254 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1962 



1918. The figure of 0.196 pound per cubic inch displacement has never 

 been closely approached. 



The 5-inch bore cylinders, assembled and brazed together by Manly 

 himself, were built up of steel i/ig inch thick, lined with Yiq inch of 

 cast iron.^ Water jackets were steel 0.020 inch thick. The difficulty 

 of the brazing operation is mentioned by Manly and can well be 

 imagined. Cylinder heads and valve pockets were machined inte- 

 grally with the 1/16" inch-thick barrels. 



The engine completely anticipated modern large aircraft engines in 

 the use of the radial arrangement with a master connecting rod, the 

 cam and valve-gear arrangement, and the use of crankcase, cylinders, 

 and other parts machined all over to carefully controlled dimensions. 



Manly's skill as an engineer and machinist was matched by his 

 courage in making two (unsuccessful) takeoff s from the top of a 

 houseboat, without previous instruction or experience as a pilot and 

 in an airplane without landing gear. His survival of two crashes 

 into the icy waters of the Potomac River testifies to his quick think- 

 ing and skill as a swimmer. In contrast to the poor preparation for 

 the Manly attempts, the Wright brothers, before making their first 

 powered flights, had become skilled aviators by virtue of over 1,000 

 flights in gliders of a size and type quite similar to that of their first 

 powered airplane. All early Wright machines were equipped with 

 landing skids. 



Nowadays it is hard to appreciate the difficulties of these early air- 

 craft-engine builders. Although successful automobiles were in op- 

 eration both in Europe and in the United States, most of them were 

 equipped with engines far too heavy and too low in power for air- 

 plane use. Accessory equipment such as spark plugs, carburetors, 

 and magnetos was not available on the open market and had to be 

 obtained from reluctant automobile builders or else built by hand. 

 Worst of all, there was no established body of good practice, and de- 

 tails of existing practice were either very difficult to find or else held 

 as closely guarded secrets. In view of these difficulties, the accom- 

 plishments of the Wrights and Manly are all the more remarkable. 



ENGINES 1907-1909 



After the Wrights had demonstrated the actuality of airplane flight, 

 a period of nearly 3 years elapsed before anyone else flew in a 

 heavier-than-air craft. Meanwhile the Wrights increased their dura- 

 tion of flight to more than half an hour and their distance to nearly 

 25 miles, both records accomplished in their flight of October 5, 1905. 

 In 1906 the Hungarian Vuia, the Dane Ellehammer, and the Brazilian 



* Later development shows this to have been unnecessary. Steel cylinder bores have 

 been used since the Gnome engines of 1909. 



