Indian Defence Review

B-2 Bombers

Today, many nations have hundreds of multi-mission, flexible fighter aircraft on their inventory. And now that aerial refuelling has become the norm for most advanced air forces, including the IAF, a multirole fighter can match the range of a strategic bomber. The other major advantage the bomber holds over the fighter – that of far greater weapons load, has also been reduced to some extent with the widespread availability of PGMs. Any major air force that has aerial refuelling capability and specialist PGMs can undertake strategic missions without inducting and risking prohibitively expensive bomber aircraft such as the American B-2A Spirit or the Russian PAK-DA. Therefore, it seems unlikely that other nations will be tempted to acquire or produce strategic bomber aircraft.

The Northrop Grumman B-2A Spirit, an American heavy penetration strategic bomber, is the most formidable airborne weapons platform in the world today. Powered by four General Electric F118-GE-100 jet engines, it has a high subsonic cruise speed, an unrefuelled intercontinental range of approximately 9,600 km and a maximum payload of 18 tonnes of smart bombs and conventional Precision Guided Missiles (PGMs) or 16 nuclear weapons carried internally. It features low-observable (stealth) technology that no other strategic bomber shares. And stealth enables it to breach many previously impenetrable anti-aircraft defences.

But this impressive capability comes at a price. The B-2A is the fruit of a massive development programme that cost almost $45 billion but produced just 21 jets for a unit procurement cost of approximately $1.157 billion (1998 dollars) before it was prematurely terminated. Not even the world’s richest nation can casually spend such sums, especially when the ever more potent defences of its adversaries could conceivably take out one or more bombers during a future live strike. Therefore, will the B-2A Spirit be the last aircraft of its ilk? What does the future hold for the strategic bomber and strategic bombing itself?

The Genesis of Aerial Strategic Bombing

The military potential of aircraft began to be exploited just a few years after the Wright Brothers’ epochal first flight at Kitty Hawk in December 1903. And the outbreak of the First World War in July 1914 was the perfect catalyst for the rapid development of military aviation. Designers and operators soon began to define various categories of warplanes, the main groups being fighters, bombers and reconnaissance aircraft. Fighter aircraft were usually smaller, lighter, faster and more manoeuvrable while bombers were larger, heavier and slower but had longer ranges and greater payload capacities. Reconnaissance aircraft were generally unarmed and relied on high speed, high altitude and guile to evade detection and interception.

It is unclear when the first practice bombs were dropped in flight, but the first actual bombing of a city took place on the night of August 24-25, 1914, when a German airship dropped eight light bombs on Antwerp in Belgium. Soon, thereafter, heavier-than-air machines like the Russian Sikorsky Ilya Muromets bombers and the German Gotha GV heavy bomber began to be employed for bombing missions.

Aerial strategic bombing is a systematically organised and executed military strategy employed to defeat the enemy by destroying its morale or its economic ability to produce and transport materiel required for military operations. The aim is to compel the adversary to accept peace or surrender rather than continuing the conflict.

It was between the two World Wars that the theory of strategic aerial warfare and strategic bombing really took off. General Giulio Douhet in Italy, Marshal of the Royal Air Force, Hugh Trenchard in Great Britain and General Billy Mitchell in the United States, played a major part in advocating the military utility of a strategic bombing campaign. They postulated that massive and sustained aerial bombardment of the enemy’s homeland would weaken its ability to fight by destroying important military infrastructure. It would also trigger a collapse of civilian morale and force the enemy government to capitulate.

However, there was a hitch – most air forces did not have the capability to mount the required weight of attack to validate these theories.

During the course of the Second World War, which broke out in September 1939, the belligerents on both sides did acquire such capability and conducted several strategic bombing campaigns. In some cases, thousands of aircraft would be dispatched to drop tens of thousands of tonnes of bombs over a single enemy city in a matter of hours. And the results would be evaluated in terms of the number of square miles of city destroyed. However, the predicted collapse of the enemy’s will to fight never really happened.

The single most devastating attack in the history of human warfare was not a nuclear strike. It was a low-level aerial bombing raid over Tokyo on the night of March 9–10, 1945, undertaken by the US 20th Air Force based in the Mariana Islands in the Pacific Ocean. The raid consisted of 334 long-range B-29 Superfortress bomber aircraft that dropped 1,665 tonnes of incendiary bombs. It resulted in the destruction mainly by fire of almost 16 square miles of Tokyo, caused at least 100,000 Japanese deaths and about one million injuries and left over one million homeless. It dwarfed the allied raids on Hamburg and Dresden and the nuclear attacks mounted by the US on Hiroshima and Nagasaki on August 06 and 09, 1945.

After the Second World War, the 1949 Geneva Conventions and Protocol I of 1977 prohibited deliberate or indiscriminate attacks against civilians and civilian objects, even if the area contained military objectives, and specified that the attacking force must take necessary precautions and steps to spare the lives of civilians and civilian objects. Since then, many limited and localised wars have been fought including the Korean War, the Vietnam War and the conflicts in West Asia. In all these conflicts, aerial strategic bombing was mainly employed against military targets, while civilian ones were engaged only if they directly supported the war effort. And while the campaigns did often cause many civilian casualties, these were mostly reckoned to be ‘collateral damage’ – the killing or wounding of non-combatants or damage to non-combatant property during an attack on a legitimate military target.

The Strategic Bomber Today

The modern strategic bomber is a medium-to-long-range penetration bomber designed to drop large amounts of air-to-ground weaponry on a distant target with the intention of degrading the enemy’s capacity to wage war. It is almost invariably armed with long-range precision weapons. Only the US, Russia and China have true strategic bombers and only the US has capable bombers in considerable numbers. However, even tactical fighter jets such as the F-15E Strike Eagle of the United States Air Force (USAF) and the Sukhoi Su-30MKI of the Indian Air Force (IAF) can be tasked to carry out strategic bombing missions using PGMs.

America’s strategic bomber fleet currently numbers 159 aircraft made up of the Boeing B-52H, the Rockwell B-1B Lancer and the Northrop Grumman B-2A Spirit. The B-2A is the world’s only operational stealth bomber and is expected to remain in service till 2060.

Russia’s 127-aircraft strategic fleet is a mix of the older turboprop-powered Tupolev Tu-95 and the supersonic Tupolev Tu-22M plus just 16 of the more modern Tupolev Tu-160 supersonic heavy bombers. None of these are really survivable in an intense AD environment, and hence the Russian Air Force (RAF) deploys them armed mainly with long-range standoff missiles.

China has in service about 120 bomber aircraft operated by the People’s Liberation Army Air Force (PLAAF). All of them are the practically obsolete Xian H-6 – a licence-built version of the Soviet Tupolev Tu-16 twin-engine jet that dates back to 1954.

What is common to these three nations is the age of their fleet. Apart from America’s 20 operational B-2A jets, the bulk of the world’s bombers are of vintage technology. That is likely to change over the next 15 to 20 years as all three nations strive to build futuristic bombers. It is certain that any new strategic bomber will have a marked degree of stealth capability; else it will have slim chances of survival in highly contested environments.

The US B-21: Setting Tomorrow’s Agenda

For the better part of a century, America’s global military influence has depended heavily on its air power, especially the rapid technological advances it incorporates in its combat fleet, long before other nations can be similarly equipped. And its bomber aircraft are a major factor in this strategic dominance narrative. That is why the advent of a new US strategic bomber is being watched with interest around the world. What will this aircraft entail?

It will use stealth, guile and firepower to run the gauntlet of what the US military terms the enemy’s Area-Denial and Anti-Access (AD/A2) capability. Indeed America’s potential adversaries – Russia and China, can create a virtual fortress and prevent US forces from coming within hundreds or even thousands of kilometres of their territory by using advanced integrated Air Defence (AD) systems with long-range engagement capabilities. They can even take the battle to the Americans by deploying ballistic and cruise missiles to threaten US military installations and carrier strike groups over an entire region.

These factors have been taken into account while conceptualising the Northrop Grumman B-21 Raider, a long-range strategic bomber now under development for the USAF. The formal designation ‘B-21’ signifies that this is the first American bomber of the 21st century. The B-21 is expected to be smaller than the B-2A and carry a lighter weapon load. It will probably have only two engines against four fitted on the B-2A and its jet exhaust will most likely be diffused over the rear of the aircraft’s upper fuselage in order to drastically reduce its infrared and radar signature especially from lower viewing angles.

Not surprisingly, artist’s depictions of the new aircraft are of a flying wing design similar to the B-2A and the now defunct Next-Generation Bomber (NGB) project. The NGB, a proposed stealthy, subsonic, medium-range, medium payload bomber, was initially projected to enter service around 2018, but it was superseded by the LRS-B project which culminated in the October 2015 award of the B-21 development contract to Northrop Grumman.

The B-21 will replace the B-1B, the B-52H, and eventually the B-2A. However, it is misleading to categorise the B-21 as a mere bomber. The secretive new aircraft is actually a fifth-generation global precision attack platform that will have the characteristics of a bomber, fighter, reconnaissance platform, and electronic attack aircraft rolled into one – a true multi-role military aircraft. It is being described as a “long-range sensor shooter” with the ability to strike deep within enemy territory at a time and place of its choosing. It will have large-capacity data fusion and transmission capability and will share information and target data with early warning aircraft and strategic reconnaissance aircraft. It will control swarms of Unmanned Aerial Vehicles (UAV) and itself have an optionally unmanned capability. In the words of a retired USAF general, “It will have a sensor suite and communications capability on it such that it will be able to act as a critical node inside the future combat cloud, where weapon systems will all be linked together and sharing information in a way that we’ve never done before.”

Featuring new stealth technologies, the B-21 is designed to penetrate and operate in even the world’s most advanced AD systems and deliver a diverse and devastating payload of weapons, including conventional stand-off and direct-attack weapons as well as thermonuclear weapons. To this end, it will be packed with electronics – advanced electronic warfare, laser warfare and cyber warfare equipment to keep it safe from future surface-to-air missiles and other AD threats. In fact, it will start its mission by taking out most enemy defences and military communication facilities. This will enable other vulnerable strike jets armed with less potent weaponry to ingress safely and carry out attacks against their own designated targets.

The USAF plans to purchase at least 100 B-21 Raider aircraft at a cost of $564 million each (2016 dollars). There’s also the development cost estimated to be at least $23.5 billion, a figure that is bound to rise because the B-2A Spirit development programme eventually gobbled up almost twice that amount. In March 2017, the B-21 bomber completed a preliminary design review and the USAF expressed satisfaction with the progress of the programme. The B-21 will have open systems architecture, permitting it to quickly integrate new technologies as they emerge. The aircraft is expected to enter service in the mid-2020s, with Initial Operating Capability (IOC) expected to be attained only around 2030. The USAF Global Strike Command wants a total of some 175 to 200 bombers of various types in service.

Russia’s Riposte: The PAK DA

Russia is following a twin-track approach with regard to its future strategic bomber fleet. By 2019, its upgraded Tupolev Tu-160M2 long-range supersonic bomber is likely to perform its first flight. The aircraft’s Kuznetsov NK-32 Series-2 engine gives it improved performance and may increase its flight range by at least 1,000 km compared with the existing bomber. But since it has very limited stealth characteristics, it will probably be armed mainly with long-range standoff cruise missiles carried internally. For instance, the Raduga Kh-101/Kh-102 air-launched cruise missile with an estimated range of up to 4,500 km will keep the bomber well out of the enemy’s danger zone.

Further into the future is Russia’s next-generation four-engine subsonic heavy payload strategic bomber called Tupolev PAK-DA (Prospective Aviation Complex for Long-Range Aviation). According to reports, it is the first Russian bomber optimised for stealth and will have a flying wing design consisting mainly of radar-absorbent material. It will eventually replace most of the RAF’s older strategic bombers since stealth is considered essential to give an attacking bomber some chance of survival against the highly lethal US defences. It is likely to have a maximum take-off weight of 110 tonne and fly 12,500 km without refuelling. Its weapon load of up to 30 tonne may include long-range nuclear and conventional cruise missiles, including hypersonic missiles, and a variety of PGMs.

In March this year the first full-scale model of the PAK-DA was built. It is estimated to cost $160 million, far less than the forthcoming US B-21 bomber. It is not likely to enter service before 2025.

Both the Tu-160M2 and the PAK-DA are expected to be armed with the Russia’s latest anti-ship weapon – the Raduga Kh-32 missile that is due to enter service shortly. The Kh-32 is a wonder-weapon in its own right – a 1000-km range hypersonic multi-purpose cruise missile that may eventually be armed with a nuclear warhead. It is designed to take out radar stations, warships (especially aircraft carrier battle groups), bridges, military bases and power stations. Fitted with an inertial navigation system, it is hard to jam. Neither is it vulnerable to most AD systems because it flies at an altitude of 40 km. According to Russian sources, “Air and missile defence systems today cannot detect a diving warhead, which moves down at a speed of over 5,400 kmph.”

China Plays Catch-Up: the Xian H-20

It is well known that China is making enormous strides in all kinds of weaponry. As part of its military modernisation programme, China is keen to field a new long-range strategic bomber for the PLAAF. It is reportedly aiming for a subsonic bomber with a minimum unrefuelled range of 8,000 km and a payload capacity in excess of tonnes, including conventional and nuclear weapons load. The aircraft is expected to have good electronic combat capability including the ability to deflect or destroy incoming missiles and neutralise ground-based anti-aircraft defences. At this stage it is unclear if the Xian H-20 will be an entirely new design or based on the existing H-6K bombers. But it is safe to assume that it will be a stealthy aircraft, which in turn makes it a strong possibility that it will have a flying wing design similar to the B-2A Spirit.

China, of course, has a long way to go before it can design and build such an advanced aircraft. Although it is making headway in stealth design with aircraft such as the Chengdu J-20 fifth-generation fighter aircraft and the cheaper and somewhat less capable Shenyang J-31, a strategic bomber is a much bigger project. A major question mark is regarding the Chinese aviation industry’s capability to build high-performance turbofan engines. But the industry is already progressing well with other technologies necessary for the development of a stealth bomber, including air inlet design, composite materials, cruise missiles, PGMs and nuclear weapons. And China has proved extremely adept at acquiring or emulating critical military technologies despite the best efforts of its potential adversaries to deny it these capabilities.

Way to Go… or Not?

Clearly, the world’s three most powerful nations are determined to build an advanced strategic bomber aircraft that they hope will be survivable in the lethal AD environment expected to prevail around 2050. To this end, the bombers will be richly endowed with low-observable characteristics and a range of offensive and defensive capabilities. But is it wise to sink enormous sums of money into such platforms?

Designing and building a stealth aircraft requires a complex set of engineering processes and comes at the cost of numerous performance compromises. More worryingly, without constant maintenance and huge expense, such aircraft soon lose their low-observable qualities. Many nations are already striving to develop alternative detection techniques, like infrared and acoustic sensors and a classic cat-and-mouse game is in progress between the AD engineers and stealth technologists. Hence there is no assurance that stealth bombers will be able to successfully evade detection for long. If they become detectable they will also be vulnerable and will then probably be restricted to launching long-range weapons from well outside the enemy’s lethal zone. That is why unmanned and optionally manned bombers are being developed simultaneously with manned bombers.

Today, many nations have hundreds of multi-mission, flexible fighter aircraft on their inventory. And now that aerial refuelling has become the norm for most advanced air forces, including the IAF, a multirole fighter can match the range of a strategic bomber. The other major advantage the bomber holds over the fighter – that of far greater weapons load, has also been reduced to some extent with the widespread availability of PGMs. Any major air force that has aerial refuelling capability and specialist PGMs can undertake strategic missions without inducting and risking prohibitively expensive bomber aircraft such as the American B-2A Spirit or the Russian PAK-DA. Therefore, it seems unlikely that other nations will be tempted to acquire or produce strategic bomber aircraft.