F-102 Delta Dagger fighter jet

The Convair F-102 “Delta Dagger” was a product of the ensuing Cold War years following the close of World War 2 in which jet technology and aerodynamics advanced to all new tiers. As such, development of evermore powerful and streamlined aircraft ensued giving rise to one of the more exciting periods of military aviation. One of the primary threats to both Western Europe and United States interests remained the long range, nuclear-capable bombers of the Soviet Union to which “interceptors” were developed in response.

The interceptor was built on the concept of pure speed and engaged aerial targets with missiles at range using complex computer fire control systems (FCS). The F-102 served as a deterrent for such enemies during its early tenure while eventually evolving to a limited ground attack mount by the time of the Vietnam War. Used by less than a handful of nations worldwide, the F-102 served just over 20 years before being formally retired from service. While sharing a undeniable appearance to the upcoming F-106 “Delta Dart”, the F-102 was more of an interim interceptor design until the original project goals were fulfilled in the F-106.

In August of 1945, the United States Army Air Force, just beginning to wind down war time operations of World War 2, was high on the idea of jet-propelled aircraft and put forth a requirement for an interceptor aircraft with supersonic capabilities. Jet propulsion was in its infancy during the war while many technological hurdles were eventually overcome – including the arrival of the first operational jet fighter – the German Messerschmitt Me 262. The USAF required a maximum speed of 700 miles per hour with a service ceiling of 50,000 feet – these two qualities would ensure a Soviet bomber counter. Convair eventually turned to the works of German engineer Alexander Lippisch who championed the use of the “delta-wing” area design when concerning high-speed flight. Convair was born in 1943 from the merger of CONsolidated Aircraft and Vultee AIRcraft (hence the “CONVAir” naming). Convair was eventually acquired by General Dynamics and lost to history.

Convair F-102A

Convair put work into a delta-wing inspired development of their own known under the designation of “XF-92A” for the USAF. The concept incorporated extremely swept leading wing edges with straight trailing edges while eliminating the horizontal tailplanes found in traditional aircraft designs. First flight of the experimental airframe occurred on April 1st, 1948. Power was derived from a single Allison J33-A-29 series turbojet engine of 7,500lbs thrust, providing speeds of 718 miles per hour with a service ceiling of 50,750 feet. The fuselage was well-streamlined but rather stocky in shape, capped by a triangular vertical tail fin and accompanying triangular main wing assemblies aft of a framed cockpit enclosure. The engine was aspirated through the open nose enclosure. However, pilots did not revere the type due to its inherently violent flight tendencies and underperforming qualities. The USAF eventually completed the research project with a formal cancellation.

In October of 1948, the USAF delivered a new set of requirements for an interceptor built around the highly advanced MX-1179 electronic fire control system (FCS) to manage the proposed onboard radar and missile weaponry. The aircraft would have to feature Mach 2-capable speeds and be production-ready by 1954 with the hope of stocking the USAF inventory with a highly-capable interceptor and Soviet bomber deterrent. The project advanced along two fronts – Hughes was selected to produce the critical FCS while Convair eventually won the rights to develop the airframe. Utilizing the knowledge gained during development of the XF-92, Convair put forth their new XF-102 prototype which was of similar form.

The XF-102 was not unlike the XF-92 before it though featuring a much longer fuselage and larger area delta-wings. As in the preceding design, all wing surfaces were triangular in shape with pointed tips and swept leading edges. A single engine was buried in the tubular fuselage to provide the needed thrust while a cockpit was fitted well-ahead in the design. While intended to fit the upcoming Wright J67 (based on the British Bristol-Siddeley Olympus under license) series turbojet engine, delays forced the selection of the Westinghouse J40 series for the interim. When the J40 project proved a disaster, the Pratt & Whitney J57 series was selected instead. Development of the MX-1179 FCS was also still ongoing and this forced the installation of the less-complex MG-3 FCS system for the time being. The XF-102 would, therefore, serve as a technological stepping stone in working out project kinks while the major technological components were advanced on their own timeline. It was seen that the XF-102 would give rise to the basic F-102A production series interceptor while a later mark, the F-102B, would institute the required FCS and engine as planned. In this approach, the USAF would be given a capable interceptor until the program goals were fully met, resulting in a very streamlined end-product.
As in other USAF programs, the XF-102 prototype was advanced to become the evaluation “YF-102″ model form.

First flight was recorded on October 24th, 1953 though this prototype was lost less than two weeks later. A second flyable prototype was made ready by January of the following year and went airborne, proving performance lacking – she could not break the sound barrier, achieving only subsonic flight. Convair engineers then worked to correct the problems inherent in their YF-102 design by applying the German wartime-inspired “Whitcomb Area Rule” design approach which enabled fixed-wing airframes to reduce drag when reaching and exceeding Mach 1 speeds. The YF-102 airframe was then largely revised with a longer fuselage (4 feet was added) that was pinched at its midway point. Additionally, a newer, more powerful version of the J57 turbojet engine (PW J57-P-23 of 16,000lbs thrust) was installed and aspirated by revised air intakes that were themselves larger. Wings were further refined and, in this modified form, the YF-102 graduated to The YF-102A was first flown on December 20th, 1954 and was able to reach the required supersonic speeds and service ceiling thusly proving the redesign effort successful. With the new aircraft refined to acceptable levels, the USAF ordered the type for serial production as the “F-102 Delta Dagger”. The initial production mark would become the “F-102A” and 889 would ultimately be manufactured by Convair. The arrival of the F-102 marked the first production delta-wing supersonic aircraft in operational service anywhere in the world. Production spanned until September of 1958.