Welcome to This Date in Aviation History, getting you caught up on milestones, important historical events and people in aviation from April 6 through April 8.
April 6, 1938 – The first flight of the Bell P-39 Airacobra. At the beginning of WWII, the P-39 Airacobra was America’s principal fighter aircraft in service. And while its lack of a turbo-surpercharger rendered it ineffective as a high altitude interceptor or fighter, it would prove to be a potent force against ground targets and low-flying bombers, particularly in the hands of Soviet pilots. In 1937, the US Army Air Corps issued their most ambitious requirements to date for a new fighter, calling for 1,000 pounds of heavy armament including a cannon, a tricycle landing gear, and a level airspeed of at least 360 mph and a climb rate that could attain 20,000 ft in less than 6 minutes. The proposal also called for a turbo-supercharged Allison engine to provide high-altitude performance. With all the armament the Army requested, particularly the large cannon, Bell had to find a way to fit it all in the airframe. So, they decided on the innovative solution of placing the engine behind the pilot, with a drive shaft that passed under the cockpit and turned the propeller through a gear system. The placement of the engine also helped with the fighter’s center of gravity, and while some pilots were concerned about the drive shaft running underneath the seat, the system proved safe and reliable. With the nose section empty, Bell could fill it with the M4 cannon, a weapon specifically designed for the Airacobra and manufactured by Oldsmobile. This made the P-39 essentially the first aircraft to be designed around a gun rather than an engine. Because of its heavy recoil, the cannon had to be placed on the aircraft’s centerline, and it fired through the center of the propeller spinner.
When testing of the XP-39 prototypes commenced, initial speed results were not what the Army had hoped for. They ordered that the aircraft be evaluated in a National Advisory Committee for Aeronautics (NACA) wind tunnel to see if the body shape could be streamlined further to increase speed, and it was here that the history of the Airacobra took a fateful turn. The turbo-supercharger for the Allison engine was cooled by a scoop on the left side of the aircraft, and NACA said the ducting had to be redesigned to eliminate the scoop. However, there was simply no place to move the scoop in the tightly packed fuselage. So Larry Bell made the controversial decision to continue development with the turbo-supercharger removed, instead using only a single-stage supercharger. While speeds did increase, the lack of the turbo-supercharger effectively limited the Airacobra to service below 12,000 feet, rendering it ineffective as an interceptor or high-altitude fighter. And once armor was added, the weight increase put a further drag on the Airacobra’s performance. Nonetheless, the P-39 went to war in the Pacific, where it proved a potent weapon against enemy ground targets and shipping. The Airacobra also saw service in the Mediterranean, notably with the Tuskegee Airmen of the 99th Pursuit Squadron. The British found the Airacobra almost wholly unsuited to their needs, and only fitted one squadron with the type. The rest they sent to Russia. And it was in Russia where the P-39 found its greatest success. The Russians appreciated the heavy firepower provided by the cannon and machine guns, as well as the Airacobra’s rugged construction. They particularly liked the Airacobra’s reliable radio. Nearly half of the 9,588 P-39s built were shipped to Russia, and though relegated to lower level missions, the Russians used the Airacobra primarily in the air-to-air role, where it proved lethal against German bombers, and could also hold its own against German fighters. Russian pilot Alexander Pokryshkin scored 47 of his 59 victories in an Airacobra, making him the highest scoring P-39 pilot of the war. The Airacobra was continuously developed throughout WWII into a myriad of variants, including an attempt at a navalized version called the XFL Airabonita, and the larger, more powerful P-63 King Cobra, which was adopted by the Soviet Air Force. (US Air Force photo)
Short Take Off
April 6, 1924 – The start of the first successful flight around the world. In 1923, the US Army Air Service requested that Douglas Aircraft Company develop an aircraft specifically for completing a circumnavigation of the globe. Douglas modified 5 Douglas DT torpedo bombers, and 4 of them departed from Sand Point, Washington, heading west. Owing to crashes, only two completed the journey, which covered 27,553 miles and took 175 days to complete, landing back in Seattle on September 28. The two aircraft made 58 stops along the way. The successful flight helped establish Douglas as a major aircraft manufacturer. (US Army photo)
April 6, 1890 – The birth of Anthony Fokker. Anton Herman Gerard “Anthony” Fokker was born in the Netherlands Indies and was a Dutch pilot, aviation pioneer and aircraft manufacturer. During WWI, Fokker produced some of the most famous German aircraft, including the Dr.I triplane which became synonymous with Manfred von Richtofen, better known as the Red Baron, and the D.VII biplane fighter (which was designed by Reinhold Platz). Following the war, when the Treaty of Versailles prohibited Germany from producing warplanes, Fokker took his business to the Netherlands where he developed the famous Fokker F.VII Trimotor. Fokker moved to the US in 1927, but died of meningitis in 1939. (Anthony Fokker photo via US Library of Congress; Dr.I photo by Matthias Kabel via Wikimedia Commons)
April 7, 2006 – The first free flight of the Boeing X-37. Also known as the Orbital Test Vehicle (OTV), the X-37 is an unmanned, reusable spacecraft that is a 120% scale derivative of the Boeing X-40. Similar to the much larger Space Shuttle, the X-37 is boosted into orbit by a launch vehicle, then returns to Earth to land as an unpowered aircraft. The X-37 is operated by the US Air Force and has completed 3 orbital missions carrying a classified payload. A 4th mission was launched on May 20, 2015, with the X-37 expected to remain in orbit for 200 days. (NASA illustration)
April 7, 1994 – The attempted hijacking of Federal Express Flight 705. Disgruntled FedEx pilot Auburn Calloway boarded the cargo flight as a deadheading pilot, carrying a guitar case filled with hammers and a spear gun. He planned to kill the pilots with the hammers (having the spear gun as a last resort) to make their injuries look consistent with a crash. Then, he planned to crash the McDonnell Douglas DC-10-30F (N306FE) so his family could collect a $2.5 million life insurance policy. Though the pilots were seriously injured in the attack, they managed to subdue Calloway and land safely. Despite a defense of insanity, Calloway was convicted and sentenced to two consecutive life terms. (Photo by André Du-pont via Wikimedia Commons)
April 7, 1967 – The first flight of the Aérospatiale Gazelle. Designed for light transport, scouting and light attack duties, the Gazelle was the first helicopter to employ the fenestron enclosed tail rotor configuration, which reduces tip vortex loss, protects the tail rotor, and also protects ground crews from the spinning rotor. The Gazelle entered service in 1973, and currently serves the air forces of 20 nations and has seen combat in Lebanon, Rwanda and the First Gulf War. More than 1,700 Gazelles were produced between 1967-1996, and it remains in service today. (Photo by Jerry Gunner via Wikimedia Commons)
April 7, 1922 – The first mid-air collision between two airliners. One aircraft, a de Havilland DH.18A (G-EAWO), was flying mail from Croydon in England to Le Bourget in France. On board were the pilot and a young steward. The other aircraft, a Farman F.60 Goliath (F-GEAD), was flying in the opposite direction with a pilot, mechanic, and three passengers. With low clouds and drizzle, the pilots were flying just below the clouds and following a road, but the British pilot was keeping the road to his right, while the French pilot was keeping the road to his left, putting them head-on to each other. The crash, 60 miles north of Paris, killed all seven occupants. As a result, rules were adopted to agree on a right-side offset when following roads, and official air lanes were adopted for heavily travelled routes. (Photo authors unknown)
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)
Recent Aviation History Posts
If you enjoy these Aviation History posts, please let me know in the comments. And if you missed any of the past articles, you can find them all at Planelopnik History.