The Unusual History of Transport Bomber Planes
For nearly 80 years, desperate air forces have dropped bombs from cargo carriers
Last month, Moscow announced that it added bombs to the Ilyushin Il-76 transport aircraft. The news and supporting photos—which showed the hulking airlifters on a snowy airfield, with dumb bombs hanging under their wings—was surprising.
But as we noted, adapting transport aircraft to serve as bombers is nothing new. In the past, these types of aircraft typically came about because of expediency, above all during conflict.
Russia is not at war—not officially, at least—but Soviet-designed transports have long been able to drop bombs as a secondary mission. Even quasi-civilian transports once rolled off Soviet production lines with bomb shackles and defensive gun turrets attached.
If an air force finds itself with a shortage of bombers, it could always add offensive weapons to transport aircraft—even if these planes lack the means to accurately deliver such payloads.
Purpose-designed bomber aircraft first went into combat during World War I. And after the war, several nations developed dedicated transport planes.
Because these new transports were so similar to the bombers that preceded them, a new type of hybrid aircraft—the transport-bomber—emerged to carry troops and drop bombs.
These planes hauled soldiers and cargo to far-flung outposts during peacetime, but could go on the offensive if required, taking part in the colonial “policing” actions typical of that era.
The British Bristol Bombay was characteristic of these interwar transport-bombers. It was a twin-engine monoplane that could carry 24 troops or an equivalent load of cargo, or deliver up to 2,000 pounds of bombs from racks under the fuselage.
In the offensive role, the Bombay saw action during World War II, and served in the Middle East and North Africa. But they soon gave way to dedicated bomber planes that were more survivable and generally better suited to the task.
The Savoia-Marchetti SM.81 Pipistrello was the Italian air force’s first three-engine transport-bomber. It served during the Second Italo-Ethiopian War and the Spanish Civil War.
But by World War II, the increasing vulnerability of transport-bombers in general, and of the SM.81 in particular, became apparent. Before long, the Italians relieved the Pipistrello of most of its front-line combat duties. It continued serving as a transport plane and in second-line roles.
The German Junker Ju 52 was another tri-motor transport with bombing capabilities.
Although Germany billed the Ju 52 as a civilian airliner to equip the emergent Deutsche Luft Hansa airline before World War II, it issued the plane simultaneously to the still-secret Luftwaffe, which used it as a bomber in the Spanish Civil War. During that conflict, the plane took part in the notorious bombing of Guernica.
By the outbreak of World War II, the Ju 52, like the Bombay, became obsolete in the dual-bombing role. After serving in the 1939 invasion of Poland in an offensive capacity, the Tante Ju spent the rest of the war as the Luftwaffe’s primary transport workhorse.
In the 1930s, aerial bombing was still a relatively new way of waging war, and few nations could afford to field fleets of transport-bombers … let alone proper bombers. But for those countries that lacked the resources or strategic forethought, there were other options.
In 1931, the Chilean navy rebelled against its government. In response to the mutiny, the Chilean air force gathered all available aircraft near the port of Coquimbo, where the naval fleet called home.
Alongside purpose-designed bombers, both light and heavy, the air force sent two Ford Tri-Motor transports adapted for bombing missions. The crews dropped bombs through a hole in the plane’s lavatory floor.
The Chilean bombers had little success in their raid on the fleet, but combined with an attack on the naval barracks by ground troops, the mutineers soon surrendered.
When Colombia and Peru went to war over disputed territory in the Amazon region in 1932, the Colombians hurriedly adapted civilian aircraft for bombing duties, and managed to hit back at the Peruvian invasion force.
They did it by taking a pair of Junkers F13 float planes—borrowed from the civilian airliner SCADTA—and cut bomb holes in the floor. While their effect on the outcome of the conflict was negligible, the combat use of the aircraft prompted a major expansion of the Colombian air force.
World War II
At the outbreak of World War II, the ill-equipped British Royal Air Force needed every aircraft it could get. One temporary solution—the RAF hastily upgraded several existing transport planes.
The impressive Short S.26 G-class was a maritime airliner Imperial Airways regularly flew on transatlantic routes prior to the outbreak of war. The RAF rushed the three examples into service to fill an urgent requirement for a maritime patrol bomber.
In this guise, the flying boats came with bomb shackles, flares and even an air-to-surface radar. The S.26 saw service off the coasts of Scotland and West Africa, but one aircraft crashed and the remaining two returned to civilian duties by the end of 1941, when more appropriate equipment became available.
The American Douglas C-47 Skytrain rivaled the Ju 52 for the title of most versatile transport of the war. The United States heavily used the plane in both the European and Pacific theaters.
The U.S. supplied the Soviet air force with a license-built Skytrain, known as the Lisunov Li-2. Moscow lacked a serious heavy bomber fleet, and used the Lisunov for offensive missions when required.
The Soviet engineers tailored a version for bombing missions, with additional defensive guns in the nose and modifications for internal or external bombs. And if necessary, the crew could simply lob smaller bombs out of the plane’s freight door.
The Soviets modified other Li-2s in the field, as was the case during the Soviet raid on the Finnish port of Oulu in March 1942.
The U.S. also sent the Skytrain into action as a makeshift bomber. In the Pacific theater, the “Jungle Skippers” of the U.S. Army Air Forces’ 317th Troop Carrier Group transported soldiers and cargo around the islands of Manila Bay, snuffing out the last pockets of Japanese resistance.
In April 1945, the unit went on the offensive itself, and carried out napalm bombing missions against Japanese-held Carabao Island.
After World War II, the technical and financial demands of bomber development in the jet age meant that modern, purpose-designed bombers were out of reach of all but a handful of nations.
The result was that many countries continued flying aging wartime designs, or reached for extemporized solutions—when the situation demanded it.
During the first two decades of its existence, Israel struggled to get its hands on any kind of effective weapons—bombers included. In the 1948 War of Independence, the Israelis used a motley collection of light civilian aircraft—Austers, Piper Cubs, Fairchilds, Bonanzas and a Dragon Rapide—to drop light bombs and incendiaries on targets around Jerusalem.
The crews stored bombs in the airplanes’ cabins—or even on their laps—and delivered them by hand. More potent was the World War II-era Curtiss C-46 Commando transport, which the Israelis employed as a night bomber to help blunt the advance of Egyptian forces.
When India and Pakistan went to war in 1965, both countries’ air forces had concentrated on building up impressive fighter inventories, with less attention paid to bomber aircraft.
In numerical terms, Pakistan was at a considerable disadvantage. It fell upon the Lockheed C-130 Hercules of the Pakistani air force to bomb Indian tank and gun concentrations, while bomb-laden fast jets struck the prized Indian airfields.
Typically flying by night for their own protection, the Pakistani “Hercs” could carry an impressive load of 18 1,000-pound bombs each. By the time of the 1971 Indo-Pakistani War, the Indian air force emulated its foe, and employed Antonov An-12 transports—the Soviet answer to the C-130—in an offensive capacity, attacking troop concentrations and fuel and ammo dumps.
The air wars in Southeast Asia saw a variety of efforts to create transport-bombers—on both sides. French-operated Ju 52s and C-47s were among the first aircraft to drop bombs during the conflict in 1946.
For the U.S. military in Vietnam, pinpoint accuracy was a lesser concern with the BLU-82 Daisy Cutter, a monstrous weapon dropped with a parachute from the rear ramp of U.S. Air Force and South Vietnamese C-130s.
The Pentagon intended the 15,000-pound bomb to clear jungle landing zones for helicopters. The largest conventional bomb at the time, the South Vietnamese also used the BLU-82 against key communist targets.
After use as a mine-clearance device during the 1991 Gulf War, the BLU-82 returned to offensive duty as an anti-personnel weapon during the early stages of Operation Enduring Freedom. The last operator of the BLU-82 were the MC-130E commando transports of the 711th Special Operations Squadron. The unit dropped the U.S. Air Force’s final operational Daisy Cutter in 2008.
But in the early 1970s, with the war in Vietnam drawing to its conclusion, South Vietnamese C-130s mounted a last-ditch effort to stem the communist advance as North Vietnamese forces moved closer to Saigon.
The South Vietnamese C-130As could drop 24 750-pound bombs carried on six pallets, delivered off the rear ramp. An enduring problem of using transports as bombers is the typical lack of accuracy—so Saigon’s C-130s carried a Beacon-Only Bombing System calculator, into which crews could feed target coordinates.
By contrast, the North Vietnamese used the diminutive Antonov An-2 biplane for strike operations. In January 1968, Hanoi earmarked these transport-bombers for a remarkable mission that aimed to put a remote mountaintop radar station in Laos—that helped direct U.S. air strikes—out of action.
Since the bulk of the North Vietnamese air force was busy defending the homeland—and consisted heavily of interceptors—Hanoi judged the antiquated-looking An-2 as the best tool for the job. The North Vietnamese added rocket pods to the plane’s wings, and vertical tubes in the cargo hold for launching mortar rounds.
Four Antonovs carried out the raid, but the two designated strike aircraft chose the wrong target—an Air America operations building—and one of the planes crashed after taking ground fire.
The remaining An-2s turned and ran, but an Air America Bell UH-1D Huey helicopter intercepted the planes in flight. A combination of rotor wash and AK-47 fire from aboard the Huey downed a second An-2—one of the most unusual aerial victories of the conflict.
The C-130 was back in action as a bomber during the Argentine invasion of the Falkland Islands in 1982. Argentina’s Hercules transports delivered troops, artillery and air-defense equipment to the occupied islands—and flew maritime surveillance missions and aerial refueling sorties for Argentine jets.
On May 29, a C-130 equipped to carry bombs hit the British tanker British Wye, north of the island of South Georgia.
The plane dropped eight bombs, but only one of these hit its target, and failed to detonate. The presence of British Royal Navy Sea Harrier fighters deterred any further such efforts by the Argentines.
During Croatia’s independence war in the early 1990s, An-2s—former civilian crop-sprayers—flew into action on bombing missions with GPS equipment for improved accuracy.
The Croatians dropped improvised bombs adapted from fuel cans—and boilers packed with explosives and metal bars. In December 1991, a Serbian SA-6 surface-to-air missile shot down one of the Croatian bombers.
But the most extensive use of transport-bombers in recent years has been in Africa. Beginning in the early 1990s, primarily Soviet-designed transports—colloquially known as “Antonov bombers”—have waged a little-known and particularly bloody war in Sudan.
Initially, the Sudanese air force dropped Soviet-made bombs from the rear ramps of An-12 and An-26 transports. Later, Khartoum resorted to locally-made bombs—typically fuel drums filled with explosives and shrapnel.
Most remarkably, Sudan hired civilian operators—both local and foreign—who used the aircraft against the rebel Sudan People’s Liberation Army. On several occasions, the Antonov bombers attacked humanitarian relief centers.
It seems unlikely that Russia’s Il-76s will see combat in their bombing role anytime soon—not least because they are far more important as the backbone of the armed forces’ air assault capability.
But the very fact that the Kremlin is putting the planes through their paces for offensive missions indicates the transport-bomber concept still generates interest, even if they’re only a last resort.