by Van Powell
CHAPTER XXII
DARING AND DISASTER
Careless of the attention they might attract, Don and Chick rode thelow altitudes toward the sheet of water before the boathouse. Chick hada parachute flare ready.
Don signaled.
Overside went the flare, to ignite and throw its fierce, white glareover the approach.
As it settled Don spiraled down, far enough away to make his pass atthe water, power-stalling to a safe drop onto the surface.
He gunned the engine enough to bring them close to the old wharf andthen let the incoming tide drift them, while Chick, out on a pontoon,sidewise to the piling, caught the rope they had cut and left hangingsome nights earlier.
To draw the ship closer was no task.
Securing it, and taking the precaution of pocketing the partspreviously removed from the helicopter carburetor, Don passed them upto Chick, whose agility had enabled him to reach the planking of thedock.
"Now," Don helped by Chick, made the level and drew a small flashlampout of his coat, "let's see, first, if anybody's up here."
The light of the small torch danced to and fro as they stood in theopen door of the old building.
"Nobody at home!" Chick declared, following the light into corners,behind the table, still lying on its side where it had been overthrownin the former struggles, and lifting the trap in the dark corner.
"Down we go!" Don whispered.
"Nothing to stop us."
Their light, showing a rusting iron ladder, also revealed the surfaceof stagnant water, around a small landing stage, built to float up anddown with the tide. Around it, thickly clustered, were the dozen doriesowned by Toby Tew.
Boards, on the lee side, nailed to the string-pieces, served to keepwind out in storms, and since the boarding was carried down below thetide marks, disturbances from wind drift did not much affect thetethered crabbing boats.
"If we find anything," Don held the light while Chick descended, headbent to screen his eyes, "if we find a projector, and a battery, itwill narrow down our suspicions to Toby, and point to him after all."
"It will!" Chick agreed, reaching up to take the light, then jumpingfrom the lower rungs of the hanging ladder which did not quite go downto the platform, allowing for its rise with the tide.
"Here I come!"
Don, with Chick lighting his way, made the climb and jump.
"Nothing on the platform," remarked Chick sending the beam to and fro.
"Put it on the dories--that's it. There!"
A note of triumph was in Don's voice.
They hurried to the edge of the platform, drew a dory close, and werequickly within its cluttered hull.
A tarpaulin, dragged aside, revealed, in the light, a good-sizedbox-like metallic contrivance, its sides rounded, with a sort ofchimney on top: there was, besides, a large, circular tank, and asmalled metal case.
"Here's a portable projector," Don identified the metallic object, "andthere is the 'head' and probably film, in that smaller case. But wheredoes he get his light?"
"Maybe that tank holds acetylene gas," suggested Chick.
Don, unfastening the projector lamp-house, exclaimed in elation.
"I know!" he cried.
The round, pure white object set in a holder within the lamp-house,identified by Don as a calcium disk, told him the source of light.
"This calcium gives the whitest, most brilliant light there is," hedeclared. "See, Chick! The tank probably contains oxygen, under astrong pressure. Yes--there's a gauge, and a pet-cock to regulate thegas flow. The tank connects, by this rubber hose, to the base of theburner, and the thing on the lamp, like a bent finger, pointing towardthe calcium disk, is to throw the oxygen jet onto its surface. Then itglares like all get-out!"
"Let's row the dory, and never mind the Dart: she'll stay put," Chickfound oars on the staging in a big box.
They found quite a direct channel, along the shore line from theboathouse to the position in which the helicopter still lay tethered.
Expertly, as Chick obeyed his orders, Don assembled the parts of theapparatus in the cockpit of the helicopter. Iron, or perhaps aluminum,pieces, set into the coaming, enabled them to attach the portableprojector, and to swing it to and fro, and direct it up and down.
"Did you ever fly a helicopter before?" Chick asked, as they perfectedthe connections between tank and the lamp base.
"No. But it's simple! I mean--I can do it! You see, Chick, my flyingexperience will let me handle the tractor propeller, just the same asin the Dart."
"I suppose so! And I see that all you have to do about the top set ofblades is to throw in a clutch that meshes the gears on the uprightmast. The mast is set in a step and bearing in the body frame. It issquared into the gear that turns it--I guess you can manage it."
Don agreed.
Nevertheless, being a cautious youth who believed in being forehanded,he went over the curious, squat fuselage, tracing gas, oil,water-cooling and other feeds and piping. Then he examined the engine.Except that it was of a make he had not handled, it offered nodifficulties.
Assuring himself that the gas gauge indicated at least several hours offuel supply, and that he understood the controls for the liftingmechanism, Don operated the momentum starter. Its handle, rapidlyrotated, gave a big, heavy wheel considerable momentum. Then, applyingits control, he transmitted the power thus achieved to the engine andafter several attempts the starter caused the charge in a cylinder tobe ignited as the flywheel turned onto a point where a firing currentpassed into a charge of fuel mixture.
At once the engine took up its revolutions.
Don manipulated the throttle until he became fairly conversant with thepower response, then, carefully, being sure that all was well, and thatthey had the film already threaded properly in the projector and thatChick comprehended the handling of the fuel for the lamp jet, he easeddown the engine, let in the upper blade clutch, and saw the mast whirlits fan-like top slowly.
Gradually, as Chick cast loose the ropes, Don increased the speed ofthe upper blades, leaving the forward propeller idle.
The speed of the rotating fan soon began to be felt; but they did notrise.
"Don!" Chick, sensed a solution, having studied a good deal about thevarious points of airplane design, "remember that when a pontoon is inwater, as it lifts, the suction of the surface increases and has astrong pull to keep it from leaving: that's why they design a pontoonwith a 'step' so the contact is with the top of the water, and not downin it."
"That's right," Don agreed. "We'll have to go forward a little as welift. On land that wouldn't be necessary. In water it may."
The experiment was tried: he used the thrust-propeller, and in shortorder they were rising: then he cut out the forward speed, until he hadmade some tests of lifting speed with the horizontal blades.
"Here we go!" he cried finally. Go they did--up and forward.
"Aside from the handling of the upper fan," he mused, "this isn't muchdifferent from a slow cruising airplane. The tail and propeller controlare similar--rudder and elevators; but I'll have to remember the turnis made without ailerons to bank. We don't have to bank on a turn. Wejust rudder around, and the upper blades keep us on a stable keel as weturn--here, we do it!"
Around swung the forward propeller, and Don directed the craft towardthe higher levels on a slanting line that climbed it and alsoprogressed it toward the airport.
He saw, when they came close to the open space, figures on theilluminated tower balcony, watching upward.
Someone blinked a flash lamp.
"That means 'O.K.'" he murmured.
"We can put on our show!" cried Chick, also misinterpreting the signalthat they did not pause to spell out in full.
Swiftly, with the engine gunned in, Don lifted the helicopter above thesmall groups of fluffy, white cloud that gave him excuse for hisexperiment. The airport vanished beneath the mist and the shroudingclusters of dense, s
moky-white vapor.
Don swung the nose, as they hovered, drifting only slightly.
Thus he maneuvered into a position where his understanding of theangles they had worked out enabled Chick to train the projector on amass of white vapor just over the edge of the bay.
He threw up his arm.
The beam of the white light glowed, and Chick quickly maneuvered it,through a threaded-up section of transparent, non-inflammable film,into the cloud. He began to turn the crank. Darkness ensued in thecloud as part of an opaque film covered the light.
Suddenly Don screamed.
"Stop!"
He threw up his arm, trying to signal Chick.
But the younger chum, intent on his handling of the intense light andthe focusing tube of the lenses, as well as the proper course of thefilm as it jerked downward, paid no attention, failed to hear the cryand did not see the signal, his eyes being turned downward and away.
From the airport came screeches, as of warning, terror or distress.
The crash siren was going!
Don, from their high point, looking alertly around the horizon, hadobserved that the midnight mail 'plane, behind schedule, was coming,low and fast, over the swamp.
It all happened in a few instants.
On came the mail 'plane.
Up above the clouds, hidden from the mail ship by vapor, Chick crankedhis projector.
As the mail ship approached, near the edge of the swamp, out on thecloud leaped the glow that suffused it, went through it, made of it aweird, terrifying set of illuminated atoms of moisture. Onto that planeof light leaped the black silhouette of an oncoming ship. The swing Dontried to make, to turn the vision away from its screen, did not help,since they had no forward speed to cause the rudder to work.
Hideous terrors gripped the young pilot. He knew what was about tohappen. The pilot of the mail ship, already superstitious, and aware ofthe ghostly stories that had been flung far and wide, would look towardthat cloud as he dropped the nose toward the airport approaches.
It couldn't be helped. The spectre in the clouds was flying right athim as his ship disappeared from Don's sight under the cloud over whichthey hovered.
Swiftly he cut the speed of the upper blades. They began to settle.
"What will we find on the ground?" Don muttered.
