532 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 1939 



Presetit speeds are moderate — 125 miles per hour perhaps — and 

 it is not easy to see, in this type of construction, a serious rival to 

 the conventional form for either high speed or heavy weight carry- 

 ing, as in the modern conventional forms referred to earlier. As 

 a relatively safe "family carriage," however, this type does appear 

 to have possibilities, and its future development will bear close 

 watch. 



The true helicopter appears finally to have made its appearance 

 in Germany, though detailed information is lacking. With the 

 shaft vertical in still air, this type of structure is capable of ver- 

 tical ascent or descent. In moderate wind with the shaft inclined 

 against the wind, the same results are possible. When a suitable 

 altitude has been reached, the shaft is inclined so as to give a for- 

 ward component to the pull of the propeller, and a horizontal com- 

 ponent to the motion results. This type of structure has long 

 been the subject of repeated effort. It is too soon to prophesy as 

 to what place it may be able to take in the field of air transport. 

 As with the autogiro, it does not seem likely that speeds compa- 

 rable with those attainable with conventional forms can be hoped 

 for. With the development, however, and satisfactory solution of 

 the problem of control in the air — a problem somewhat trouble- 

 some with both the autogiro and the helicopter — it may well take 

 its place with the autogiro in types of service where the special 

 characteristics of these forms meet peculiar and limiting conditions. 



Air transport is the newest of those agencies whereby we move 

 things about (ourselves included) over the face of the earth. 

 Transport is one of the major factors which has given us the pro- 

 found differentiation between the physical conditions of our modern 

 life as compared with the life of our forebears of the centuries gone 

 by. Until 1903 our movements were, so to say, two-dimensional. 

 With the achievement of the Wright Brothers, in 1903, a third 

 dimension was opened up. Man began to fly. And so air transport 

 is only an infant among other and older agencies, one regarding 

 which many problems yet remain for study and solution ; but, withal, 

 an infant of lusty growth and seemingly destined to go far. The 

 mission of air transport is to serve the public; and to render such 

 service acceptable, continuously improving combinations must be 

 found of the distinguishing characteristics: safety, economy, 

 weight-carrying capacity, speed, and comfort. The story of the 

 past 36 years gives good ground for faith in the future and that 

 the unfolding years will indeed bring such improving combinations 

 in full measure with basic advances in science and technology — 

 advances on which all improvement in the material content of our 

 lives must depend. 



