A later model, the JN-4H, was also developed to train pilots for the faster and more powerful aircraft that were appearing. To develop the JN-4H, a JN-4D was modified to accommodate a 150 hp Hispano-Suiza engine, built by the Wright Company and the radiator area and fuel capacity were increased. A total of 929 JN-4Hs were built from the end of 1917 to the November 1918 armistice. They were equipped with machine guns and bomb racks for advanced training and were assigned to various specialized training groups-bombing, fighter, reconnaissance, and aerial gunnery units.