Popular Mechanics, May 1947
With stubby wings like half barrels flanking its fuselage, it resembles nothing you've ever seen in the air before--but it flies! Some experts who've seen it still can't understand why.
And before you recover from the shock of watching this strange craft perform in the sky, its inventor, Willard R. Custer, has many more surprising claims to make.
He says planes of this design can: take off and land at 15 miles an hour in 50 feet of space, lift twice the pay load of present transports using the same power, and either hover overhead or pierce the supersonic speed zone. And he supports his claims with results from Army and privately conducted tests.
Heart of this remarkable performance is the Custer Channel Wing, adaptable to any type air craft, and to piston, jet or rocket power. In contrast to conventional airfoil, it is shaped like the lower half of a tube and has an adjustable-pitch propeller at the rear. The propeller's tips sweep almost the entire trailing edge.
Simply stated, an ordinary wing is fashioned so that air pressure--or lift--is built up beneath it and decreased above it, as the plane speeds along the runway, until a slight difference between the two makes the plane fly. Atmospheric pressure on all sides of the wing is a constant 14.7 pounds per square inch at sea level when the plane is standing perfectly still. Modern transports like United Air Lines' DC-6s reach 125 miles an hour and use over 3800 feet to get off the ground, and they touch down at 100 miles an hour, using more than 1800 feet to stop.
Custer's method is to relieve the pressure above the wing by the propeller's sucking action at the rear of the channel, and let the undisturbed pressure of nearly a ton per square foot below the wing lift the plane off the ground. Instead of moving the plane to achieve lift he gains it by moving air masses through the channel. To better control the lower- pressure air thus created within the wing, he has built up its sides above the propeller's center and slightly constricted the forward portion.
This funnels more air to the propeller, increasing its efficiency so much that the pitch has to be adjusted to absorb unused horsepower, Custer says. In contrast to this concentrated lift, a conventional wing's efficiency varies along its entire length. Since the channel will lift 75 percent of the plane's weight without forward motion, very little movement is needed to add the 25 percent that makes the craft airborne.
His unorthodox attack on the problem of finding more efficient ways to fly can probably be laid to the fact that Custer is an auto mechanic by trade, not an aeronautical engineer. So he cut a simple and unique path to his solution. He uses familiar objects instead of complex technical formulas to illustrate his arguments.
Although the invention has many important potentialities if completely successful, Custer prefers to stress the safety features that will further popularize flying. With it, he points out, planes can sink slowly to earth through the worst weather, onto deep snow or any other kind of unprepared ground, at landing speeds slower than a man runs. The crash hazards of blind approaches and landings at high speeds are eliminated. Another important item is that all the controls of the channel wing plane are conventional and it is easy to fly.
While most experiments with the wing have been in wind tunnels and laboratories, a test ship flew more than 100 hours over a government field at Beltsville, Md., using 75-horsepower engines. The engines and propellers were mounted on metal supports extending across the upper rear section of each channel.
During those first test flights the plane, weighing only 1785 pounds with pilot, was held to a top speed of 60 miles an hour. Take-offs and landings were made under 100 feet, upwind, downwind and crosswind.
Two series of nonflying tests were later made by the Air Materiel Command at Wright Field. One fact established during trials was that the wing's lift increased even when its chord, the distance from front to rear, was reduced by half. Frank D. Kelley, president of the National Aircraft Corporation, said that a second flying model using a short channel wing will be ready for flight tests this fall at Hagerstown, Md.