ThomasP
Senior Master Sergeant
The Curtiss P-1 Hawk either had a slipper tank when it entered service in late-1925, or was retrofitted with them shortly after. I do not know if the tank was droppable.
P-1 Hawk 1925
P-1A Hawk 1926
The earliest US aircraft with DTs that I have been able to find pictures of are the Boeing F4B/P-12 series of fighters from the early-1930s. Although these photos are of later models, the F4B-1 used a similar style slipper tank when it entered service in early-1930. The slipper tank was listed as "jettisonable" in the manuals.
F4B-4 (F4B-1 entered service in 1930)
P-12E 1932
P-1 Hawk 1925
P-1A Hawk 1926
The earliest US aircraft with DTs that I have been able to find pictures of are the Boeing F4B/P-12 series of fighters from the early-1930s. Although these photos are of later models, the F4B-1 used a similar style slipper tank when it entered service in early-1930. The slipper tank was listed as "jettisonable" in the manuals.
F4B-4 (F4B-1 entered service in 1930)
P-12E 1932