The finest example of the all-rounder genre may well have been the magnificent U.S. McDonnell-Douglas F-4 Phantom fighter bomber, which was the best in the world at a wide variety of combat roles for more than 20 years from the mid-1950s well into the 1970s. Its designated successor, the McDonnell-Douglas F-15 Eagle, was also a superb all-rounder performing, like the F-4, for the Israeli air force in combat operations as well as for the U.S. Air Force. But even the F-15 was significantly larger, more complex and therefore far more expensive per unit cost than the F-4.

However, there have also been plenty of examples of supposedly multipurpose warplanes that proved to be flying turkeys -- plagued by development problems and soaring development and unit costs that proved disappointing at pretty much every role to which they were assigned. A classic case of this was the F-111 variable wing aircraft back in the 1960s that was Robert McNamara's pride and joy during his disastrous tenure as secretary of defense during The Vietnam War.

One of the excellent aircraft scrapped to make way for the F-111 was the British TSR-2 supersonic strike bomber. It is significant that no follow-up design utilizing the F-111's variable wing technology has ever been put into development and operational use in any significant numbers since then.

Usually, even excellent aircraft perform poorly in secondary roles for which they were not primarily designed. The British Vickers Supermarine Spitfire was one of the most successful, famous and beloved fighter aircraft of all time. More than 22,000 of them were built. But its aircraft-carrier version, the Seafire, was plagued by problems.

Also, the older, slower, but much more durable Hawker Hurricane, while far inferior to the Spitfire in performance, especially at high altitudes, was much more effective carrying bombs, rockets and cannon in ground support roles in the Western Desert campaigns during World War II.

Similarly, the Hurricane's designated successor as the Royal Air Force's prime combat aircraft, the Hawker Typhoon, also designed by the great Sir Sidney Camm, in fact proved disappointing in that role, due mainly to its cumbersome lack of maneuverability. But it proved to be a fabulous tactical ground support aircraft due to its speed, robust construction, power and capacity as a formidable weapons platform.

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(Next: The Sturmovik example)