Two whistles, low but clear, came out of the night All three silently left the narrow trench and wriggled forward across the open. The hangars loomed up before them, seeming preposterously tall from their position on the ground. Within a few yards of their goal De Richleau stood up, he helped Simon to his feet, and with Marie Lou on the other side, supported the wounded man round to the front.
The sliding door of the hangar stood a little open; they squeezed through. The only light was the reflection from Rex’s torch — he was already busy in the cockpit examining the controls. No trace of a sentry was to be seen.
In the uncertain light the ’plane seemed a strange monster; Rex leaned out. “There’s a step-ladder by her tail. Get Simon in the back.” De Richleau found the ladder and propped it against the side.
“Go on,” said Simon. “I can manage now, don’t worry about me.” He hauled himself up by his hands and one sound leg; fortunately, his wound had not reopened owing to the care they had taken in getting him so far. The Duke disappeared to find the petrol pump, and Marie Lou to keep watch outside.
The pump was only a few yards away, and De Richleau struggled manfully with the heavy wirebound rubber hose. At last he got the nozzle to within a few feet of the ’plane — Rex climbed down and gave an extra heave — a moment later petrol was pouring into the empty tank.
“Do you think you can handle her?” De Richleau asked.
“Sure,” came back the cheerful answer. “The helicopter’s no essential part of the construction. I was scared it might be; we couldn’t have sailed up through the roof! But it’s all O.K. I reckon we can taxi out and take off in the open like any other ’plane.”
“Where is the sentry?”
Rex jerked his head towards the back of the hangar. “Tucked up in a corner there, poor bum. I guess he never knew what hit him. Come on — now the reserve tank, then we’ll get right out of here.”
They heaved again on the weighty hose; when the tank was full they threw it on the ground, and turned their attention to the hangar doors — great sheets of corrugated iron and steel on rollers.
Marie Lou was outside, a small silent shadow — standing motionless and intent, her eyes riveted in the direction of the wireless music — the singing had stopped.
Rex and De Richleau put their shoulders to the sliding doors. Luckily the runners were well oiled; before long they had the hangar wide open. They could see the ’plane better now, it was a big double-engined monoplane, the engines fixed centrally a few feet above the wide metal wings, with propellers fore and aft. Immediately beneath, in the body, was a small cabin, with open seats for the two pilots side by side in front. Before each was fixed a wicked-looking machine-gun. At the back of the cabin were twin seats for observers, each equally well armed. The roof of the cabin bulged up in a wide funnel to the engine so that a mechanic inside could attend to them in flight. A tall shaft rose from the centre of the engines bearing the wings of the helicopter.
The Duke touched Marie Lou on the arm. “Quick, up into the back with Simon.”
He began to haul the nozzle of the petrol hose from under the ’plane. Rex had already clambered up into the pilot’s seat. “Don’t waste time monkeying with that,” came his sharp whisper.
“One moment, my son,” De Richleau persisted, dragging the hose outside the hangar.
“The ladder! What shall I do with it?” came Marie Lou’s voice.
“Shove it clear of the ’plane,” Rex called back softly.
From her seat beside Simon she gave the ladder a push. There was a loud clang as it struck the corrugated-iron side of the hangar. It shattered the silence like a blow on a giant gong.
“That’s torn it,” said Rex, angrily. “For God’s sake come on.” De Richleau clambered hastily up beside him.
With straining ears they listened for the sound of running feet. It did not seem possible that such a sound should pass unnoticed, but nothing stirred.
“All set?” cried Rex, loudly. There was an answering cry from Simon and the girl in the back. “Praises be she’s the latest thing in ’planes with an electric starter,” he added to the Duke, but the latter part of his sentence was lost in the roar of the engine. In the corrugated-iron hangar the noise reverberated like thunder — the ’plane remained quite stationary.
“Can’t you start her?” yelled the Duke, apprehensively, in Rex’s ear.
“Sit tight!” Rex bawled back.
The roar of the engine drowned every other noise, but in the distance, on the right, squares of light showed where the hut doors were being thrown open, and against the light little figures could be seen hurrying forward.
Suddenly the dark shape of a man loomed up right in front of the hangar; he shouted something — but what, they could not hear. He did not carry a rifle, and in the faint glow his face expressed surprise.
De Richleau levelled his automatic — another second and he would have pulled the trigger. With a gasp he lowered his pistol and stooping, yelled through the cabin to Simon: “Don’t shoot! For God’s sake don’t shoot!”
“Time to go home,” said Rex to himself, as he smiled in the darkness. He had not wasted the last few moments. Better to take the risk of a few shots as they left the ground, than chance a dead cold engine conking out fifty yards from the shed.
Slowly the big ’plane slid forward — the man ducked hurriedly under the right-hand wing — in a moment they were in the open and gathering speed.
As the ’plane left the shed the din of the engines lessened. A whole crowd of men surged out of the darkness, shouting and gesticulating. Somehow, to the occupants of the ’plane, they looked stupid and helpless — waving their arms and opening their mouths when not a word they said could be heard. One fell over backwards as he jumped aside to avoid the onrush of the metal wing. The speed increased — the cool night air rushed past — the ’plane began to bump gently in great leaps along the level ground; almost in an instant the running men were left behind, swallowed up in the shadows.
“We’re off!” cried Simon, to Marie Lou, and for the first time the girl realized that they had left the ground. Another group of hangars rushed past them, twenty feet below — they both looked back. The crack of a rifle came to them faintly from the hangar. It was followed instantly by a great sheet of flame.
The Duke gave a chuckle of delight — he had come through the small cabin and joined them unnoticed.
“What — what happened?” gasped Simon.
“I left the petrol turned on in front of the sheds,” De Richleau smiled, grimly.
“That’s why you called out to me not to fire?”
He nodded. “I only just remembered in time myself. If I’d shot that man the flash from my pistol would have blown us up.”
‘The hangars — they are on fire,” cried Marie Lou excitedly.
They were climbing swiftly now. Far below them, and to the rear, they could see the flames leaping upwards, and in the red glare little dots of men scurrying to and fro. The great arena of the camp was plainly discernible, and, encircling it, the darker ring of the illimitable forest.
A bright shaft of light shot up from one corner of the air-park, followed by another and another from different spots below. “Searchlights,” said the Duke. “They are trying to pick us up. I wonder if they have antiaircraft guns?”