Welcome to This Date in Aviation History, getting of you caught up on milestones, important historical events and people in aviation from April 8 through April 10.
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. The 707 went on to become one of the most successful airliners of the era and an icon of the early jet age. But a new trend began to develop 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. However, Boeing found themselves lagging behind competing airliners such as the Douglas DC-9, Fokker F28 Fellowship and British Aircraft Corporation BAC One-Eleven, all of which had advanced to the point of flight certification testing.
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 as its predecessor and allowed for the use of the same cargo pallets as the earlier airliner. 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 and the 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 company also purposely made the airliner as close to the ground as possible to facilitate ground servicing, and even included an optional air star in the rear of the airliner. The first 737 was constructed at Boeing’s Plant 2 in Seattle, and was the last new airliner to be produced in the same building where the B-17 Flying Fortress, B-47 Stratojet and B-52 Stratofortress had been built. Despite the building’s size, the tail of the first 737 couldn’t be attached inside, so it 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), reduction in the production of the 747, and an order for the T-43 version of the 737 from the Air Force, Boeing was able to keep production going. They were also able 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.
One of the secrets of the 737s success has been the airliner’s ability to continually adapt to changing times in a volatile airliner industry. 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.
In the early 1990s, 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. 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. Faced with even stiffer competition from Airbus, development of the venerable 737 airframe continued into the 21st century with the arrival of the 737 MAX beginning in 2011. The MAX 7, MAX 8 and MAX 9 are basically re-engined -700, -800, and -900 airliners with a few additional aerodynamic tweaks such as a tail cone borrowed from the 787 and new split scimitar winglets. It features still more efficient CFM International LEAP-1B engines for greater range and fuel economy, and the MAX 9 seats a maximum of 220 passengers, a load that exceeds even the highest capacity of the 707. Deliveries of the MAX began in 2017, and Boeing has orders on the book for more than 4,300 aircraft, though two crashes late in 2018 and early 2019 caused the type to be grounded until updates to flight control software and other modifications can be made.
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 five seconds somewhere in the world. As for the prototype, it never entered commercial service, though it did operate as a flying laboratory for NASA for 20 years, and is now on display at the Museum of Flight in Seattle, Washington.
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.
April 9, 1964 – The first flight of the de Havilland Canada DHC-5 Buffalo, a cargo and transport aircraft developed from the DHC-4 Caribou and designed for extremely short takeoffs from rugged or unimproved airstrips. Unlike its piston-powered predecessor, the Buffalo features a pair of General Electric CT64 turboprop engines. It was originally pursued by the US Army as a replacement for the Caribou before all fixed-wing aircraft were transferred to the US Air Force. However, the Air Force wasn’t interested in adopting it and only 122 were built. The type certificates for all the de Havilland transports were purchased by Viking Air in Canada who plans to restart production of a newer, more powerful version of the Buffalo as the Buffalo NG (Next Generation).
April 9, 1959 – NASA announces the Mercury Seven, the first American astronauts. America’s first astronaut class was selected to take part in the manned Project Mercury spaceflights from May 1961 to May 1963. Alan Shepard was the first Mercury astronaut to travel in space in 1961, just one month after Soviet Cosmonaut Yuri Gagarin. He was followed by Gus Grissom, then John Glenn, who was America’s first astronaut to orbit the Earth. They were followed by Scott Carpenter, Wally Schirra, and Gordon Cooper. The seventh member of the group, Deke Slayton, was grounded for health reasons, but served as NASA’s Director of Flight Crew Operations until 1972 and finally went to space as part of the Apollo-Soyuz Test Project in 1975. The Mercury Seven formed the core of American astronauts, and members of the group played a role in all NASA space missions of the 20th century.
April 10, 1963 – The first flight of the EWR VJ 101, a supersonic vertical takeoff and landing (VTOL) interceptor developed as a replacement for the Lockheed F-104G Starfighter. Two aircraft, designated X-1 and X-2, were completed during the five-year test program. The X-1 performed the first successful hover in April 1963, then the first transition to forward flight five months later. In all, a total of 40 level flights, 24 hover flights and 14 full transitions were performed. On July 29, 1964, the X-1 reached Mach 1.04 without using an afterburner and, though the program showed promise, it was canceled in 1968 after its role was changed from interceptor to fighter.
If you enjoy these Aviation History posts, please let me know in the comments. You can find more posts about aviation history, aviators, and aviation oddities at Wingspan.