Murray Leinster (Duke Classic SiFi) (16 page)

He lapsed into silence again.

Joe considered. He frowned.

A pushpot, outside the building, hysterically bellowed its way across
the runway and its noise changed and it was aloft. It went spiraling up
and up. Joe stirred his coffee.

There were thin shoutings outside. A screaming, whistling noise! A
crash! Something metallic shrieked and died. Then silence.

Talley, the co-pilot, looked sick. Then he said: "Correction. It's been
five pushpots exploded and five pilots killed this week. It's getting a
little bit serious." He looked sharply at Joe. "Better drink your coffee
before you go look. You won't want to, afterward."

He was right.

Joe saw the crashed pushpot half an hour later. He found that his
ostensible assignment to the airfield for the investigation of sabotage
was quaintly taken at face value there. A young lieutenant solemnly
escorted him to the spot where the pushpot had landed, only ten feet
from a hangar wall. The impact had carried parts of the pushpot five
feet into the soil, and the splash effect had caved in the hangar
wall-footing. There'd been a fire, which had been put out.

The ungainly flying thing was twisted and torn. Entrails of steel tubing
were revealed. The plastic cockpit cover was shattered. There were only
grisly stains where the pilot had been.

The motor had exploded. The jet motor. And jet motors do not explode.
But this one had. It had burst from within, and the turbine vanes of the
compressor section were revealed, twisted intolerably where the barrel
of the motor was ripped away. The jagged edges of the tear testified to
the violence of the internal explosion.

Joe looked wise and felt ill. The young lieutenant very politely looked
away as Joe's face showed how he felt. But of course there were the
orders that said he was a sabotage expert. And Joe felt angrily that he
was sailing under false colors. He didn't know anything about sabotage.
He believed that he was probably the least qualified of anybody that
security had ever empowered to look into methods of destruction.

Yet, in a sense, that very fact was an advantage. A man may be set to
work to contrive methods of sabotage. Another man may be trained to
counter him. The training of the second man is essentially a study of
how the first man's mind works. Then it can be guessed what this
saboteur will think and do. But such a trained security man will often
be badly handicapped if he comes upon the sabotage methods of a second
man—an entirely different saboteur who thinks in a new fashion. The
security man may be hampered in dealing with the second man's sabotage
just because he knows too much about the thinking of the first.

Joe went off and scowled at a wall, while the young lieutenant waited
hopefully nearby.

He was in a false position. But he could see that there was something
odd here. There was a sort of pattern in the way the other sabotage
incidents had been planned. It was hard to pick out, but it was there.
Joe thought of the trick of booby-trapping a plane during its major
overhaul, and then arming the traps at a later date.... A private plane
had been fitted to deliver proximity rockets in mid-air when the
transport ship flew past. There was the explosion of the cargo parcel
which was supposed to contain requisition forms and stationery. And the
attempt to smash the entire Platform by getting an atomic bomb into a
plane and having a saboteur shoot the crew and then deliver the bomb at
the Shed in an officially harmless aircraft....

The common element in all those sabotage tricks was actually clear
enough, but Joe wasn't used to thinking in such terms. He did know,
though, that there was a pattern in those devices which did not exist in
the blowing up of jet motors from inside.

He scowled and scowled, racking his brains, while the young lieutenant
watched respectfully, waiting for Joe to have an inspiration. Had Joe
known it, the lieutenant was deeply impressed by his attempt at
concentration on the problem it had not been Major Holt's intention for
Joe to consider. When Joe temporarily gave up, the young lieutenant
eagerly showed him over the whole field and all its workings.

In mid-morning another pushpot fell screaming from the skies. That made
six pushpots and six pilots for this week—two today. The things had no
wings. They had no gliding angle. Pointed up, they could climb
unbelievably. While their engines functioned, they could be controlled
after a fashion. But they were not aircraft in any ordinary meaning of
the word. They were engines with fuel tanks and controls in their
exhaust blast. When their engines failed, they were so much junk falling
out of the sky.

Joe happened to see the second crash, and he didn't go to noon mess at
all. He hadn't any appetite. Instead, he gloomily let himself be packed
full of irrelevant information by the young lieutenant who considered
that since Joe had been sent by security to look into sabotage, he must
be given every possible opportunity to evaluate—that would be the word
the young lieutenant would use—the situation.

But all the time that Joe followed him about, his mind fumbled with a
hunch. The idea was that there was a pattern of thinking in sabotage,
and if you could solve it, you could outguess the saboteur. But the
trouble was to figure out the similarity he felt existed in—say—a
private plane shooting rockets and overhaul mechanics planting booby
traps and faked shippers getting bombs on planes—and come to think of
it, there was Braun....

Braun was the key! Braun had been an honest man, with an honest loyalty
to the United States which had given him refuge. But he had been
blackmailed into accepting a container of atomic death to be released in
the Shed. Radioactive cobalt did not belong in the Shed. That was the
key to the pattern of sabotage. Braun was not to use any natural thing
that belonged in the Shed. He was to be only the means by which
something extraneous and deadly was to have been introduced.

That was it! Somebody was devising ingenious ways to get well-known
destructive devices into places where they did not belong, but where
they would be effective. Rockets. Bombs. Even radioactive cobalt dust.
All were perfectly well-known means of destruction. The minds that
planned those tricks said, in effect: "These things will destroy. How
can we get them to where they will destroy something?" It was a strict
pattern.

But the pushpot sabotage—and Joe was sure it was nothing else—was not
that sort of thing. Making motors explode.... Motors don't explode. One
couldn't put bombs in them. There wasn't room. The explosions Joe had
seen looked as if they'd centered in the fire basket—technically the
combustion area—behind the compressor and before the drive vanes. A jet
motor whirled. Its front vanes compressed air, and a flame burned
furiously in the compressed air, which swelled enormously and poured out
past other vanes that took power from it to drive the compressor. The
excess of blast poured out astern in a blue-white flame, driving the
ship.

But one couldn't put a bomb in a fire basket. The temperature would melt
anything but the refractory alloys of which a jet motor has to be built.
A bomb placed there would explode the instant a motor was started. It
couldn't resist until the pushpot took off. It couldn't....

This was a different kind of sabotage. There was a different mind at
work.

In the afternoon Joe watched the landings, while the young lieutenant
followed him patiently about. A pushpot landing was quite unlike the
landing of any other air-borne thing. It came flying down with
incredible clumsiness, making an uproar out of all proportion to its
landing speed. Pushpots came in with their tail ends low, crudely and
cruelly clumsy in their handling. They had no wings or fins. They had to
be balanced by their jet blasts. They had to be steered the same way.
When a jet motor conked out there was no control. The pushpot fell.

He carefully watched one landing now. It came down low, and swung in
toward the field, and seemed to reach its stern down tentatively to
slide on the earth, and the flame of its exhaust scorched the field, and
it hesitated, pointing up at an ever steeper angle—and it touched and
its nose tilted forward—and leaped up as the jet roared more loudly,
and then touched again....

The goal was for pushpots to touch ground finally with the whole weight
of the flying monstrosity supported by the vertical thrust of the jet,
and while it was moving forward at the lowest possible rate of speed.
When that goal was achieved, they flopped solidly flat, slid a few feet
on their metal bellies, and lay still. Some hit hard and tried to dig
into the earth with their blunt noses. Joe finally saw one touch with no
forward speed at all. It seemed to try to settle down vertically, as a
rocket takes off. That one fell over backward and wallowed with its
belly plates in the air before it rolled over on its side and rocked
there.

The last of a flight touched down and flopped, and the memory of the
wreckage had been overlaid by these other sights and Joe could think of
his next meal without aversion. When it was evening-mess time he went
doggedly back to the mess hall. There was a sort of itchy feeling in his
mind. He knew something he didn't know he knew. There was something in
his memory that he couldn't recall.

Talley and Walton were again at mess. Joe went to their table. Talley
looked at him inquiringly.

"Yes, I saw both crashes," said Joe gloomily, "and I didn't want any
lunch. It was sabotage, though. Only it was different in kind—it was
different in principle—from the other tricks. But I can't figure out
what it is!"

"Mmmmmm," said Talley, amiably. "You'd learn something if you could talk
to the Resistance fighters and saboteurs in Europe. The Poles were
wonderful at it! They had one chap who could get at the tank cars that
took aviation gasoline from the refinery to the various Nazi airfields.
He used to dump some chemical compound—just a tiny bit—into each
carload of gas. It looked all right, smelled all right, and worked all
right. But at odd moments Hitler's planes would crash. The valves would
stick and the engine'd conk out."

Joe stared at him. And it was just as simple as that. He saw.

"The Nazis lost a lot of planes that way," said Talley. "Those that
didn't crash from stuck valves in flight—they had to have their valves
reground. Lost flying time. Wonderful! And when the Nazis did uncover
the trick, they had to re-refine every drop of aviation gas they had!"

Joe said: "That's it!"

"That's it? And
it
is what?"

Then Joe said disgustedly: "Surely! It's the trick of loading CO2
bottles with explosive gas, too! Excuse me!"

He got up from the table and hurried out. He found a phone booth and got
the Shed, and then the security office, and at long last Major Holt. The
Major's tone was curt.

"Yes?... Joe?... The three men from the affair of the lake were tracked
this morning. When they were cornered they tried to fight. I am afraid
we'll get no information from them, if that's what you wanted to know."

The Major's manner seemed to disapprove of Joe as expressing curiosity.
His words meant, of course, that the three would-be murderers had been
fatally shot.

Joe said carefully: "That wasn't what I called about, sir. I think I've
found out something about the pushpots. How they're made to crash. But
my hunch needs to be checked."

The Major said briefly: "Tell me."

Joe said: "All the tricks but one, that were used on the plane I came
on, were the same kind of trick. They were all arrangements for getting
regular destructive items—bombs or rockets or whatever—where they
could explode and smash things. The saboteurs were adding destructive
items to various states of things. But there was one trick that was
different."

"Yes?" said the Major, on the telephone.

"Putting explosive gas in the CO2 bottles," said Joe painstakingly,
"wasn't adding a new gadget to a situation. It was changing something
that was already there. The saboteurs took something that belonged in a
plane and changed it. They did not put something new into a plane—or a
situation—that didn't belong there. It was a special kind of thinking.
You see, sir?"

The Major, to do him justice, had the gift of listening. He waited.

"The pushpots," said Joe, very carefully, "naturally have their fuel
stored in different tanks in different places, as airplanes do. The
pilots switch on one tank or another just like plane pilots. In the
underground storage and fueling pits, where all the fuel for the
pushpots is kept in bulk, there are different tanks too. Naturally! At
the fuel pump, the attendant can draw on any of those underground tanks
he chooses."

The Major said curtly: "Obviously! What of it?"

"The pushpot motors explode," said Joe. "And they shouldn't. No bomb
could be gotten into them without going off the instant they started,
and they don't blow that way. I make a guess, sir, that one of the
underground storage tanks—just one—contains doctored fuel. I'm
guessing that as separate tanks in a pushpot are filled up, one by one,
one
is filled from a particular underground storage tank that contains
doctored fuel. The rest will have normal fuel. And the pushpot is going
to crash when that tank, and only that tank, is used!"

Major Holt was very silent.

"You see, sir?" said Joe uneasily. "The pushpots could be fueled a
hundred times over with perfectly good fuel, and then one tank in one of
them would explode when drawn on. There'd be no pattern in the
explosions...."

Major Holt said coldly: "Of course I see! It would need only one tank of
doctored fuel to be delivered to the airfield, and it need not be used
for weeks. And there would be no trace in the wreckage, after the fire!
You are telling me there is one underground storage tank in which the
fuel is highly explosive. It is plausible. I will have it checked
immediately."