The Peacemaker

On August 6, 1945, a solitary B-29 Superfortress dropped an atomic bomb on the city of Hiroshima, 3 days later, another bomb was dropped on the city of Nagasaki. It was the only time in history that nuclear weapons were used in an armed conflict, together, the two bombings killed more than 220 thousand people and brought Japan to surrender, saving thousands of American soldiers lives that didn’t have to fight to take over the country.

WWII was finally over but another war had already started the Cold War. Since 1945, the Soviet Union spies gathered a consistent amount of intelligence from the Americans, allowing them to successfully detonate its first nuclear bomb on August 29, 1949, ending the American nuclear monopoly much sooner than the Western world thought.

Throughout the 1950s, both superpowers kept piling up their nuclear arsenal, but since neither one of them had the technology of the intercontinental ballistic missiles yet, the only way to deliver the doomsday payload was flying bombers over the enemy territory.

If the Americans want to reach Moscow, the heart of the Soviet Empire, that is a staggering 18,000 Km round trip, starting from Alaska, which is the closest American territory from the Soviet Union. The B-29, the most advanced bomber at the time, has only a 9,000Km range.

The United States Army Air Force was already thinking about a strategic intercontinental bomber as early as 1941, considering the worst-case scenario of the whole of Europe (including United Kingdom) falling into the hands of the Nazis and the necessity of flying bombing mission from USA all the way to Germany and back without stopping for refuelling.

Consolidated (which would later on merge with Vultee Aircraft and became Convair) won the contract with its B-36 (the other competitor was Boeing and Northrop) but since the Allies held their ground in Europe, there was no real need for this “super-bomber” during the war.

Preparations for the end of the world

With the prospect of a confrontation against the Soviet Union looming on the horizon, the USAAF gave the green light to Convair to go ahead with the production of the B-36. The prototype flew on August 08, 1946.

The B-36 was a revolutionary aircraft, designed to be powered by nothing less than 6 radial piston engines mounted on a “pusher” configuration (at the back of the wings). It is a massive machine, the biggest piston-powered airplane ever produced. Let’s check some numbers:

Length: 49.40 m (162 ft)

Wingspan: 70.10 m (230 ft)

Empty weight: 73,371 Kg (166,165 lb)

Max take-off weight: 185,973 Kg (410,000 lb)

Payload: 39,000 Kg (85,980 lb)

In ideal conditions, the range of the B-36 is 16,000 Km but when fully loaded and combat-ready the range would drop dramatically.

Powerplant

Such a colossal aircraft would need some serious horse power, and that was provided by 6 Pratt & Whitney R-4360 Wasp Major, air-cooled, radial engines, with 28 cylinders (4 rows of 7 cylinders), displacing 71,489 liters ( 4,362 cid). It is the largest-displacement aviation piston engine to be mass-produced in the United States, and at 4,300 hp (3,200 kW) the most powerful.

Even with all this raw power, the B-36 needed a very long runway for take-off, but Convair solved this problem by adopting four General Electric J47 turbojet engines, with 5,200 lbs of thrust each, mounted on pods, close to the tip of the wings, the addition of these engines created a popular B-36 slogan: “six turning and four burning”.

The ideal operational ceiling of the B-36 was 40,000 ft but with the extra power provided by jet engines, the bomber could comfortably fly at 50,000 ft, and reach a top speed of 700 Km/h, well above the reach of most of the fighters of that time. When flying at cruise speed, the jet engines were shut down to save fuel.

Armament

The B-36 was designed for conventional bombing, with a payload of 39 tons, but it could easily be converted to become a nuclear bomber. The plane also had heavy defensive firepower, nothing less than six remote-controlled, retractable gun turrets alongside the fuselage, one on the tail and one on the nose, each one equipped with a pair of 20mm cannons.

Operational problems

The first units of the B-36 started to be delivered to many Bomber-Wings across the USA in 1948, the first 60 planes didn’t have the jet engines but later on Convair retrofitted them. They were also delivered without the gun turrets, which were also installed later.

Thanks to its impressive performance and range, the B-36 was also used for high-altitude reconnaissance missions, for this role, the plane was stripped of every defensive armament

The Wasp engines when mounted “backwards” (pusher configuration) have the inconvenience of exposing the carburetors to the incoming cold air and inevitably getting frozen when flying at high altitude, causing engine malfunction. In some extreme situations, the frozen carbs would allow too much gas inside the engine (rich mixture) and this unburned fuel would ignite when touching the very hot exhaust manifold. The ground crew then changed the plane’s slogan from “six turning, four burning” into “two turning, two burning, two smoking, two choking and two more unaccounted for.” The problem was fixed in the later version with the adoption of a carburetor heater device.

During gunnery practise, the vibration of all the 20mm cannons firing at once commonly caused the aircraft’s electronics to malfunction, leading to failure of the aircraft controls and navigation equipment; this contributed to the crash of B-36B 44-92035 on 22 November 1950. Later on, the gun turrets were removed, (only the tail guns stayed, operated by radar), the Air Force concluded the gun turret was an obsolete piece of equipment and the biggest enemy of the B-36 would be anti-aircraft missiles. That brought the crew member down from 15 to 9 and saved a lot of weight.

The first version of the bomber was designed with single-wheel main landing gear, equipped with gigantic tires, the largest ever manufactured for an airplane, up to that time, 9 feet 2 inches (2.79 m) tall, 3 feet (91 cm) wide, and weighing 1,320 pounds (600 kg), with enough rubber for 60 automobile tires. Since most of the airplane’s weight was supported by two tires only, they placed so much pressure on the pavement that the B-36 required at least 17 inches thick concrete runways, restricting its operations to the Fort Worth airfield (adjacent to the plant of manufacture) and to a mere two USAF bases beyond that. It didn’t take too long for Convair to realize the single-wheel design was a mistake and it was soon replaced by a four-wheel boogie.

The mission

A typical doomsday mission would consist of crossing the Soviet border flying from bases in Alaska or Greenland, dropping the nukes and safely landing at any allied air bases, in the Middle East or Europe.

The Strategic Air Command (SAC) wanted maximum alert to retaliate any Soviet attack; to achieve this, different bomber-wings took turns flying the B-36, fully loaded with nuclear bombs, close to the border, 24/7.

The crews had the confidence to carry out the mission successfully but just a few of them actually believed the plane was fast enough to escape the blast of a 15 megaton nuke.

During training, it was common to fly the B-36 for over 24 hours non-stop, but the bomber was fairly well equipped to give the crew a minimum level of comfort during those long missions, with bunk beds, a toilet, and a little stove.

The B-36 was a controversial weapon, it was very expensive and complicated to build and maintain, but in the early 50s, it was the only airplane capable to carry out a nuclear attack anywhere on the planet.

In a time when neither of the superpowers had the ballistic missile technology, the plane was considered the perfect deterrent against the USSR and for that reason, it was nicknamed the Peacemaker.

An experimental airplane by nature

The 1950s was an era of extreme aeronautical developments, the jet engines, supersonic speed, and the space race, and besides all that, every crazy idea was worth the shot. The B-36 was employed in a variety of experiments throughout its service life, and perhaps one of the most interesting is the nuclear propulsion system where a small reactor would provide power to keep the plane flying non-stop for weeks, maybe months.

Another curious project was the idea of carrying a parasite F-84 jet fighter and releasing it in case of incoming hostile fighters over the battlefield or simply for reconnaissance purposes.

The retirement

During the Korean War (1950-1953) the Americans came across the new generation of the Soviet jet fighter, the MIG-15, this new plane was powerful, maneuverable, and well-armed; at this point, the Air Force knew the B-36 career was over.

By 1952 the USAF had already approved the B-36’s replacement, the Boeing B-52, but thanks to military budget restrain of the mid-50s, they kept the B-36 operational until the end of the decade.

Between 1946 and 1959, a total of 384 B-36 were built, in different versions. Out of this number only 5 units, sent to museums, escaped the scrapyard.

The US Navy called the B-36 a billion Dollar blunder and advocated that this money should have been used in more efficient, carrier-based, jet bombers. Although the Air Force was always sympathetic to the idea of well-trained crews flying heavy bombers over the Soviet territory, it was the ballistic missile technology, (either based underground in the US soil or carried by submarines) that became the ultimate deterrent weapon against the full-scale Armageddon war.

The B-36 remains today as a 1940s engineering marvel, the plane came into service just when the aeronautical designs were shifting from piston to jet engines, and that was primarily the reason for its early retirement.

During its 11 years career, the B-36 was never sent into combat, and that is the uncontested proof it lived up to the name Peacemaker.