Staff Writer (Updated: 4/18/2016):
In many ways, the Kfir became the ultimate development of the French Dassault Mirage III fighter line, though stocked with Israeli avionics and a myriad of airframe changes to differentiate the new aircraft form her French-based origins. Though commonly associated with the IAF, the Kfir has also seen operational service (albeit quantitatively limited) with Colombia, Ecuador, Sri Lanka and the United States of America (in the latter serving with both the United States Navy and the United States Marine Corps).
Any nation with the relatively short military history of modern-day Israel knows a thing or two about what she needs to wage war. Essentially born into fighting for its sheer survival, Israel had long since relied on the purchases of foreign aircraft to fill the inventory of its Israeli Air Force and Israeli Defense Force. The country had already made good on the purchase of its first Mach 2-capable jet fighters in the Dassault Mirage III series, becoming the first such foreign customer of the French aircraft. The Mirage III was an all-weather delta-winged speedster that proved hugely successful on the open market with some 1,422 examples produced - no small feat in the post-World War 2 world. Israel operated the type throughout the 1960s and featured the aircraft prominently (with success) in the 1967 and 1973 Arab Wars as well as other less-intensive conflicts.
Such experience with the French system unveiled a few noticeable limitations when considering IAF needs. While a stellar air-to-air fighter, the particular Israeli Mirage IIICJs were not wholly-suited to the multirole requirements of the IAF. Additionally, the Mirage III was underpowered with her base engine and ill-suited for the required ranges in the types of sorties that the IAF would be partaking of in the near future. The Mirage III also required plenty of runway surface for its take-off and landing procedures. To top it all off, Israeli pilots had outgrown the usefulness of the original avionics suite.
Israel had begun receiving deliveries of Douglas A-4 Skyhawks and McDonnell Douglas F-4 Phantom IIs by the end of the 1960s with both American-made aircraft proving quite capable in covering Israeli air defence/air superiority roles. Perhaps most important was the Israel right to license produce the excellent General Electric J79 turbojet engines that were powering its F-4 Phantoms - a fact that would come into play in the future development of the Kfir.
Initially teaming with the French firm Dassault Aviation, the two countries formulated a daytime ground strike version of the Mirage III airframe to be designated the Mirage 5 (original using the Roman "5" as in "Mirage V"). The Mirage 5 would feature a similar large surface delta-wing layout, a lightened maintenance load and an increased internal fuel capacity for improved range. Fifty examples of this new aircraft were made ready by 1968 but an arms embargo imposed by the French government against Israel the year before spelled doom for the deal. As such, no Mirage Vs were delivered to Israel but instead reallocated out to the French Air Force.
Undeterred, the Israelis set about fulfilling the IAF requirement through other avenues. This involved the brazen theft of some 250,000 Mirage-related documents from the offices of Luftech Corporation accomplished via the Israeli intelligence service. Luftech was subcontracted out by Sulzer Engineering Corporation in Switzerland, the latter itself signed on by Dassault to help in the license-production effort of French Mirages. Such covert actions proved a success and afforded the Israelis everything they needed to know about the French system.
Before time, a two-seat Mirage IIIBJ flew with its J79 turbojet engine in September of 1970. A two-seat Kfir prototype was made airborne on October 19th of that same year. An unlicensed copy of the Mirage V (known in Israel as the "Nesher") soon appeared and was re-engined with the J79, flying in September of 1971. The Kfir prototype was refined with new Israeli avionics, a reinforced undercarriage and a redesigned cockpit under the designation of Ra'am (or "Thunder"). This first flight took place in June 1973.
Engineering of the new system was accomplished in a relatively short length of time and, though a General Electric turbojet and Rolls-Royce turbofan were both considered for the new fighter, the finalized Kfir unsurprisingly fitted the proven GE J79. The Spey turbofan was of British origin and powered the British fleet of McDonnell Douglas F-4K Phantoms and Blackburn Buccaneers. As can be expected, the availability and local license-production of the J79E1 turbojet (regarded as the most powerful of the J79 engine line) in Israel made the decision that much easier. It did, however, force a stricter export policy for any future Kfir sales overseas - these requiring US State Department approval.
Selection of the J79 forced a complete redesign of the existing Mirage III airframe. The J79 was larger, shorter and provided for 11% more mass flow at the expense of higher operating temperatures than the original Mirage III powerplant. The fuselage was widened and shortened while the intakes were enlarged, the latter to profile increased airflow into the turbojet engine. The engine, in whole, was shielded with titanium and an airscoop was fitted to the leading edge base of the vertical tail fin to help with afterburner cooling. The added weight and expected field operations of the new aircraft were handled through a revised and reinforced undercarriage. A J79-engined Mirage IIIB served as another Kfir prototype, this time fitted with foreplane canards and strakes, and took to the air in 1974. When all was said and done, the Israelis had essentially gone ahead and produced an entirely new aircraft.
Production Kfirs began delivery to the IAF between 1974 and 1975, missing out on actions in the Yom Kippur War of 1973.
The IAI Kfir sports a tail-less delta wing planform, basically defining it as an aircraft not featuring horizontal tail planes. The main wings, large in surface area and low-mounted onto the fuselage, dominate the design and provide the necessary lift and control surfaces. The wings themselves make up over half the length of the fuselage and feature noticeable sweep back along the leading edge ending in clipped wingtips and a tapered trailing edge with subtle sweep. The delta shape begins just aft of the side intakes and continue aft, stopping just forward of the exhaust port. The main wings are complimented (in most Kfir models) by a pair of smaller forward-mounted implements known as canards. Canards are used in aircraft to improve handling and provide additional lift at low-speeds usually supplying more inherent benefits than initially intended - sometimes none at all. The canards on the Kfir are mounted noticeably higher than the main wings and just ahead of the main wing components.
Part of the Kfirs identifying features include its slim nose cone leading up to the two-piece canopy covering the cockpit. The cockpit is situated well-forward in the fuselage and the sloping nose section aids in relatively unobstructed views both forward and down as well as above and side to side. The intakes are situated just aft of the cockpit to either side and are capped by internally-mounted inlet cones. The fuselage features a raised spine running from the rear of the cockpit to the base of the vertical tail fin. The tail fin is relatively large and sports sweep back along both the leading and trailing edges. The tail fin extends some length over the exhaust opening at rear. A thin ventral fin is apparent under engine exhaust port.
The undercarriage is fully retractable and of a conventional tricycle arrangement made up of two main single-wheeled landing gear legs and a single-wheeled nose leg. The nose leg retracts rearward under the cockpit floor while the main landing gear systems fold forward and toward the fuselage centerline.
Standard armament for the Kfir is a pair of 30mm Rafael DEFA 553-series cannons. Each gun is afforded between 120 and 140 rounds of ammunition that can be utilized to hit both the air-to-air or air-to-surface role with equal fervor. To compliment this armament, the Kfir can field various munitions along its five (or seven) external hardpoints with two at underwing positions and three hardpoints placed along the fuselage. The general benefits of the delta form allow for such increased payloads and internal fuel thanks to the added wing area when compared to that of traditional swept wing planforms.