Recently, The National Interest explained the Convair F-102 Delta Dagger, the U.S. Air Force’s first operational supersonic interceptor and the first aircraft to feature the delta-wing configuration). Now, let’s take a closer look at the aircraft developed from the F-102—its marginally improved derivative, the Convair F-106 Delta Dart, which served as the Air Force’s last specialized interceptor before the elimination of the concept.
Introducing the Delta Dart
The F-102 was not an especially successful aircraft; its performance was unremarkable, and its safety record was poor. But Convair believed they had the seed of a successful airframe in the delta-wing design. So Convair set about improving their F-102, to offer the Air Force a more capable delta-wing interceptor. The project came to be known as the F-106—featuring a similar delta wing and, like the F-102, an internal weapons bay.
The F-106 did feature distinct differences from the F-102, however. The F-106 had a more powerful Pratt & Whitney J75 turbojet engine, which was essentially a bigger-brother, higher-thrust variant of the J57 engine featured on the F-102. Additionally, the plane’s air inlet was heavily redesigned to allow for a variable-geometry inlet duct that was appropriate for a wider variety of speeds. Applying lessons learned from the botched F-102 prototype, the F-106 incorporated the “area rule,” a design procedure used to reduce an aircraft’s drag at transonic speeds, notably absent from the F-102’s prototypes—which suffered performance setbacks as a result.
Despite the on-paper improvements, flight testing revealed that the F-106 performed only marginally better than the F-102. Disappointed with the F-106 performance specs, the Air Force, who had initially intended to purchase 1,000 F-106s, scaled back the order to just 350. The new interceptor was delivered and became operational in 1959, serving as the Air Force’s primary all-weather interceptor.
Flying the Delta Dart
The F-106 was the default U.S. interceptor throughout much of the Cold War—an era when interceptor aircraft were deemed especially important for fear of a Soviet bombing run against American targets. The F-106 performed well enough, with Mach 2.3 speed, a 57,000-foot service ceiling, and a 29,000-foot per minute climbing rate. Yet the F-106 never saw action in combat of any kind. Convair proposed multiple improvements to the F-106 over the course of her service run, i.e., improvements to the radar and communications, but these were never implemented. Instead, the F-106 was left as is, and eventually withdrawn from the U.S. Air Force fleet during the 1980s.
In the final years of the F-106’s service, the interceptor-only role had grown obsolete. The F-106 was replaced by the fourth-generation McDonnell Douglas F-15 Eagle, a multirole air superiority fighter with a Mach 2.5 max speed. Never since the F-106’s retirement has the Air Force fielded a true interceptor aircraft—which is consistent with more recent U.S. military trends of crafting versatile aircraft rather than highly specialized ones. Indeed, the post Cold War-era has called for the consolidation of roles into single platforms, such the F-15E, F-16, and F-35—relegating the very premise of the F-106 to the past.
About the Author: Harrison Kass
Harrison Kass is a senior defense and national security writer with over 1,000 total pieces on issues involving global affairs. An attorney, pilot, guitarist, and minor pro hockey player, Harrison joined the US Air Force as a Pilot Trainee but was medically discharged. Harrison holds a BA from Lake Forest College, a JD from the University of Oregon, and an MA from New York University. Harrison listens to Dokken.
Image: Wikimedia Commons.
