Review by Takis Diakoumis.
The North American XB-70 Valkyrie was conceived as the ultimate heavy bomber for the USAF to penetrate Soviet defences and deliver its doomsday payload. During the 1950s, when Soviet counter-air was largely made up of anti-aircraft artillery and fighters, it was thought a Mach 3+ aircraft flying at extreme altitudes was the only vehicle capable of reaching targets deep inside the Soviet Union.
While never put into full-scale production, the Valkyrie prototypes represented a huge leap in engineering capability for the United States. The enormous engine ‘six-pack’ was designed to operate in continuous afterburner and advancements in metallurgy and use of titanium on higher temperature sections, like wing leading edges, would enable the massive aircraft to accelerate beyond Mach 3.
Later developments in surface-to-air missiles, as well as the shoot-down of Gary Powers’ U-2 in 1960, would begin to spell the end of the XB-70 and, after almost $1 billion for the delivery of the two prototypes, the program was cancelled in 1961 before any flights were made. With little mission flexibility in the complex airframe, and with tactics moving to low-level penetration, the design was deemed to offer little more than the B-52.
As the program shifted to advanced aerodynamic research, the Valkyrie’s first flight was eventually completed in 1964 by the first prototype. A more advanced second prototype first flew in 1965, but, following a number of Mach 3+ flights, would be involved in a tragic mid-air collision, during a photo shoot for engine manufacturer General Electric, the following year. Testing with the surviving aircraft continued until 1969.
Graham Simons’ latest entry covers the exciting development and test history of this important aeronautical masterpiece in fine detail. Using a number of Air Force and NASA sources, he pieces together the engineering genesis of the Valkyrie as he traces its complex development from the charged Cold War political environment through a challenging test cycle where successful engineering firsts were often matched by as many setbacks.
The events leading to the tragic loss of the second prototype are forensically covered as is the investigation and analysis of the accident and subsequent report findings. As that flight was intended as a promotional shoot for General Electric, the demise of the second prototype is eerily captured in still and video footage.
The text is littered with a large number of photographs, illustrations and tables throughout as Simons concludes his journey with the first prototype making its final flight into Wright-Patterson AFB to be displayed as a centrepiece at the National Museum of the US Air Force.