The Curtiss HS-3 was an improved version of the HS-1 and HS-2 patrol flying boats, but only six were built before development stopped after the end of the First World War.
The Curtiss HS-1 was a single engined biplane flying boat that had been developed from the twin engined Curtiss H-14. The Navy had ordered twenty of these twin engined aircraft, but cancelled the order after testing the prototype. Curtiss then replaced the two 100hp engines of the H-14 with a single 200hp Curtiss engine to produce the HS (Model H, Single engine). This aircraft did interest the Navy, and was soon ordered into production. The production version was powered by the new Liberty engine, and became the HS-1L. This was followed by the HS-2L, which had a wider wingspan and could carry two 230lb bombs, making it more of a threat to the U-boats.
During 1918 a combined US Navy and Curtiss team worked on an improved version of the HS, the HS-3. The HS-1 and HS-2 had narrow hulls with wide sponsons at the front to act as the planing surface. On the HS-3 the entire hull was widened, removing the need for these sponsons. It also gained a new vertical tail, but kept the HS-2L wings.
Only six HS-3s were built – four by Curtiss (A5459-A5462) and two by the Naval Aircraft Factory (A5590-A5591). The HS-3 outperformed the HS-2L but not by enough to make it worth placing into full production when so many of the older aircraft were already available. As a result work on the HS-3 stopped after the end of the First World War.
Engine: Liberty 12
Crew: 2 or 3
Span: 75ft 6in
Length: 38ft 7in
Height: 14ft 7in
Empty weight: 4,550lb
Gross weight: 6,432lb
Maximum take-off weight:
Max speed: 89mph
Climb Rate: 3,120ft in 10 minutes
Service ceiling: 6,500ft
Endurance: 5.3 hours
Armament: One flexibly mounded 0.3in Lewis gun
Bomb load: Two 230lb bmbs