the Air Force mandated that Consolidated design a four-wheeled bogie-type wheel system for each main gear unit instead, which distributed the pressure more evenly and reduced weight by 1,500 pounds (680 kg).

8. B-36 in production.

The propulsion system of the B-36 was unique, with six 28-cylinder Pratt & Whitney R-4360 'Wasp Major' radial engines mounted in an unusual pusher configuration, rather than the conventional four-engine, tractor propeller layout of other heavy bombers. The prototype R-4360s delivered a total of 18,000 hp. While early B-36s required long takeoff runs, this situation was improved with later versions, delivering a significantly increased power output of 22,800 hp total. Each engine drove a three-bladed propeller, 19 feet (5.8 m) in diameter, mounted in the pusher configuration, thought to be the second-largest diameter propeller design ever used to power a piston-engined aircraft. This unusual configuration prevented propeller turbulence from interfering with airflow over the wing, but could also lead to engine overheating due to insufficient airflow around the engines, resulting in inflight engine fires.

9. Beginning with the B-36D, Convair added a pair of General Electric J47-19 jet engines suspended near the end of each wing; these were also retrofitted to all extant B-36Bs. Consequently, the B-36 was configured to have ten engines, six radial propeller engines and four jet engines, leading to the B-36 slogan of "six turnin' and four burnin' ". The B-36 had more engines than any other mass-produced aircraft. The jet pods greatly improved takeoff performance and dash speed over the target. In normal cruising flight, the jet engines were shut down to conserve fuel. When the jet engines were shut down, louvers closed off the front of the pods to reduce drag and to prevent ingestion of sand and dirt. The jet engine louvers were opened and closed by the flight crew in the cockpit, whether the B-36 was on the ground or in the air. The two pods with four turbojets and the six piston engines combined gave the B-36 a total of 40,000 hp for short periods of time.

10. The crew and equipment reqired to get and keep a B-36 in the air.

The Wasp Major engines had a prodigious appetite for lubricating oil: each engine required a dedicated 100 gal (380 l) tank.[citation needed] Normal maintenance consisted of tedious measures, like changing the 56 spark plugs on each of the six engines; the plugs were often fouled by the lead in the 145 octane anti-knock fuel required by the R-4360 engines. Thus, each service required changing 336 spark plugs. Another frequent maintenance job was replacing the dozens of bomb bay light bulbs, which routinely shattered during test firing of the ball turret guns.

The B-36 was too large to fit in most hangars. Since even an aircraft with the range of the B-36 needed to be stationed as close to enemy targets as possible, this meant the plane was largely based in the extreme weather locations of the northern continental United States, Alaska and the Arctic. Since the maintenance had to be performed outdoors, the crews were largely exposed to the elements, with temperatures of −60 °F (−51 °C) in winters and 100 °F (38 °C) in summers, depending on the airbase location. Special shelters were built so that the maintenance crews could be given a modicum of protection. Ground crews were at risk of slipping and falling from icy wings, or being blown off the wings by propeller wash running in reverse pitch. The wing roots were thick enough, at 7 ft (2.1 m), to enable a flight engineer to access the engines and landing gear during flight by crawling through the wings. This was possible only at altitudes not requiring pressurization.

11. A GRB-36 Carrying a YRF-84F modified for FICON (Fighter Conveyor) test.

The FICON project, involved a modified B-36 (called a GRB-36D "mothership") and the RF-84K, a fighter modified for reconnaissance, in a bomb bay. The GRB-36D would ferry the RF-84K to the vicinity of the objective, whereupon the RF-84K would disconnect and begin its mission. Ten GRB-36Ds and 25 RF-84Ks were built and saw limited service in 1955–1956.

12. NB-36H used in the ANP test.

In May 1946, the Air Force began the Nuclear Energy for the Propulsion of Aircraft (NEPA) project, which was followed in May 1951 by the Aircraft Nuclear Propulsion (ANP) program. The ANP program used modified B-36s to study shielding requirements for an airborne reactor to determine whether a nuclear powered aircraft was feasible. Convair modified two B-36s under the MX-1589 project. The Nuclear Test Aircraft (NTA) was a B-36H-20-CF (serial number 51-5712) that had been damaged in a tornado at Carswell AFB on 1 September 1952. This aircraft, designated the XB-36H (and later NB-36H), was modified to carry a 1 MW, air-cooled nuclear reactor in the aft bomb bay, with a four-ton lead disc shield installed in the middle of the aircraft between the reactor and the cockpit. A number of large air intake and exhaust holes were installed in the sides and bottom of the aircraft's rear fuselage to cool the reactor in flight. On the ground, a crane would be utilized to remove the 35,000 pounds (16,000 kg) reactor from the aircraft. To protect the crew, the highly modified cockpit was encased in lead and rubber, with a 1-foot-thick (30 cm) leaded glass windshield. The reactor was operational, but did not power the aircraft; its sole purpose was to investigate the effect of radiation on aircraft systems. Between 1955 and 1957, the NB-36H completed 47 test flights and 215 hours of flight time, during 89 of which the reactor was critical.

13. An XB-52 next to a B-36H.

With the end of fighting in Korea, President Eisenhower, who had taken office in January 1953, called for a "new look" at national defense. His administration chose to invest in the Air Force, especially Strategic Air Command. The Air Force retired nearly all of its B-29/B-50s to be replaced by the new Boeing B-47 Stratojet. By 1955, the swept wing Boeing B-52 Stratofortress was entering the inventory in substantial numbers, replacing B-36s.

The two main factors contributing to the obsolescence of the B-36 and leading to its phaseout were:

The Peacemaker was not designed for aerial refueling, and required intermediate refueling bases to reach its planned targets deep in the Soviet Union.

Its slow speed made it vulnerable to Soviet jet interceptor aircraft, making long-range bombardment flights over Soviet territory extremely hazardous, seriously compromising its ability to reach its planned target and return.

14. The YB-60, the jet-powered, swept wing version of the B-36, cancelled in favour of the B-52.

15. The XC-99 the cargo version of the B-36.

16. B-36's Awaiting scrapping at AMARC, Davis-Monthan AFB.

The scrapping of B-36s began in February 1956. Once replaced by B-52s, they were flown directly from operational squadrons to Davis-Monthan AFB, Arizona, where the Mar-Pak Corporation handled their reclamation and destruction. Defense cutbacks in FY 1958 compelled the B-52 procurement process to be stretched out and the B-36 service life to be extended. The B-36s remaining in service were supported with components scavenged from aircraft sent to Davis-Monthan. Further update work was undertaken by Convair at San Diego (Specialized Aircraft Maintenance, SAM-SAC) until 1957 to extend the life and capabilities of the B-36s. By December 1958 only 22 B-36Js were still operational.

On 12 February 1959, the last B-36J built, AF Ser. No. 52-2827, left Biggs AFB, Texas, where it had been on duty with the 95th Heavy Bombardment Wing, and was flown to Amon Carter Field in Fort Worth, where it was put on display. Within two years, all B-36s, except five used for museum display, had been scrapped at Davis-Monthan AFB.

17. B-36J AF Serial Number 52-2217 on display at the Strategic Air and Space Museum.

18. B-36J AF Serial Number 52-2220 on display in the Cold War Gallery at the National Museum of the United States Air Force.