The Flying Flapjack: The real flying saucer

We think we know what someone means when they call something “airplane-shaped,” but real-world aircraft come in a surprising variety of forms. Two particular oddities were so far out on the bell curve that they were known as the “Flying Flapjacks.”

In 1930, farmboy Charles H. Zimmerman (1908–1996) graduated from the University of Kansas with a Bachelor of Science degree in Electrical Engineering and a minor in basic aircraft design. Immediately after this, he went on to join the National Advisory Committee for Aeronautics (NACA) and Chance Vought Aircraft company, where he showed a remarkable aptitude for novel airplane designs.

One thing that particularly drew his interest was the idea of discoidal aircraft – what are more popularly known as flying saucers.

Though we often think of disc-shaped aircraft as something super-advanced, circular-winged flying machines go back to Swedish scientist, philosopher and mystic Emanuel Swedenborg, who designed an elliptical-shaped craft in 1714. This never got past the drawing board stage, but the idea kept cropping up again and again with many variations on a circular shape and performance that spanned from interesting to rubbish.

Like his predecessors, Zimmerman saw a circular-wing aircraft as something with the potential to literally take off straight up. This is because a circular wing has a low-aspect ratio. This is the ratio of the length of the wings to their width – so a high aspect ratio means long, narrow wings, while a low aspect ratio means short, wide wings.

It also means that you can get a lot of lift for a not very wide wingspan as well as a lot of payload space in and on the airframe. Bottom line: with a circular wing, you get an aircraft that can take off from ridiculously short runways or even vertically if there’s a headwind.

While at Chance Vought Aircraft, Zimmerman worked on a series of models to develop his theories, including a largish one with electric motors that flew by remote control – though not very well.

The problem was that circular wings have a number of drawbacks – not the least of which is that such wings have a lot of drag because the wingtips generate massive vortices. To overcome this, Zimmerman had the idea of putting huge propellers at either end of the wing to break up these vortices and increase lift.

After a number of failed attempts to interest the US military, the US Navy granted Chance Vought a contract to build a full-size, flying demonstrator prototype designated the Vought V-173, also known as, along with its successor, Zimmer’s Skimmer, the Flying Pancake, or (most commonly) the Flying Flapjack.

The goal was to create a new fighter aircraft with exceptional low-speed handling and high-speed potential that would be suitable for carrier-based operations. As the first step, the V-173 was the proof-of-concept prototype to study and develop the basic aerodynamics of the design before scaling up to a practical fighter.

It was such a bold idea that the entire project was designated top secret. However, the Flying Flapjacks were plagued by delays that only became worse after the United States entered the Second World War in 1941.

Following wind tunnel tests, the prototype V-173 was completed and made its maiden flight on November 23, 1942 with test pilot Boone T. Guyton at the controls. This first flight came after months of setbacks because of vibration problems with the complex gearbox that connected two contra-rotating wooden propellers to the two 80-bhp Continental A-80 engines.

The V-173 was impressive with its 23.3-ft-wide (7.1-m) circular wing/fuselage constructed out of wood and fabric. Despite this, the structure was surprisingly strong. The 2,670-lb (1,211-kg) hull sat on a spindly, fixed tripod undercarriage that was selected for its lightness and mechanical simplicity, though this arrangement did increase drag while reducing speed and efficiency.

Between 1942 and 1943, the V-173 flew 190 times with not only Guyton in the single-seat cockpit, but Charles Lindbergh, the first man to fly the Atlantic Ocean solo in 1927. In many ways, its performance was astonishing. It had a stall speed of 20 mph (32 km/h) and could take off from a runway only 200 ft (61 m) long.

If there was a stiff wind, it could take off vertically. This was of particular interest to the Navy because it meant the V-173 could not only take off from crowded carriers, but even ship decks.

In the air, it had a maximum speed of 138 mph (222 km/h), a range of 200 miles (322 km), and a service ceiling of 5,000 ft (1,524 m). In addition, the circular wing made it ultra-maneuverable, with the ability to make tight turns, which is very attractive in a fighter. It was also remarkably stable and controllable, even at speeds as low as 20 mph (32 km/h), and was very difficult to stall even on purpose.

On the minus side, the tail control surfaces needed a lot of tweaking to correct a lot of issues caused by the unusual wing and how the air flowed over it. In addition, at low speeds the pilot at times had to resort to handling it like it was a helicopter, which is a bit difficult if you’ve never even seen one.

This was all very promising, but the V-173 wasn’t an actual fighter, so in 1944 the US Navy ordered two prototypes built of the Vought XF5U Flying Flapjack that was intended as an actual armed fighter plane.

The XF5U shared the same circular, low-aspect-ratio airframe as its predecessor, though it was larger, stronger, and with more advanced performance. The most obvious change was that instead of wood and canvas, the aircraft was made out of metalite, which is balsa wood sandwiched between thin sheets of aluminum. In addition, the engines were upgraded to a pair of Pratt & Whitney R-2800-16 radial piston engines, each producing 2,300 bhp, that were buried inside the wing and fed by huge air scoops and spun two large metal counter-rotating propellers. Meanwhile, the fixed undercarriage was replaced with a heavier retractable one.

The ultimate Flying Flapjack, having a wingspan of only 32.3 ft (9.85 m), could carry four M2 Browning .50 caliber machine guns or four 20-mm cannons plus two 1,000-lb (454-kg) bombs or drop tanks.

Though the XF5U never took to the air aside from a couple of brief hops, the estimated maximum speed was 425 to 550 mph (684 to 885 km/h), with a range of about 1,000 miles (1,600 km), a service ceiling of 32,000 ft (9,750 m), and a take off distance of a mere 300 ft (91 ft) in a dead calm.

If that wasn’t enough, the new, forward nacelle-mounted cockpit had a bespoke ejector seat to throw the pilot clear of those alarming propellers in the event of a bail out.

The continuing delays faced by the project meant that the XF5U hadn’t flown by the time the war ended in 1945. By 1947, only one prototype was completed, but the design was still having problems with its gearbox, especially when it came to vibrations. This raised flight safety concerns and there was talk about moving the project from Connecticut to Edward Air Force Base in California, but the aircraft was too wide to be transported by road and it couldn’t be dismantled. Since the alternative was to ship it to California via the Panama Canal, the idea was dropped.

On the bright side, the Flying Flapjack had superior performance characteristics compared to the aircraft the Navy used during the war, and its short wingspan would have made it better suited for carrier operations. It was also one of the most distinct aircraft ever made. Despite the tight security, sightings of the Flying Flapjacks produced a string of UFO sighting reports by the public.

Since then, there has been speculation that the US government encouraged the flying saucer mania as a cover for its experimental aircraft. Of course, there are others who say the experimental aircraft were a cover for the saucers. The truth can be found in my dog-eared, hand-written, 800-page manifesto that I keep next to me at all times in a stained Marks and Spencer’s shopping bag to prevent the Reptiloids from getting it.

For such an odd plane, the Flying Flapjack had an equally odd end. If it had flown a few years before, it might have revolutionized aerial warfare. Instead, progress overtook the XF5U with the emergence of jet engines and the project was cancelled on March 17, 1947.

That, in itself, wasn’t too unusual, but the Navy brass panicked at this point. Not only had jets come in, there was also a lot of postwar pressure to cut military spending drastically. The fear was that if Congress found out that there was an aircraft that could take off vertically, it might cancel the construction and operation of aircraft carriers. As a result, the only completed XF5U prototype was ordered to be unceremoniously destroyed.

Sad, but the Flying Flapjack had the last laugh. Its wing construction was so strong that the Navy couldn’t even break it up with a wrecking ball – though, in the end, it was finally turned into scrap. Meanwhile, the V-173 was eventually donated to the Smithsonian Institute and today is on display at the Frontiers of Flight Museum in Dallas, Texas.

But the Flying Flapjack wasn’t a technological dead-end. Many of the design aspects found their way into later aircraft like the Convair XFY Pogo and other tail-sitter VTOL designs. Also, Zimmerman himself went on to work on a number of VTOL and STOL aircraft concepts, including flying platforms and personal air vehicles.

Still, it would have been nice to have seen the Flying Flapjack take to the sky as a full-blown fighter with its huge props as it jinked about on its disc wing, machine guns blazing. As a second best, there’s always imagination or googling boxes of old model kit covers.

What might have been.