Aviation oddity- Ball-Bartoe Jetwing

[evangilder]

While looking up something else this morning, I found this article about an interesting design that apparently didn't go beyond the prototype. Sounds like a great concept.

When jet engines came into widespread use, in the 1950s, engineers pondered the high-energy exhaust they produced. If it could be ducted and blown over the wing, the increased airflow would increase lift. With more lift, wings could be smaller, which enabled higher speeds, and with a blown wing there would be enough lift to support the slow speeds military aircraft needed to land on unimproved runways and aircraft carriers.

Employed since 1956 by the Ball Corporation, manufacturer of glass canning jars, Otto E. "Pete" Bartoe was named company president in 1969. A gifted engineer with a practical bent, he convinced Ball to finance a spinoff company to explore his ideas about a blown wing. In 1973, the Ball-Bartoe Aircraft Corporation was formed in Boulder, Colorado. Over the next four years, Bartoe produced more than 200 engineering drawings, which Brad Davenport ("a master mechanic and an amazingly productive worker," says Bartoe) and Sig Williams turned into the experimental Ball-Bartoe Jetwing.

A Pratt Whitney JT15D-1 turbofan was mounted in the nose, well ahead of the cockpit and wing. The hot airstream exited the engine core, entered a bifurcated duct, and exhausted just outside the fuselage through slots in the top skins of both wings. Air from the fan was directed aft by vanes in the duct and ducted farther out through slots on the leading edges. About 70 percent of the wingspan was bathed in the exhaust stream.

Mounted inches above the main wing was an "augmentor," a small wing; exhaust gases passed through a slot between the two. A phenomenon Bartoe calls "supercirculation" caused the lower pressure in the slot to draw in more air and increase lift. At the trailing edge, large flaps rotated and extended up to 52 degrees. They remained in contact with the top skin and made use of the Coanda effect, in which airflow bends to follow a curved surface. With the flaps down, the "bend" in the airstream provided downward thrust and enabled the Jetwing to fly as slow as 40 mph.

The Jetwing first flew in 1977, at Mojave, California, with Lockheed test pilot Harold "Fish" Salmon at the controls. The blown-wing configuration generated more than twice the lift of a conventional wing of the same area. The Jetwing flew slowly enough that Bartoe could use his Super Cub as a chase plane.

After Salmon completed the initial testing, Bartoe flew the Jetwing back to Boulder. The 106-gallon fuel tank allowed only 40-minute flights, so the trip required 11 refueling stops. Because many of the airports Bartoe used carried only gasoline, a pickup truck carrying jet fuel followed him.

"It was fun to fly," Bartoe recalls. "It was extremely quiet. As long as the engine was running, you couldn't stall it. Landings were interesting: The jet blast came off the deployed flap, bounced off the ground, and forced the tail up. If you reduced power, the tail would come down suddenly, just as the wing was losing lift. But everything happened at such a slow forward speed that it was manageable."
In a Navy program, the Jetwing landed in a mere 300 feet—this from an airplane that could reach 350 mph.

The Jetwing was the only aircraft that used the blown wing for propulsion as well as lift, but in the 1950s and '60s many designers experimented with blown flaps. Currently displayed at the Wings Over the Rockies Air and Space Museum in Denver, Colorado, the Jetwing remains the world's only blown-wing tailwheel jet aircraft.

Oldies and Oddities: Blown Away | History of Flight | Air Space Magazine

 

[Gnomey]

That looks really weird and doesn't seem like the best of ideas. Still an interesting read.

 

[evangilder]

The STOL capabilities would be really interesting. Although the amount of fuel it ate up was a little much.

 

[Aaron Brooks Wolters]

I think with today's engine tech though it would be more efficient, don't you?

 

[vikingBerserker]

That's really interesting, cool post.

 

[evangilder]

I think with today's engine tech though it would be more efficient, don't you?

Possibly, but it flew in 1977. I guess engine technology has changed quite a bit in the 30+ years, but I think it has a lot to do with how much power was needed to create the lift.

 

[Gixxerman]

I guess it developed became the Boeing YC14 the Antonov An 72?

 

[Crimea_River]

Engine failure could be exciting. And why the qualifier "tailwheel"? Does that mean there was one on tricycle gear?

 

[Balljoint]

These posts came up while reviewing old wisdom. Pete Bartoe was the best engineer I ever worked with -period and by far. His blown wing effort was probable because he wanted to and as a reward for many prior contributions. It was built in a hanger at the Boulder Airport rather as an ambitious homebuilt. And it performed as designed, though of marginal cost/performance.

Pete was born at Paris Island and, in person, was almost a parody of a DI, actually a bit intimidating. He had a Gypsy Moth for fun and designed aircraft as an avocation. His Skyote design was highly praised. Also for fun, he sailed 32 footer to New Zealand and back. As real work he invented the spin-stabilized satellite and an early deep-diving submersible, the Sea-TV sub. His efforts won prestigious engineering awards in several disciplines.

Nobody asked, but he's gone now and came across as a bit light duty in this thread.

 

[R Pope]

One of those things that had to be tried, it might have gone somewhere....Sort of like the Lanier experimentals, the advantages were overcome by the disadvantages.