570 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1941 



better need be expected. It was noisy, it was none too comfortable, 

 but, after a fashion, it did the job. 



The Curtiss Condor (pi. 1, fig. 3) appeared in 1930. Although a 

 biplane in accord with the earlier traditions, it nevertheless marked 

 a distinct advance in two respects. First, it had two engines and 

 would actually fly at a reasonable altitude in a satisfactory manner 

 when one engine was inoperative. Secondly, it made a very distinct 

 contribution toward comfort for passengers, both from the standpoint 

 of the luxurious seats which it provided and, more particularly, 

 because of the installation of sound-deadening means which reduced 

 the cabin noise level to a point approximating that of other means 

 of transportation. It had a cruising speed of 116 miles an hour. 



In Europe at about this time there appeared the Handley-Page 

 Hannibal (pi. 2, fig. 1), a biplane type equipped with four engines 

 but cruising at under 100 miles an hour. A fair degree of comfort 

 was provided but its slow cruising speed would not seem to justify 

 the long period of service that it had on Imperial Airways. 



A sesquiplane, the French Breguet Model 39, was developed in 1934, 

 and the German Junkers triplane came out that same year. Like the 

 Ford, this latter was all-metal construction and had three engines, 

 but, unlike the Ford, it had a low-wing rather than high-wing ar- 

 rangement. 



In this country, the next plane which should have special mention 

 was the Boeing 247 (pi. 2, fig. 2) , also appearing in 1934. Cruising 

 speeds were raised to 180 miles per hour by this ship which also had 

 most of the present-day features of form, including all-metal low- 

 wing twin-engine monoplane construction with retractable landing 

 gear. This type is still giving good service on several air lines. In 

 1934, there also appeared another version of the Curtiss Condor, the 

 chief contribution of which was the introduction of the sleeper ar- 

 rangement for night flying. Plate 2, figure 3, illustrates the interior of 

 this ship alternatively arranged for use during the day and at night. 

 With planes of this type American Airlines started its popular cross- 

 country sleeper schedules. 



As to flying boats : a step ahead occurred when the Sikorsky S-42 

 was placed in service on Pan American Airways. Although the first 

 large boat used by that company was the Consolidated Commodore, 

 nevertheless, the S-42 and S-42 A were and still are standard equip- 

 ment for the South American runs. Plate 3, figure 1, shows this 

 Sikorsky. 



It was also in 1934 that the Douglas DC-2 appeared, embodying all 

 the essential improvements which are used in the present-day air trans- 

 port. In addition to the use of two-engine, low-wing all-metal mono- 

 plane arrangement with retractable landing gear, introduced by Boe- 



