I Built My Own Flying Leafblower of Death

This 1960s-style close-air-support concept was too weird for its time

I Built My Own Flying Leafblower of Death I Built My Own Flying Leafblower of Death

Uncategorized February 9, 2014 0

The Convair Model 49 was part plane, part helicopter—and one of the strangest aircraft designs in American aviation history. A little too strange, in... I Built My Own Flying Leafblower of Death

The Convair Model 49 was part plane, part helicopter—and one of the strangest aircraft designs in American aviation history.

A little too strange, in fact. The Model 49 never made it past the concept stage. And 50 years later it still boggles the mind.

So of course I had to build one of my own … in scale-model form. It’s silly, but with such an outrageous and obscure aircraft, building a tiny copy helps you visualize just what the Hell the Model 49’s engineers were thinking.

I used a kit designed by Fantastic Plastic, which has made a name for itself through its line of unusual and downright freaky aircraft kits, based on designs both real and fictional. When Iran announced it produced a stealth fighter, Fantastic Plastic produced a plastic kit that helped me visualize how bogus it is.

With a few hours and some glue, I got a better grasp of the Model 49, too.

Steve Weintz photo

Tailsitters and ring-shaped wings

As the Cold War came to the geopolitical forefront and technology reshaped conflicts, the Pentagon struggled to keep pace with its own machines.

One of the most radical changes was with “air-mobile” tactics coupled with helicopters. This allowed soldiers to rapidly deploy across wide areas, the choppers dropping troops close to the enemy.

With the CH-47 Chinook’s introduction in 1962, the Army and Marines could fly 20 troops or a jeep and a howitzer to a distant landing zone at 190 miles per hour.

But the Chinook’s smaller predecessors—including the Huey—couldn’t keep up in either range or speed. These motley field-modified helicopters were not fast enough to escort the big twin-rotor Chinooks, nor heavily-armed enough to provide fire support once they arrived.

To solve this dilemma, in 1964 the Army released requirements for a new aircraft called the Advanced Aerial Fire Support System.

The AAFSS was supposed to have a top speed of 220 miles per hour—fast enough to escort incoming heavy transports. It had to hover at 6,000 feet and have a range sufficient to ferry itself from California to Hawaii. It was to feature the first electro-optical infrared targeting system for a helicopter.

It also had to pack some serious heat—enough to blow the daylights out of a landing zone while keeping its nose down as long as needed.

Almost 150 companies participated in the AAFSS competition, with an eye toward a contract award in late 1965.

Convair Model 49 concept. Convair art

The finalists, Sikorsky’s S-66 design and Lockheed’s AH-56 concept, both featured sleek, narrow-bodied, winged fuselages with fore-and-aft tandem cockpits and gun turrets. Both designs were compound helicopters, meaning they used tail propellers to increase speed.

Meanwhile, the Navy experimented with aircraft designed to take off while sitting on their tails before transitioning to horizontal flight—and vice-versa. These “tailsitters” were promised to combine the advantages of helicopters with the performance of fixed-wing planes.

Convair’s XPY-1 “Pogo” was the more successful of the two Navy prototypes. But neither Convair’s nor Lockheed’s machine proved easy to fly. Landings were especially hair-raising, despite swiveling cockpit seats.

Imagine backing a rental truck up to a wall, except the truck is standing on its loading door and you’re looking up at the sky.

In France, tailsitter experiments culminated in the SNECMA Coleoptere. It was both more and less elegant than it sounds. The Coleoptere’s design placed a jet engine in the middle of a circular, ring-shaped wing with the pilot riding atop the engine pod. The aircraft’s stability and flight was controlled by steering the jet exhaust.

The ring-shaped wing was supposed to generate lift as the aircraft transitioned from vertical to horizontal and then level cruising. The upper and lower halves of the ring acted somewhat like the wings of a biplane, although with some complex aerodynamics at work.

SNECMA’s Beetle did not fly that much better than the American tailsitters. Visibility and control remained major obstacles. But Convair’s engineers combined the tailsitter with the circular wing and added a strange new cockpit arrangement.

The result was a kind of flying, sci-fi leafblower.

Steve Weintz photo

Dash and hover

To solve many of the thrust and control issues with tailsitters, Convair mounted big counter-rotating propellers inside the Model 49’s wing.

The cockpit was also mounted on a hinge, allowing the pilots to remain level regardless of the aircraft’s tilt.

It traveled in two modes. Dash mode was like a conventional airplane. The Model 49 lay on its side, its cockpit in line with its fuselage. The aircraft’s annular wing added lift to the huge thrust of the shrouded propellers and turboprops.

In hover mode, the barrel-shaped aircraft morphed into a flying tank. On contact with the enemy, the leafblower rotated and aimed its weapons downward. Its armor was tough enough to withstand impacts from 12.7-millimeter projectiles.

Three turboprop engines mounted on the annular wing drove the propellers through a series of shafts and gearboxes, like a helicopter’s powertrain.

The outside mounting allowed for easy maintenance, as opposed to crawling into the shroud to access the fuselage. The engine pods attached to the fuselage through vanes, connecting to airfoil-shaped sections of wing to form a ring shape.

Three fully elevating and traversing ball turrets housed two 7.62-millimeter machine guns and a 30-millimeter autocannon—or extra guns and a small rocket launcher.

Additional mounts on the engine pods on either side were for various anti-tank and anti-personnel missiles, including Shillelagh and BGM-71 rockets.

The Model 49 might have carried that same weapon as the M-50 Ontos, the “armored shotgun” vehicle used by the Marines in Vietnam. A Convair promotional film shows the aircraft mounting six 106-millimeter recoilless rifles, three on each side.

The North Vietnamese Army feared the Ontos tank. A flying leafblower tank would have scared them to death.

Steve Weintz photo

Swiveling cockpit

On the ground, the Model 49 looked like a broken toy. The cockpit—which seated two pilots—swung on a hinge. During the hover-and-attack mode, the cockpit sat at a horizontal angle, but transitioned to the vertical position for level flight.

The hinge system isn’t well-specified in available documents, but it would have needed to be tough enough to keep the crew attached to their aircraft during the sorts of wild maneuvers expected of the Model 49.

Entering the aircraft was simple enough. The crew climbed into the cockpit using an attached pole-ladder to reach the wing’s leading edge. A second ladder descended from the cockpit.

As might be expected, the Army brass didn’t know what to make of Convair’s flying leafblower of death. Despite the company’s test results demonstrating the feasibility of the shrouded-rotor alternative, the Army instead selected the more conventional Cheyenne.

When Lockheed ran into significant problems with the Cheyenne, the Army handed the prize to Bell.

On its own, Bell produced a sleek, two-seat attack helicopter from a combination of Huey parts and new engineering. The result was the AH-1 Cobra, which entered Vietnam in 1967 and still serves the Marines today in a modified form.

The Cobra set the standard for attack helicopters and looks the part.

The Model 49, on the other hand, looks like an escapee from Jonny Quest.

Convair art