http://www.starfighter.no/web/hi-alt.html

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Most were of course comparatively simple targets, BAGDER, BEAR and
BISON in all varieties. Some were slow like CUB on the "milk run",
others were high and fast as BLINDER. The most difficult were the
ones that went low in ground clutter and the slow ones at high
altitudes. A BADGER at mach 0.6 at 40.000 feet made life troublesome
for a 104-driver, particularly at night. I see that you´re doubting,
shouldn´t a 104 manage a slow BADGER? Remember that the fighter had
high stallspeed. At mach 0.6 at that altitude it would barely be
above stallspeed and well behind the power curve. Intelligence
reports had for a long time described a Sovjet "U2" and we were well
aquainted with MANDRAKE and FOXBAT. We wanted to encounter and
photograph or engage such targets. By the way, BACKFIRE wasn¹t seen
until long after the zoom program was completed, but there were
rumours.





Regards...