HISTORIC AIRPLANES: Douglas
Produced by the Douglas Company, the M2 airmail
biplane was a single-bay biplane with the conventional form
of axleless undercarriage. The fuselage, a truss of steel
tubes and tie rods, was made in two detachable sections. The
engine section was detachable at the station at the front
wingbeam and the engine cowling was hinged to facilitate inspection.
The fuselage aft of the firewall was covered with fabric.
The wings, vertical fin, and horizontal stabilizer were of
standard wood beam and built-up rib construction, with the
elevators and rudder made of Duralumin tubing. The power plant
was a 400-hp, Liberty water-cooled engine, with nose radiator.
Two main fuel tanks, each of sixty gallons capacity and made
of sheet aluminum, were so mounted in the lower wing that
they could be jettisoned by the pilot. A small 10-gallon gravity
tank was located in the upper wing.
mail compartment was situated in front of the pilots cockpit,
sealed from the engine by a fireproof bulkhead, and lined
with reinforced Duralumin. It was six feet long, had a capacity
of 58 cubic feet, and could carry up to 1,000 pounds of mail.
A unique feature was the provision of two removable seats
that permitted carrying passengers or reserve pilots from
one field to another. The passengers were seated well down
in the compartment and protected by suitable windshields.
Access was provided by the use of aluminum covers over the
top, arranged and constructed so that, with passengers aboard,
the roof door could be folded down. providing a cockpit opening.
- Text courtesy of the Smithsonian Institution's
Air and Space Museum
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