Prepared for an attack, a 1st Aero Squadron enlisted man takes his defensive position under a “REO” truck manufactured by the R.E. Oldsmobile Company. Note the chain drive, which was quite common to trucks well into the 1920s.
United States Army Signal Corps
1916
<a rel="nofollow" class="external free" href="http://www.afhso.af.mil/shared/media/document/AFD-100928-064.pdf">http://www.afhso.af.mil/shared/media/document/AFD-100928-064.pdf</a> The 1st Aero Squadron and the Mexican Punitive Expedition of 1916