In the years immediately following World War II, the US operated a huge variety of aircraft, ranging from older prop aircraft like the Mustang and B-50 to jets like the Shooting Star and Sabre. Those who grew up in that era remember these designs fondly, and over the years many have become iconic symbols of the early Cold War period.
Today we look at the largest mass-produced piston-engine aircraft to ever fly—an aircraft well remembered for its huge size and unique design—the B-36 Peacemaker, and the legacy it has left ever since its introduction.
BACKGROUND
The B-36 traces its origins to World War II. Before the US formally entered the war in 1941, the possibility of a German victory in the UK caused serious concern. While the Germans had been hoping for a future peace with America, there was equal effort afforded to developing weapons to strike the US mainland. This would culminate in the Amerikabomber request for a proposal in 1942—a long-range bomber able to strike the American East Coast (preferably with supersonic capabilities) and return to Europe. This would involve a trans-Atlantic bomber mission spanning approximately 11,600 kilometres, or 7,200 miles.
Driven by similar fears, America would begin developing its own long-range bomber. It would need to have a range of at least 9,000 kilometres, be able to fly high, strike targets in Europe, and then head back towards Greenland.
On April 11, 1941, the United States Army Air Corps sent out its first request. Just like the Luftwaffe, they wanted an ambitious new design, pushing the limits of what was possible. Initial requirements included a 45,000-foot service ceiling, in the hopes of avoiding AA fire. They desired a max range of 19,000 kilometres (almost 12,000 miles), a combat radius of 6,400 kilometres (almost 4,000 miles), and a payload of around 10,000 pounds. This proved unrealistic, and the requirements were slightly lowered. Heading up this new concept would be Consolidated, later renamed Convair, which had won a tender in October 1941.
At this stage, the design was in a semi-finalized state. Referred to as the B-36, it was perceived as competing primarily against Northrop's flying wing concept—the B-35. Unlike the flying wing, this would be a larger six-engine bomber, with an airframe reminiscent of the B-29. Upon entering the war, Consolidated was given orders to slow research on the B-36 program in order to speed up production of the B-24 Liberator. Nevertheless, progress continued to be made.
A mockup was first presented in July 1942. After inspection, the project was ordered to relocate from California to Fort Worth, Texas, and to switch out the large twin tail that had been installed with a single tail. The military also requested the installation of a large, modernised radio system and newer engines. This would all add up, costing the project an extra few months.
The development of this large bomber would pick up pace as the war in the Pacific dragged on, and by 1943, higher priority was afforded to it. Convair received a request on July 23 to start producing 100 aircraft. This took place on the same day that Heinkel had begun work on their own long-range bomber—a six-engined platform as part of the Amerikabomber program.
By this point, the primary objective was no longer striking German positions in a potentially occupied England. Rather, the goal was to have a platform that could overcome the constantly changing situation in the Pacific. Hawaii could send a long-range bomber directly to strike Japan and return home, eliminating the need to secure close air bases.
PRODUCTION
Manufacturing of the B-36 followed shortly, with some delays; on August 20, 1945, the first finished aircraft was revealed, and the first flight would take place on August 8, 1946.
The resulting aircraft was impressive, almost entirely thanks to its size and unique engine layout. In typical World War 2 bomber style, it retained a large crew. 15 people would be onboard at one time, with the front and back compartments connected via a tunnel. A crew member would lay on the trolley and pull it with a rope, much like the method from the Great Escape.
Referred to as the XB-36, this first concept was somewhat underwhelming in terms of real-world performance, but by December 4, 1947, a second prototype took to the air, with newer Pratt and Whitney R-4360 engines.
The first production aircraft finally arrived in 1948. Due to rapidly changing conditions in air combat, these first models—B-36 Alphas, or Peacemakers—were intended for training only, basically an interim platform, until a further upgraded model could be delivered. They lacked external armament, and other necessary implementations were pending.
SPECS
In terms of specs, the B-36 was impressive in many regards. Apart from an incredible 70-meter wingspan, the aircraft itself was heavy, with an empty weight of 166,000 lb, almost as heavy as a modern B-52H. Loaded up, the aircraft had a maximum takeoff weight of 410,000 pounds—again, not that much less than a modern B-52.
It featured four bomb bays, capable of carrying up to 87,000 pounds of bombs; later models would add capabilities to integrate nuclear weapons.
The aircraft was not particularly fast, with a top speed of 700 km/h, however at altitude - with a service ceiling of 43000 feet - it could achieve a combat range of 6500 kilometers, with a ferry range of up to 16000 kilometers. The aircrew could—if need be—stay in the air for up to 40 hours.
COLD WAR SERVICE
With the war now over, the arrival of the B-36 proved problematic. It could perform its intended function, but there was no immediate need, and rapidly advancing jet technology threatened its future.
Nevertheless, with the perceived threat of the Soviets growing, Strategic Air Command decided to employ the aircraft. While newer, better designs were already on the table—like the B-52 and B-47—during the late 1940s and early 1950s, the B-36 remained the only reliable method of delivering weapons at long range into Soviet territory—a feat Convair proudly marketed the aircraft with. What's more, at this stage, the aircraft's 40,000 feet cruising altitude was believed to make it immune to interceptors.
The most obvious new weapon for the aircraft to manage was the nuclear bomb, many variants of which now exist. The B-36A's layout didn't allow for these bigger bombs, but when later models came in, they were changed to fit bigger warheads, like the huge 42,000-pound Mark 17 hydrogen bomb. It was the only US military aircraft that could carry this weapon. It was also the only aircraft capable of carrying the T-12 Cloudmaker seismic bomb, weighing in at 43600 pounds.
Luckily, in November 1948, the first B-36B models arrived. They were combat-ready, with fully functioning external defences and the ability to field certain nuclear bombs. These aircraft were thus Strategic Air Command's only intercontinental nuclear delivery platform at the time and were an invaluable security asset.
Issues continued to plague the aircraft throughout this period. For example, early models had very uncomfortable crew compartments, a shortage of spare parts, and ridiculous maintenance schedules for ground crews. Simply changing the aircraft's 336 spark plugs, which took ages to complete, exemplified such problems.
Nevertheless, with no clear alternative yet produced, the aircraft remained in production. The D model would further improve the design, adding four jet engines mounted under the wings. Used in short bursts, these jets massively improved takeoff performance and allowed for safer, faster passage over target areas. When not in use, streamlined louvres closed off the fronts of the engines. It also had newer prop engines, better radar, and better crew compartments.
OPERATIONAL HISTORY
The aircraft emerged from the war with a scattered operational history. In the late 40s and early 50s, it was used often as a test platform. The primary goal in many cases was to adapt a parasite fighter system to the aircraft. In one case, a B-36 was used to accommodate an RF-84 recon aircraft in its bomb bay. In another instance, the aircraft mounted two F-84s to its wingtips, leading to a fatal collision.
However, beyond this, a newly emerging task for the aircraft was recon. The development of the RB-36D proved its capability in this department. With an extended crew of 22, the bomb bay was replaced by different compartments. In one, electronic countermeasures; in another, photoflash bombs; in a third was fuel; and in a fourth was a darkroom and 14 recon cameras, which could be loaded and developed on the fly. This new modification had an incredible 50-hour flight time at altitudes of 50000 feet, with further modifications allowing it to reach 58000 feet.
In this role, the aircraft was—for a time—invaluable, as it was the only plane able to carry such an array of recon cameras. In one example, a custom-built 6100mm lens was fitted, able to resolve a golf ball from an altitude of 45000 feet (almost 14,000 meters) and 12.4 miles (or 20 kilometres) away.
Soon after, such promising results led to the construction of similar recon models using the old XB-36 and Alpha models, as well as the conversion of newer H models. Some of these began operating in recon roles across the Arctic, photographing Soviet positions, and supposedly flying over China.
Finally, by 1954, the J model had emerged alongside a "Featherweight" program to modernise the increasingly outclassed aircraft. It removed the weighty gun turrets, simplified internal compartments, removed unnecessary hardware like the XF-85 parasite aircraft mount, and dropped the crew from 15 to 9.
CONCLUSION OF PROGRAM
By the early 1950s, despite the upgrades, the aircraft was considered obsolete. The US Navy in particular took issue with the project. They believed that priority should be given to procuring modernised aircraft carriers and carrier-capable fighters, claiming that carrier-based aircraft—not bombers—had been the decisive factor in winning the Pacific War and would be crucial in winning future conflicts. In one famous incident, the Navy had been pushing for the first true supercarrier—the USS United States—to be developed. The Air Force pushed back, instead desiring the B-36 to continue. In 1949, the Peacemaker won out, and the supercarrier was cancelled. Uproar ensued in what is today known as the Revolt of the Admirals, leading to several firings, retirements, and changes in the Navy.
The other major shock came in late 1950. Overnight, the arrival of the MiG-15 in Korea had made obsolete the remaining B-29 prop bombers, and the same was now true of the B-36. While there was some question over earlier straight-winged jets, the MiG-15 outclassed everything. Flying a prop bomber now posed a significant risk.
Immediately after the Korean ceasefire, the White House began reviewing the Air Force. Almost all Strategic Air Command B-29s were retired and replaced by the new B-47. Similarly, the B-36s faced scrutiny due to their slow speed, lack of aerial refuelling capabilities, and high cost.
With the arrival of the B-52 in 1955, the decision was made to phase out the design, and from February 1956, the Peacemaker was slowly phased out. Delays with the B-52 meant some B-36s were kept in service, living off of parts procured from decommissioned airframes, but retirement continued, until on February 1959 the final aircraft was flown to its retirement.
The Peacemaker thus came to an end. Convair attempted to continue the design but without success. Early in 1950, they had presented the YB-60 concept, essentially a jet powered, swept wing version. Using the same engines as the B-52, the YB-60 was able to carry more cargo and was more cost-effective due to its use of older parts. However, due to its slow speed and the use of B-36 components, it handled poorly. Nevertheless, Convair had successfully fulfilled its prototype contract to compete with the B-52. In response, the Air Force accepted the two YB-60s in 1954; however, they never flew again and were scrapped within months.
Later, realising this, Convair presented an airliner with the same general configuration, but the revolutionary Boeing 707 quickly outclassed it.
CONCLUSION
Convair would end up finding success in the Convair 880 airliner, but as for the B-36 platform, it would not outlive the 1950s.
Delays during the war significantly hampered the design. If given a higher priority, the design might have emerged during the war. Given such rapid technological advances, the aircraft exemplified how quickly a design was made obsolete during the early jet age, outclassed completely within less than half a decade. Despite this, even in relative obsolescence, the B-36 was an amazing sight for onlookers who grew up in the 1940s and 50s and remains today an impressive aircraft.