Boeing History: The Model 40A

Model 40a

The Model 40A used an air-cooled Pratt & Whitney Wasp engine that was about 200 pounds lighter than the water-cooled engines used to power its competitors. The biplane used welded-steel tubing throughout its fuselage but could still carry a heavier load and was less expensive to operate.

It was the first Boeing airplane to carry passengers, with room for two people in a tiny cabin, as well as cargo space for mail. Twenty-four of the mail planes built were ready to fly July 1, 1927, for their first day of airmail service between San Francisco and Chicago. The 25th was delivered to Pratt & Whitney as a flying testbed.


First flight: May 20, 1927
Model number: 40A
Classification: Commercial transport
Span: 44 feet 2 inches
Length: 33 feet 2 inches
Gross weight: 6,000 pounds
Top speed: 128 mph
Cruising speed: 105 mph
Range: 650 miles
Ceiling: 14,500 feet
Power: 420-horsepower P&W Wasp engine
Accommodation: Pilot, 2 passengers, 1,200 pounds of mail