This deHavilland (model DH-4B) is part of the museum's centerpiece atrium exhibit, Moving the Mail.
Side view of a deHavilland DH-4 airplane
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From 1918-1926, the Post Office Department operated the nation's first airmail service. For airplanes, postal officials turned
to the military which turned over more than just aircraft. Army pilots flew the first airmail trips, including the inaugural
routes between Washington, D.C. and New York City which began on May 18, 1918. For these first flights, pilots used Curtiss
JH-4 (Jennies) aircraft. In June the Post Office Department, using its own pilots, took over the service. In 1918 the Post
Office Department requested 100 deHavilland airplanes, model DH-4, from the army. Created by Geoffrey deHavilland, these
planes had been built both in England and the United States during the last years of the war. Like most of the 2,500 fighter
planes built in the United States by 1918, few DH-4 aircraft even saw battle.
Although the airplanes range (350 miles) and load capacity (500 pounds) were good, deHavillands were not suited for the rigors
and demands of airmail service, having been built for high-altitude military observation use. The most precarious design flaw
was the placement of cockpit. Pilots were too easily trapped between the engine and the mail compartment. Minor crashes turned
deadly, as entangled pilots were burned alive. The planes quickly gained a macabre nickname—flaming coffins. Among those
killed in the early deHavilland airmail flights was Carl Smith, who stalled out over Elizabeth, New Jersey, while testing a
DH-4 on December 16, 1918.
In January 1919, the DH-4s were removed from service for extensive renovation work. The cockpit was moved to the rear
and was rimmed with padded leather for cushion in rough landings. The exhaust stacks were extended beyond the cockpit,
so pilots would no longer be blinded by their own exhaust fumes. To make the planes more durable, the linen fabric
fuselage was replaced with plywood sheets over wood struts. The landing gear was repositioned and larger wheels were
installed. The DH-4 instrument panel also had problems. The airplanes compass was notoriously unreliable. When flying
east, the compass could oscillate from east to 90-degrees north. Air pressure through a metal pipe activated the
airplane's air speed indicators. Unfortunately, the pipes, placed on the bottom wing's leading edge, were regularly
filled with mud. More seriously, the altimeter registered 1,000 feet for each 1" around the scale, making it useless
below 1,000 feet.
When the retrofitted deHavillands (now known as DH-4B) were returned to service, the improvements proved enormously
successful. In their first year of service, deHavilland airmail planes carried more than 775 million letters. The
plane quickly became known as the workhorse of the airmail service. In 1921, as an additional safety measure,
pilots were assigned individual planes and allowed to modify them to meet their individual demands. The DH-4Bs
began to retire from airmail service in 1926 when the Post Office Department began to contract the service from
private carriers. When the Post Office Department relinquished control of the airmail service to private industry,
entrepreneurs used the money they made from carrying the mail to maintain and expand their routes and upgrade their
services.
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deHavilland DH-4 at the Omaha, Nebraska, airfield
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