Old School – Boeing Model 40B

On the second evening of the2013 Cargo Facts Aircraft Symposium, attendees were treated to a reception at Seattle’s Museum of Flight. Greeting attendees was one of the very earliest cargo planes – though it would today be considered a “combi” – a 1920s vintage Boeing Model 40B. The plane on display is a functional replica, though several original Boeing Model 40’s do survive and one is still airworthy.

The Model 40 was Boeing’s first aircraft designed specifically for air mail routes. Created to replace the trouble-prone, WW1-era DeHavilland DH-4, the Model 40 was initially designed around a postal service requirement that mandated the water-cooled WW1 era “Liberty” engine, despite the fact that more modern air-cooled alternatives were available from Pratt & Whitney and Wright. The Post office purchased the water-cooled prototype but awarded its DH-4 replacement contract to Douglas and the M2, another competitor for the contract.

Soon after, Boeing mated the Model 40 design with the Pratt & Whitney Wasp engine – and the the company’s first serious commercial aircraft was born in the form of the Model 40A. The creation of the 40B could not have come at a more auspicious time – because in early 1925, congress turned over all the air mail routes to private contractors – and the 40B was the most reliable, capacious, and sturdy aircraft available for those routes. It could carry 1,200 lbs of mail and two brave passengers, and it formed the basis of the Boeing Air Transport (BAT) fleet, specifically created to be a wholly-owned air mail carrier. Later, the Model 40B was stretched to make room for two more passengers.

The 40’s capacity and lack of a radiator (the rival Douglas M-2 and Curtiss Carrier Pigeon were still powered by the “Liberty” engine) allowed for far more efficient operations – and resulting prices that could undercut competitors substantially while offering superior service. On a typical route, such as San Francisco-Chicago, BAT submitted a bid of $1.50 a pound for the first thousand miles and 15 cents additional for each 100 mile increment after that. Western Air Express, which later became Western Airlines, could only bid $2.24 and 24 cents additional. BAT was profitable from the start. In those days, the flight from Chicago to San Francisco, with the stops, took 23 hours. Service commenced in July, 1927.

The boom times of the 1920s and the free-for-all atmosphere of the early Air Mail system wouldn’t last for long – the Air Mail Act of 1930 changed the way the Post office paid airlines for their services, and by 1933 Postmaster General Walter Folger Brown would be embroiled in scandals related to the awarding of postal contracts. But the Model 40 was a huge leap for Boeing and the right aircraft at the right time.

For more information on the Museum’s Model 40B, click here.

To see additional highlights from Cargo Facts Symposium 2013, visit our companion website, cargofactssymposium.com.

Photographer: Alex Kwanten