128 ANNUAL REPORT. SMITHSONIAN INSTITUTION, 1908. 



Gar. — The car is boat shaped, like that of the Patrie. It is sus- 

 pended 13 feet below the gas bag. 



Motor. — The motor is a 20 to 21 horsepower, four-cylinder Daimler- 

 Mercedes. 



Propellers. — There are two propellers 8.2 feet in diameter, each hav- 

 ing two blades. They are placed one on each side, but well up under 

 the gas bag near the center of resistance. The transmission is by belt. 

 The propellers make 800 revolutions per minute. 



Stability. — The same system, with planes, is used in the Von Gross 

 as in the Patrie, but it is not nearly so well developed. At the rear 

 of the rigid frame attached to the gas bag are two fixed horizontal 

 planes, one on each side. A fixed vertical plane runs down from be- 

 tween these horizontal planes, and is terminated at the rear by the 

 rudder. A fixed horizontal plane is attached on the rear of the gas 

 bag, as in the Patrie. The method of attachment is the same, but the 

 plane is put on before the inflation in the Gross airship, afterwards in 

 the Patrie. The stability of the Gross airship in a vertical plane is 

 rejDorted to be very good, but it is said to veer considerably in attempt- 

 ing to steer a straight course. 



The many points of resemblance between this dirigible and the 

 Lebaudy type are worthy of notice. The suspension or means of 

 maintaining stability and the disposition for driving are in general 

 the same. As first built the Gross had a volume of 14,128 cubic feet 

 less than at present, and there was no horizontal plane at the rear of 

 the gas bag. Its maximum speed is probably 15 miles per hour. 

 As a result of his experiments of 1907, Major Von Gross has this year 

 produced a perfected airship built on the same lines as his first, but 

 with greatly increased volume and dimensions. The latest one has a 

 volume of 176,000 cubic feet, is driven by two 75-horsepower Daimler 

 motors, and has a speed of 27 miles per hour. 



On September 11, 1908, the Gross airship left Berlin at 10.25 

 p. m., carrying four passengers, and returned the next day at 11.30 

 a. m., having covered 176 miles in the period of a little over thirteen 

 hours. This is the longest trip to date, both in point of time and dis- 

 tance, ever made by any airship returning to the starting point. 



The Parseval. 



The Parseval airship is owned and controlled by the Society for the 

 Study of Motor Balloons. This organization, composed of capital- 

 ists, was formed practically at the command of the Emperor, who is 

 very much interested in aerial navigation. The society has a capital 

 of 1,000,000 marks, owns the Parseval patents, and is ready to con- 

 struct airships of the Von Parseval type. The present airship was 

 constructed by the Riedinger firm at Augsburg, and is operated from 



