Swiftly, yet with an even movement, wings, hitherto lying snugly against the chassis, were outspread. Taking into consideration the length of the battleplane from nose to tail—barely fifty feet—the space from tip to tip of the wings looked disproportionately small. Each wing projected fifteen feet from the side, and curved backwards like that of a bird. The fabric from which the wings were made was composed of thin, specially-treated aluminium, in plates overlapping each other like tiles on the roof of a house.
"Now, Tracey," continued Desmond Blake, "see if you can coax the motors to start. If you can manage a car-engine you will be able to get them to fire. There's no danger of the bird taking flight. She's pinned down to the floor securely. At the same time I don't think I would run the motors all out, if I were you."
Deftly Dick set to work turning on the petrol and flooding the carburettor.
"Is it necessary to prime the motors?" he asked.
"They ought to fire without," replied the inventor. "There's the self-starter—that lever on your right."
At the first attempt the engines fired easily. In spite of being in a confined space there was very little noise, thanks to the efficient silencer. It was doubtful whether the purr of the motors could be heard beyond the limits of the grounds.
Yet, although the fabric of the battleplane trembled under the pulsations of the motors, the wings remained motionless save for the vibration imparted to the whole contrivance. Seeing Dick's look of enquiry the inventor pointed to a lever close to the lad's right hand.
"Gently with it," he cautioned. Depressing the lever Dick was aware of a terrific air-current rushing overhead. Dead leaves and pieces of aluminium sheeting that were lying on the floor of the shed were whisked up and flung about with great velocity. Peering over the edge of the coaming Dick could see that both wings were now beating the air with terrific violence, being actuated by a number of rods working on concealed cams. Supplementary rods imparted a second motion to the wings, the innermost and rearmost edges of which moved up and down independently of the primary movement of the fore part.
Stretching out his hand the inventor cut off the electric current, and the motors came to a standstill.
"Cannot afford to waste petrol in these hard times," he said with a smile. "You've seen enough to form an idea of how the plane flies. The mere up and down flap of the wings is insufficient; it is the peculiar twist of the after part that does the trick—something after the principle of a man sculling a boat by means of a single oar working over the transom. If he were to waggle the blades of the oar to and fro without giving a dexterous twist nothing would result except a see-saw motion of the boat. It certainly would not move ahead through the water, except for the tortuous movement of the oar."