Although the end of the Cold War has led to a reduction in the armed forces, the US fleet of nuclear-capable bombers is still the largest and most capable in the world. These bombers were part of the Strategic Air Command (SAC) until its abolition in 1992 then moved to Air Combat Command. On 7 August 2009, the new Global Strike Command came into existence, combining the B-52 and B-2 forces with the Minuteman missiles, with emphasis on the nuclear role. The initial plan was to declare it operational on 6 August, but it was realised that announcing a new nuclear command on the anniversary of Hiroshima was a really bad PR move. It should also be noted that these bombers are now de-alerted- it would take a number of weeks to get them nuked up again. Platforms that did not enter service in a nuclear role are listed in [Square brackets].
B-29 SuperfortressThe only nuclear launch vehicle to have actually been used to drop nuclear bombs in combat- the Enola Gay and Bockscar were B-29s. Directly copied by the Soviets as the Tu-4 "Bull", after a bunch of them had to land in the USSR during World War II. As the Soviets were neutral at that time vis Japan (not entering until the very end), they confiscated the aircraft.
B-50 SuperfortressA variant of the Superfortress (originally designated the B-29D) equipped with more powerful engines (the engines used on the previous versions had a distressing tendency to overheat to the point of catching fire; the newer engines, among the most powerful piston engines ever produced for the aviation industry, were also more reliable). The designation change was made in order to skirt the post-World War II budget cuts.
B-36 PeacemakerThe successor to the B-29 in US service; it was probably the first truly intercontinental bomber. The jet engines of the era were still rather unreliable and fuel-thirsty, so it had six huge piston engines mounted in its wings, in a pusher configuration no less. The thing was huge; although it wasn't the heaviest, it was the largest combat aircraft ever constructed (the record for "heaviest combat plane" goes to the Tu-160 and there are larger transport aircraft). It carries what still qualifies as an enormous bombload (up to 86,000 pounds of ordnance). It dates back to the WWII era; the US was worried about the security of Airstrip One...err, the United Kingdom, and wanted a bomber that could reach targets in Europe from the North American mainland. (Admittedly, Sealion was a crapshoot at best, but that's another story.) There's just something about it, in terms of aesthetics it would fit nicely into BioShock if the game wasn't set underwater. Anyway, it was slow, especially compared to jet bombers like the B-47, although that one was somewhat short-legged and had to be based relatively close to the Soviet Union in order to reach its targets there. Later, in order to give them a higher dash speed over a target and through the worst of the Soviet air defenses, they were fitted with four jet engines in two underwing pods (2 engines per pod), so later variants had a total of ten engines, resulting in a joke about "six turning and four burning" note . Its sheer size, coupled with it being constructed mostly out of magnesium, led to its Fan Nickname of "Magnesium Overcast". It also carried a ridiculous amount of defensive armament (The Other Wiki lists sixteen cannons). Later, though, the cannons (except for the tail guns) were deleted along with other stuff in an effort (called the "Featherweight" program) to increase range and service altitude (afterwards, some of the Featherweighted B-36s were documented to reach heights of well over 50,000 feet—making them quite hard to intercept for a while, until fighter and SAM designs became advanced enough to allow for effective interception). An all-jet-powered, swept-wing derivative, the XB-60, lost the competition to the Boeing B-52.
B-47 StratojetA Boeing offering; a graceful looking jet bomber and the ancestor of no less than three distinct aircraft: the B-47's larger brother, the B-52, the accompanying KC-135 tanker aircraft and the revolutionary 707 airliner. It served alongside the B-36 for a while before both were replaced by the B-52. They were rather short-legged, mostly being based in the UK. Variants with cameras were used for armed photo-reconnaissance (!) over the Soviet Union, including a really ballsy mass overflight of Vladivostok.
B-52 StratofortressThis one's been around a while (1955 was when the first version entered service) and may stay around until about 2040. The aircraft has a massive range (about 10,000 miles without refuelling), a big carrying capacity and can fire stand-off cruise missiles. Far more widely known by a rather vulgar nickname that notes its size, weight, physical unattractiveness and the fact it is a very potent weapon. Remains the US's primary nuclear bomber (the B-1B no longer being able to carry nukes and the B-2 being limited in number). 94 B-52H bombers are left of the 744 built. Took a conventional role as far back as Vietnam (with an entire sub-type being converted for that role back then, because the thing couldn't carry enough bombs otherwise) and still used in that role today. All had tail-guns, but the remaining B-52H bombers have had these removed, as they're now not much use. The aircraft was used in the Gulf War (firing conventional cruise missiles while over Saudi Arabia), Afghanistan and Iraq. The fact that it has a massive radar-cross section is irrelevant in the latter.
B-58 HustlerNotable for its massive underfuselage weapons pod, the Hustler was capable of sustaining about Mach 2.2 for over an hour (setting a lot of records for the time) and was designed for a role in Europe. When improved Soviet air defences meant the thing had to fly low level (limiting the range still further), it became too expensive to upgrade and the things were taken out of service about 12 years after they'd arrived.
XB-70 ValkyrieA North American offering. The US was worried about how well their bomber force could survive in the face of Soviet air defenses; for a while, their answer was to fly higher and faster, and the XB-70 was the ultimate expression of this trend: a high-altitude Mach 3+ jet bomber which could generate lift by riding its own sonic shockwaves. In the late 1950s it was believed that improvements in SAMs and air defense technologies would overtake what was manageable and practical for a manned aircraft, putting the viability of the B-70 in question. The B-70 program was put on hold in 1958/59 while a thorough evaluation of this issue was conducted. This showed that the promised advances in surface-to-air missiles were not taking place and were unlikely to be attained any time soon. In fact, even today surface to air missiles have not reached the level of performance predicted in 1957 and the B-70 would still be beyond their effective reach. It was also claimed that the Valkyrie had radar and thermal signatures that were abnormally large. This also was incorrect; the B-70 did have a very large radar cross sections from the side but nose-on it had only 40 percent of the RCS of a B-52 and this could be cut still further by using radar absorbing materials already being used on the SR-71 and A-12. Nor was the production B-70 likely to be that costly; USAF figures for a 350 aircraft fleet with 60 reconnaissance RS-70s was about $18 million per aircraft. This was twice the cost of a B-52H or 50 percent more than a B-58A. What really killed the B-70 was the need for funds to develop a multi-role combat aircraft that eventually became the F-111. The two XB-70s that were built were very valuable research aircraft, and very much deserving of their moniker. (Although, in context as a nuclear bomber, "Valkyrie" (from the Old Norse valkyrja, "chooser of the slain") as a nickname was also petrifyingly literal.) The XB-70 also has an interesting legacy in the Lensman Arms Race it touched off. The Soviet heard about it and developed the MiG-25, basically a Mach-3 rocket engine with huge wings to keep it from falling out of the sky, as a counter. The Americans, misinterpreting the MiG-25 as an air superiority fighter, developed the F-15 as a counter. The Soviets then trotted out the Su-27 to deal with the F-15, the Americans trotted out the F-22 to deal with the Su-27... and the USSR collapsed. As it stands, America and the F-22 have won; and we should leave it at that, because the F-22 causes enough Flame Wars as it is.
B-1B LancerKnown among the crews as the "Bone" ("B-ONE" spelled out). The B-1A project was terminated due to being too expensive, and Carter (although he couldn't really say it at the time) deciding to focus his efforts on the B-2 instead. Reagan restarted the project with some modifications (reducing the max speed and turning the plane into a low-level penetrator) as the B-1B, and in all 100 were built. 67 remain in service with others lost in accidents or cannibalised for parts. With a four-person crew (women have flown it into combat), it has been optimised for the conventional role- i.e. it no longer can carry nukes- and used in a number of conflicts as such. It has an internal bomb load of 37,000 kg, second only to the Tu-160. It could add another 27 tonnes externally, but this is both pretty much prohibited by START I (which also effectively bars the plane from carrying air-launched cruise missiles) and would compromise the quasi-stealth capability of the aircraft (though neither has stopped the USAF from hanging targeting pods at these points, partly because the Taliban don't have radar) - it's estimated to have a radar cross-section 1/50 of the similar sized B-52. A proposed upgrade, the B-1R, would fully recommission all external hardpoints, upgrade the radar to track air targets, and allow bombs to be interchangeable with air-to-air missiles to create the world's largest fighter plane (as well as giving it the world's most awkward nickname for an aircraft).
B-2A SpiritThe Stealth Bomber. It's not impossible to detect on radar, just extremely, extremely hard. Developed to drop nukes on the USSR, it still does nuclear training, but is now used mostly in a conventional role. Its first combat use was in Kosovo, where after being written off beforehand as an overly expensive aircraft that couldn't fly in rain and could be picked up by basic radar systems, it proved its detractors 100% wrong and has pulled off the longest-distance bombing raids in history. 132 were planned, but only 21 were built due to the end of the Cold War, resulting in a very high per-unit cost (at $2.1 billion dollars per airframe, each is worth the same as one third of the cost of an entire aircraft carrier - or, literally, more than its weight in gold). With the recent destruction of one in a crash (the two-man crew ejected and survived), the number stands at 20, mostly based at Whiteman AFB.
Nuclear-powered bomber proposalsThat's right. As if arming them with nuclear weapons wasn't bad enough, they came up with a bunch of screwy proposals. They'd have had to carry a lot of shielding and seat the crew as far away as possible from the reactor, for obvious reasons. And it would probably be best if the crew didn't have too many children, for similarly obvious reasons. As insane as it may sound, it did offer some range and performance advantages; in the end, though, the concept was rendered obsolete by, among other things, ICBM technology. A modified NB-36 actually flew with a reactor onboard, although this was just a small 1MW model and the idea was to test the effects of radiation on aircraft systems and crew. There was a proposed B-36 derivative, the Convair X-6, which would have been a bona fide nuclear flier. Eek.
F-111 AardvarkThe Aardvark (it only acquired its nickname formally at the retirement ceremony in 1996) was the world's first production swing-wing aircraft. A two-seater supersonic battlefield interdiction and deep-strike aircraft, it was exported to Australia and would have gone to the UK as a Vulcan replacement, but the latter was canceled due to budgetary reasons. The F-111 was developed in the TFX (Tactical Fighter, eXperimental) program and intended for use by both the Air Force and Navy. The Air Force's version, the F-111A, was designed for low-level deep-penetration strikes against ground targets, while the Navy's F-111B was intended to be a carrier-based high-altitude interceptor. Ultimately the B model it was too heavy to land on carrier decks, and was abandoned in 1968. (The USN replaced it with the F-14 Tomcat, also a swing-wing fighter and the star of the movie Top Gun. Grumman, brought in to assist General Dynamics with the 'vark thanks to the former's experience with naval aviation, took their experience with the F-111B and applied much of what they learned to the Tomcat.) The F-111A, meanwhile, turned up in Vietnam in 1968 for combat testing in real conditions, where three were lost, due to terrain-following radar problems rather than enemy action. Once those problems had been sorted out, it proved quite effective- it didn't need escorts. With progressive enhancements, it got even better. It featured in the 1986 attack on Libya and played a big role in Desert Storm in 1991. It could carry free-fall tactical nuclear weapons (in an internal weapons bay or externally) and had provision for a defensive cannon. It was assigned to Tactical Air Command and some were based at RAF Lakenheath in the UK. It is quite fair to say that the F-111 was one of the most feared US aircraft of the Cold War by the Soviet Union. Low-level performance was excellent.
FB-111The SAC version of the Aardvark, with up to 6 SRAMs and an increased wingspan to allow more fuel to be carried. It was capable of conducting strikes in the USSR, with tanker support, from the continental United States. With the B-1B entering service, this became surplus to requirements and the end of the Cold War meant the aircraft were converted to become the F-111G, mostly used for training, with some passed to Australia.
EF-111A RavenAlso known as the "Spark-Vark", this was the electronic warfare version of the F-111, designed to mess with the opponent's instrumentation and communications. Had Sidewinder provision, but rarely used it. In the Gulf War, one managed to gain an air-to-air kill without firing a shot, after disorientating an Iraqi pilot to the extent he flew into the ground. Then it happened in reverse to another aircraft. This turned out to be the only kill of any F-111 or F-111 derivative aircraft. Retired from US service in 1998.
Orbital BombersIn the 1950s, there were proposals to develop an orbital bomber, launched via a Titan missile. Eventually, this changed into the X-20 Dyna-Soar (Dynamic Soarer), an orbital spy plane, which was eventually cancelled in favor of MOL (Manned Orbiting Laboratory), a spy space station. Finally, the USAF had pretty much all of their own manned space flight proposals cancelled in the late 1960s in favor of spy satellites, like Corona and the Key Hole series.
"Next Generation Bomber"A confirmed USAF plan, a next-gen stealth bomber intended for 24-hour operations, unlike the B-2, which is limited to night flying. However, the new Obama administration has stated it believes that the B-52/B-1/B-2 grouping will serve for the time being and the project is proposed for cancellation. Democratic Presidents don't tend to like bombers. Republican Presidents do. Not everyone agrees with this decision.
AGM-12 BullpupThe first mass-produced air-to-surface missile, it could be steered via the launching pilot. A nuclear version was made.
AGM-28 Hound DogNamed after the Elvis Presley song. A nuclear-tipped stand-off weapon intended to be used by B-52s, so as to improve their survivability in the face of Soviet air defenses, some of the best in the world if stretched thin in some places.
AGM-48 SkyboltA cancelled Air-Launched Ballistic Missile (ALBM)- yep... Was intended to be the successor to the Hound Dog. The British were also planning to go for this one for their Vulcans, but went for the Resolution class boomers and Polaris.
ADM-20 QuailIt doesn't really count, but it's still worth mentioning; this was an air-launched decoy missile intended to be carried by B-52s. Obsolete by the early '70s, but before then, it was expected to be capable of fooling Soviet air defense radars.
AGM-69 SRAM (Short Range Attack Missile)Designed to replace the Hound Dog, this missile could perform "one major maneuver" in flight, attacking stuff behind the bomber for example. Retired in 1990, with safety concerns being the cited reason. B-52 could carry up to twenty of these 200 KT warhead missiles.
AGM-86 ALCM (Air Launched Cruise Missile)An air-launched Tomahawk in many respects, capable of sustained low-level flying at subsonic speeds and a range of over 1,500 imperial miles. 5 or 150KT W80-1 warhead and pretty accurate, it's the main air-launched bomber weapon of the US today- carried by B-52s. The B-version is nuclear-equipped. Surplus of those have been converted into conventional missiles and used in several US conflicts.
Mark 3Basically the exact same design as the "Fat Man" implosion-type bomb, only it used uranium instead of plutonium.
Mark 4Basically a mass-produced version of the "Fat Man" bomb, it entered service just in time for the Korean War if the Korean War ever came to that point. The only real difference between a Mark 4 and a "Fat Man" was in the production method, meaning that only a B-29 or larger could carry it, and typically only one. If an American bomber was carrying a nuke in the immediate post-WWII/Cold War period, it most likely would've been this (and again, the bomber would've by necessity been most likely a B-29).
Mark 6 and Mark 13The last nukes to carry the design legacy of "Fat Man," the Mark 6 was an improved Mark 4 and the Mark 18 had the highest explosive tonnage rating for a fissile (non-thermonuclear) bomb in U.S. inventory.
Mark 17The United State's first thermonuclear bomb, so large it could only be carried by a B-36, and was retired out of necessity when that aircraft in turn was retired.
After thisMost U.S. nuclear bombs had relatively short service lives; from this point on, the U.S. would settle on missiles for the delivery of strategic nuclear warheads, particularly ICBMs and SLBMs. If for some reason a strategic-level nuclear bomb had to be dropped on somebody, the protocol was to simply load-up a bunch of B61s or B83s into a B-52; considering how a B-52 can carry a lot of these things, it wound up being more effective than just dropping a single mega-nuke.