260 § ANNUAL REPORT SMITHSONIAN INSTITUTION, 1944 
TABLE 2 
8. E.5 Spitfire FW 190 
Percent Percent Percent 
Sirueturest ost Se ee Ee Se ee ee ee 29.7 28.9 30.9 
Power plants. 2 ots 20 290. 2 Sea ey es re eee ee 37.1 38. 0 35. 7 
Ur) We CEE GST eee ST Ss ee Se SE AS 15.4 16.6 14.3 
BOSQUE oe TEE Bate “Ae tit ep. BSS 17.8 16.5 19.1 
Oba oF PES oP Sa OS A See ay Se 100.0 100.0 100. 0 
Primary load! factor 8 so aoe eee ee ee 10. }-2t2 vcs eeee 
For the bomber, the reduction in (po is rather less than for the 
fighter on account of the drag of defensive armament, but otherwise 
the influences operating have been much the same. 
Toward the end of my paper I shall say something about what 
further improvements in drag are in sight and what problems we 
have to solve in order to achieve them. 
WEIGHT ANALYSIS 
Let us look next at the weight picture. The Spitfire weighs four 
times as much as the S. E. 5; the Lancaster, nearly five times as much 
as the 0/400. What has made it possible to carry so much additional 
weight per square foot of wing surface—for the fighter four times, 
for the bomber six times as much? In the airplane itself, first, the 
development of flaps giving higher maximum lift coefficient and higher 
drag; second, power plants of much greater power per unit weight; 
and, third, constant-speed propellers to make the power fully 
available over a wide speed range. But larger and better airfields, 
permitting higher take-off and landing speeds and better flying tech- 
nique, have contributed even more. The effective maximum lift 
coefficient has risen by about 65 percent. Even so, the touch-down and 
take-off speeds, with the higher wing loadings, are 50 to 80 percent 
higher. 
A comparison of the weight analyses and load factors of the fighters 
is given in table 2. As a matter of interest, I have given also the 
weight analysis for the FW 190. 
How has this remarkable similarity of weight distribution been 
maintained? From the structural point of view, it is essentially by 
increasing wing loading four times that it has been possible to go 
from braced biplane to monoplane with nearly double the primary 
strength, from fabric covering to a metal skin, and from a fixed to a 
retractable undercarriage with no significant changes in percentage 
structure weight. 
From the point of view of the power plant, we have to record a rise 
in the net output per pound of complete plant in the ratio of about 
7to4. The complete plant of 1942 includes both constant-speed pro- 
