The XF3F-1 first flew on 20 March 1935. To clear the airframe for carrier service, the Navy demanded punishing terminal-velocity dive tests — power-on plunges to the aircraft's absolute limit, followed by a maximum-g pull-out. On 22 March, company test pilot Jimmy Collins took the prototype through a programme of these dives. On the final, most violent recovery the structure failed under the enormous loads and the aircraft broke up in the air, killing him.

Collins was no anonymous test hand. He was a well-known barnstormer and aviation writer whose posthumously published essays, collected as Test Pilot, laid bare the fatalism of the profession — he had, by some accounts, a clear sense of the danger of the assignment. A second prototype was later built and also lost before the strengthened design was finally proven and ordered into production. The F3F's remarkably clean service record and its improbable airworthy survivors are all the more striking set against how bloody and expensive its birth actually was.

Wrap a compact airframe around a big radial engine and you get a very fat fuselage. Grumman's FF, F2F and F3F all shared that rotund, barrel-like body, and crews duly nicknamed them the "Flying Barrel" — sometimes the "Beer Barrel." The look was accentuated on the later Cyclone-powered F3F-2 and F3F-3, whose broader cowling made the barrel fatter still.

It was never a term of abuse. The shape came from a deliberate engineering choice: packing real structural strength, a powerful engine and a retractable undercarriage into the smallest, strongest possible package, at the cost of a fashionable silhouette. Pilots wore the nickname with affection, the way people name a stocky, dependable working dog. In an age when the sleek monoplane was becoming the symbol of progress, the Flying Barrel was a reminder that at sea, in 1936, toughness and agility still beat elegance.

Unlike fighters whose wheels swung into the wings, the F3F drew its main gear up and inward into wells in the sides of its deep fuselage. There was no hydraulic system for it: the pilot turned a crank in the cockpit — commonly remembered as about thirty turns — to raise or lower the wheels. On every take-off, one hand flew the aeroplane while the other wound the gear up; on every approach, the process reversed, at the busiest and most dangerous phase of a carrier landing.

It was slow, heavy and demanding, but it was tough and reliable, and it hid the wheels well enough to matter aerodynamically. Most importantly, the arrangement carried straight over into the F4F Wildcat, which kept a hand-cranked, narrow-track undercarriage into WWII combat — a quirk that caught out many a green Wildcat pilot and traced directly back to these biplanes. Forget one detail about the F3F and you can still recognise its family by the wheels.

The F3F was no museum piece in its day — it was the fleet's fighter. It flew with US Navy squadrons aboard USS Ranger, Saratoga, Yorktown and Enterprise, and with Marine squadrons such as VMF-1 and VMF-2. In the late 1930s, if you saw an American carrier fighter turning over the fleet in its bright pre-war squadron colours, it was very likely one of these stubby biplanes.

Those years were the crucible of US carrier aviation. Doctrine for deck-launched interception, formation tactics and gunnery was being written in real time, and the F3F was the aircraft it was written on. The young officers who mastered the Flying Barrel — its narrow gear, its hand crank, its slow deck approach — were the same men who, a few years later, would take Wildcats and Hellcats into the largest carrier battles in history. The F3F's most important sorties were the thousands of unremarkable training flights that built the fleet's fighter arm.

When the Navy sought the F3F's successor in the mid-1930s, Grumman's first answer was not a leap into the future but another biplane — the XF4F-1, essentially an evolved Flying Barrel. The Navy, increasingly convinced by the monoplane, was unenthusiastic. Grumman scrapped the biplane and redesigned the airframe as the monoplane XF4F-2 and then XF4F-3: the Wildcat.

The Wildcat kept the F3F's rugged structure, its barrel-ish fuselage and its hand-cranked, narrow-track gear, but shed the second wing and gained speed, guns and range. The F3F is therefore the direct ancestor of the Wildcat — and through the Wildcat, of the Hellcat and Bearcat that dominated the late-war Pacific. The entire Grumman carrier-fighter dynasty of World War II, the "cat" line that helped win the naval air war, traces its bloodline straight back to this obsolete little biplane. Few aircraft that never fired a shot in the war did more to shape it.

In August 1940, First Lieutenant Robert "Bob" Galer of the US Marine Corps was forced to ditch his F3F-2 in the Pacific off San Diego after an engine problem. He got out; the aircraft sank into deep water and was written off. It was, at the time, an unremarkable peacetime mishap.

Galer's war was anything but unremarkable. Commanding a Marine Wildcat squadron over Guadalcanal in 1942, he shot down more than a dozen Japanese aircraft — often against the odds and while badly outnumbered — and was awarded the Medal of Honor, eventually retiring as a brigadier general. Then, in 1988, came the epilogue: his sunken F3F-2 was located on the seabed off San Diego and raised. The restoration reportedly revealed that a valve failure, not pilot error, had brought him down half a century earlier. One officer's career neatly threads the whole story together — the biplane, the monoplane that replaced it, the war the F3F never fought, and the strange resurrection of a fighter from the ocean floor.

In 1936 Grumman built a one-off civil aerobatic aircraft, the G-22 "Gulfhawk II," for Major Al Williams, the celebrated demonstration pilot of the Gulf Oil Company and a former Navy racing pilot. It blended F2F and F3F features and wore a vivid orange-scarlet Gulf livery. For more than a decade Williams flew the Gulfhawk II across the United States and Europe, performing gruelling inverted-flight and low-level routines that doubled as advertising for Gulf's aviation fuels and as a very public stress test of Grumman's engineering.

The Gulfhawk II's endurance in the punishing airshow circuit was itself a testament to the barrel's strength, and it kept the family's design in the public eye long after the military F3Fs had retired. It survives, beautifully preserved, in the Smithsonian's National Air and Space Museum — and it is the reason one of the type's handful of survivors is technically a civilian G-22 rather than a US Navy F3F.

Obsolete as a fighter by 1941, the F3F still had real value as a hot, honest advanced trainer. A powerful radial, a tail-dragging stance, a retractable undercarriage and genuine fighter agility made it an ideal stepping-stone for pilots about to graduate onto the Wildcat. Survivors were sent to naval air stations such as Corpus Christi, Texas, and Miami, Florida — the famous 1942 Kodachrome photographs of colourful F3Fs at Corpus Christi date from exactly this period.

Others became utility and communications hacks, ferrying people and priorities around the sprawling wartime training establishment. It was unglamorous, invisible work, far from any headline. But in those quiet flights the last biplane fighter helped forge the very pilots who would win the carrier war it never saw — a second career arguably more consequential than its first.

Grumman fighters earned a wartime nickname — "the Grumman Iron Works" — for their uncanny ability to absorb battle damage and still bring their pilots home. That culture of deliberate over-building did not appear fully formed with the Wildcat; it was established with the FF, F2F and F3F, whose airframes were stressed for the brutal, repeated shock of carrier landings and for hard peacetime aerobatics.

The proof is literally underwater. The F3F's structure was strong enough that, decades after individual aircraft sank, corroded airframes could be salvaged from the seabed and rebuilt to fly again — something almost no contemporary type could survive. When Grumman engineers later built the Wildcat and Hellcat to shrug off cannon fire, they were applying a philosophy first worked out on a fat little biplane. The Iron Works began as a barrel.

The F3F's survival story is unusually literal: a number of the airframes flying today were recovered from underwater. Galer's F3F-2 came up off San Diego in 1988, and other flyable examples were rebuilt using the wreckage of F3F-2s that had gone down in Hawaiian waters in the late 1930s, when pre-war training accidents put more than one Flying Barrel on the sea floor.

Cold, comparatively low-oxygen water preserved enough of the rugged Grumman structure — and enough of the harder-to-replace fittings — to make restoration possible where a lesser airframe would simply have dissolved. The result is a remarkable second life for a fighter type that had been written off half a century earlier, and the direct explanation for why anyone alive today can watch a 1930s US Navy biplane fighter actually fly. The sea took these aircraft; decades later, it gave a few of them back.

Timing is everything, and the F3F's timing spared it. Had the Pacific war begun two or three years earlier, the last US Navy biplane fighter would have met the Mitsubishi Zero over the fleet, and the result would almost certainly have been grim — the F3F was slower, more lightly armed, and could not dive with a modern monoplane. Its virtues, agility and toughness, would not have saved it from an opponent that simply refused to fight on its terms.

But by the time of Pearl Harbor the F3F had already been retired from carrier squadrons in favour of the Buffalo and the Wildcat. It never saw combat, and so it never suffered the reputational massacre that befell the Buffalo over Midway. The F3F retired undefeated precisely because it retired in time — an accident of the calendar that turned a fighter which would have been slaughtered into one remembered with affection. There is a lesson in that about how thin the line between "beloved classic" and "flying coffin" can be.

Fewer than a handful of F3Fs are airworthy, owned by dedicated warbird collectors and museums, and their appearances are genuine events rather than routine. To see one is to watch aviation history breathe: an open-cockpit, hand-cranked, radial-engined biplane fighter — the very last of its kind in US Navy service — hauling around the sky in the sunshine, its fat fuselage and braced wings unmistakable against a modern airshow line-up.

It is single-seat, effectively priceless, and emphatically not for hire — you cannot buy a ride in one, and no operator offers F3F flights. But it is real and it flies, which is more than can be said for many far more famous aircraft of its generation. For an aviation enthusiast, catching one of these barrels in the air is a rare privilege; if the flying itself is what you are after, that is where a genuine, bookable warbird or fighter-jet experience comes in.