Kiwi’s heart leaped as one tremendous bolt of lightning flashed before his eyes, just ahead. He felt the entire plane quiver under the impact of the blows struck by the wind. They had become accustomed to the roar of the motor, and now it seemed as though they could hear the noise of the storm.
As the wind howled by, they could feel the air growing colder and colder. Kiwi watched the magnetic compass, set up high above the instrument board, swing first one way and then the other with the twisting and turning of the plane as it was buffeted by the winds.
Jack had stopped all attempts to use his wireless, and had his spare control stick in place ready to help the Skipper should he tire from his tremendous exertions. Both their faces showed the strain of flying through the storm.
As the cold increased, sleet began to beat against the windows, and Jack glanced out uneasily to catch the first indication of ice forming on their wings. He realized the seriousness of such a happening. The upper and lower surface of the wing was cambered, or curved, in a scientific way to help lift the load of the plane, and anything that changed this curve would destroy its lifting power. Therefore at the first sign of ice forming on the wings they must begin a hunt for warmer air currents. Ice often formed with great rapidity, and knowing this both the Skipper and Jack watched closely for the first tell-tale sign. The engine was throttled back about a quarter to the best cruising speed.
There seemed to be no end to the storm. It had been nearly half an hour since they had left the clear sunshine and entered into this ominous twilight. They had held their altitude, knowing that it was no use to try to climb above the clouds, and having no assurance that it would be better lower down. Every little while rain would suddenly fall, and as suddenly stop.
All at once they were conscious of a thin film of the dreaded ice forming over the cockpit windows. Jack slipped back the glass panel and looked out. There on the leading edge of the wing was the unmistakable sign that ice was starting to form. In uneven lumps it was building slowly backwards....
Jack told the Skipper the disquieting news and shouted to Kiwi to slide back to his window in the rear compartment to see if the trailing edge of the wing was also gathering ice. Kiwi’s window was not as badly obscured as were those in front. He could see a thin layer of ice on the trailing edge working forward with great rapidity, and he crept over the tank to report this to Dad.
“We’ll try it lower,” Dad said. “We may strike some warm air there.”
Shutting off the engine as much as he dared, they coasted on down and down.
They tried it at the five thousand foot level for a few minutes. If anything they accumulated ice faster.