The North American XP-82 Twin Mustang, Tom Reilly's Eleven-Year Restoration in Kissimmee, and the Last Propeller Fighter in American History

The North American XP-82 Twin Mustang is the only aircraft in American history to hold two distinctions simultaneously: it was the last propeller-driven fighter ever ordered by the United States Army Air Forces, and its production descendant, the F-82, scored the first three aerial victories of the Korean War. In early 2018, after eleven years of restoration work by Tom Reilly’s team in Kissimmee, Florida, the original Merlin-powered XP-82 prototype flew again - the only airworthy example of its type on earth.

A Design That Looks Impossible

The XP-82 stops people on the ramp. Two complete fuselages. One shared center wing section and a common horizontal stabilizer. Two Packard-built Merlin engines turning in opposite directions, their counter-rotating propellers canceling the left-turning torque tendencies that define single-engine flight. The pilot sat in the left fuselage; the right seat accommodated a navigator, radar operator, or co-pilot.

North American Aviation designed the XP-82 to share a large percentage of components and manufacturing tooling with the existing P-51 Mustang production line. It was an audacious configuration built on a proven foundation - not a reinvention from a blank sheet.

Why the Army Air Forces Needed It

By 1943, American war planners were already modeling the final phase of the Pacific war: a strategic bombing campaign against the Japanese home islands by Boeing B-29 Superfortresses, followed by a full-scale invasion. Those B-29s would need escort fighters capable of flying extreme-range round trips and still carrying enough fuel to engage Japanese interceptors over the target.

The P-51 Mustang was the finest single-engine escort fighter in existence. But Japan was a very long way from any forward base American forces could realistically hold. The XP-82’s internal fuel range tested at approximately 2,200 miles. With drop tanks, it could theoretically fly from California to Hawaii and land with reserves. Army Air Forces commanders placed a contract for more than 500 aircraft.

The Counter-Rotating Sound

Those two twelve-cylinder Merlins, turning in opposite directions, produced a sound unlike anything else in the air. A single Merlin has its own even, layered beat. Two independent aircraft in formation produce an out-of-sync drone. The XP-82’s counter-rotating engines created something different - a braided harmonic, two overlapping waves of power bound into a single voice that belonged to no other aircraft on the planet.

The people on the ramp at Kissimmee in 2018 heard that sound for the first time in decades when the restored prototype ran up to power.

The War It Was Built for Never Happened

August 1945 ended the Pacific war before the XP-82 reached operational squadrons. The atomic bombings of Hiroshima and Nagasaki brought Japan’s surrender and rendered Operation Downfall - the planned invasion of Japan - a planning document rather than a campaign. Most of the 500-aircraft contract evaporated overnight.

Aircraft that did reach production were redesignated F-82 as the Air Force transitioned away from Army Air Forces naming conventions. These production models underwent a significant change: complications with the Packard-Merlin licensing arrangement led to installation of Allison V-1710 engines in place of the original supercharged Merlins. The Allison was a capable motor - it had powered earlier P-51 variants before the Merlin swap transformed that design - but it gave up high-altitude performance against the supercharged Merlin. Pilots who flew both versions had opinions on that trade. Those opinions were not always polite.

The Korean War: First Kills from the Last Propeller Fighter

When North Korea crossed the 38th parallel on June 25, 1950, F-82 Twin Mustangs flew some of the very first American combat missions of the war. The first three aerial victories credited to American pilots in Korea all went to F-82 crews.

The last propeller fighter contract in American history produced the first combat kills of a brand new war. That symmetry was not planned. It was simply how the calendar turned.

By the time the Korean War wound down, swept-wing jets had replaced the F-82 entirely. Surviving Twin Mustangs went to museums, storage, and the Davis-Monthan Air Force Base boneyard in Arizona. Some were scrapped. By the end of the twentieth century, airworthy Twin Mustangs were extraordinarily rare, and the original Merlin-powered XP-82 prototype was down to one surviving candidate capable of ever flying again.

Tom Reilly’s Eleven-Year Restoration

Tom Reilly operates a restoration shop in Kissimmee, Florida. Outside warbird circles he is not a widely known name. Inside them, he is as close to legendary as the community produces.

His team understood a critical distinction before touching the XP-82: cosmetic restoration produces an aircraft that looks perfect on static display. Airworthy restoration produces an aircraft that can leave the ground - and that demands a completely different standard. Every fastener, hydraulic line, seal, and bearing has to function, not just appear correct. Someone would be in those cockpits at altitude with nothing but the quality of the restoration between them and the ground.

The XP-82 project exceeded even that standard.

The two Packard-built Merlin engines had to be located, disassembled completely, inspected, machined where necessary, and rebuilt from their cores. Counter-rotating Merlins configured for the XP-82’s specific installation are not found in surplus dealers’ back rooms. Parts that no longer existed anywhere had to be fabricated from scratch - which required original engineering drawings. Those drawings had survived through several corporate incarnations of North American Aviation, and finding them in the early 2000s required serious archival research.

Reilly’s team also tracked down retired engineers - men who had worked in North American’s Inglewood, California plant in the 1940s - who might remember a specific assembly technique, a material specification, or a torque value never recorded in any surviving document. Some of those men were in their eighties and nineties by then. The window to reach them was closing every year. The oral history embedded in that generation of aviation engineers is irreplaceable, and every year more of it disappears permanently.

Eleven years. Nearly four thousand days of serious work. Budget pressures, sourcing dead ends, parts that failed inspection, measurements that did not match drawings. The kind of commitment most people who start a project of this scale do not finish.

Tom Reilly finished it.

First Flight: Early 2018

In early 2018, the XP-82 Twin Mustang flew again for the first time in decades. The first sortie was deliberate and conservative - get the aircraft airborne, verify control response, run the systems, confirm that everything built on the ground functioned in the air as designed. Then bring it back and debrief every reading with the crew waiting below.

It flew. Eleven years of fabricated parts, rebuilt engines, hydraulic seals, and control cables lifted off the runway in Kissimmee and climbed into a Florida sky.

The XP-82 flies airshows now. When it taxies past the crowd line, people stop what they are doing. The shape alone arrests you. Then those two counter-rotating Merlins come up to power, and there is nothing else like it flying anywhere on this planet.

Why This Matters

An aircraft that flies carries information no photograph or digital model can replicate: the way the controls feel, how the structure loads under G, how the airframe responds to turbulence. Books and drawings provide specifications. A flying aircraft provides the experience - and that experience is a direct connection to the engineers, test pilots, and combat crews who built and flew these machines under conditions we can study but never fully know from the outside.

When the last airworthy example of a type stops flying, that connection is permanent. Static museum examples survive as sculptures in aluminum and steel. The aircraft in motion - in its element, being what it always was - disappears.

The team in Kissimmee chose not to let that happen to the XP-82.

Key Takeaways

The North American XP-82 Twin Mustang was the last propeller-driven fighter ordered by the U.S. Army Air Forces, designed in 1943 to escort B-29 Superfortresses on extreme-range missions over Japan.
Internal fuel range reached approximately 2,200 miles; with drop tanks, the XP-82 could theoretically fly from California to Hawaii with reserves.
Production F-82s flew the first American combat missions of the Korean War and are credited with the first three aerial victories scored by U.S. pilots in that conflict, beginning June 25, 1950.
Tom Reilly’s Kissimmee, Florida shop completed an eleven-year restoration of the original Merlin-powered XP-82 prototype; it flew again in early 2018.
The restored XP-82 is the only airworthy example of the original prototype anywhere in the world.