The X-5 and the Rise of Variable Geometry Wings in Jet Aircraft
The X-5, the 5th X-plane on the series was set to explore the unknown horizons of flying as all X-planes were destined to do. Following the first lead of the first X-plane, the X-1 which successfully demonstrated that a jet aircraft could very well fly faster than the speed of sound by breaking the sound barrier, it was designed on a specifically tailored mission on its own. To demonstrate the possible uses and advantages of variable geometry wings in jet aircraft.
It was very well observed by leading aerodynamicists from nature through the flight of birds that the configuration of the bird’s wings play a vital role in the attainment of every flight according to whatever purpose it was meant for. When eagles soar and wish to save energy from flapping their wings, they tend to extend those wings in full span to ride with the wind and air currents. When peregrine falcons dive down after finding their target, they tend to partly clip in those wings to attain high speeds in achieving a swift flight maneuver aiding in snatching their prey from the ground. These fascinating natural wonders among flying creatures became the very basis of mankind’s technology in advancement through the field of aeronautics.
The German Influence
Again, just like in the flying wing design and stealth technology, it was the Germans who first put it into practice. An incomplete Messerschmitt P.1101 fighter aircraft prototype with swept back wings was one among the many aircraft designs recovered by the US troops at the fall of Germany after the war and was taken back to US for further study. Despite the initial damage in transporting the prototypes, the P.1101 was delivered to Bell factory in New York where bell engineers studied the aircraft from which its Chief Designer Robert J. Woods based a similar design which became the basis for the X-5.
Two X-5s were made and were completed in February 1951. Three sweep positions for the wings were devised at angles of 20?, 40? and 60? adjustable in flight which made the designs a bit complicated than the P.1101. A design flaw rooted on a badly positioned tail and vertical stabilizer showed another problem considering that certain sweep angle settings for the wings has the tendency to develop an irrecoverable spin in flight. The X-5 made its first flight in 20 June 1951 which started a series of almost 200 flights at altitudes of 40,000 ft and at speeds of Mach 0.9. Considering the irrecoverable spin as mentioned earlier, one prototype was lost in 14 October 1953 when the aircraft failed to recover after a spin following a 60? wing sweep angle setting. This caused the death of its test pilot USAF Captain Ray Popson at Edwards Air Force Base.
The F-111 Aardvark Fighter Bomber
F-14 Tomcat Interceptor/Multirole Fighter
B-1 Lancer Supersonic Strategic Bomber
Above Images by Wikimedia Commons
The Success of the Research
The surviving prototype remains at the National Museum of United States Air Force at Wright-Patterson Air Force Base near Dayton, Ohio. It was delivered to the museum in March 1958 before it was officially retired in December of same year. The X-5 attained research data necessary for further jet aircraft development employing variable geometry wings which paved way for the F-111 Aardvark fighter bomber in 1964, the F-14 Tomcat in 1970 and the B-1 Lancer supersonic strategic bomber in 1974. Other countries have employed the same design technology as seen from Soviet Mig-23 Floggers and French Dassault Mirage Gs which both took to the air the same year in 1967, then of course there’s the joint project between Britain, West Germany and Italy that resulted to the Panavia Tornado which took the skies in 1974.