The arms race continued in all areas of the war. When the high altitude Junkers 86P was seen as a ‘speck of silver’ high above Britain in 1942, countermeasures were needed. It was ‘only’ a reconnaissance aircraft but it could not be allowed to operate unchallenged – the military build up in Britain was now moving up a gear or two.
One of the aircraft adapted to counter it was the Mosquito. The high altitude version was also stripped down of armament, given longer wings and an improved engine. The ace night fighter John Cunningham was one of the first operational pilots to give it a trial flight, in April 1943. His regular Navigator, C.F. Rawnsley, was with him, and wrote a memorable account of their first flight:
I watched the waving wing-tips flexing upward as we started to gather speed for the take-off and after an incredibly short run we were soaring into the air. The altimeter needle was almost spinning around the dial as the earth shrank swiftly away below us.
In two minutes we had passed the ten-thousand foot mark, and in ten minutes we were nearing thirty thousand feet. It would have taken us the best part of forty minutes to climb to that height in our orthodox, heavily-armed Mosquitos, even by flogging the engines hard.
The earth below us began to look remote, a world apart, a faraway pattern of tiny fields and toy lakes and little smudgy scars that puny man called towns. A layer of broken cloud formed the base of our new world, and even that was far below us. We were free in the empty sky, and we could look up into the vast, indigo depths of frozen space.
The small, fierce sun threw harsh shadows on the wing, and as we climbed the sky became darker and darker, and the windows began to frost over until only part of the windscreen and a few patches at the side remained clear. This was all quite different from what I had known of even our fairly regular flights to the higher altitudes of about twenty-five thousand feet. The cabin pressure was at an artificial thirty-two thousand feet, but the altimeter needle, slowing down now, had just passed the mark for forty-three thousand feet.
I became vaguely aware of a slight pounding in my ears, and there was a strange, blinkered feeling around my eyes. Pins and needles ingled in my left knee, and my lungs were pulling heavily, sucking in oxygen. But these things were only incidental, and I was there to do a job. There was another of the Mosquitos about somewhere, and we were to do a radar interception on it.
Up at that height the spinning scanner of the A.I. set never even glanced at that far off earth, and the responses on the cathode ray tube were as clean and as clear as a May morning. Only the firm, sharp arc of the blip from our target showed up, circling the tube and shrinking towards the centre as we drew nearer. If only all our interceptions could be as clean as that one!
John was satisfied, and at his word I looked up from the A.I. set, up and out into the hard, bright glare around us. A dense stream of white vapour was pouring back over our heads, and for a few seconds it seemed to me to be coming from nowhere.
Then, right in front of us, I saw the other aircraft. So perfectly blended were paint and sky that the wings and the fuselage of the Mosquito were only barely visible. The blue paint that on the ground had looked so blatant was now blending perfectly with the deep indigo of the background, and only the dark oil streak beneath each engine Cowling showed up clearly. But behind, of course, the dazzling white vapour trails streamed out for miles.
John turned back on the homeward run and we changed places with the other Mosquito so that they could check their A.I. I looked around, and through the half-frosted windows I could see the sweeping curve of the horizon. It was the first time that I had seen for myself that it really did curve, and that the earth was round.