North American F-100 Super Sabre Fighter-Bomber / Air Superiority / Tactical Reconnaissance Aircraft
Though not without issues early on, the North American F-100 Super Sabre jet evolved into one of the finest American fighter aircraft.
Authored By Staff Writer; Content ©www.MilitaryFactory.com
The North American F-100 Super Sabre was developed as the successor to the F-86 Sabre, another North American product. The F-86 Sabre proved a war winner for the Americans in the Korean War, tangling with the likes of the new Soviet jet-powered fighter - the Mikoyan-Gurevich MiG-15 "Fagot" - in much the same way that the North American P-51 Mustang succeeded against German and Japanese foes before it in World War 2. By this time, North American Aviation had built up an impressive history by supplying these successful designs in changing times. The F-100 Super Sabre was no different - it was an in-house development that was presented to the USAF and ultimately accepted into service. The aircraft came about at a time when aviation engineers were convinced that Mach 1+ sustained flight was capable - with the sound barrier being broken just years before by military aviator Chuck Yeager in his Bell XS-1 - now the challenge lay in ironing out a Mach 1-capable design to be mated with a consistently performing and powerful turbojet engine. Likewise, the Soviet Union and her Mikoyan-Gurevich bureau was also hard at work, beginning development of what would eventually become the MiG-19 "Farmer" - effectively the F-100 Super Sabre's contemporary - though the two aircraft never saw combat against one another.
The F-100 was affectionately known as the "Hun", no doubt due to its "F-100" (one-HUN-dred) designation.
In early 1949, North American Aviation was exploring ideas for Mach 1 sustained flight as an in-house development. The success of the F-86 Sabre lay in several sources, in particular were the captured aerodynamic documents from Germany following World War 2 and advanced testing being done through the National Advisory Committee on Aeronautics (NACA). These, coupled with true aviation engineering began to push the threshold of military aviation design to an all new limit. The changing times and advancing technology present following World War 2 and into the 1950's made achieving Mach 1 sustained flight all the more reachable.
North American looked to the successes inherent in their F-86 Sabre design to try and produce a worthy successor consistent with the evolving battlefield. The 35-degree wing sweep of the Sabre was developed into a greater 45-degree angle coupled with a modified fuselage. This design route produced a slightly better fighter concept but a ceiling was inevitably reached that required the use of a capable powerplant to break the airframe out and over the Mach 1 threshold on a consistent basis. After several turbojet developments were entertained, a General Electric brand J47 with afterburning was selected and coupled with the F-86D "Dog Sabre" - the all-weather version of the successful Korean War jet fighter with the identifiable "snout" nose assembly. This design was showcased for the USAF and rejected. A modified F-86E followed only to be rejected once more. A third design was submitted for review - this being a combination of the first and second design submittals - and was finally accepted for further development.
The aircraft became known as "Sabre 45", denoting its 45-degree wing angle sweep and its F-86 Sabre origins. A Pratt & Whitney J57 series was selected as the new powerplant and was itself to become as legendary as the Sabre series. The J57-P-7, as thirsty as it was, still provided the best bang and performance for the new fighter considering all the other frontrunners at the time. North American Aviation submitted a proposal for two prototype models to be constructed based on the Sabre 45 design study and the USAF granted the contract along with provisions for a possible 94 Sabre 45 production models in the future. The USAF officially christened the new design as the F-100A series on December 7th, 1951.
Many challenges lay ahead for the design group and no stone was left unturned. To achieve consistent Mach 1 flight would require a completely new airframe approach. As such, the 45-degree wing sweep was coupled with a thinner overall air foil when compared to that on the F-86 Sabre production models. Of particular note for the wings was also the design decision to place the ailerons inboard as opposed to outboard. In effect, this provided the new aircraft with exceptional rolling capabilities in high-speed flight but also curtailed wing twisting and bending. The wings were also kept low on the fuselage with the stabilizers behind it kept lower on the empennage - below the wing chord plane essentially. These stabilizers were known as "all-flying" surfaces for they moved as complete pieces in unison with one another. The system was constructed as separate components but held together by a single tubular fastener, allowing for the system to move as one entire unit. This was important in that the stabilizers were charged with dealing with any airflow "downwash" emanating along the wing trailing edges. This had a propensity to force the aircraft to nose up. The F-100 would become the first aircraft to incorporate this feature into its design. The empennage was dominated by a conventional vertical tail fin that sported the rudder.
The forward-mounted air intake duct opening was fitted into an extended nose assembly with the intake opening now more of an oval with a thinner lip than that as found on the original Sabre. This allowed for a good amount of air to be forced inwards toward the turbojet engine. By comparison, the new design was a full quarter longer than the original Sabre, with ductwork running about the first half of the fuselage and the engine taking up the second half. Because of the nature of the materials needed, even the manufacturing facilities would need special attention to keep the construction of the aircraft as consistent as possible across all production models leaving factories.
The fuselage was properly contoured with the cockpit sitting forward of the design under a clamshell canopy. Construction of the fuselage was of a semi-monocoque design with stressed skin. The pilot sat in a climate-controlled and pressurized tub with windshield defrosters to combat high-altitude/high-speed icing. Probably the most important element of his position was his ejection seat - this coming in two flavors. The first type was a simple ejection seat process that initiated jettisoning - first the canopy and then the seat with the pilot via cartridges. The second type featured a 7,500lb thrust rocket and cartridge system which jettisoned the canopy first, followed by the pilot in his powered chair, blown clear of the aircraft. The rocket-powered escape method allowed for improved low-altitude escapes though both methods provided the pilot to benefit of safe ejection at any speed and at any altitude.