Sunday, 12 April 2015

The Convair B-36 Peacemaker

The first thing you should know about the B-36 is that it was big. When I write about airplanes from World War 2, I often use words like 'colossal' and 'huge', but this is little misleading, since I usually mean "colossal - by the standards of the day." Really, even the largest aircraft of the period would be reckoned as medium-sized by today's standards; not so the B-36. It had a wingspan of 70m (230 ft), which is a bit bigger than the Boeing 747-8's, and was nearly the width of an American football field. It was 50 m (162 ft) long, about 15 stories high if it was tilted on its nose.  It had a combat weight of 262,000 lbs (119,000 kg) and a max takeoff weight of 410,000 lbs (186,000 kg), which is all the more remarkable as it used piston engines, not turbines, to achieve flight. (It is in fact the largest piston powered/second largest prop-powered aircraft ever made, only beaten in the latter category by the Antonov An-22 turboprop.)  Speaking of engines, it had six, which soon got a supplementary boost with four additional jet engines. Each engine drove a propeller 5m across, and could have doubled for a small wind turbine. The B-36's control surfaces alone had more square footage then entire wing area of the B-24. It was an aircraft that, compared to its contemporaries, was built on a nightmare scale.

 The second thing you should know is that the B-36 is something rather unusual - it was simultaneously a revolutionary design, and an anachronism. It was the first intercontinental strategic bomber, and set many of the benchmarks that future designs would aim for, but it did it with technology from a decade before such designs became common. So it was decidedly a (giant) odd duck - the last of the 1940s bombers, operating in the turbulent times of the 1950s. This period (the late 1940s-1950s) was one of the great innovative times in aeronautics, as turbines, both as jets and as turboprops, would recast the aviation world into one that we know today. The end result was that the B-36 was a clockwork and vacuum tube miracle machine doomed to have a very short career in the USAF, with its intimidate successors, the B-52 Stratofortress and the U-2 spyplane are still in front line service today. So it was a bunch of firsts, but also a bunch of lasts.

Soaring Ambitions

The story of the BiG-36  starts in August 1941, when the Defense Department of the United States issued contract for a new bomber. The performance the contract wanted was, in a word, immense. This new bomber was to carry a bomb load of 10,000 lbs over 10,000 miles (that is, with a combat radius of 5000 miles.) The contract also specified the ability to operate in the stratosphere, at an altitude of 41,000 ft. This  altitude is regularly flown by airliners today, but in 1941 only a few military reconnaissance aircraft could reach this height - putting the world's largest, heaviest bomber at that altitude was quite a tall order. At the time, America was worried that if Britain was defeated, there would be no way to carry out a strategic bombing campaign against Nazi Germany. The high-flying aspect of the contract was a necessary defense - it was above the range of flak guns, and would severely limit the abilities of possible interceptors. The goal behind the new contract was to create a bomber that could fly from "Newfoundland Airbase", (later known as Gander, NL) to Berlin, bomb it, and then return, all without refueling - in other words, a bomber that could cross oceans to attack targets.
 This was a hugely ambitious design specification in 1941. The charts on the left convey how much, if you consider that the B-17 was the major bomber in service when the contract was issued. Still, unlike other states that dreamed of making a trans-oceanic bomber, the USA had a few advantages. For one, American industry had been experimenting with very large bombers for some time, the most significant of which was the XB-19 prototype made by Douglas. For another, the United States was the best in the world at building strategic bombers - even when this outsize contract was issued, the two companies that would respond with proposals, Boeing and Consolidated, had begun mass production of the B-17 and the B-24 Liberator, respectively. Both these companies were hard at work engineering next generation strategic bombers, the B-29 Superfortress and the B-32 Dominator, which would give a wealth of experience with the technologies needed to make a trans-ocean strategic bomber. In addition to this, the Americans (in stark contrast to the Germans) would have engines that would be able to power the sky-leviathan. Not having to play catch-up in engine technology was a key advantage. (Oh and the United States had the world's largest industrial base, was the world's richest nation, and had a deep pool of engineering talent thanks to its then cheap and highly effective public education system, and would not have its industry disrupted by air raids. Y'know, little stuff like that.)

The basic design was dictated by the technology of the time, in a way so simple and logical that I can imagine a Consolidated engineer sketching the whole thing out while smoking a pipe. The enormous range and payload requirement meant a similarly gigantic fuel capacity, since aerial refueling was not a thing. This in turn inevitably meant a gigantic size. Because this was a combat aircraft, it would also have to defend itself against the enemy. With World War 2 technology, that meant two things: one, a fearsome battery of defensive guns, and more importantly, the ability to fly very high. The single engined fighters of the day with their piston engines, unless heavily modified, would have a great deal of trouble staying aloft at 41,000 ft, let alone being able to do effective combat maneuvers.  Flak guns simply didn't fire into the stratosphere at the time - while it was technically possible, it was twice the altitude of the typical attacking bomber.

This early rendering with the split tail could be mistaken for similar Nazi projects of the day.

Also: argh.
The rationale for the B-36 shifted with American priorities in World War 2. Consolidated won the contract, but had done very little work on it before Pearl Harbor brought the United States into the war. Initially a hedge against capitulation by Great Britain, priorities then dictated that Consolidated concentrate all its efforts in construction of the B-24, and on the engineering side, focus on the B-32. The B-36 project was never entirely stopped or cancelled, though at this time it went slowly. The battle in the Pacific to capture islands held by the Japanese renewed interest in the design by the Defense Department. Taking islands held by the fanatical soldiers of the Japanese Army proved very costly to the US military, and for a time, having a bomber that could attack Japan from Hawaii seemed a good investment. Initially, the contract was to produce only two aircraft as prototypes, and the head of Consolidated, Loius Johnson, complained that he was having a hard time enticing subcontractors to bid on the project with such a low production run. So, in 1943 the war department ignored the official rules, and signed a contract for an order of 100 B-36s.

 By the war's end, the B-36 was coming together as a prototype - but had not even been taken out of Convair's factory by the time the Japanese officially surrendered. (Consolidated had merged with another aerospace firm, Vultee, and the new firm was christened Consolidated-Vultee, later mashed into the much simpler name Convair.) The initial prototype, the YB-36, was revealed to the world only a few days after the end of World War 2 - but would only fly a year later in 1946. By now, the B-36 had found a new purpose in life: being the first intercontinental atomic bomber.

The first prototype next to a B-29. If there's one thing the B-36 program can teach you, is that you show how big a thing is by putting it next to smaller things.
The first prototype was different only in its cockpit configuration from the production models - the USAF requested a larger greenhouse to improve crew visibility. The second prototype flew a year later, and was for all intents and purposes the first production aircraft.

American bomber development, 1936-1946.

 "I don't want to call it the 'Annihilator' - maybe something bitingly ironic?" 

The bomber had changed little from initial concepts. The B-36 had a simple cylinder fuselage for ease of making hull sections pressurized, and a conventional tail. It had a tricycle gear arrangement, pioneered on the XB-19, and later used on the B-29 and the B-32. A greenhouse nose for bombing and navigation was a standard feature of the day, soon to die out on American aircraft. . The engines were a pusher configuration to improve airflow over the wings - these engines were Wasp Majors, the final iteration of Pratt and Whitney's family of Wasp aircraft motors. With 28 cylinders, the 71 liter radial engine that was both turbo and supercharged, with a power output anywhere from 2500 to 3800 hp, depending on the model. The engine was a bit too late for World War 2, but powered many post war aircraft, from flying boats like the Hughes "Spruce Goose" and the Mariner Mars, to the C-119 Flying Boxcar, to the B-50 Superfortress, a re-engined B-29. The giant props were a necessity for effective high altitude flying, and produced a very distinctive low frequency rumble.

The most striking feature of the B-36 series was its wings - as mentioned, 230 ft with a very high aspect ratio, they were designed for generating enough lift in the stratosphere for its massive payload of fuel and bombs. These wings are the largest ever put on a combat aircraft, even to this day. The nickname "aluminum overcast" followed the B-36 as it did the B-17, B-24, and B-29, but it was a misnomer - most of the fuselage was made of a special lightweight magnesium alloy to reach the specified performance targets. Like the B-29, the B-36 had a pressurized tunnel running through its immense bomb-bays so crew could move between the forward and aft cabins - but in the B-36, the tunnel was so long that it came with a little cart the airman could pull himself along on. There was also a stove for cooking, a chemical toilet, and even bunks strung in the after-cabin rafters for sleepy crew. While this was nice, don't confuse this with comfort as we know it: crew had to wear flight suits in case of depressurization at all times - think of working in an especially noisy boiler room in a flight suit, and you have the gist of it. In another very World War 2 feature, the B-36 also had the heaviest defensive armament ever fitted on an aircraft: operational versions had radar guided 20mm cannon in the nose and tail, and three turret bays mounting pop-up dual 20mm turrets. The crew depended on the variant or the mission, but was usually 15: a pilot, a co-pilot, a flight engineer, a radio man, a radar operator/bombardier, navigator, a second radio man, and 8 gunners - three in the forward deck, five in the aft. The top speed for all this weight varied as well, but was 613 km/h (381 mph) in the B-36B version on just props. Range was 16,000 km and an early endurance flight by a B-36 lasted 43 hours, making it the world's longest range aircraft by a fair margin.

The nose was the aesthetic high point of the B-36's design.
Cobra Commander would have loved these things.
A man in the access tunnel.
Another place the B-36 was "the world's best by a fair margin" was payload. The B-36 had a standard payload of some 32,700 kg (72,000 lbs) of bombs, with that payload scalable up to 39,000 kg (86,000 lbs) if range could be sacrificed. To put that in perspective, the standard load was the capability of three and a half B-29s - or if you prefer (breaking out the ol' calculator here) 5 Avro Lancasters, 14.4 B-24s, 16 B-17s, or 24 B-25s. In addition to what might actually literally be a metric fuckton of explosives, the B-36 could carry many other bombs. These included the "tallboy" and "grand slam" oversized bombs used to sink the German battleship Tirpitz. Then you get to the T-12 "Cloudmaker", a conventional bomb designed to cause earthquakes. Designed to penetrate the earth at supersonic speeds, the bomb then detonates, creating localized tremors.

These payloads were but the aperitif before the main course of the B-36: nuclear weapons. These changed enormously over the B-36's lifetime, but a single nuclear-armed B-36 had a greater destructive potential than an entire fleet World War 2 era B-29s. This would be increased enormously as the B-36s career went on.  (Just in case you are unfamiliar, nuclear weapon yield is measured in tons of TNT. A thousand tons makes up a kiloton, and a thousand kilotons makes up a megaton. The Hiroshima bomb is reckoned to have an output of 15 kT, and the Nagasaki bomb is thought to have been 19 kT.) In the first half of the B-36's career, it carried fission warheads similar to those dropped on Nagasaki. Depending on the bomb's core, the yield could be as little as 1 kT, or as much as 160 kT for the initial production series of American atomic weapons. These early bombs were inert until a crewman actually got into the bomb bay and inserted the bomb's core. At least once while practicing this over New Mexico, sudden turbulence caused the man in the bay to grab onto the manual release lever to balance, and thus, open the bomb bay doors and drop the bomb. The crewman actually survived, holding onto that lever for dear life until the bay doors could be closed. The bomb lacked a core and thus couldn't have detonated, but it fell less than ten kilometers from Sandia, NM, the location of the American atomic bomb factory. Laughs all around!

A  propaganda film on the B-36. The opening shot is positively amazing and could have inspired the famous shot of the Star Destroyer in the first Star Wars. It also has a shot of the hydraulic turrets deploying, and the (once again) Star Wars-like aiming device the gunners use with the turrets. The plane being shown is apparently a late model B-36, as it has jet engines, quick-opening bomb bay doors and the "pointy brassiere" rear radar dome. 
While the tracks actually worked, more conventional wheels would be used in production models.
The original wheels were cartoonishly huge. 
The early development was not without issues. For one, the XB-36's landing gear was composed of just three gigantic wheels, which gave it such ground pressure that it could only take off and land from three airfields on earth - one of these being the factory airfield. This arrangement also put undue stress on the landing gear, which cracked in an early test. The ground pressure problem was so serious unique caterpillar tracks were tried out, before multiple wheel bogies were revealed as the solution. From an engineering perspective, the B-36 was relatively untroubled - surprisingly the real struggles the aircraft would face would be political.

"Gentlemen! You can't fight in here! This is the war room!"

When World War 2 finally ended, what America wanted was to return to normal. Millions of men in the armed forces looked forward to resuming their lives, and millions at home looked forward to their return. Everybody was looking forward to the economy returning to market driven enterprise, rather than the close-to-command economy necessary to kill fascists. The US government for its part was looking forward to returning military affairs to normal, and cut the budget for the military by 90%. The armed services wanted to return to normal as well - though, like everybody else, first they had to figure out what the new normal actually was.

Relations began to chill between the east and west as soon as the Third Reich was dead, though it had yet to metastasize into the Cold War. The Soviet Union was clearly the new threat on the horizon - but one that had no ability to threaten the United States itself. Soviet forces had no bombers like the B-36, and possessed no aircraft carriers or a blue-water navy. This was comforting - but only to a point. The Soviets had 100 divisions in Europe, and astoundingly could draw on another 200 divisions in a relatively short time-frame. In Germany the United States had precisely one division, a numerical disadvantage that didn't bear thinking about. Early post-war estimates said that the Soviets could have taken the rest of continental Europe in 20-30 days had they wanted to, with opposing forces being little more than a speed bump to the Red Army. 

Facing the Red Army, the United States had a very clear trump card: nuclear weapons. As soon as the United States Army Air Corps became its own service, the United States Air Force (USAF), the new service was not shy in claiming ownership over that trump card. Breaking itself into a Tactical Air Command (TAC) and Strategic Air Command (SAC), SAC was the first and most important delivery method of atomic bombs. The B-36 fit into the new scheme of things perfectly: for the near future, the only two other atomic bombers were the B-29 Superfortress and its variant, the B-50. Both of these aircraft would have to be staged relatively close to its targets in order to attack, while the B-36 had a huge combat range, even with a mk. 3 implosion bomb. Initially, the USAF pictured the 100 B-36s it had ordered as atomic bombing specialists, kept in reserve in case more forward bases were wiped out in a enemy first strike. The plan was simple: if the Soviets moved against western Europe, SAC's first move would be to burn every Soviet city it could with nuclear fire. It was also clear that even with close basing to the Soviet Union, the Superfortress twins simply didn't have the range to accomplish this mission - any attack would sacrifice the bomber crews when their airplane ran out of fuel. Another point for the B-36.

The first B-36s in training red.
At the same time, the other services were trying to assimilate what their role was in a world with atomic bombs. The US Navy wanted to build a new carrier fleet so that it could have long range nuclear armed bombers, and be able to stage the new jet aircraft off of carrier decks. In the newly restricted defense budgets, it was decided that America could afford new atomic bomber B-36s, or these new carriers, but not both. The US Navy began attacking the B-36 in print, eventually spending $500,000 on ads attacking a rival service's program. This campaign got crazy when Louis Johnson, former head of Convair, became Secretary of Defense. One of his first acts was to order more B-36s - and he found the money by cancelling the Navy's new carrier program, including the United States, the first new carrier who's keel had just been laid. The collective freakout by the US Navy admirals over this is now remembered in American history as the Revolt of the Admirals. This event was notable for several reasons, including that it stated an open debate on how nuclear weapons should be used - the Navy (in an irony that would ring down through time) described SAC's plan for targeting Soviet civilians as 'un-American.'The B-36, for its part, was shall we say "obsolesce-shamed," with the US Navy asserting the B-36 was already obsolete in its intended role, and was a "billion dollar blunder." There was also much speculation if the new aircraft could actually survive in a jet-powered combat environment. One British engineer in 1948 attacked the B-36 as "piston-engined gigantism" and wrote that it would be a "sitting duck" to jet fighters. The US Navy claimed that its new Banshee jet fighter could match the B-36 at its 41,000 ft attack altitude; the USAF declined to test this theory. The accusations of impropriety were so loud an actual congressional investigation was convened, which cleared Convair and the B-36 of all charges. Still, like a girl who had a traumatic experience and never quite got over it, this fear over its obsolescence would haunt the B-36's entire career. These anxious feelings were also added to by SAC's first commander, George C. Kenney.  While he wouldn't last long in the post, he felt that future designs would dictate staging close to the Soviet Union, making the unusually expensive B-36 superfluous. 

The USAF and Convair fought back to defend their gigantic sensitive girl, both on the engineering side and with a PR push.  The B-36 was dubbed "Peacemaker" as part of this process, a name that frankly, never caught on. (Today 'B-36' is usually how it is referred to, and SAC crews preferred the name "big stick". While I'd like to imagine this was a tip of the hat to Theodore Roosevelt and it "speak softly and carry a big stick" dictum, since a B-36 with atomic warheads is about a big a foreign policy stick as can be imagined,  I'm guessing it was because the B-36 was a giant tube with wings and a tail.) Print ads extolled the awesomeness of the new bomber, as does this little film I found , and it is fairly bombastic, no pun intended.

High points:

1. At the start, America has basically none of these things now, ouch 1950s narrator

2. A happy young family looks up to see literally a fleet of B-36s drone by

3. The narrator keeps using nautical metaphors, describing the B-36 as a "Dreadnought" and later saying they "patrol the sea of the air" above America. This is presumably to annoy the US Navy.

4. Shots of the Ft. Worth factory in the late 1940s assembling the B-36. They show how they had to tilt the big honkeys just to get them outside. They also show the airport baggage cart-like thing they used as a lunch car on the factory floor.

5. "When reason fails, *STRENGTH* prevails."

The technical side saw a search for increased power. First with the VDT program, an attempt to crank even more power out of the Wasp Major powering the B-36 and the B-50, which ended in failure. The next idea was a success: jet power. The B-47 Stratojet was by this time in development, and it featured six jet engines, four in twin jet pods. This twin jet pod was added to the outboard wings of the B-36.  The engines when on doubled the effective power of the B-36, but like all early jet engines, were very fuel thirsty, so they were typically left off in flight, being used only on takeoff and on attack runs at high altitude. This gave the B-36 a 'dash' speed past the 400 mph barrier. Late model J series B-36s had a maximum speed of 418 mph, or 672 km/h.  The jets also had doors to close the inlets when not in use to improve aerodynamics. These mods were applied to all A and B versions, making pictures of six-engined B-36s somewhat unusual. (In the film above, this is the visual tell that the airplanes shown are A and B models.) These mods were made official in the 'D' version of the Peacemaker.

There was another program in the works since 1945 to help defend the B-36 against fighters...and even the Nazis would have to doff their hats at its sheer insanity. The extreme range of the B-36 made escort fighters out of the question - so some big brain started wondering if it would be possible for the B-36 to take escorts with it. The result of this brainstorm was the Douglas XF-85 Goblin, a tiny jet fighter that could actually fold its wings to fit inside the B-36's bomb bay. Deployed and recovered by an elaborate trapeze, the Goblin lacked landing gear entirely, and had a half-hour endurance. The B-36 was to become the second flying aircraft carrier used by the US military, the first being about the only things ever flown to make the B-36 look small: the US Navy airships Akron and Macon. The concept actually worked in tests, but the Honda Civic-sized Goblin did not perform especially well, and it was decided that "fits in a bomb bay" and "effective jet fighter" were mutually exclusive concepts.

The Goblin was well-named.

Robot claws of freedom
1948 was a big year for the big bomber. First, 1948 saw the start of production, with the first A types being released to the Carswell AFB, conveniently right across the runway from the Convair factory in Ft. Worth, Texas. These first aircraft were never armed and meant initially as trainers, and by the accounts of some, pretty rough. Jim Little, who told of his time with the B-36 in his book RB-36 Days at Rapid City "that the upper wing skin would actually pull loose from the wing ribs [...] you would meet [the plane] with a crew of 30 or 40 sheet metal men." The B series would be the first combat-ready variant.

July 1948 also saw bigger events. The Cold War kicked off with the Soviets blockading Berlin in an attempt to drive Great Britain, the USA, and France out. (When partitioning Germany, the Soviets were given what would become East Germany - save Berlin itself. Berlin was seen as so important to Germany that it was divided into four parts. The other three powers were connected to the other sectors by a land bridge which was controlled by the Soviets. The Soviets closed the land bridge during the blockade.) In response, the USAF  managed to resupply Berlin by the air, and the man in charge, General Curtis LeMay, was rewarded with command of SAC. LeMay would be SAC's iconic commander, making it into an elite inside the USAF. LeMay was also a bomber man through and through, and fully supported the B-36 program. General LeMay's logic was extremely simple: war with the Soviets was in the long run inevitable - and would quite possibly be started by the Soviets in a surprise attack. Therefore, the job of SAC was to be at all times ready to fight this war. The concept of 'deterrence' was nothing new - the difference in LeMay's case is that he was sure that attacking Soviet targets with nuclear weapons would actually happen. The B-36 was the best current vehicle for the job, and would be needed until it could be replaced.
You don't want to know how many maintenance hours this flyby took.
In addition to getting a new ally, defense spending increased markedly - even if the B-36 was seen as a stopgap, it was now a necessary stopgap. During the Berlin Airlift, President Truman moved 150 B-29s to Germany, in case of an actual attack by the Soviets. If the threat was made nuclear by Truman, it was a bluff Captain Kirk would be proud of. The USAF only possessed about a dozen B-29s with the "silverplate" modifications for dropping atomic bombs, and they were all back in New Mexico, at the Roswell AFB. Even more amazingly, the nuclear stockpile didn't exist in 1947. Truman was shocked to discover that while he had been using atomic bombs as his big stick against the Soviets, the military draw-down had seen the Los Alamos lab abandoned - to the point that many of the design details of the "gun-style" Little Boy bomb that destroyed much of Hiroshima was lost. "Perhaps one" Nagasaki-style implosion bomb could be rendered operable on short notice. Work was started on redesigning the implosion bomb that was dropped onto Nagasaki into a design suitable for mass production, with fancy things like safety features to prevent accidental detonation.

One more development happened in 1948 - the USAF asked if a reconnaissance version of the B-36 could be made. In the late 1940s, the best aerial reconnaissance cameras were also gigantic, so any aircraft hoping to use them would need lots of interior space, in addition to the ability to fly high above possible air defenses. The B-36, with its enormous size and unique flying characteristics, made an ideal platform for this work. The bomb bay forward of the wings was converted into a crew cabin, with the enormous  camera getting its own hatch to spy on the world. The second and third bomb bay were refitted with extra fuel cells, and the fourth bomb bay was retained, to drop flash bombs and parachute flares for nighttime photography. This new aircraft was christened the RB-36. The B-36 would never fire a shot in anger - it was the RB-36 that would see real missions and face real danger from the enemy. 1/3rd of all B-36s produced would be the recon version. The As when they returned to the Convair factory to get jet engines were modified into recon birds as well, and became RB-36 Es. The crew on one of these recon flyers was increased up to 22, and the range of these birds was several thousand kilometers greater than the bomber model. The cameras alone weighed some three tons. These RB-36s performed reconnaissance missions all over the world, including over China and the Soviet Union.
RB-36s had a extra pressurized section aft of the cockpit, which makes them easy to tell from B-36s.
Above and below are RB-36s with their square camera ports open. These were really big cameras.

A model list with the B-36 is somewhat more pointless then most - B and RB-36s were modified to later standards frequently. The TL;DR version is that As and Bs were the 'early', non jet versions, and the D-J versions were fairly similar to one another. If talking actual capacity, the most important factor is if the later lightweight modifications were made, with is usually identified by a Roman numeral after the name, IE a B-36H (III) has both 'featherweighting' mods. (I) was the removal of all defensive guns save the tail gun, and (II) was removal of the bunks, stove, and the fire suppression system. For nerd reasons, both mods together were (III).


B-36A - Trainers without any weapons, the first four were accepted June 26th 1948. These models would be later converted to RB-36Es. Production 21;

B-36B - The first fully armed and operational version. Improved Wasp Majors with water injection had 2500 hp each. All airframes were later upgraded to the B-36D standard. Production 62;

B-36C - A proposed version that never left the drawing board. The B-36 C was to have engines facing forwards and a new version of the Wasp Major engine, called the Wasp Major VDT. This engine was also to have been used on the B-50. The 'C' was cancelled when the engine was abandoned.

B-36D - Improved version with jet pods on the outer wings. New B-36Ds production totaled 26, with 54 B-36Bs being modified to the D standard. The main addition on top of the jets was a new, very complex bombing radar, which allowed the B-36 to find and attack targets regardless of night or cloud cover.

RB-36D. 'D' version of the reconnaissance version. Production 24.

RB-36E - Recon version built from B-36As, built to the RB-36D standard.

B-36F - Revised and improved from the D version, these aircraft had higher output Wasp Majors and better avionics. 34 were made.

RB-36F - The Recon B-36F. 24 were produced.

B-36H: Similar to the F, with revised avionics and a better interior. The major production run of the B-36 was the H model, with 156 aircraft being delivered.

B-36J: The final production version, the J had strengthened landing gear, and additional fuel tanks, giving range a slight boost. 22 were made, the last being delivered on August 14th, 1954. Some of these aircraft where built at the factory as per the "featherweight" mods.


B-36G / YB-60 - An attempt at making a swept-wing, jet powered B-36. Two were made. The prototypes had a higher bomb load than the rival B-52, but a lower top speed and no air-refueling capability. It was ignored by the USAF, as the B-52 was clearly superior.

XC-99 - One B-36 was built into a twin-decked cargo carrier. It served in Korea and around the United States in the early-mid 1950s.

NB-36H - A B-36 that carried a critical nuclear reactor (!) aloft as part of early tests exploring the construction of nuclear powered aircraft. It and similar Soviet experiments taught something very important - don't build a nuclear powered aircraft.

The NB-36H.
The Korean War: Defense Reaction

Get it?!?
By 1950, the B-36 program had survived its awkward adolescent phase. The existing aircraft were operational, if not upgraded from its A and B types yet. Two Strategic Bombardment wings were now operational, as was one Strategic Reconnaissance wing. If President Truman needed to fight a Bear, he now no longer needed to win by bluffing it. The USAF claimed that the B-36 could bomb 'any industrial center on earth with nuclear attack', but that was in fact hyperbole. Even the extremely long range B-36 couldn't hit everywhere from the Continental US. That said, the ability of the B-36 to fly long distances and find targets was considerable. A B-36 flew from Carswell AFB in Texas to Hawaii, dropped a practice bomb, and then returned to Texas. Flying from Maine, a B-36 could thus fly to Lenningrad and return.

The detonation of the first Soviet atomic bomb in 1949 signaled a new phase of the Cold War, as the Soviets and the United States began to pour huge resources into the nuclear arms race. The B-36 in this era was well suited, as while thermonuclear weapons were still being developed, only the B-36 had the capacity to carry what in the first generation would be physically giant bombs.  In the meantime the B-36 made do with a variety of steadily more powerful atomic bombs, and the science of nuclear weapon building advanced as fast as aeronautics.

The Korean War was a significant event in the B-36's career, even though B-36s were never used in combat. (All three bomber wings at the time were deployed to the far east, with the strategic reconnaissance wing being used extensively to spy on communist activity. It seems that like the later B-2 stealth bomber, the B-36 was considered too prestigious and valuable to actually be used in combat. Though had General MacArthur had gotten his way and actually used atomic bombs against the Chinese, the B-36 likely would have been the delivery system.) The first effect what an increase in B-36 orders, and in defense spending generally, as America decided a large peacetime military would be necessary to contain communism. Another effect was the surprisingly poor showing of World War 2 combat aircraft. B-29s proved vulnerable to MiG-15s, and were forced to adopt night bombing tactics. Somewhat more surprisingly, the P-51 Mustang, one of the best fighters of World War 2, was found to be lacking against turbine-powered opponents. While many more B-36s would now be built, it was now clear that the USAF intended to replace all of its combat designs with turbine-powered aircraft when such models were fully developed. (General LeMay was perfectly comfortable with this, later saying "all bomber designs were placeholders for future models," though he did expect all B-52s to be replaced by B-70 Valkyries.) Deterring Communist aggression was gonna take many nuclear bombers, and the B-36 became the United States based reserve in that force.

America's new military normal was thus found: instead of peace, it would be constant vigilance against a nuclear armed enemy equipped with weapons the Nazis could only dream about. Like the other sorts of normal in post-war America, it proved to be a mixed blessing.

It should be noted as well that the Soviets during this time had no aircraft comparable to the B-36. They instead concentrated their efforts at fielding next generation replacements. While this was a smart move, it meant NATO had a trump card the Soviets had no equivalent to.

"MOMMMMMMM! Witness me! Witness me!"
 International Business Machine

A early model B-36 with all the stuff you will need to keep it flying.
The late Korean war, until about 1955 was the peak of B-36 operation. SAC training had well-familiarized crews with the virtues and vices of the big stick. Despite its immense size and mechanical complexity, the B-36 had a very good safety record, partially due to the high standard of crew training, and partially due to the good flying characteristics of the Peacemaker. One rather amazing accident happened in 1955 when a B-36's rudder literally fell off, and the pilots still managed to land the aircraft safely. Some of this safety record might also be due to the sheer redundancy of power plants the aircraft had. With ten engines, it was difficult to imagine a power failure bringing down a B-36.

That said, there were still accidents. The biggest accident was very Texas - a tornado rolled through Carswell AFB, damaging 100 B-36s and writing off one airframe - once again, it was a good thing that Carswell was next door to the Convair Ft. Worth factory. (This incident was notable as it disclosed to the general public that the Air Force had at least one hundred sky-levithians on its active list.) Another accident on the coast of British Columbia in 1950 saw the loss of a B-36, some of her crew, and the loss of an atomic bomb. The bomb had a dummy core, but it took several months to find the crash site in BC's mountainous terrain, where American special forces destroyed the bomb and anything else classified at the wreck. A more unfortunate crash happened in Newfoundland in 1953. A RB-36 was returning to the United States after a reconnaissance mission, flying from the Azores. The North Atlantic was true to type that evening: black and stormy, with visibility near zero. The RB-36 was flying at 1000 ft to save fuel, and anticipated strong head winds off the coast of Newfoundland. What the crew didn't realize was that the headwind had become a tailwind, putting them some 120 nautical miles further west than they realized. Presumably, the aircraft would have ascended to a safer height had they known their true position;  as it was, they had actually drifted down to a mere 800 ft. As a result, the RB-36 encountered an 836 ft hill at 400 mph. All were killed instantly. This incident is also notable as the senior officer on board was a Brigadier General Richard E. Ellsworth - in memorial the SAC base in Rapid City, South Dakota, was renamed by President Eisenhower Ellsworth AFB - a important USAF base to this day.

The accident aircraft in happier days.

Not much of the magnesium alloy survived the fire, but the tail, the turrets and the jet engines are still recognizable
A problem never entirely solved was with the engines. The engine was designed to face forwards, but of course were faced backwards, creating cooling issues. These were aggravated by flying in the stratosphere, where the thin air was less efficient at cooling. On top of this, the backwards engine configuration could cause the carburetors to freeze, and start engine fires. In short, engine overheating and fires remained problems throughout the B-36's career. The Wasp Majors also had a enormous thirst for oil; each engine had a 100 gallon oil tank, which engines could consume on a single flight if not in top shape. Speaking of which, the start-up sequence for the Wasp Majors if improperly done could coat the engine with oil, fouling the plugs and carbs, necessitating a cleanup by ground crew before flight.  Another problem not entirely solved was with the defensive battery of turreted cannons. Against the envisioned attackers of the time (viz. subsonic fighters with machine guns) it no doubt would have been effective - but the recoil from all those guns firing would regularly break bulbs, unplug cables that really should be plugged in while in flight, and generally broke shit. This was a maintenance nightmare in a aircraft with some 7000 vacuum tubes. As a engineering trade off, the B-36 was roughly as complex and maintenance-intensive as the equivalence weight in expensive Swiss watches. After every flight, every spark plug on the Wasp Majors had to be changed. Each engine had 36 spark plugs, and with six engines, that meant 336 spark plugs had to be swapped after every flight. Imagine a Strategic Bombing Wing with 20-30 B-36s, and you are beginning to understand the maintenance necessary to keep a wing of B-36s flying. It is perhaps instructive that from the F model onward, B-36s gained a second flight engineer.  Even the process of taking off in a B-36 was labor intensive, it taking an hour and a half from removing the landing gear safety pins to actual takeoff. The B-36 was not a quick scrambler. This was not a problem in the early days of the Cold War, especially as the big bird was based stateside, where any nuclear attack by the Soviets would have taken hours to reach - but it was another limit that the World War 2 era design imposed.

Maintainers also had to beware of a fall from the B-36's wing to the hard concrete far, far below. In this shot a censor has blanked out something in the background.
A flash of the B-36's cockpit, taken between the engineer stations. Trigger warning: analog gauges

"Step 1 of 573:remove landing gear pin from landing gear lock hole."
On the plus side of the ledger, the adventures of the RB-36s also gave some hope that the B-36 could actually defend itself. The Peacemaker had some decidedly unusual flight characteristics for aircraft at the time - it was not only a high flyer in combat, but an aircraft that could maintain its speed in the stratosphere. Soviet (like American) jets, were built for high performance at lower altitudes, and as a consequence, simply couldn't reach the RB-36 at 50,000 ft. RB-36 pilots report Chinese MiG-15s trying to intercept them over China - and simply stalling 15,000 ft below them. Throughout the mid-1950s, this edge was enhanced with the aforementioned 'featherweighting' modifications. These boosted the speed of the Peacemaker a little, but more importantly substantially boosted the ceiling. Featherweighted B-36s could approach 60,000 ft. Making things even more difficult for would-be interceptors was that at high altitudes the B-36 could also frequently outmaneuver interceptors, thanks to its high aspect ratio wings and large control surfaces - a large advantage in the gun-and-cannon era of fighters.

Warplanes just wanna fly: this bomber tipped onto its tail thanks to high winds creating lift with the wings.

A late 1940s Life Magazine illustration of the B-36 defending itself.
This makes me think that the B-36 could have defended itself successfully during the early and mid 1950s, even against advanced adversaries such as the Soviet Union. Somewhat more doubtful was the ability of the B-36 to survive the munitions it was supposed to drop. In March 1954, B-36s participated in the "Operation Castle" bomb tests, America's first full-scale hydrogen bomb explosions. Flying at roughly the distance as an attacking B-36 would be during the bomb's detonation, the participating B-36s took heavy damage from the blasts.

This did not stop SAC from using the B-36's uniquely large payload to become the delivery vehicle for the Mk. 17 hydrogen bomb. The largest bomb (physically) ever deployed with American Nuclear forces - it was 7 m (24 ft) long and a meter and a half wide, it weighed 21 tons. Most deployed atomic bombs are the result of further work by scientists once a warhead design had been proven viable - the Mk. 17 was different, as it was just the 'physics package' of the Castle tests crammed into an aerodynamic casing. Like the Castle devices, the Mk.17's maximum yield was 15 MT, or 15,000 kT. That's well over a thousand times more powerful than the atomic bombs used in World War 2. The scaling up of firepower from a chemical bomb like a 'Tallboy' to Atomic bombs, to the mk. 17 represents possibly the greatest increase in firepower ever to happen to...any weapon of war, ever? In practice, these bombs were so powerful that engineers struggled to find a delivery method that would allow the survival of the attacking plane. For a time (and I'd love to have seen a mockup of this) the USAF was thinking of having the B-36 be a mothership to a unmanned B-47 Stratojet, which would act as a very large cruise missile to deliver the mk 17. This was abandoned only because the issue of control and guidance proved insoluble. Drogue parachutes turned out to be the answer - it slowed the bomb's decent and allowed the B-36 to get to a sort-of safe distance. (The design of these chutes actually came from a German scientist found through operation Paperclip. The 'ribbon' chute had been commissioned by the Nazis to air drop tanks.) The use of these bombs was so important in the minds of defense planners that an earlier hydrogen bomb that never entered mass production, the Mk.16, was issued to B-36 units without a drogue chute. The Mk.16 had different internal mechanisms that were liquid based and very maintenance intensive, but had a similar output to the Mk. 17.  Had they been used, they certainly would have destroyed the attacking bomber. Despite a decade of work, atomic bombing was once again turning into a suicide mission. In the meantime, Mid 50s and later B-36s often had anti-flash white undersides, but paint is slim assurance against a 15 megaton explosion.

Two B-36s with the new white undersides.
If you need images rather than numbers, you can always check out the brilliant NUKEMAP by Alex Wellerstein. Alternately, here are two GIFs (compressed from about a minute to a few seconds) from Mr. Wellerstein's invaluable blog, Restricted Data. They are of the first Soviet thermonuclear test, also 15 Megatons. I include these mostly for the second shot seen from the Siberian village, which provides scale. 

A B-36 in flight with anti-flash white. Gen. LeMay encouraged rhyming things when possible to aid memorization (lies.)
SAC Livery was standardized later in the B-36's career, and you can see the SAC crest and the anti-flash white. Here the aircraft commander reviews his crew's weekly poem submission.
While the B and RB-36 remained a cornerstone of global deterrence, the USAF continued to experiment with trying to make the B-36 into a mother-ship for launching and recovering smaller aircraft. These experiments would be called FICON (FIghter- CONveyer) experiments. This time the thinking was modified: now the B-36 was to be used as a mothership for a parasite fighter already accepted in the USAF. This aircraft was a F-84 Thunderjet, which would be armed with a small nuclear bomb. The F-84 would detach, fly to a target, nuke it, and return to the B-36. This nesting doll tactic was to allow the USAF to place nukes even in areas with heavy air defense. (Now that I'm thinking of it, there were many tactics you could have used with this approach, one of which would be to have a FICON B-36 accompany a group of B-36s. The FICON fighter could nuke the air defenses near a nation's border - letting the rest of the B-36s attack without fear.) The parasite action worked in flight tests, but when deployed, it was with with reconnaissance in mind. F-84K recon fighters and B-36s were operational in FICON units for about a year, between 1955 and 1956.The program was terminated in part because of the B-52 now replacing the B-36 in active service, and the U-2 program replacing the RB-36 in reconnaissance.

"Think warm thoughts, boy..."

One of the biggest hits of 1955, "Strategic Air Command" starred Jimmy Stewart as a baseball player returning to the air force. Produced with the assistance of the USAF, it was kind of the 1950s version of Top Gun, save the Gay innuendo but with considerably more smoking. This clip is from the start of the movie, showing off the takeoff maneuver of the B-36. SAC's public reputation peaked around this era - it went into decline a few years later when "Doctor Strangelove" and "Failsafe" reached theaters.

Exit Left Pursued by a Bear

B-36 production ended in 1954, with the few factory-built J types.  This was also the year that B-36 types in service peaked. The high water mark of the program saw 209 B-36s and 133 RB-36s in USAF service. That's four strategic reconnaissance wings and six "heavy bombardment" wings. Numbers would decline after this - 1955 saw old B-36s sent to the scrapyard for recycling, to provide parts for the rest of the fleet. 1955 also saw the Boeing B-52 Stratofortress be accepted for service by the USAF.

A somewhat weather-beaten B-36 at a late 1950s airshow.
 The B-52 had started life in 1945, before the B-36 had even flown. Initially imagined as a strategic bomber of similar capability and style to the B-36, it went through many design evolutions, going from a design that was very B-36-like, save that it used turboprop engines:

to a swept wing jet bomber, of much lower capacity than the B-36, but with a much higher speed.

The B-52 was a strategic bomber similar in mission to the B-36, with the crucial difference that it used all the advances in aeronautics that the B-36 was developed in ignorance of.

Other technologies also spelled "obsolescence" for the B-36. Missiles, both from surface sites and launched from aircraft, negated the safety the B-36's high altitude flying gave it. Missiles, being rocket propelled, have no problem in the upper atmosphere, as the successor to the RB-36, the U-2, would soon discover. The Soviets were replacing their early jet fighters with much more capable models, ones that would have made short work of a intruding B-36. The most basic technology undermining the Peacemaker was even simpler - in flight refueling. The USAF (along with the Red Air Force and everybody else) came to the same revelation about long range aircraft that the Nazis did, too late, in World War 2: that it was far simpler to master in-flight refueling than it was to build aircraft like the B-36. Not only was it simpler, but it meant that aircraft could be far more capable at the same time, not having to trade off performance for range. To drive this point home in 1955, B-52s flew around the world without stopping via in-flight refueling. With that fact established, there was little point in the B-36.

Once Convair gave up on the B-36, it moved on to a jet bomber capable of flying at mach 2 for hours at a time, the B-58 Hustler. Here a B-36 flies its succsessor across country. The B-36 and B-58 would share one strange connection: both only lasted a decade in service thanks to evolving technology.
 The Soviets also deployed a long range strategic bomber superior to the B-36. The Tu-95 Bear had swept wings that gave it similar performance to the B-52. It used turboprop engines, with each Kuznetsov NK-12 with conta-rotating props generating 12,000 hp each. In addition to being more fuel efficient than the B-36, the four turboprops made as much power as the ten engines on the B-36. The Bear, in its modernized Tu-142 form, is still in service today in Russia and India. The Bear also could be refueled in the air.

The small but critical differences in technological eras.
The aircraft of the USAF, 1955. Plane nerds will be able to pick out aircraft descended from World War 2 designs - but by now, these are all support aircraft.
A big ol' image of the aircraft of the USAF in flight. The B-36 is bringing up the rear.
As soon as the new jet-bomber B-52 had been accepted by the USAF, they began to supplant the Peacemaker. As B-52s entered strategic bombardment squadrons, B-36s left them. During this time RB-36s still in service were re-designated "reconnaissance bombers" - retaining their recon abilities but being modified to drop nuclear bombs. The featherweighted options kept the B-36 in operation during this time, but by 1959, the last B-36s were sent to the desert boneyard. (USAF maintainers no doubt breathed a sigh of relief.) The RB-36 was supplanted by the then-secret U-2 spyplane. It'd been a hell of a ride: from strategic trump card to the scrapyard in a decade.

B-36s being recycled, apparently belonging to the 'U.S. Air Porce'.
Unlike some of the other aircraft I've written about here, a few remain in museums and on display, though none are in flying condition. A RB-36H is kept at the Castle Air Museum in California. B-36Js can be seen at the SAC air Museum in Ashland, Nebraska, the USAF Museum in Dayton, Ohio, and the Pima Air Force Museum in Tuscon, Arizona. There's also a B-36 named "The Spirit of Ft. Worth" guarding the entrance of the industrial park where the Convair factory once stood. So if you ever need a yardstick for "big", you can still see it.

Beats being melted down, that's for sure. On the left you can make out one of those first prototype giant wheels.