The Curtiss JNS was the designation given to those JN-4Hs and JN-6Hs that were reconditioned after the First World War, eliminating the differences between the two types.
After the war those Jennys powered by 90hp engines were quickly withdraw. However the JN-4H and JN-6H, both of which used the 150hp licence built Hispano-Suiza engines, were considered to be more suitable for continued use. Many of them were reconditioned after the war, and the differences between the two models were eliminated. These aircraft were given the new designation JNS. The main difference was that the JN-4H had ailerons on the upper wing only, and the JN-6H on the upper and lower wings. This added weight to the aircraft, and reduced its top speed by 10mph and its service ceiling to 6,000ft. As a result the ailerons were removed from the lower wings of the JNS.
This programme continued until 1925. By this point the JNS was the most important aircraft with the National Guard, but was fading from the Army inventory. In 1919 the Army had 3,285 aircraft in service, by 1927 that had dropped to only 37. The last JNS aircraft in US Army service were scrapped in September 1927.
The JNS used three different engines, all versions of the licence built Hispano-Suiza. These engines were given letter designations after Wright-Martin became Wright Aeronautical in 1919. The JNS used either 150hp Wright A or I engines or 180hp Wright E engines, with the designations JNS-A, JNS-I or JNS-E.
It isn’t entirely clear how many were produced, as the method of giving them serial numbers isn’t consistent, but Putnam’s detailed book on Curtiss Aircraft gives an estimate of 247 from known serial numbers.