At 3:58 on the afternoon of 29 May 1951, a red P-51 Mustang lifted off from Bardufoss in northern Norway with one man in it and no radio navigation aids ahead of him worth the name. Charles Blair was going to fly over the North Pole to Alaska, alone, in a single-engined fighter, using the sun.

Ten hours and twenty-seven minutes later he landed at Fairbanks. The magnetic compass had been useless for most of it, exactly as he had expected.

A racing Mustang with a wing full of fuel

Excalibur III had already had two lives before Blair got hold of it. Built in Dallas as a P-51C-10-NT, it was bought after the war by the Hollywood stunt pilot Paul Mantz, painted red and named Blaze of Noon. Mantz won the Bendix Trophy transcontinental race with it in 1946 and again in 1947. Renamed and flown by others, it placed second in 1948 and third in 1949.

Mantz had done something drastic to make that possible. He stripped out the standard 90-gallon self-sealing tanks and turned the entire wing into a fuel tank — a wet wing. That modification is the whole reason the transpolar flight was physically possible.

Pan American bought the aircraft for Blair, its chief pilot. He first named it Stormy Petrel, then settled on Excalibur III after the Sikorsky VS-44 flying boat he had flown for American Export Airlines.

Four months earlier: New York to London

Blair had already used the Mustang to make a point about the jet stream. On 31 January 1951 he flew it from New York to London in 7 hours 48 minutes, averaging 446 mph and climbing as high as 37,000 feet in an unpressurised single-seat fighter.

It was a remarkable time for a piston-engined aeroplane. It was never an official record, because nobody had arranged for the Fédération Aéronautique Internationale to observe it.

Navigating where the compass lies

The polar problem is simple to state and brutal to solve. Near the magnetic pole a magnetic compass wanders or simply points at the ground. In 1951 there were no satellites, and over the Arctic Ocean there were no radio beacons either.

Blair's answer was to navigate by the sun. Working with Captain Philip Van Horn Weems, the retired US Navy officer who had spent a career turning celestial navigation into something a pilot could use at speed, he had a set of sun lines calculated in advance for specific positions and specific times. In the cockpit he checked them with an Astrocompass Mark II.

The flight plan was geometry. North along the 20th meridian east, across the Pole at 22,000 feet, south down the 160th meridian west to latitude 70 north, then a turn southeast for Fairbanks. If the sun lines were wrong, or if he flew them badly, there was no diversion airfield and no rescue.

They were not wrong. He arrived.

What it proved

President Truman presented Blair with the Harmon International Trophy at the White House on 18 November 1952. The award exists for exactly this kind of thing.

The practical consequence was bigger than the trophy. Blair had demonstrated that the polar route was navigable and therefore that it was commercially usable. Within a few years airlines were flying over the top of the world, cutting hours off Europe-to-Asia and Europe-to-west-coast schedules. The Cold War air forces were paying attention too: in 1959, by then a brigadier general in the Air Force Reserve, Blair led two F-100 Super Sabres non-stop from England to Alaska over the Pole.

He kept flying to the end. Blair was killed on 2 September 1978 when a Grumman Goose he was captaining for his own airline, Antilles Air Boats, suffered an engine failure shortly after takeoff in the Caribbean. He was 69.

Excalibur III was given to the Smithsonian by Pan American in 1952. It hangs at the Udvar-Hazy Center now, restored, still red. It is worth standing under it and remembering that this small fighter once flew over the North Pole with one man and a sun table.

Sources: Smithsonian National Air and Space Museum, This Day in Aviation, Wikipedia, and Smithsonian Magazine. No archival film of the transpolar flight could be verified for embedding.