发行时间：0001.01.01
总页数：82
编辑：
综保科技
摘要：
The American Helicopter
An Overview of Helicopter Developments in America 1908-1999
Michael J. Hirschberg July 2000
Executive Summary
The first powered vertical flights in the US began only five years after the US had taken the lead in aeronautical engineering with the first powered flight of the Wright Brothers. But it was not until over 35 years later that the first practical US helicopter was flown, some five years behind the Europeans. The events of World War II and the widespread t...
普通账号
