Exel number 4 Tri-Axial - pioneer helicopter
Exel #4 "Tri-Axial", one of a series of helicopters with counter-rotaing rotors and airscrews, designed and built by George Exel of Clifton NJ. from 1920 to 1930
Picture No
13156271
Media ID
47773911
Size
5433px x 4428px
(5.8MB)
Credit
(c) The Peter Butt Aviation Collection / Mary Evans
Source
Unattributed photographer - scanned from original print
Date
1926
