Work Horse of the U.S. Air Service: The DH-4

The DH-4 was an ever-present element of the U.S. Army Air Service during and after World War I. When the United States entered WWI in April 1917, the Aviation Section of the Signal Corps had only  132 aircraft, all obsolete. Modeled from a combat-tested British De Havilland design, the DH-4 was the only U.S. built aircraft to see combat during World War I. With inadequate funding to buy new aircraft, the newly created U.S. Army Air Service continued to use the DH-4 in a number of roles during the lean years following the war. By the time it was finally retired from service in 1932, the DH-4 had been developed into over 60 variants.

The 1,000th DH-4 Sent to France

During World War I, the Air Service used the DH-4 primarily for daytime bombing, observation and artillery spotting. The first American-built DH-4 arrived in France in May 1918, and the 135th Aero Squadron flew the first DH-4 combat mission in early August. By war's end, 1,213 DH-4s had been delivered to France. 

Unfortunately, the early DH-4s had drawbacks, including the fuel system. The pressurized gas tank had a tendency to explode, and a rubber fuel line under the exhaust manifold caused some fires. These problems led to the title of "The Flaming Coffin," even though only eight of the 33 DH-4s lost in combat by the U.S burned as they fell. In addition, the location of the gas tank between the pilot and observer limited communication and could crush the pilot in an accident.

Perhaps the most notable mission flown in the DH-4 was the brave attempt by 1st Lt. Harold Goettler and 2nd Lt. Erwin Bleckley of the 50th Aero Squadron to find and assist the famed "Lost Battalion" on 6 October 1918. During a resupply mission to this surrounded unit, their DH-4 was shot down. Both men posthumously received the Medal of Honor.

Of the three U.S. companies that built the DH-4 during World War I, the largest producer was the Dayton-Wright Company of Dayton, Ohio. The Air Service ordered over 12,000 DH-4s, but a number of problems kept initial production figures low and construction quality poor. The many changes involved in converting the design to American production standards, along with the use of the American Liberty 12-cylinder engine rather than the Rolls Royce engine of the British model, contributed to early production delays.

As the months of 1918 passed, however, quantity and quality improved considerably. By the end of the war, Dayton-Wright delivered 3,106 DH-4s, while the Fisher Body Division of General Motors built 1,600 and the Standard Aircraft Corporation added another 140, bringing the total to 4,846. The remaining 7,500 DH-4s still on order were cancelled.

The DH-4 at the USAF Museum, Wright-Patterson AFB, Ohio

With few funds to buy new aircraft in the years following WWI, the Air Service used the DH-4 in a variety of roles, such as transport, air ambulance, photographic plane, trainer, target tug, forest fire patrol, and even as an air racer. In addition, the U.S. Post Office operated the DH-4 as a mail carrier.

The DH-4 also served as a flying test bed at McCook Field in the 1920s, testing turbo-superchargers, propellers, landing lights, engines, radiators, and armament. There were a number of notable DH-4 flights such as the astounding New York to Nome, Alaska, flight in 1920, the record-breaking transcontinental flight in 1922 by Jimmy Doolittle, and the first successful air-to-air refueling in 1923.

From 1919 to 1923 over 1,500 DH-4s were modified  to DH-4Bs by moving the pilot's seat back and the now unpressurized gas tank forward, correcting the most serious problems in the DH-4 design. A further improved version was the DH-4M whereby over 300 DH-4s received new steel tube fuselages.

Continued raids by Mexican bandits on American homesteads led to the creation of the United States Army Border Air Patrol in June 1919. Comprised of eight squadrons and a photographic unit at its peak, the Border Air Patrol operated out of a string of rough airfields along the U.S.-Mexico border. Despite the loss of aircraft and aircrews to the harsh conditions in the Southwest, the Border Air Patrol's operations helped put an end to bandit attacks by the summer of 1921.

This reproduction DH-4B is marked as a photographic aircraft used by the 12th Aero Squadron in the early 1920s to take pictures of the U.S.-Mexico border and potential emergency landing fields.

TECHNICAL NOTES:
Crew: Two (pilot and observer/gunner)
Armament: Two .30-cal. Marlin machine guns in the nose and two .30-cal. Lewis machine guns in the rear; 322 lbs. of bombs
Engine: 400-hp Liberty 12
Maximum speed: 128 mph
Range: 400 miles
Ceiling: 19,600 ft.
Weight: 3,557 lbs. loaded