90 years ago – a postal aeroplane’s futuristic design
In 1930, Boeing created the revolutionary Monomail, which made traditional biplane construction a design of the past. The Monomail wing was set lower, was smooth, made entirely of metal and had no struts (cantilevered construction). The retractable landing gear, the streamlined fuselage and the engine covered by an anti-drag cowling added up to an advanced, extremely aerodynamic design.
A single prototype was constructed for evaluation by both Boeing and the US Army, but no mass production ensued, and the aircraft eventually joined Boeing’s fleet on the San Francisco–Chicago airmail route from July 1931.
The unusual aircraft’s three-part cargo compartment, accessible from above, was located directly behind the engine; The unit could carry a total of 6.2 cbm. (ah)