This use of a camera obscura as an anti-aircraft sighting device is attributed to “a Peruvian inventor.” While similar devices were used to simulate bombing runs, this armed variant seems not to have been built (Popular Mechanics, April 1916).
Popular Mechanics (April 1916) is startled by Sikh soldiers’ use of the chakram. This seems to be the most modern account of its use, other than by Xena Warrior Princess.
The chakram hasn’t really developed a wide user base–it’s more of a niche weapon.
Surprisingly, this idea of a parachute-retarded golf ball–featured here in the June 1916 issue of Popular Mechanics–has popped up a number of times over the years:
While this 1916 “safety airplane” might be considered a forerunner of the V-22 Osprey, its combination of pivoting engine, seat, and wings was wildly unstable (Popular Mechanics, June 1916):
The combination shovel, helmet, mess tin: wisely, the Army passed (Popular Mechanics, Feb. 1917).
Although motorcycles with sidecars continued to be developed in most armies right thought WW2, this moto-machine gun emplacement never caught on. Popular Mechanics, Feb. 1917.
Austrian Stephan Petroczy built this helicopter with three 120HP engines and counter-rotating props near the end of WW1; tethered like a balloon, it reached a height of 150 ft. The observers were carried in the drum mounted above the props (Popular Mechanics, June 1921, p. 828).
Hardcore snowmobiling–towed behind a motorized sled with a spiked wheel! (Popular Mechanics, March 1917)
This New Hampshire rig has the classic configuration: engine in front supported by skis; tracked rear drive (Popular Mechanics, March 1917):
