1. #21
    The 104's design's main drawback was it's proneness to "pitch-ups", where vortices from the wing/fuselage joint would hit the tail from above and create a downforce onto the elevator that the pilot couldn't oversteer - especially, as those vortices are highly energetic and detach/ re-attach chaoticly.
    A similar phenomenon is called "deep stall".

    A pitch-up accident was taken on video in 1983, when at an airshow at Rhein-Main AIrbase (Frankfurt Intl. Airport), a canadian CF-104 departed controlled flight and crashed into a car full of people (that sadly died).
    The pilot ejected and survived.

    That's the video:


    Note the pilot pitching-up at 9s and doing it again after briefly re-gaining control in a partially inverted/ nose-low position.
    Sad crash, but that's the risk with t-tails anyway.
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  2. #22

    Comments on F-104A/-19

    I'd like to add a few comments to Walt BJ's postings. First, BJ captures the spirit and soul of the F-104A/-19 very well. No kidding. The -19 changed the game big time.

    I spent four years at Homestead -- May of 1965 to August of 1969. I logged 800 hours in the Zipper and got to experience the transition from the old J-79-3B to the -19. I will make a posting later on an engagement we had with TAC F4E's flying the -19 that illustrates life in the vertical plane Walt describes so well but for now I just want to comment on a unique feature of the F-104 not previously mentioned but very important. I had the advantage of a degree is aeronautical engineering at Texas A&M and this gave me some extra insight into the F-104's unique design.

    One characteristic of supersonic flight is that the center of lift for any given airfoil is at the quarter-chord point, i.e., one fourth of the way back from the leading edge of the wing. Aerodynamic stability in the vertical plane requires that the center of gravity of the aircraft be forward of the center of lift. This in turn establishes the amount of pitch control power needed for maneuvering in the vertical plane. But for supersonic flight, the center of lift moves aft to the 50 percent chord point resulting in a decrease in pitch control power primarily because the moment arm from the center of lift to the cg is increased. Thus for aircraft like the F-106 and F-4, when they are supersonic at high KIAS, they do not have enough control power to pull maximum G's, consequently limiting maneuverability in the vertical plane. Kelly Johnson designed the large horizontal slab where the entire slab deflects providing max G capability limited only by KIAS. Consequently, when it comes to air-to-air, the Zipper dominates in the high-fast supersonic domain.

    By the way, heard from an old friend, Jim Nelson (3000 hours in the Zipper) that Walt passed away about 3 years ago. BJ will always have a special place in my memories both for the unique guy he was and for the fact that he "baptized" me after my solo flight in the Zipper by picking me up like I was a sack of potatoes, throwing me over his shoulder and throwing me in the canal that bordered our ramp with all the turtles and alligators.
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