Here is biographical information, and links with plenty of examples of his work are here and here.
Tinsley worked in color when doing magazine covers, but much of his article illustrations were two-color, the norm for the likes of Mechanix Illustrated, where he did a good deal of illustration following World War 2.
During the 1930s his drawing wasn't always accurate, but he improved somewhat as time went on. Apparently his editors and fans weren't troubled.
This seems to be a Curtiss BF2C or something like it. The fuselage is too large, too long, if we use the pilot as a scale reference. The upper and lower wings are out of perspective, seeming too close together.
Shown here is the Boeing model 299, or XB-17 Flying Fortress that first flew in 1935. Although Tinsley got the various parts in roughly the correct shapes, they are out of scale. The perspective is off -- the axes of the wings and horizontal stabilizers on the tail diverge with distance, whereas the opposite would be correct. Also, the 299 was never painted, nor were other 1930s B-17s, yet Tinsley gave it current Army Air Corps colors (sort of -- the green is wrong and the orange should be more yellow).
This is a Fokker G I two-place fighter that flew for the first time in March of 1937, about the time the magazine hit the news stands. Therefore, Tinsley must have been working from other drawings and perhaps photos of the plane on the ground. As usual, details are wrong. For instance, the unit housing the pilot and gunner is too small relative to the rest of the aircraft. Further, for some reason the plane doesn't carry actual Dutch insignia.
Featured here are two Junkers Ju 86 bombers, but they are carrying civilian rather than military markings.
That's a Northrop YB-49 flying wing bomber. I'm not sure why rocket-like flames are spewing out behind its jet engines. The escort fighters are purely Tinsley's imagination. Their fuselages resemble that of the Bell XS-1 that broke the sound barrier the previous October. The wings and tail are swept back, unlike the XS-1. On the other hand, Tinsley's fighters seem to have rocket motors like the XS-1, but are shut off, a jet engine being in use. Yet I don't notice any air intake for a jet engine. Oh well....
Here we see what the McDonnell XP-85 (later XF-85) Goblin "parasite fighter" might have looked like had it entered service. The B-36 bomber shown in the image supposedly had a 10,000 mile range, far in excess of any potential escort fighter, so one idea was to have them carry tiny escort fighters for deployment as necessary. Two prototypes were actually built and a few test drops were made from a specially modified B-29, but the project was cancelled due to its impracticality. As usual, Tinsley's drawing is off: the XF-85 fuselage was actually shorter and chunkier, and the tail units were closer together. The B-36 is poorly drawn as well, the wings seemingly drooping and the cockpit glazing pulled too far around the side of the aircraft.
This is the left-hand part of a two-page spread. The helicopters are conjectural, so I can't criticize how they are drawn. I include this because it embodies the "gee-whiz" sort of speculative future technology that Popular Mechanics, Popular Science, Mechanix Illustrated and perhaps other magazines featured for many years. The idea of ordinary people replacing their automobiles with personal helicopters is clearly insane for a number of good reasons, including what would happen in inevitable collisions and engine/rotor failures.
The U.S. Air Force funded development of an atomic reactor powered bomber, but the project was cancelled for reasons of practicality. Here Tinsley (who wrote the article) came up with a speculative design of a delta-wing flying boat bomber that used hydro-skis like those on the Navy's XF2Y Sea Dart fighter that first flew in 1953, but never saw service.
Finally, an atomic-powered rocket ship seen blasting off (or landing, maybe), and a base on the moon.