Welcome to This Date in Aviation History, getting you caught up on milestones, important historical events and people in aviation from April 8 through April 11.
April 9, 1967 – The first flight of the Boeing 737. At the start of the commercial jet era, the emphasis was on big airplanes. The four-engine de Havilland Comet was the world’s first jet airliner, but when that aircraft began suffering from an alarming string of fatal crashes, Boeing was poised to step in with its own four-engine airliner, the 707. But there was a trend developing in the airline industry, one that called for smaller airliners to operate on shorter routes. Boeing followed the 707 with the 727 tri-jet, but airlines still wanted something smaller that would complement Boeing’s other offerings. Development of the 737 began in 1964 with plans to create an airliner that would accommodate 50-60 passengers. The German carrier Lufthansa signed on as the launch customer a year later, and requested that Boeing increase the seating capacity to 100 passengers. When United Airlines signed on to the project, they wanted an airliner with still more capacity. So the 737 was lengthened again, with the Lufthansa version becoming the 737-100 and the United version becoming the 737-200. But Boeing faced stiff competition from its competitors: the Douglas DC-9, Fokker F28 Fellowship and British Aircraft Corporation BAC One-Eleven. To speed the development process, Boeing based the fuselage of their new airliner largely on the 727, using 60% of the 727's fuselage shape, particularly the upper lobe. This gave the 737 the same cross section and allowed the use of the same cargo pallets as the earlier airliner. And bringing in the 727 fuselage also meant the adoption of 6-across seating in coach, which gave the 737 a distinct advantage over its rival Douglas, which featured 5-across seating in their DC-9. The relatively short fuselage, when mated to its swept wings, resulted in an aircraft that was just about as long as it was wide, and the 737 was dubbed the “square airplane.” Boeing also eliminated the flight engineer position, helping to set a new industry standard for only two crew members in the cockpit. The first 737 was constructed at Plant 2 in Seattle, the last new airliner to be produced in the building where the B-17 Flying Fortress, B-47 Stratojet and B-52 Stratofortress were built. Despite the building’s size, the tail of the first 737 couldn’t be attached inside, so the tail was fitted outdoors using a crane before the airliner was rolled to the production facility known as the Thompson Site. Though the 737 has since become the best selling airliner in history, its early days were less rosy. By 1970, Boeing had received orders for only 37 aircraft, and they were considering shutting down production and selling the 737 design to Japanese aircraft manufacturers. But with the cancellation of the Boeing 2707 supersonic transport (along with the loss of 50,000 jobs), and reduction in the production of the 747, Boeing freed up enough money to continue development of the 737 into a wider range of variants, including the convertible 737C model with accommodations for palletized freight, and the 737QC (Quick Change) variant that featured palletized seating and allowed for a rapid switch from cargo to passenger configurations.
Following the production of the 737-100 and -200, the last of which was delivered in 1988, Boeing began developing the -300/-400/-500 series, which would later be known as the 737 Classic, each offering improvements in range, economy and passenger capacity. Most importantly, the Classic moved the 737 into the age of modern high-bypass turbofan engines, leaving behind the cigar-shaped Pratt & Whitney JT8D low-bypass turbofans in favor of the CFM International CFM56.
Boeing undertook further development of the 737 to compete with rival Airbus and followed the Classic with the 737 Next Generation, which encompasses models -600/-700/-800/-900ER beginning in 1991. While much of the 737NG is essentially new, it retains enough commonality with earlier aircraft to make it attractive to airlines with older fleets of 737s. And in 2011, Boeing announced the 737 MAX program, which will provide newer, still more efficient CFM International LEAP-1B engines for greater range and fuel economy. Deliveries of the MAX are scheduled to begin in 2017. In July 2012, the 737 earned the distinction of being the first airliner to surpass 10,000 orders, and nearly 9,000 have been delivered so far. Today, two 737s are landing or departing every 5 seconds somewhere in the world. As for the prototype, it never entered commercial service, though it did serve NASA as a flying laboratory for twenty years, and is now on display at the Museum of Flight in Seattle, Washington. (Photo via Boeing; 737-300 photo by Konstantin von Wedelstaedt via Wikimedia Commons; photo by the author)
April 8, 1944 – The first flight of the Douglas BTD Destroyer. The Destroyer was designed in response to a 1941 US Navy request for a single aircraft to replace both the Douglas SBD Dauntless and the Curtiss SB2C Helldiver. Designed by noted Douglas engineer Ed Heinemann, the Destroyer featured a laminar flow wing and, in a first for a carrier aircraft, a tricycle landing gear. When the Navy changed its requirements, Douglas removed the extra crew member and the defensive armament. Still, only 28 were delivered before the war ended and production was canceled. (US Navy photo)