Page:Tom Swift and His Sky Racer.djvu/56

46 to prevent a rolling motion. In addition, Tom had an ingenious device to automatically adapt his monoplane to sudden currents of air that might overturn it, and this device was one of the points which he kept secret.

The motor, which was air-cooled, was located forward, and was just above the heads of the operator and the passenger who sat beside him. The single propeller, which was ten feet in diameter, gave a minimum thrust of one thousand pounds at two thousand revolutions per minute.

This was one feature wherein Tom's craft differed from others. The usual aeroplane propeller is eight feet in diameter, and gives from four to five hundred pounds thrust at about one thousand revolutions per minute, so it can be readily seen wherein Tom had an advantage.

"But I'm building this for speed," he said to Mr. Jackson, "and I'm going to get it! We'll make a hundred miles an hour without trouble."

"I believe you," replied the engineer. "The motor you and your father have made is a wonder for lightness and power."

In fact, the whole monoplane was so light and frail as to give one the idea of a rather large model, instead of a real craft, intended for service. But a careful inspection showed the great strength it had, for it was braced and guyed in