Papy Gunn’s Folly
At 7:42 a.m. on August 17th, 1942, Captain Paul “Papy” Gunn crouched beneath the wing of a Douglas A-20 Havoc at Eagle Farm Airfield near Brisbane. The air smelled of welding smoke, hot oil, and Queensland heat. Mechanics were cutting and fitting steel where the bombardier’s compartment used to be, welding .50-caliber machine guns into the nose as if they were building an entirely new aircraft from the inside out.
Gunn was forty-three. He had spent twenty-one years in the Navy. And his wife and four children were trapped in a Japanese prison camp in Manila.
The Fifth Air Force was losing bombers faster than replacements arrived. In July alone, the 3rd Attack Group had lost eleven A-20s trying to hit Japanese convoys from high altitude. Bombardiers could not reliably hit moving ships. When crews dropped lower to improve accuracy, Japanese deck guns shredded them. Captain Ed Larner had watched three crews burn in the Coral Sea the previous week. Meanwhile, Japan was reinforcing New Guinea almost at will.
Gunn had a different idea.
If bombers came in low enough, they could skip bombs across the water like stones and hit ships at point-blank range. But to survive the approach, they needed to overwhelm deck guns with forward firepower. That meant turning bombers into strafers.
The problem was simple: the A-20’s nose carried four .30-caliber machine guns, and .30-caliber rounds bounced off ship plating like hail. Gunn needed .50s—four of them—mounted where the bombardier sat, firing straight ahead. Combined, they could throw roughly 1,700 rounds per minute into a ship’s bridge and gun crews.
General George Kenney, newly assigned as commander of the Fifth Air Force, gave Gunn one week to prove the concept could work.
Gunn scavenged the .50-caliber guns from wrecked P-39 and P-40 fighters. The pilots were dead. The guns weren’t. He built a steel frame inside the A-20’s nose to mount the weapons. Each gun weighed about sixty-four pounds. Add mounts, ammunition, and feed systems and the weight came forward hard—enough to shift the center of gravity so badly the first test flight nearly killed the pilot. The aircraft barely climbed. It wanted to nose over.
Gunn spent two days rebalancing the plane, moving equipment aft and adjusting trim. The second test pilot reported the aircraft “flew like it was angry,” but it flew.
On September 12th, sixteen modified A-20s hit the Japanese airfield at Buna. They came in at treetop height, guns hammering. They destroyed fourteen aircraft on the ground and suppressed every anti-aircraft position. Not a single A-20 was lost.
Kenney wanted more. But the A-20 had limits: short range, light bomb load, and not enough room to evolve into what Gunn had in mind. Gunn needed a bigger platform.
He needed the B-25 Mitchell.
Building the Gunship
In December 1942, Gunn pulled the bombardier and nose guns out of a B-25C and installed four fixed .50-caliber guns in the solid nose. Then he added four more in external cheek packs. He rotated the top turret forward. Ten forward-firing guns.
Then he added two more guns on each side—fourteen guns total—spitting roughly 215 pounds of lead per second.
The ground crews called the aircraft Papy’s folly.
The prototype was nose-heavy. On takeoff it wanted to drop out of the sky. Gunn had to hold full back pressure on the stick just to keep it level. But once airborne, the B-25 became something else entirely—a flying destroyer.
Kenney ordered twelve more conversions immediately. At Townsville, the 81st Air Depot Group worked eighteen-hour days, modifying every available B-25. By February 1943, thirty strafers were ready for combat.
Kenney sent the blueprints to Wright Field in Ohio.
The engineers studied them and sent back a message: the modifications were impractical. The airplane would be too heavy. The balance would be wrong. It wouldn’t fly properly. They recommended grounding every modified B-25 at once.
Kenney was in Washington when the message arrived. He walked into General Hap Arnold’s office where the Wright Field engineers were waiting to explain why Gunn’s gunship was impossible.
Kenney told them twelve of those “impossible” airplanes had just played the key role in destroying a Japanese convoy in the Bismarck Sea. Every transport sunk. Sixty more strafers were already being modified in Australia.
Arnold practically ran the engineers out of his office.
The Battle of the Bismarck Sea
It began with intercepts on February 28th, 1943. Allied codebreakers in Melbourne decrypted Japanese naval messages: a convoy was leaving Rabaul—eight transports, eight destroyer escorts, nearly seven thousand troops bound for Lae on New Guinea’s north coast.
Kenney had seventy-two hours to stop them.
The convoy would cross the Bismarck Sea between New Britain and New Guinea—four hundred miles of open water. Japanese commanders believed monsoon weather would shield them: low clouds, heavy rain, poor visibility. Bombers couldn’t hit what they couldn’t see.
They were right about the weather.
They were wrong about what the bombers were going to become.
On March 2nd, reconnaissance aircraft spotted the convoy steaming south through the Vitiaz Strait. B-17 Flying Fortresses attacked from 15,000 feet through breaks in the clouds, dropping 137 bombs. Crews claimed hits. Post-battle analysis showed they sank nothing. High-altitude bombing against moving ships didn’t work.
The convoy kept coming.
That night, the ships scattered. Transports hugged the New Guinea coast. Destroyers formed a screen. Japanese commanders expected to reach Lae by dawn on March 4th, unload under fighter cover, and change the war in New Guinea.
They had no idea what was coming at first light.
On the evening of March 2nd, Captain Ed Larner briefed the strike force at Port Moresby: twelve B-25 strafers, thirty modified A-20 Havocs, Royal Australian Air Force Beaufighters, and P-38 Lightnings to handle Japanese Zeros.
The strafers would attack at mast-head height—fifty feet above the water. The plan was simple: overwhelm deck guns with concentrated forward firepower, skip bomb the ships while their gunners were stunned, and get out before fighters arrived.
Larner had flown exactly one practice mission using the tactic.
When his navigator asked what happened if the strafers took fire on the approach, Larner answered honestly.
“We’ll find out tomorrow.”
Nobody slept.
At 06:30 on March 3rd, the strike force assembled over Cape Ward Hunt—137 aircraft. The B-17s went first, drawing defensive fire high.
Then the strafers came.
Larner led the B-25s in from the southeast at wave-top height. Twelve aircraft. Fourteen forward-firing guns per plane. One hundred sixty-eight guns total, coming in like a wall of metal three hundred yards wide.
On the transport Kyokusei Maru, Japanese lookouts saw them at two miles. The captain ordered hard to starboard.
Too late.
The B-25s opened fire at 800 yards. The .50-caliber rounds walked across the water and tore into the ship’s superstructure, shredding the bridge and killing anti-aircraft crews before they could traverse their guns.
Three B-25s dropped bombs at close range. One skipped off the water, struck the hull below the waterline, and detonated inside the engine room. Another hit amidships. A third missed.
Kyokusei Maru was dead in the water within thirty seconds, burning and listing. It sank within the hour.
Then Teiyo Maru tried to run.
The transport’s maximum speed was fifteen knots. The B-25s were doing 240 knots. The outcome was arithmetic.
Strafers bracketed the ship from both sides. Streams of .50-caliber fire converged on the deck. Gun crews died at their positions. Bridge windows shattered. Officers collapsed at their stations. Eight bombs were dropped—five hit.
The ship broke in half.
Soldiers trapped below decks never made it to the surface.
Teiyo Maru sank in six minutes.
Across the convoy, chaos multiplied. Australian Beaufighters hammered destroyers trying to screen the transports. Then the strafers arrived and finished what the first waves began.
By 0900, the convoy was scattered across forty square miles of ocean—transports burning, destroyers crippled, survivors in the water wearing full combat gear that dragged them under.
At 1400, the strafers returned with fresh bombs and full ammunition loads. Japanese fighter cover was absent—the Zeros had landed at Lae to refuel and were still on the ground.
The transport Oigawa Maru took repeated hits and capsized.
The transport Iō Maru suffered catastrophic explosions. Its magazine detonated in a blast visible from Port Moresby 130 miles away. When the smoke cleared, there was nothing left—no wreckage, no survivors. Approximately 1,800 troops vanished in seconds.
Modified A-20s hunted the crippled destroyers. The destroyer Asashio was struck while attempting rescue operations and burned into the night, sinking at dawn on March 4th.
By the evening of March 3rd, the Japanese convoy was destroyed: eight transports sunk, four destroyers sunk. Of nearly seven thousand troops who left Rabaul, fewer than 1,200 reached Lae. Another 2,700 were rescued and returned to Rabaul. The rest died in the Bismarck Sea.
Allied losses: four aircraft—one B-17 and three P-38s—thirteen aircrew killed.
MacArthur called it one of the most complete and annihilating combats of all time. Japan never again attempted to reinforce New Guinea by convoy.
And the turning point—the hinge that made it possible—was Paul Gunn’s “impossible” gunship.
“Impossible” Goes to the Factory
Back in Australia, Wright Field engineers were still drafting their report explaining why the B-25 modifications couldn’t work.
Kenney sent Hap Arnold a message on March 5th. The subject line read: “Commerce destroyer modifications approved for production.”
In Washington, Arnold called North American Aviation’s president, J.H. “Dutch” Kindelberger. Kindelberger said his engineers needed to see the modifications.
Arnold said he was sending the man who designed them.
Paul Gunn was going to California.
Gunn didn’t want to leave. His wife, Polly, and their four children were still in Santo Tomas internment camp in Manila. They had been held since January 1942. Fourteen months. Every mission Gunn flew felt like a step toward freeing them. California felt like flying in the wrong direction.
Kenney made it an order. The Fifth Air Force needed hundreds of factory-built strafers, not field prototypes. Gunn was the only man who could show North American how to do it right.
Kenney promised Gunn would be back in the Pacific within six weeks.
He was.
Gunn landed in Long Beach on March 27th, 1943. The plant sprawled across 140 acres. Twenty thousand workers ran three shifts. One B-25 rolled off the line every four hours.
Engineers studied Gunn’s hand-drawn sketches. They asked for stress calculations. Gunn said he didn’t have any. They asked about wind-tunnel testing. Gunn said he’d tested it by flying it. They asked about the center-of-gravity problem. Gunn showed them what he’d moved aft to compensate.
One engineer warned muzzle blast would peel the fuselage skin around the cheek mounts. Gunn agreed—it did—and then showed the blast tubes he’d welded to extend beyond the propeller arc.
Problem solved.
The factory spent two weeks converting field improvisation into production drawings: reinforcing the nose, redesigning mounts, adding heavier gauge aluminum patches, calculating trim adjustments down to the pound and inch.
On May 10th, 1943, the first factory-built B-25G rolled off the line: solid nose, multiple .50s, and a 75mm M4 cannon.
The cannon recoiled four feet when fired. The whole aircraft shuddered. The navigator reloaded by hand. One round every thirty seconds.
Gunn told them it would work against ships—maybe not against anything fast.
North American built 400 B-25G strafers. Then came refinements: the B-25H with improved cannon systems and fourteen forward-firing guns, and later the B-25J, which removed the cannon and increased gun concentration—eighteen forward-firing guns, the most heavily armed production bomber in history.
Thousands were built. Hundreds went to the Pacific. The concept spread across theaters.
The name changed, the mounts changed, the factory paperwork became neat and official—but the idea remained Gunn’s: if you couldn’t hit ships from high altitude, you would fly low enough to look sailors in the eyes, and you would bring enough forward firepower to survive long enough to skip a bomb into the hull.
The War Becomes Personal Again
Gunn returned to Australia exactly six weeks later. His family was still in Manila.
The strafers kept hunting. They attacked barges, harbors, fuel facilities. Japan stopped moving supplies in daylight. The strafers learned night attacks with radar, coordinated strikes with PT boats that lit targets at the last second.
The Japanese called the modified B-25s Black Death.
In 1944, the Fifth Air Force’s strafers destroyed aircraft on the ground, sank ships, and killed tens of thousands of enemy troops. And Gunn kept modifying—adding fuel tanks for range, improving cooling, adjusting ammunition loading, inventing solutions the night before missions.
He flew even when he didn’t have to, because every sortie felt like a thread pulling him closer to Manila.
Then, on November 27th, 1944, Japanese bombers struck Tacloban airfield at 0330. Gunn was in the operations tent when the first bombs hit. Shrapnel tore through canvas. A fragment struck his leg, severing an artery. Another hit his shoulder.
The surgeon said he would not fly for six months—maybe longer. The wounds qualified him for medical retirement.
Gunn refused to go home.
He wasn’t leaving until his family was free.
February 1945: Santo Tomas
The Battle of Manila began on February 3rd, 1945. Fighting went house to house. The Japanese had declared the city a fortress.
Santo Tomas internment camp was liberated on February 3rd—3,700 prisoners freed.
Polly weighed 89 pounds. Their daughter Julia weighed 63. Their son Nathaniel had malaria. The youngest had dysentery.
But they were alive.
Gunn flew to Manila on February 4th against medical orders. He walked with a cane. His leg was still bandaged. He didn’t go to a flight line.
He went to Santo Tomas.
Polly didn’t recognize him at first. He had lost forty pounds. His hair had gone gray. She thought he was a doctor—until he said her name.
The official report would later state: Colonel Paul I. Gunn was reunited with his family on February 4th, 1945, at Santo Tomas internment camp.
The reunion lasted four hours.
Then Gunn returned to Leyte, because his medical leave wasn’t finished and the war wasn’t either.
Aftermath
By war’s end, thousands of B-25s had been built, and a huge portion of the most effective anti-shipping aircraft in the Pacific carried forward-firing gun packages rooted in Gunn’s original field improvisation.
The engineers had called it impossible. The battle proved otherwise.
Gunn never flew combat again. His leg wound ended his operational career. He retired as a full colonel on June 30th, 1948.
He rebuilt Philippine Airlines with war-surplus aircraft and expanded it through the late 1940s and 1950s until it became an international carrier. He gave money to veterans’ groups. He rarely spoke about what he’d done.
General Kenney wrote later that Gunn’s mechanical genius and combat innovation changed the course of the war in the Southwest Pacific—that without the strafers, the Bismarck Sea would have been a Japanese victory, and without that, New Guinea and the road to the Philippines might have been impossible.
Gunn never complained about promotions denied or medals argued over.
He had what he fought for.
His family was free. The Philippines were liberated. The war was won.
That was enough.
