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 machineguns. 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 undercarriage, 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. The two passengers were carried in an enclosed cabin behind the pilot's open cockpit and it was powered by a 400hp Liberty 12. One aircraft (race number 32) was entered in the Aviation Country Club Trophy Race at the Pulitzer Races, Detroit, in October 1922. Piloted by Lt. H.R. Harris of the USAAS, it won against three other competitors.
Company test pilot Howard Rinehart is the pilot in the Honeymoon Express, the two passengers are unidentified."