51
Hong Kong's temperatures don't go as high as India's, but they are hot enough to affect machinery. The B-29's new instruments were especially vulnerable. In tropical areas (Hong Kong is semi-tropical), temperatures inside a B-29 during a hot day could reach 150°F (65.5°C). Besides affecting crew comfort, the heat takes a toll on the B-29's engines, which would be damaged if the temperature of its cylinder heads exceeded 428°F (220°C). If the engines haven't yet been damaged, they would have suffered decreased efficiency due to the higher temperatures, thereby requiring longer takeoffs. Temperature variations also affect the air pressure of a B-29's tyres. Improper inflation of tyres affects the takeoff and landing distance of an aircraft, and could result in shorter tyres life.42 Hence, early morning takeoffs were recommended if the B-29 were to operate from Hong Kong. A temperature of 75°F (24°C) demanded a 10 percent increase in runway length (due to the lower efficiency of the B-29's engines), and 20 percent if the temperature reached 100°F (37.7°C). But summers in Hong Kong would not be conducive to the efficient operation of a B-29, for even early morning temperatures during this period would have reached or exceeded 75°F.44
43
Humidity and heavy rains can cause corrosion, fungal build-up, and ultimately malfunctions on idle B-29s. Electrical equipment is particularly at risk to such weathering, and when that is gone, the B-29 has lost its technological edge. Idle engines are also affected by heavy weathering, which can contaminate engine oil with impurities and thus damage the engine.45
Then there is the all-powerful typhoon, which could pose a serious threat to B-29 operations. In July 1946, Hong Kong was hit by another typhoon, and Kai Tak got the worst of it. Winds of up to 130 knots were recorded. The runway was holed, and five transport planes and two Sunderland flying boats, all unserviceable, were lost - a testimony to the vulnerability of grounded aircraft to the weather and anything else. The toll would have been higher had some aircraft not been evacuated prior to the typhoon's arrival. Although the Allies did not have the power of foresight during the war, they already knew about the 1937 typhoon, which also damaged Kai Tak.46
A loss of seven planes might have seemed tolerable to the materiel-rich Allies, but not so in the case of the B-29. It was the most expensive project of the war (US$3 billion in those days) - even more expensive