How the B-25 Became the Deadliest Gunship of World War II

And he was about to change the course of the air war against Japan. Papy Gun was no ordinary officer. Born in Quipman, Arkansas in 1899, he had already lived what most would consider a full life by the time World War II reached the Pacific. He had spent 21 years as an enlisted naval aviator, teaching himself to fly in his spare time because his lack of formal education barred him from becoming an officer.
After retiring from the Navy, he’d moved to the Philippines where he ran a small airline with his wife and four children. Then Pearl Harbor was attacked and everything changed. When the Japanese invaded Manila, Gun’s family was captured and sent to an internment camp. He himself barely escaped, evacuating to Australia, where he found himself back in uniform, this time in the Army Air Forces with a captain’s commission.
The war gun found in Australia was not going well. American and Australian forces were barely holding on in New Guinea, fighting a desperate defensive campaign against a seemingly unstoppable Japanese advance. The problem wasn’t just on the ground. In the air, American bombers were proving woefully inadequate for the kind of warfare the Southwest Pacific demanded.
Medium altitude bombing runs against Japanese ships were exercises in futility. Bombs dropped from 10,000 ft rarely hit their targets. Japanese cargo ships and transports warned by the sound of approaching engines simply maneuvered out of the way. Even when bombs did hit, they often failed to sink the heavily constructed vessels.
The margin of error was too great, the targets too maneuverable, and the Japanese too adept at defensive sailing. The commander of the Allied Air Forces, Lieutenant General George Churchill Kenny, understood the problem all too well. Kenny was a World War I fighter ace who had learned his trade in the skies over France.
He was innovative, aggressive, and willing to try unconventional solutions. When he arrived in Australia in July 1942 to take command, he immediately began looking for ways to make his air forces more effective. One of the first things he noticed was that the third bombardment group had taken delivery of a number of A20 Havoc light bombers.
But these aircraft were proving only marginally more successful than the medium bombers. They could carry bombs and they were relatively fast. But they couldn’t hit moving ships any better than anything else in the infantry. This is where Papy Gun entered the picture. Kenny was taken to meet Gun at Charter’s Towers by Lieutenant Colonel John Davies, commander of the Third Bombardment Group.
Davies, known to everyone as Big Jim, had recognized Gun’s mechanical genius and was already putting him to work on various modifications. When Kenny arrived at the field, he found Gun in a maintenance shelter, sleeves rolled up, installing machine guns into the nose of an A20. The old naval aviator had a theory. If they couldn’t hit ships from medium altitude, they needed to go lower, much lower, down to 250 ft above the water.
At that altitude, bombing accuracy would improve dramatically. But there was a problem. Flying that low meant exposing the attacking aircraft to devastating anti-aircraft fire from the ship’s light guns. Japanese destroyers and cargo vessels bristled with 20 mm and 25 mm automatic cannons.
And at low altitude, these weapons were murderously effective. Gun solution was elegantly simple. If they were going to fly low, they needed guns. Lots of guns. Forward firing guns that could sweep the decks of enemy ships before the bombers came into range, suppressing the anti-aircraft fire and giving the attacking aircraft a fighting chance.
He’d already begun scrging 50 caliber machine guns from Rexed P40 fighters scattered around Australia and he was installing them in the A20’s nose compartment. Four forwardfiring 50 caliber Browning machine guns all aimed straight ahead, all controlled by the pilot. Kenny immediately grasped the potential.
He authorized Gun to continue the modifications and assigned him to his personal staff as a special projects officer. The old naval aviator went to work with a vengeance. Within weeks, 16 modified A20s were ready for combat. On September the 12th, 1942, they were put to the test in a raid on the Japanese airfield at Buuna.
The results were spectacular. Flying at treetop level, the Strafers tore across the airfield. Their combined firepower shredding Japanese aircraft parked in the open and tearing into fuel dumps and ammunition stores. The Japanese were caught completely by surprise. They had never faced anything like this concentrated low-level firepower.
Buildings exploded, aircraft burned, and personnel scattered in all directions. The attack proved guns concept worked, but the A20 had limitations. Its range was relatively short, restricting it to targets within about 200 m of Allied airfields. It couldn’t carry a particularly heavy bomb load and there simply weren’t enough A20s in the theater.
Most of the available aircraft were being sent to the Soviet Union under lend lease. What Kenny needed was something with more range, more payload capacity, and more firepower. He needed the B25 Mitchell. The North American B-25 Mitchell medium bomber had arrived in the Southwest Pacific in early 1942 assigned to the third bombardment group.
It was a solid reliable aircraft powered by two right 2600 radial engines that gave it a top speed of around 270 mph and range of over,300 m. The early models carried a crew of six and were armed with a collection of 30 and 50 caliber machine guns in various positions, plus up to 3,000 lb of bombs. But like all the other bombers in theater, it had been designed for medium altitude level bombing runs.
And in that role, it was proving only marginally effective against shipping and ground targets. Gun and Jack Fox, North American Aviation’s field technical representative in Australia, had been discussing B25 modifications since June of 1942. Fox had even sent drawings back to the factory in California showing how 50 caliber machine guns could be mounted in the Bombardia’s nose compartment.
But at the time, there weren’t enough B-25s to spare any for experimental modifications. That changed after the success of the A20 Strafers. Kenny gave Gun and Fox authorization to convert one B-25 and see what they could do. The aircraft they chose was B-25C serial number 4112 437. The modification was straightforward in concept but tricky in execution.
Since low-level attacks would be delivered by the pilot, not the bombardier, the bombardier’s position and all the plexiglass in the nose could be eliminated. In its place, Gunn and his team at Eagle Farm airfield in Brisbane installed four 50 caliber machine guns with 500 rounds per gun, all aimed directly forward and all controlled by the pilot.
The guns were positioned through the former bomb aiming panel, which made sealing the installation relatively easy. Two more pairs of 50 caliber guns were installed in external package housings on either side of the lower fuselage just below and behind the cockpit. The upper turret’s twin 50 calibers could also be trained forward to add to the firepower, though they weren’t controlled by the pilot.
The result was a bomber that could bring eight 50 caliber machine guns to bear on a target in a single devastating salvo. There was just one problem. Would it fly? The weight distribution had changed significantly with all those guns and ammunition in the nose. The aircraft had to be carefully balanced and nobody was quite sure how it would handle.
Gun took it up himself for the test flight. The ground crew had christened it Papy’s Folly, a name that reflected their skepticism about whether this crazy contraption would actually work. But Gun was confident. He’d done the calculations. He checked the weight distribution. and he knew his aircraft. He fired up the engines, taxied out, and took off without incident.
The B-25 flew perfectly. In fact, it flew better than expected. The solid nose actually improved the aircraft’s aerodynamics slightly compared to the glaze bombardier’s position. When word got back to General Kenny that the conversion was successful, he immediately authorized the modification of 12 more B-25s, enough to equip an entire squadron.
The 90th Bombardment Squadron, part of the third bombardment group, was selected to receive the modified aircraft. The squadron had recently lost its commander, Captain William Red Johnson, in a transit crash on New Year’s Eve, and morale was low. The new commander was Captain Ed Lana, a barrel-chested, aggressive pilot who wore his service cap pushed back on his head and had a reputation for being willing to settle arguments with their fists.
Lana was skeptical at first. The idea of using a medium bomber for low-level strafing and skip bombing seemed crazy. Medium bombers were supposed to fly at altitude, drop their bombs, and go home. But Kenny had confidence in him and Gun was persuasive. By the end of December 1942, Lana and his squadron were at Port Moresby learning to fly their new aircraft and practicing a radical new tactic.
That tactic was skip bombing. The concept wasn’t entirely new. The British had experimented with bouncing bombs during World War I. More recently, Major William Ben of the 43rd Bomb Group had successfully used skip bombing with B17 Flying fortresses against Japanese shipping. The principle was simple.
An aircraft would approach a target ship at very low altitude, around 200 to 250 ft, flying parallel to the ship’s length at high speed, around 200 mph. At the right moment, the pilot would release bombs that would skip across the water’s surface like stone, slamming into the ship’s side below the water line where the hull was most vulnerable.
If the bomb missed, it would explode close enough to the hull to cause damage from the blast. Combined with the suppressing fire from the forward guns, skip bombing promised to revolutionize anti-shipping operations. But it took practice, lots of practice. Lana’s crews trained by skip bombing the wreck of a British ship that had run ground in Port Morsby Harbor.
Years before the war, day after day, they practiced their approaches, learned to judge altitude and distance, and got used to the bonejarring experience of flying at high speed just a few hundred ft above the water. It was dangerous work. At that altitude, there was no room for error. A moment’s inattention, a mechanical failure, or a sudden wind gust could send an aircraft cartwheeling into the sea.
But gradually, the crews got better. By February of 1943, they were ready. On December 16th, 1942, before they’d even finished their training, Lana led six of the modified B-25s on their first combat mission. The target was Salamawa, a Japanese base on the northern coast of New Guinea. When they arrived over the target, they found no ships.
So Lana made a snap decision. They’d go after the airfield instead. The six strafers came in low and fast. Their combined firepower raking across the Japanese installations. The effect was devastating. Parked aircraft exploded. Fuel dumps erupted in sheets of flame. Buildings disintegrated under the hail of 50 caliber rounds.
The Japanese had never experienced anything like it. By the time the six B-25s pulled away and headed for home, they’d destroyed dozens of enemy aircraft and left the base in chaos. The Strafer concept had proven itself in combat. But the real test was still to come. In late February 1943, Allied intelligence intercepted Japanese radio transmissions, indicating that a major convoy was being assembled at Rabul.
The Japanese were planning to reinforce their garrison at Lei on the northern coast of New Guinea. The convoy would consist of eight transport ships carrying nearly 7,000 troops escorted by eight destroyers. If those troops made it to Lei, they would significantly strengthen Japanese defenses and make the Allied advance up the coast far more difficult and costly.
Kenny was determined that convoy would never reach its destination. The Allied plan was complex and carefully coordinated. B-24 liberators from the 90th Bomb Group would fly reconnaissance missions, tracking the convoy’s progress. When it came within range, B17 flying fortresses from the 43rd Bomb Group and conventional B-25s from the 38th Bomb Group would attack from medium altitude, breaking up the convoys formation and forcing the Japanese to scatter.
Then would come the Strafers. 13 Royal Australian Air Force bow fighters would go in first at deck level, using their 420 mm cannons and six 30 caliber machine guns to suppress anti-aircraft fire. Right behind them would come 12 B25 Strafers from Lana’s 90th squadron and a dozen A20 Strafers from the 89th Squadron.
P38 Lightning fighters would provide top cover against Japanese fighter aircraft. The convoy left Rabul at midnight on the February 28th, 1943. Allied reconnaissance aircraft spotted them on March 1st, but weather prevented any effective attack that day. On March 2nd, the first strikes went in, damaging one transport ship, but failing to stop the convoy.
The Japanese commander, Rear Admiral Masatomi Kamura, pressed on. He was confident his destroyers could protect the transports and he had nearly a 100 Japanese fighter aircraft providing air cover. But Kamura had never faced the kind of attack that was about to be unleashed on him. March 3rd dawned clear and bright. Perfect flying weather.
At 8:55 that morning, Major Ed Lana, who had been promoted from captain, received word that the attack was on. Within minutes, 12 B-25 Strafers were airborne, their engines thundering as they climbed away from the airfield. Many of the co-pilots and gunners were actually Australian airmen who had volunteered to fly with American units to make up for personnel shortages.
They were heading into what they knew would be one of the most dangerous missions of the war. Prem mission briefings had estimated casualties could run as high as 50%. As the various attack groups converged over Cape Ward Hunt, they could see the Japanese convoy in the distance. Eight transports in a rough formation, surrounded by their destroyer escorts with dozens of fighters circling overhead like angry hornets.
The B7s went in first from altitude, their bombs falling in long, graceful arcs. The Japanese ships broke formation, maneuvering frantically to avoid the falling bombs. Most missed, but the attacks achieved their purpose. The convoy was scattered, the neat formation broken up. Now came the bow fighters, 13 of them screaming in at wavetop height.
Their cannon and machine gun fire swept across the decks of the Japanese ships, killing gunners, destroying light anti-aircraft positions, and creating chaos. And then came Lana’s B25s. They came in low. so low that sailors on the Japanese ships could see the pilot’s faces. The noise was incredible. A rising thunder of twin engines pushed to maximum power.
At that altitude, at that speed, the world compressed to a narrow tunnel of sea spray and smoke and the rapidly growing shape of a target ship. Lana picked out a destroyer and bore in on it. At the last second, he toggled his bomb release and pulled up hard, the G-forces slamming him back into his seat.
Behind him, the two 500 lb bombs skipped across the water like flat stones on a pond, then slammed into the destroyer’s hull. One hit just forward of the bridge. The other was a near miss, but close enough that the underwater explosion tore a massive hole in the ship’s side. All around Lana, his squadron was doing the same thing.
Lieutenant Robert Chat in his B-25, nicknamed Chatter box, sent a bomb directly into the bridge of another destroyer. The fatal hit sending the ship veering wildly out of control until it collided with the transport Noima. Both ships went to the bottom together. Other B-25s attacked the transports. The combined firepower from eight forward firing 50 calibers was devastating.
The heavy slugs tore through light plating, penetrated decks, and wre havoc inside the ships. Japanese sailors and soldiers crowded on deck or below were cut down by the hundreds. Then came the A20s right behind the B-25s, adding their bombs and guns to the carnage. The attack lasted just 15 minutes.
When it was over, all seven transports were either sinking or badly damaged. Three destroyers were gone. Two more were crippled. The Japanese had never experienced anything like it. They had thought their convoy was well protected, but they had had no defense against this kind of concentrated, coordinated, low-level assault. Later that afternoon, a second wave of Strafers went in and finished off what was left of the convoy.
By March 4th, only two badly damaged destroyers remained afloat. Nearly 3,000 Japanese soldiers and sailors were dead. About 5,000 survivors were picked up by the remaining destroyers and submarines, but they were taken back to Rabul. Not one soldier reached lie. The battle of the Bismar Sea was over, and it had been an overwhelming Allied victory.
The impact of that battle rippled far beyond the immediate tactical success. General Douglas MacArthur called it a decisive aerial engagement and sent his congratulations to Kenny. More importantly, the Japanese high command was forced to recognize that they could no longer safely reinforce their garrisons by sea.
The allies had achieved air superiority over the waters around New Guinea, and the B25 Strafer was the weapon that had made it possible. General Kenny immediately ordered all available B-25s in the theater to be converted to strafers. By September 1943, 175 B25C’s and D’s had been modified at the Townsville depot in Australia.
But Kenny wanted more. He wanted factory produced strafers, not field modifications. In early 1943, he traveled to Washington to meet with General Henry Hap Arnold, commander of the Army Air Forces. He laid out his requirements for a factory-built gunship. Arnold was intrigued, but when he called in his engineers from North American Aviation to discuss the project, they told him it was impossible.
The aircraft would be too noseheavy. They said the weight distribution would be all wrong. It would never fly safely. Kenny listened to their objections with growing impatience, then told them that not only was it possible, but he already had an entire squadron of such aircraft operating successfully in combat, and they just played a decisive role in destroying an entire Japanese convoy.
The engineers were dumbfounded. Arnold immediately ordered them to return to California and figure out how to build what Gun had already demonstrated could be done. He also wanted gun brought back to the states to show them how. Major gun recently promoted, returned to the United States, and spent several weeks at North American Aviation’s facilities in California.
He brought with him detailed plans and photographs of his modifications. The engineers, swallowing their pride, studied guns work and began designing factory versions. The result was the B25G. This model featured a shortened solid nose with two 50 caliber machine guns flanking a massive 75 mm M4 cannon, the same gun used on Sherman tanks.
The idea was that a single round from that cannon could or sink a destroyer sized vessel. 400 B25gs were ordered along with conversions of 65 existing B-25C’s. The 75 mm cannon was an impressive weapon on paper, but in practice it proved troublesome. The recoil was tremendous, popping rivets and stressing airframes.
The cannon had to be manually loaded between shots, limiting its rate of fire. Smoke and cordite fumes filled the cockpit when it was fired, choking the crew. And worst of all, by the time the B-25G reached combat units in mid 1943, Japanese shipping targets were becoming increasingly scarce. The Strafers had done their job too well.
Many units in the field began removing the cannon and replacing it with an additional 50 caliber machine guns. The next factory model, the B-25H, addressed some of these problems. It featured a lighter T13E 175mm cannon, four 50 caliber guns in the nose instead of two twin 50 calibers in a repositioned forward dorsal turret, two waste guns, two in the tail turret, and four more in external blister packs.
Total forward firing armorament could reach 1450 caliber machine guns if the dorsal turret was trained forward. 1,000 B25H’s were produced, but the troublesome cannon was still there, and many units continued to remove it in favor of more machine guns. The final and most produced variant was the B25J, which entered service in late 1943.
This model was a hybrid, combining features from earlier versions. It could be configured either as a standard medium bomber with a glazed nose and bombardier, or as a strafer with a solid nose. The J model factory kit for the Strafenos included eight 50 caliber guns. Had in four more in the external fuselage packages, two in the forward dorsal turret, one in each waist position and two in the tail.
And you had a total of 1850 caliber machine guns with 14 of them able to fire forward. It was the most heavily armed aircraft in the American infantry. The combat effectiveness of these flying gun platforms was staggering. In New Guinea, the Philippines, and across the Pacific, B-25 strafers wre havoc on Japanese forces.
They attacked airfields, destroying aircraft on the ground by the hundreds. They struck at bridges, roads, and rail lines. They went after barges, and small craft that the Japanese increasingly relied on as larger ships became too vulnerable. The 409th Bomb Squadron operating in Burma became so adept at destroying bridges that they nicknamed themselves the dental clinic for their bridge work.
The tactics evolved as the war progressed. Pilots learned that the most effective approach was to come in low and fast, usually from an angle that presented the smallest silhouette to defending gunners. They’d open fire with their nose guns at about a thousand yards, the tracers arcing out ahead of them.
The sheer volume of fire from a flight of B25 Strafers was overwhelming. Nothing could survive in that cone of destruction. Anti-aircraft positions were shredded. Parked aircraft exploded. Buildings disintegrated. Troops caught in the open were cut down. And then just as they flashed over the target, the pilots would release their bombs, adding explosive power to the already devastating effect of their guns.
The B-25 Strafer proved itself in every theater where it served. In the European theater, B-25s of the 12th Air Force operating from Italy became expert at hitting German communications and supply lines. In April 1945, they used special incendiary ammunition to destroy dozens of Messid Mitu 62 jet fighters on the ground before they could get airborne.
In the China Burma, India the B25s of the 10th and 14th Air Forces struck at Japanese supply lines, airfields, and river traffic. But it was in the southwest Pacific where the Strafer really came into its own. Major Lana, who had led that first devastating attack at the Battle of the Bismar Sea, didn’t live to see the wars end.
On April 30th, 1943, less than 2 months after his triumph, he was killed in a flying accident at Doadura, he was attempting one of his trademark aggressive landing approaches, diving at the runway and pulling up sharply into a Chandelle, a climbing turn maneuver. But this time, his B-25 was heavily loaded with fuel, passengers, tools, and 2,000 lb of bombs.
When he pulled up, the aircraft stalled, went into a flat spin, and crashed. There were no survivors. He left behind a wife and two young daughters. Command of the 90th Squadron passed to Captain John Jock Henibri, who would continue Lana’s aggressive tradition and become one of the most successful B25 pilots of the war. Papygun remained in the Southwest Pacific for most of the war, continuing to work on aircraft modifications and improvements.
He flew more combat missions than almost any other officer, always testing his modifications under actual combat conditions. In late 1944, he was seriously wounded during a Japanese bombing raid on Lee in the Philippines and was sent home. After the war, he was reunited with his family who had survived their imprisonment by the Japanese.
He retired from the army as a full colonel and returned to the Philippines to rebuild his airline. On October 11th, 1957, he was flying a charter flight when he encountered a severe storm. His aircraft crashed and Papy Gun was killed. He was buried at Barancas National Cemetery at Naval Air Station Pensacola, not far from where he’d learned to fly as a young naval aviator decades earlier.
He left behind a legacy that had fundamentally changed air warfare. The B25 Mitchell went on to become one of the most produced American bombers of World War II. Nearly 10,000 were built in various models, serving with the armed forces of more than a dozen nations. It flew in every theater of the war, from the frozen wastess of the Illutians to the deserts of North Africa, from the jungles of Irma to the islands of the Pacific.
But it was as a strafer, as a low-level gunship bristling with forwardfiring weapons that the Mitchell truly became legendary. The transformation from a conventional medium bomber to what Papy Gun called a commerce destroyer was one of the most successful aircraft modifications of the entire war. The lessons learned from the B25 Strafer program extended far beyond World War II.
The concept of heavily armed gunships attacking ground targets at low level would be refined and perfected in later conflicts. The AC-47, AC19, and AC 130 gunships of the Vietnam War were direct descendants of Papy Gun’s pioneering work. The idea that overwhelming firepower, properly applied at close range, could achieve results out of all proportion to the size of the attacking force became a fundamental principle of closeair support doctrine.
Today, surviving B-25s are prized by museums and warbird collectors around the world. When these aircraft appear at air shows, they draw huge crowds. People stand and watch as these vintage bombers thunder past. And for a moment, they can imagine what it must have been like to be a Japanese soldier or sailor watching a flight of these aircraft bearing down on you at mast head height.
Eight guns in the nose blazing, bombs falling away, the roar of twin engines shaking the ground. It must have been terrifying. The story of how the B-25 became the ultimate strafer is a story of innovation born from necessity, of men willing to think outside established doctrine and of courage under fire.
It’s a story about a grizzled old naval aviator who refused to accept that things couldn’t be done differently. A young general willing to support unconventional ideas and combat pilots brave enough to fly into the teeth of enemy fire at an altitude where the slightest mistake meant death. Together they created a weapon that helped turn the tide in the Pacific War.
The B25 Mitchell Strafer stands as a testament to American ingenuity, adaptability, and the willingness to learn and improve even in the midst of desperate combat. It remains one of the great success stories of World War II aviation. a flying gun platform that struck fear into the hearts of America’s enemies and became a symbol of Allied air power at its most aggressive and effective.