height. a beri cue the pep This article tells about the pilots' experience on vast amount of equipment and preparatory detail wer Germany fly at varying ing as much as five miles up. such a flight es the that make the flight possible. attained by Britain's Royal Air Force bomber aircraft in the of three, four and five miles above the earth are course of photographic reconnaissance flights over the heart of Germany.
At such a height, when the land below shrinks to the proportions of.a relief map and islands resemble rocks in the tide, the airman flies in a strange new world of space. Extreme cold and the raritied air at such high altitudes are his two greatest. dangers, On recent night flights over Germany, temperatures as degrees of frost have been encountered and ice has on the cockpit floor inside the aircraft. against such intense cold the airman relies upon warm clothing: fur lined boots reaching above lined overalls, the closest fitting helmet, and a pair was progress: ively more ratified. To guard at against risk of premature collapse it With each thousand feet increase in height, the oxygen valve opening is slightly increased and the rate of supply quickened until, when the aircraft has reached its ceiling, the oxygen is being delivered at maximum pressure.
Breathing Impossible At about 35,000 feet, however, the low pressure of the atmosphere makes breathing impossible even with the aid of an oxygen mask; and it then becomes necessary to encase the l- airmen in an airtight pressure suit, resembling a divers outfit, inside which a termined pressure suf. ficient to permit of the inhalation of oxygen can be maintained.
The for the airman greatest lies in the slowing-up of the thought process and mental reaction which lack of oxygen induces in the human mind, Concentration becomes difficult and in the feeling of lassitude which quickly overtakes the oxygen-starved airman, even such a simple action as picking up a fallen map becomes an ort.
Apart from the physiological conditions, high altitude flying also introduces special problems relating to the aircraft itself. The supercharged en. gine has now satisfactorily overcome the difficulty of compressing a combustible mixture at a low outside pressure, a problem which previously limited aeroplanes to a maximum height of about 15,000 feet, but the thin air of great heights still takes toll of an aircraft's performance by reducing the rate of flying and rendering it far less manoeuvrable than at lower levels.
At heights approaching the aircraft's "ceiling" the attenuated atmosphere provides so little "lift" for the aeroplane's wings that, combining with the lower power of the engines, the rate of flying may fall to a fraction of the aircraft's ground-level ability. To maintain height it becomes necessary to keep the aircraft in a slightly tail-down attitude so that the wings are presented to the air-stream at their angle of maximum lift,
Text read from the printed page and cleaned; old type leaves the occasional error.