Erik Simonsen
What Might Have Been: A hypothetical view of an operational USAF/Lockheed F-90A without tip tanks on a test flight. The Lockheed XF-90 competed against the McDonnell XF-88 and NAA YF-93A in the late-1940s, early 1950s "Penetration Fighter" contract. All the competitors suffered from inadequate engine performance. The "Penetration Fighter" requirement was subsequently cancelled, but later emerged with the more advanced McDonnell F-101A Voodoo. Details are covered in Chapter 3 of the book, "U.S. Combat Aircraft Fly-Off Competitions", by Erik Simonsen. In all, the book features Ten Chapters of historic fighter/bomber competitions. Erik Simonsen photo/illustration
What Might Have Been: Although the Republic XF-103 only reached the mockup stage during the early 1950s, here are two conceptual operational USAF/Republic F-103As from the 94th FIS. The F-103 would have had a dual-cycle turbo-ramjet engine capable of Mach 4 at 75,000 ft. – the initial takeoff and cruise to intercept would be handled by an air-breathing Wright turbojet – for the high-speed approach to final intercept the ramjet would kick in – for the return to base the turbojet would be restarted. Very unique, but the Air Force thought the technology was not ready. Erik Simonsen photo/illlustration