CROSSING THE ROCKIES

Bay of Plenty Beacon, Volume 10, Issue 74, 17 January 1947, Page 4

CROSSING THE ROCKIES

QUESTION OF AIR PRESSURE FEAT POSSIBLE IN STRATOCRUISER 0 Air passengers can now cross the highest peaks of the Rocky Mountains at an effective cabin altitude of between five and six thousand feet above sea level. That is approximately the altitude of the city of Denver, states a writer in the Christian Science Monitor. This feat is possible in the 80passenger Boeing Stratocruiser, which has been described as two ships in one. First, there is the outer aeroplane which climbs swiftly to altitudes of between 15,000 and 25,000 feet to ride above the storms. Then there is the altitude-condi-tioned cabin in which air pressure and temperature are maintained at passenger-comfort levels. Let us assume that a flight is to be made from the West Coast to the Atlantic Seaboard, with a stop at Denver, Colorado. The Stratocruiser climbs to an altitude of three to five miles, but the interior of the cabin remains at an effective altitude of sea level so far as the passengers ai’e concerned. After perhaps an hour of flying, the air pressure in the cabin is gradually reduced, as though the rate of climb were about 50 feet a minute. This continues until the air pressure in the cabin is the same as the atmospheric pressure at Denver. Passengers leaving the plane at Denver, therefore, find the pressure outdoors exactly matches that in the cabin.

When the plane takes off from Denver to continue its eastward flight, the cabin pressure is gradually built up to sea level pressure, again at a rate, corresponding to a change -of altitude of 50 feet a minute. At the end of the journey, since the cabin pressure is at sea level, no time need be lost circling the airport bringing the plane down in slow spirals to allow time for the passengers to adjust themselves to the change of air pressure.