-27of the planes, roughly90per cent or more, are returning from individual strikes, Otherwise one's air force may diminish in magnitude more rapidly than the enemy's capacity to fight. Tach plane ioad of fuel must therefore cover a two-way trip, allowing also a fuel reserve for such contingencies as adverse winds and combat action, thereby diminishing range by at least one-half from the theoretical maximum, But the plane cannot be entirely loaded with fuel. It must also carry besides its crew a heavy load of defensive armor and armament, Above all, it must carry a sufficient load of bombs to make the entire sortie worth while--a sufficient load, that is, to warrant attenaant expenditures in fuel, engine maintenance, and crew fatigue, The longer the distance covered, the smaller the bomb load per sortie and the longer the interval between sorties. To load a plane with thirty tons of fuel and only two tons of bombs, as we did inour first B29 raid on Japan, will not do for a systematic campaign of strategic bombing. One must get closer to the target and thus transfer a greater propor= tion of the carrying capacity from fuel to bonbs.*? What we then come out with 12. The actual figure of loss tolerance depends on a number of variables, includ- ing replacement rate of planes and crews, morale factors, the military value of the damage being inflicted on the enemy, and the general strategic position at the moment, The 10 per cent figure used for illustration in the text above was favored by the war correspondents and press analysts during the recent war, but it mst not be taken too literally, 13, It should be noticed that in the example of the B-29 raid of June 15, 19hh, cited above, a reduction of only one-fourth in the distance and therefore in the fuel load could make possible (wmless the plane was originally overloaded) a tripling or quadrupling of the bomb load, Something on that order was accomplished by our seizure of bases in the Mariannas, some 300 miles closer to the target than the original Chinese bases and of course much easicr supplied, The utility of the Nariannas bases was subsequently enhanced by our capture of Iwo Jima and Okinawa, which served as emergency landing ficlds for returning B-29s and also as bases for escorting fighters and rescue craft. Towards the end of the campaign we were dropping as mich as 6,000 tons of bombs in a single raid on Tokyo, there~ by assuring ourselves high military dividends per sortie investment. SS