CHAPTER III
A SUCCESSFUL MODEL
Mr. Giddings was glad to accept the invitation to the trial flight. Heand his son met the Ross boys at the old race-course Saturdayafternoon. This immense, level field, with its one-mile oval and greatempty sheds, at one time had been the county's boasted fair-grounds,but two years prior to the opening of our story it had been sold to Mr.Giddings, whose residence property stretched down the side of ShadynookHill and joined it. New fair-grounds had then been established inanother and more centrally located section of the district. In the oldgrounds the boys of the neighborhood now went to fly their kites andmodel airplanes, to hold impromptu bicycle and foot races, and to playtag and hide-and-go-seek in the cavernous sheds and around the numeroussagging stables.
It was late in the afternoon--just before dusk, when the winds would beat their quietest, and others not likely to be present--that ourfriends arrived at the field. There was not a soul to be seen. Paul,who had carried his precious Sky-Bird, freed it from the wrapper andheld it up for Mr. Giddings to see. The night before he and John hadput the finishing touches to the delicate structure by adding anothercoat of varnish and attaching the little rubber-tired aluminum wheelsto the axle.
As Paul now held it up before the gaze of the great newspaper man, Mr.Giddings made no effort to restrain his admiration. "What a littlebeauty!" he cried. "Why, it's almost a perfect mechanicalrepresentation of a bird!"
"Isn't she a dandy, dad?" put in Bob, his eyes snapping.
"The Sky-Bird is really more of a bird than you may think, Mr.Giddings," declared Paul.
"Yes," added his brother John. "As you probably know, sir, a bird getsits great buoyancy from the fact that every bone in its body is hollow;in flight it fills these bones with a very light gas, which is formedby an action of its lungs in drawing in air. We have adapted thisprinciple in the wings and fuselage of this little machine. They areairtight and filled with compressed helium-gas, which isnon-inflammable and nearly as light as its highly volatile rival,hydrogen-gas."
"Hydrogen-gas is surely a dangerous commodity around fire," said Mr.Giddings. "I understand that when the big English dirigible R-34 cameacross the Atlantic last summer she was filled with hydrogen, and thather commander and crew all wore felt-soled shoes, so that they wouldnot by any chance cause a spark when they walked over her metal floorsand ladders just beneath her great bag."
"That is true," vouched John Ross. "One little spark reaching any ofthat stored hydrogen would have torn that great dirigible intofragments in one gigantic blast."
"We have handled recent newspaper copy containing mention of this newgas, helium; but I must confess I am in the dark regarding its natureand source," said Mr. Giddings. "What is it, anyway?"
"I will refer your question to Paul here," replied John. "He is theone who worked out this idea of using helium in an airplane and givingit the best properties of a dirigible without any of the dirigible'shandicap of clumsiness and excessive wind resistance. He has beenstudying the properties of helium in school, also the flight of birds."
"Well, not to get into a tiresome discourse, as Professor Herron wouldsay, I shall make this description very rudimentary," said Paul, with asmile. "During a total eclipse of the sun in India in 1868, Lockyer, aBritish astronomer, saw in the spectroscope a bright, yellow line oflight around the sun. He called it _helium_, after the Greek word forsun. So much for him. Twenty-seven years later an element was foundon earth in natural-gas in Kansas, which gave the same bright, yellowlight viewed through the spectrum. The people, finding it would notburn, disgustedly let millions of barrels of this valuable elementescape into the air, before a scientist told them that it was of untoldvalue for balloon and airship purposes. It is thought the gas comesfrom radium deposits. It has never been found in any country exceptthe United States, and only here in Kansas and northern Texas, where itoccurs in sands from 14,000 to 16,000 feet deep. Our government is nowsecuring about 50,000 cubic feet of helium per day, refusing to sell itto foreign countries, as it is all needed here, besides which it mightbe used against us in case of another war."
While Paul had been telling this, Mr. Giddings had been busy jottingsomething down in shorthand in a notebook.
"Pardon me, Paul," he said, looking up with a smile, "but this is somighty interesting that, before I knew it, my old-time reportorialinstinct had gotten the best of me, and I found my pencil at work. Ifyou have no objection I should like to use this in the columns of the_Daily Independent_ some time when it seems to fit in."
"No objection at all, sir," assured Paul.
Mr. Giddings began twirling the little twelve-inch two-bladed propellerat the nose of the model airplane. "What do you use for power to turnthis propeller?" he asked, after admiring its perfect proportions for amoment. "I don't see any rubber-bands, such as Robert here has alwaysused on his little machines."
John deftly lifted off the thin veneer hood of the airplane, anddisclosed a very small four-cylindered rotary pneumatic engine ofbewitching simplicity and lightness, which a baby could have held outin its pudgy palm.
"Paul has worked this little motor out of aluminum and brass and steel,from odds and ends," said John.
"With more or less help on the part of my elder brother," interjectedPaul.
"Well, perhaps with a little," admitted John, "more suggestive thanotherwise."
"What sets it going?" questioned Bob, curiously.
"The fuselage is divided into three sections," said Paul. "The forwardsection contains the engine here; the rear section is an airtightchamber containing helium; and the central section is also an airtightchamber, but contains ordinary air which has been pumped into itthrough a valve, using the bicycle pump John is carrying, until it isunder strong pressure. When I turn this little valve an outlet isopened for the air to escape by a tube into branches communicating witheach of these four cylinders. This works the tiny pistons, much thesame as gas in a gasoline-motor, and they turn the little crank-shaftto which they are connected, and the crank-shaft in turn revolves thepropeller on its end."
"Wonderfully simple!" Mr. Giddings exclaimed. "Wonderfully ingenious,too! Is this your invention, young men?"
"Partly, sir," replied Paul. "I understand, a company in New York ismaking a somewhat similar pneumatic motor for model airplanes, but Johnand I have made some radical improvements, to our notion. To-day'stest will tell the story."
"Let's see the propeller spin 'er up once for the fun of it," suggestedBob. "It won't do any harm, will it? Dad and I will hold on to theairplane."
"Get a good grip then," warned John Ross, "for you will find there's aterrific pull to the little rascal. Paul and I tried her in thatfashion early this morning down in the basement."
Bob and his father secured firm holds of the little Sky-Bird, one oneach side, where the propeller could not strike them.
"Ready?" asked Paul, with a smile.
"Ready!" came the answer in unison.
Paul touched the little valve in the tank chamber of the fuselage. Thenext moment there was a quiver, and then the propeller began fairly tohum. A strong, steady gust of air began to blow in the faces of theGiddingses, while they had to hang on grimly in order to keep theirlittle charge from jumping out of their arms and dashing away into theair. For fully three minutes the propeller continued to whirl withundiminished speed, then slowly it began to slow up, and finallystopped.
Both Mr. Giddings and his son wiped their hot brows as they handed theplane over to its makers.
"Whew!" said Bob, "that little mule has got a lot of pull to her."
"That she has," supplemented his father. "What sort of material is herframe made of?"
"Balsa-wood," said John.
"I never heard of that. Is it something new?"
"Yes,--to the arts of civilization, but I presume it has been used bythe Indians of Ecuador, where it grows, for scores of years in themaking of rafts, for which it is particularly well adapted. Th
e treelooks much like our southern cottonwood, and the wood apparently has nograin. It has a surprising toughness and strength, and is a trifleover half the weight of cork, weighing only 7.8 pounds per cubic foot,while the same sized piece of cork weighs 13.7 pounds."
"Has this wood ever been used in constructing full-sized airplanes?"asked Mr. Giddings.
"I think not; but Paul and I believe it will be the coming wood forthem," said John with enthusiasm. "We have used it plain on thismachine. On a large airplane it ought to be reinforced with transversesections of very thin spruce laid latticewise. That would addconsiderably to its natural strength, and increase the total weightvery little."
"H'm, h'm!" said the great newspaper publisher, "this is veryinteresting, I am sure. Now let us see how this little affair behavesitself in the air."
Paul and his brother led the way out into one corner of the big field,so as to bring what slight breeze might spring up into the head of theairplane, explaining that machines without a pilot would keep a betterkeel under such conditions. John then carefully attached thebicycle-pump and recharged the air-tank, following which he took outhis watch to time the flight. Mr. Giddings and Bob also took out theirwatches.
Paul set the little Sky-Bird down on the hard earth, in a spot wherethere was no grass or other obstacle, and with his finger on theair-valve, said: "Practically all rubber-band motors require startingthe model airplane off by picking it up and tossing it away from you upinto the air; but I think this machine will rise from the ground like alarge plane, on account of its great lightness and unusual power. Wewill now see if I am right."
To tell the truth, this being the first time he had really tried theSky-Bird in a flight, Paul was nervous as he turned the valve, removedhis hands from the graceful little plane, and straightened up.
With a whirr like the wings of a partridge as it is flushed out of thegrass by the huntsman's dog, the small machine shot forward a few feetover the smooth ground, then gracefully arose in the air and startedaway toward the opposite corner of the field. As it proceeded itcontinued to rise, until it reached a height of possibly ninety or ahundred feet, when it began to dip unsteadily.
"It's a gust of wind striking it," remarked John uneasily. "I hope sheweathers it. If there was only a pilot in her now, he could----"
But even as he spoke the Sky-Bird seemed to recover her balance.Making a pretty circle, away she sped on her course, neither rising norfalling. Like a real bird she sailed onward, the noise of her whirringpropeller now lost to her fliers, but her little pale-yellow silk wingsagainst the blue sky plainly tracing her course for them. Paul wasrunning after her now as fast as his legs could carry him. What if sheshould keep right on and go over the far fence?--he might lose thelittle darling!
That fence was a good half-mile away. For his pet to cover such adistance had not seemed within the bounds of probability to eitherhimself or John at the start, for all of their great confidence in theflying powers of the new model. Now, as he kept on running and theSky-Bird continued going with no sign of dropping, Paul really becamealarmed for her safety in landing.
But just before it reached the boundary of the grounds, the youth sawthat the airplane was slowly settling. Into the next field it flew,and the high board fence shut it from Paul's view as he came up to it.With a jump he caught the top boards, and scrambled up, springing downon the opposite side. It was to see his little machine just miss thebranches of an oak tree and settle down into some long grass about ahundred yards beyond.
He found it undamaged, and hurried back to his friends in thefair-grounds, his heart beating jubilantly at the splendid results ofthe flight. He hugged the small airplane to his heart as if it werethe most precious possession in the world, as indeed it was to him.
Mr. Giddings and Bob were loud in their praise, and John smiled in thatquiet way that told the younger brother how well pleased he was. Itwas found that the Sky-Bird had passed over the lower fence in just oneminute and three seconds, which was certainly good speed for such adiminutive contrivance. Several other flights were then made, all ofwhich were equally successful. At the conclusion Bob Giddings was soexcited that he could hardly stand still.
"Dad, isn't this little thing simply a wonder?" he exclaimed. "I'dgive anything in the world if I could own a big fellow built on thisprinciple. I'll bet it would pass anything now made."
His father looked thoughtful for a moment. Then, turning to the Rossbrothers, he observed:
"Do you think, boys, that these features could be successfully appliedto a full-sized airplane?"
"There's no doubt at all about it, to my mind, sir," replied John Ross."That's the next thing Paul and I propose doing, although I expect weshall have a hard time getting enough money to meet the expense ofmaterials. Of course we shall have the regular type of gasoline enginein place of this pneumatic arrangement, as this principle won't applyto big machines. I figure a 400 horse-power Liberty engine would carrysuch a machine two hundred miles an hour."
Again Mr. Giddings was silent a moment. Then he resumed: "John, I hearthat you have been laid off from your Air Mail job. Is that right?"
"It is, sir."
"Well, then, I am going to make a proposition to you and Paul, and in away Robert may consider himself involved, too, I expect. As you mayknow, Robert plans to be an electrical engineer, and Mrs. Giddings andmyself are anxious to encourage him in every way we can. For some timehe has been experimenting with wireless telegraph and telephoneapparatus, and has made some sets of the latter which it seems to meare an improvement over anything now on the market, particularly a setfor airplane use, which he has no means of properly testing out onaccount of the lack of the airplane. Now my proposition is just this:I will meet every expense of making a first-class full-sized airplanelike the Sky-Bird, and pay you, John, a wage equal to that which thegovernment allowed you as a pilot, if you three young men here will dothe construction work secretly, and if Robert may be allowed aone-third interest in the venture, both in the plane to be made, and inany future benefits to be derived from the patent rights."
Of course the delighted John and Paul accepted this splendid offer, andBob Giddings was so happy at the prospect of a fine big airplane inwhich to install his wireless apparatus that he actually hugged hisfather. They repaired to the Giddings home, and there, in truebusiness form, a contract was drawn up and duly signed by allinterested parties, with a notary's seal attached.
With a copy in their possession, the Ross boys hurried home, afterhaving dinner with the Giddings family, to acquaint Mrs. Ross with thegood news.