02/28/2016. Remarks by Johan Visschedijk: "During the war, Dayton Wright received contracts for 5,000 DH-4s following modification of a pattern aircraft sent from Britain to accept the Liberty 12 engine and American 0.30 in (7.62 mm) Marlin machine guns. The final total of DH-4s delivered was 3,098, the rest being cancelled. In addition, there were substantial numbers remodelled or converted to DH-4A or DH-4B standard and 155 were transferred to the USN and USMC with the designation O2B.
Dayton Wright also built the DH-4R, an unarmed advanced trainer conversion with dual controls, modified rear decking, and the gunner's position modified to an instructor's position. At least one Nine Hour Cruiser was completed, a DH-4 (s/n 30130) with an enlarged fuel tank positioned directly over the landing gear, aft of the Liberty engine and ahead of the two open cockpits. With double the normal endurance, nonstop flights were claimed possible between New York and Chicago. The D.W.H. 4 Blue Bird was a dual-control trainer version, with the same modifications, produced in small numbers for the USAAS.
The first postwar civil conversion offered was the DH-4K Honeymoon Express, a three-seat sport conversion of a DH-4B with a 1ft longer fuselage, displayed at the Aeronautical Exhibition, Madison Square Garden, New York City during March 1-15, 1919.
