"That isn't enough for a decent flight," declared John. "We'll probably be out for at least an hour, and we may use as much as fifteen gallons in that time; that's about half the consumption of ordinary airplanes, you know. We'll shove in twenty gallons more so as to be on the safe side."
"We haven't put in any oil yet," reminded Tom. "We'd better put in about two gallons, I should say. Most planes use about a half-gallon to the hour; if we use half as much, that will give us plenty of grease."
The tanks were in the lower part of the forward fuselage. With the caps removed, a hose was inserted by Paul, and then John forced the gasoline up by a small but powerful handpump until the gauge told that the required additional twenty gallons were in. The same pump would work with the oil also, and soon the viscid fluid had been transferred from the storage can on the hangar floor to its proper tank in the airplane. Thence it would feed itself up into the carbureter of the working engine by a force-pump attached to the engine, as with the gasoline.
The boys had just finished putting in the fuel when Mr. Giddings and
Bob drove up in the former's automobile.
"I expect this is a great day for you young men?" said the publisher, with a smile of greeting to all. "I know it is a time I have looked forward to myself for a good many months,—ever since I accepted the challenge of the Clarion, in fact. Is the Sky-Bird supplied with gasoline?"
"Yes, sir," said John; "we just got through with that job. We have easily enough fuel aboard now for a couple of hours' flight, and that will be long enough for a first one. New engines are always 'stiff' and should not be run too long at a stretch."
"Have you run this pair yet?"
"Oh, yes," said Bob. "We have tried them out several times, dad, and in connection with the propeller, too. They work tip-top, either connected or disconnected. I tell you, when they're in connection they certainly do make this big propeller hum!"
"I can't understand how you can operate the propeller in here," said Mr. Giddings, much puzzled. "All the airplanes I have seen have always dashed forward as soon as their propellers began to revolve under impulse of the motor or motors; there was no restraining them. I should think this machine would run through the front end of the hangar here as soon as you—"
"Pardon me, sir," interrupted John, "but we have gone those fellows one better. You forget that in the drawings we showed you there was a set of brakes designed to be worked by a control within reach of the pilot, brakes which will engage these ground wheels a good deal the same as brakes work on automobiles—by a flexible band of steel and grit-filled cotton which is made to compress over a large sort of hub on the inner side of each wheel."