CHAPTER XIII

AT WORK ON THE AEROPLANE

The following day the first box of material arrived from Kansas City, and was taken to Mr. Giles' machine shop, which, having formerly been the army stables, was a great deal larger than was needed for the machinist's work, and he was able to give Hawke and the boys a roomy s.p.a.ce at the rear.

A box from Denver came on Monday morning, and in the afternoon there was a consignment from New York. The engine was to be sent by freight from Fort Omaha, and would take some time to reach Silver City, but, as Hawke explained, it was the last thing to be used and the delay would not matter.

By Wednesday morning, therefore, which was the day after the Fourth, all was ready to go ahead on the aeroplane. The Fourth had been unusually quiet for the boys because Herb could not take part in any active festivities. While his injury had been slight, and was now practically healed, his father insisted that he should remain perfectly quiet and not become excited by unwarranted celebration. This was a hardship for so active a boy as Herb, but to please his father he obeyed without complaint.

As reparation, the rancher ordered a lavish display of fireworks from Albuquerque, and in the evening the boys were entertained by an exhibition that was worthy of young princes.

The exhilaration which followed this event, their sympathy for Herb, the grat.i.tude they felt for the generous rancher, and their eagerness to solve the mystery of the Bread Pudding ranch, which was heightened by the incidents of the last few weeks, coupled with their growing interest in aviation, gave the boys an enthusiasm for the work of constructing the biplane which guaranteed success.

Hawke set up his model in the shop for their guidance, and, desiring to start them with fundamentals, he dissected the wing of a hawk, and, the first thing Wednesday morning, explained to them the first principles of plane construction, using the formation of the wing as an ill.u.s.tration.

"The early planes were straight," he explained, "but we have since learned that the curved surfaces are far more efficient. Keep in mind the idea of the bird, the shape of his wings, and you have the best working basis for building a plane." The aviator believed, with some other specialists, that examples taken from nature were the best sort of instruction for the novice.

The materials were unpacked, including all necessary tools, and without wasting much time on preliminaries, the boys set heartily to work.

"I am planning to equip this machine with swinging wing ends," said Hawke. "This is something not used on many biplanes, but it will be necessary to have them if we are to follow the maneuvers of a bird. If the wing tips are made with a down curve at their ends, the result of swinging them to the rear will be to increase the lifting power, while at the same time reducing the resistance of the air to forward movement.

This would afford an ideal method of steering, being exactly like that employed by birds."

Later, when work was begun on these wing tips, the boys fully understood Hawke's theory.

Another innovation which Hawke planned for the machine was a mica window in the forward part of the fuselage, which would enable them to see what was pa.s.sing below them, without leaning over or altering the angle of the planes.

While the boys worked and followed directions, Hawke explained the parts and their use on the machine. Fred and Fly proved themselves the most accomplished at first, owing to their previous experience with mechanics and aeroplanes. Gray also had a previous knowledge of the possibilities of aeronautics, and it was not long before all of the boys were intelligently working on Hawke's model and making progress.

Mr. Phipps rode over from the ranch almost every day to see them at work, and was much pleased with the rapid advance his son was making.

Entirely recovered from the accident, Herb was as useful as any of his companions, and, besides evincing a great deal of mechanical skill, which he had never been called upon to display before, he readily grasped the principles Hawke continually ground into his pupils.

"You see, Dad," Herb said, when the rancher had inquired, on the occasion of one of his visits five or six days after work had been begun, about the use of the propeller, the particular part on which Herb was working, "the propeller is everything on an aeroplane. It's got to be made just right, or the whole thing goes to smash. If it wasn't for the propeller the machine wouldn't go at all," he finished triumphantly.

"Oh, indeed," remarked the southerner, an amused twinkle in his eye.

"And what's the reason for that?"

"Well, yuh see," replied Herb, seriously, not noticing the smile playing about his father's mouth, and anxious to display his newly acquired knowledge, "it's the thing that moves the machine forward, and it has almost everything to do with the pitch and speed. The surfaces of the aeroplane are called the skin, and there is some friction of air against these surfaces, and that is called skin friction. Well, yuh see, the propeller has to make the machine move through the air with the smallest amount of skin friction. It has to travel through as large an amount of air as possible in a certain time, and take as little power as possible.

Yuh understand?"

"Oh, yes," exclaimed the rancher, unable to restrain a short laugh. "How about that, Hawke?"

"He's right," responded the aviator, slapping his young pupil on the back. "He's got the dope exactly."

"Yes, but a good deal depends on the operator," chipped in Fly, who was ambitious to excel as an aviator, and could scarcely wait until the machine was finished to try his hand.

"I'm working on the box-girder," said Dunk, feeling called upon to give an account of himself.

"What's that," asked Mr. Phipps indulgently.

"It's the part that really bears the greatest weight--a sort of a beam with the weight in the center, fixed so it bears the load equally distributed. You can see one on Hawke's model."

"And one of the important things," said Jerry, not to be outdone, "is to build the plane so the guy wires remain taut, and the main spars, ribs and struts are properly placed."

"Yes, and then we have to remember to build it as light as we can and as strong as we can," put in Gray. "We want to go fast, but we don't want accidents, so we can't make it as light as we'd like. Oftentimes we have to make a part heavier to be sure it's strong enough."

Other technical information was glibly imparted when Captain Crawford dropped in occasionally. Dr. Rivers also paid the shop frequent visits, while the ladies did not neglect to show an interest in the work.

In fact, everyone in and about the fort shared the enthusiasm of the young aviators, and the aeroplane got to be the most important topic of conversation. Hawke was obliged to put a sign on the door of the shop: "NO ADMITTANCE," in order to keep away the soldiers, Greasers, loafers, and even Indians who had a habit of dropping in and interrupting the work.

About eight days after construction started they were ready for a hangar. As Mr. Phipps sent over two of his idle Greasers to erect this, work on the aeroplane was not stopped. The shed was erected just north of the machine shop, facing the old parade grounds, which was an ideal spot for the first try-out.

"I'm anxious to test my new feature of equalizing the stress and distribution of weight," Hawke explained to Mr. Phipps, who had come over with the Greasers. "I want to be able to carry all of the boys, if possible, and this is a difficult feat, for the greater the number of pa.s.sengers carried the greater is the tax on the stability of the machine. The boys have shown such unusual ability in carrying out my ideas, however, that I think I am going to be able to perfect the device and prove its efficiency in a flight or two."

The day the hangar was completed, the engine arrived. A small truck which Mr. Giles had in the shop was to be used in wheeling the aeroplane out of the shop through the big middle doors of the stable, and into the hangar.

"My, ain't she a beautiful bird," exclaimed Jerry, when they put away their tools, and were proudly viewing the result of their work, for the aeroplane was set up complete with the exception of the engine, and stood mounted on the small wheeled truck ready for removal. A trial flight was to be made in the morning.

"You can't beat that anywhere in the world," said Dunk, proudly.

"I almost feel as though she were alive," commented Herb.

"I must say you did a mighty fine job, boys," said Hawke, "and if she flies as well as she looks, we'll put in our application for medals."

"Is there any chance that she won't fly?" asked Fly anxiously.

"You never know what a brand new plane is going to do," responded Hawke, "and you're never sure till you're gliding safely up in the air, whether or not all the cogs are in tight. But I don't think there's much danger that this one won't fly."

"We'll steer straight for that old tower," said Jerry, "and see if we can't roust out the Thunder Bird--or devil bird, whatever it is."

"Better watch for it some dark night near the sheep fold," suggested Herb. "It's about due to be around here now. We haven't seen it for some time. But another rancher several miles north of father says he's had some sheep hurt and taken, so I suppose it's shifted its hunting ground for a while."

"Gee, I'm awful anxious to find out just what it is anyway," exclaimed Fred. "Certainly is a mysterious animal."

"Have you seen that old Indian snooping around here?" inquired Herb, changing the subject. "I saw him a minute or two ago peeping in through the door over there, but I didn't say anything at the time."

"Oh, I suppose he has some superst.i.tious idea that this is a destroying evil spirit we're building," said Carl. "Only I wish he would keep away.

The way he stands around and peers makes me nervous."

"He doesn't seem to pay any attention to the "No Admittance" sign,"

remarked Hawke, smiling.

"Suppose he can't read English," said Carl. "But I have a sneaking suspicion that he can understand it. It's an old trick of the Indian to stand around and look as innocent as a brick wall, and yet take in everything you say."

"We've been talking a lot about the Thunder Bird lately," observed Fly.

"Maybe that's interested him."