530 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 39 



the Akron, and more recently the Macon. Two questions present 

 themselves. Can the airship be built with a reasonable margin of 

 safety? And, granting this, what is its promise for economic and 

 effective commercial service ? 



First we must specify that the airship shall be inflated with helium 

 gas. Our world monopoly of the supply of this gas is, of course, 

 a matter of common knowledge. The use of this chemically inert 

 gas will completely dispose of the hazard which caused the loss of 

 the Hindenhurg, inflated, as she was, with hydrogen gas. With this 

 hazard eliminated, we have left the normal hazards of failure of the 

 structure under adverse weather conditions. The record of the Graf 

 Zeppelin in her around-the-world trip and later in regular com- 

 mercial service between Germany and South America, together with 

 the record of the Hindenbiirg aside from the fatal hydrogen con- 

 flagration, go far to prove, in commercial service, a high degree of 

 safety and security. Thus, for the Graf Zeppelin, we have a record 

 of about 17,000 hours of flying service over about 1,000,000 miles of 

 distance with safe carriage of 13,000 passengers on 144 ocean cross- 

 ings. Similarly for the Hindenburg up to the time of her destruc- 

 tion, the record shows 3,000 hours in flight, 210,000 miles distance, 

 with the safe carriage of 3,059 passengers. Mention may also be 

 made of the record of the small airships comprising our own Good- 

 year "blimp" fleet, with the appearance of which, at least, I presume 

 we are all familiar. This shows, to the end of 1937, 112,379 flights 

 covering 67,847 hours in the air and 3,010,000 miles of distance, with 

 a total of 302,248 passengers carried with no casualties or even 

 injuries. 



If you ask me to explain our own less favorable record with a 

 loss of three naval ships out of four which we have operated, I 

 could perhaps make the attempt, but it is too long a story. The 

 designs of the AJcron and Macon, the most recent ships designed 

 and built in this country, date back now 10 years. During that 

 period we have learned much with regard to the hazards for which 

 airships must be prepared. Especially is this the case with regard 

 to the stresses on the control surfaces in gusty, turbulent air. We 

 know now that the structure of these surfaces with their supporting 

 framework was not adequate to meet the stresses to which they might 

 be subjected under such adverse weather conditions as must occa- 

 sionally be expected, especially when serving as an adjunct to a 

 naval fleet, rather than on commercial service. 



Not only has experience taught dearly bought lessons regarding 

 these matters, but certain programs of research carried on in the 

 Airship Institute at Akron, Ohio, have thrown much additional 

 light on this subject. Still other recent programs of research at 



