"sttp" wrote in message
...
Elsewhere I've read that the Tomcat flies "units" of AoA, not degrees,
with its AoA range of -10 to +40 degrees being converted to units in the 0
to +30 range. That would mean the formula for converting units to degrees
in that plane is [UnitsAoA = .6 * DegreesAoA + 6]. I've also read that
approach AoA for the F-14 is 15 units, which would be... 15 degrees! Holy
crap. Is that correct? That seems awfully high (too far nose up) to me,
especially given the Hornet's ideal 8.1degrees. Can anyone confirm or
correct these values? Or is there something weird going on with wing angle
of incidence (or something else) that throws a spoke in my assumption that
15 degrees AoA means 12 degrees nose up on approach. (15, minus 3 for the
glideslope.) Any help appreciated. Thanks!

Scott

A complex question. Units are, of course, not degrees. Issue, exactly what
equates to "zero" in the calculation? Usually the armament datum line,
waterline, or whatever the manufacturer chooses to call it. In the case of
the Turkey, the aircraft's envelope exceeds the AOA display limits ... you
can be flying at pegged AOA, well sort of flying. Adverse yaw could bite
you pretty hard if you had a heavy hand. For that matter, the old Phantom
could be there too ... but not for very long. The point, your assumption
that the gauge equates to the envelope is faulty.

IIRC, aircraft attitude (as reflected on the VDI attitude indicator and
mirrored on the HUD) was about 11 degrees nose high in level flight at
optimum AOA, somewhere around 8 degrees on a 3 degree glideslope (anybody
with more recent time in the jet ... feel free to chime in with
corrections). The airplane had a pretty pronounced cocked-up attitude on
speed, but not necessarily more so than the Phantom. It also had a large
hook/eye value (which affected lens setting for the target crossdeck
pendant).

The Hornet (and its bigger friend, the Rhino) are the only USN aircraft I
know that actually display AOA in pure and simple degrees as opposed to the
artificial "units." Of course it's capable of sustaining prodigious AOA, on
the order of 55 degrees with the current control programming.

Approach speed for a carrier aircraft is a brew of several objectives. You
want to be as slow as is practical. Attitude on touchdown is critical. You
want to be comfortably faster than L/D max. You need to preserve good
visibility over the nose (a big driver in the F-8J in which the engineers
came up with one number and after a few T&E passes at the ship had it
lowered slightly for pilot vis).

R / John