“Here’s the horizontal rudder,” the officer explained, pointing out the two smaller, parallel planes which were attached to the extreme end of the light frame that protruded from the body of the aëroplane like an enormously long tail. “By a system of wires and pulleys, it is connected with the lever next to the seat. You pull that lever forward and the rudder is thrown upward, inclining the big plane so that the air strikes it underneath and drives it upward. In the same way when the lever is thrown back, the plane is deflected the other way and the machine descends. In flying it’s always necessary to give the plane the least possible upward inclination, so as to get the full benefit of the air striking against it.”
Merriwell nodded understandingly.
“This rudder above it is the vertical rudder, I suppose,” he said. “It looks exactly like the rudder on a boat.”
“It is like it, and acts the same way. You use that in making a turn, and it is controlled by the lever next to the other one. Pushed forward, it turns the rudder to the right, backward, to the left. When you’re flying straight ahead it’s kept upright, of course.”
He pulled a worn, red leather notebook from his pocket and slipped off the rubber band.
“It’s this way,” he went on, as he drew a simple diagram on one of the pages.
Dick bent his head over the book, while Holton explained in detail the principle of rudder control, illustrating his meaning with rough sketches. When he had finished, the Yale man straightened up and looked again at the machine.
“It’s quite as simple as I thought,” he said slowly. “I believe I could operate it with a little practice. Eight-cylinder engine, isn’t it?”
“Yes, and it’s a little beauty,” the officer said enthusiastically. “I’ve never had a bit of trouble worth speaking about. It’s a French make and only weighs a fraction under three pounds per horse power. It drives the crank shaft, which runs under the seat out to the propeller in front.”
Dick examined the engine closely. It was beautifully made and took up a surprisingly small space.