Why America’s Mach 3 Valkyrie Bomber Became a Strategic Dead End
For decades, the speed appeared to be the key attribute in strategic bombing missions. Thus, the North American XB-70 Valkyrie was conceived to be the ultimate solution in the field. Being equipped with six engines, the bomber was expected to cruise at Mach 3 speed above 70,000 feet and pass through the defended airspace too fast to be intercepted.
However, this approach became obsolete very soon. The shooting down of the U-2 aircraft by the S-75 SAM in 1960 showed that the altitude was not a sufficient guarantee of safety anymore, thus, low altitude penetration began to dominate in the following decades. In addition, ICBMs took the responsibility of delivering nuclear weapons rapidly, whereas the XB-70 was more likely to become a high speed platform for tactical strikes. As a result, the bomber lost most of the justification for its existence.
Nevertheless, the project proved that its concept was quite realistic and viable. Indeed, the second prototype attained the velocity of Mach 3.08 during flight trials and provided valuable information for the researchers in aerodynamic heating, intake performance, stability, and other crucial characteristics of the aircraft in sustained supersonic flight regime. Furthermore, this project promoted further investigations in high speed aerodynamics and helped to design better bombers, although not in the way it was expected by the US Air Force initially.
The experience in developing the XB-70 showed that it is possible to design the aircraft which meets all technical criteria but fails in terms of its operational effectiveness because of the changes in military doctrine. This conclusion is applicable to any nation. For instance, the Soviet Union tried to produce its Mach 3 bomber named Sukhoi T-4 “Project 100.” However, it turned out that the cost, the manufacturing process, and the military requirements did not allow using this plane effectively in practice. Thus, both projects illustrate the idea that strategic needs often exceed the capabilities of cutting edge airframes very quickly.
Finally, there was a tragic accident during the 1966 formation flight involving an unauthorized F-104 jet aircraft. Although the pilot of this fighter was flying in the approved zone, he apparently got distracted and flew too close to the XB-70’s wingtip. Therefore, the small aircraft crashed into the Valkyrie, which resulted in the death of two people and severe injuries for the crew of the bomber. Later, the investigators claimed that the F-104 might have been drawn by the wingtip vortex created by the larger bomber. Hence, this incident deprived the test program of the second prototype.
In general, the remaining XB-70 continued its activities until 1969, providing the scientists with additional data regarding supersonic flights. Thus, the Valkyrie became a test aircraft rather than a weapon despite initial goals. This example demonstrates another important lesson in airpower studies. The history of modern bombers such as the B-2 Spirit and B-21 Raider proves that their survivability is more dependent on stealth than on speed. Conclusion Overall, the story of the North American XB-70 shows that a great aerospace vehicle does not always become a breakthrough in military aviation due to changes in military doctrine.
