Powered by two Pratt & Whitney F-100-PW-100 turbofan engines, it is capable of speeds in the Mach 2.5 range. The F-15 Eagle can carry a heavy and devastating complement of weaponry such as internal 20mm M-61A-1 rotary cannon, plus four AIM-9L Sidewinder anti-aircraft missiles.
The early production F-15 was designated the F-15A, while the two-seat version was called the B model. In 1979, an improved and upgraded F-15 was introduced. One notable change was a 15% increase in internal fuel capacity, while even more fuel was made possible by utilizing conformal tanks that snuggle beneath the wing and against the jet inlet ramps. In order to accept this extra fuel weight, the landing gear had to be reinforced. These modified F-15's are called the C-type for the single-seater and F-15D for the two-seat version.
In 1981 the Japanese Air Self Defense Forces (JASDF) begin to employ these improved F15's. With the addition of their own designed electronic equipment, they are designated the J (single seat) and DJ (two-seat). The F-15J has been the centerpiece of Japan's air defense system since its purchase several years ago.