Hornet HUD

On 9/22/05 9:23 PM, in article
,
" wrote:

Hi all. I'm just about finished with what I think is going to be a
pretty realisitc freeware Hornet HUD for the MS flight simulator. Being
the newbie wannabe Hornet pilot that I am (heheh), I have a few
questions that may seem silly, but I would like to get some of these
finer details right. I was hoping maybe someone in here might know. I
have the ladder, vector, AoA bracket and other basics working
properly, but....

1) What is on-speed AoA for the Hornet? I've seen 8.1 degrees, but have
seen video (Military channel, probably) that had the AoA bracket
centered on the vector, with the jet on final to the carrier, on
glideslope, and with the waterline only about 2 degrees above the
horizon. Now I'm no mathemetician, but... that's only about 6 degrees
AoA, right. So what gives? ;-) Is this a case of units AoA vs. degrees
AoA or something... (in which case, what's the conversion?) Or is there
something else I'm missing? (I can't imagine that something so
fundamental would be adjustable in cockpit.)

The waterline represents the aircraft datum line. I'm not sure what you're
seeing, but the math is simple. When the aircraft is on approach to the
carrier (3 degree glideslope taking wind into account), and the AOA is the
optimum 8.1 degrees, the W should be 5.1 degrees above the horizon. That's
the way it works unless there's a problem with the ADI that's generating the
W symbol.

2) Pitch ladder drift with yaw.... I like when the ladder drifts left
and right with the vector, because it gives such clear trend info with
heading, wind, etc., but I know many will whine that the ladder
sometimes drifts off the side of the HUD. Is ladder drift always ON, or
can it be switched off by the pilot?


The pitch ladder will drift with the velocity vector when it is uncaged.

3) ILS needles. Are they centered on the waterline, or on the velocity
vector? I believe I've seen this both ways too, even with the gear
down, but wouldn't bet too much on that.... Right now I have it
switchable, but prefer them on the waterline mark since it seems too
cluttered when they're on the vector.


Both SPN-41 (ILS) needles and SPN-46 (ACLS) "tadpole" are centered on the
velocity vector unless the HUD is in standby mode (e.g. after an INS
failure)... then they're centered on the waterline symbol.

4) Radar altitude. Is this a switchable thing, or does it show up only
when below a certain altitude, or... something else?


Switchable. RADALT can be selected to the HUD with the flip of a switch.
There are HUD cues to delineate what the altitude source is. For instance,
an R next to the altitude box indicates that the jet thinks the RADALT is
valid and the AGL altitude is displayed in the HUD. A flashing B indicates
that RADALT has been selected to the HUD and that baro altitude is displayed
instead.

--Woody

Any hints with any of this? Anyone... ;-) Thanks for any info.

Thanks again. Great info. One more, if you don't mind: does the ACLS
tadpole act more like a flight director (like, say, the intersection
point of standard civilian jet ADI needles), or does it simply act more
like supersensitive ILS needles? I know it's the little cue that ends
up (hopefully) on top of the velocity vector, with a dot in the middle,
but am not sure which of the above it actually functions as.

FYI, I'm also investigating to see if there's a way to record the
deviations from AoA, lineup and glideslope every, say, 10th of a second
or so, and then use statisitcs (root mean square, probably) to
calculate a landing grade. (A kind of mathematical LSO!) There's almost
certainly a way, but I doubt if Microsoft created those variables in a
way that would make it as easy as it seems.

On 9/29/05 9:41 AM, in article
,
" wrote:

Thanks again. Great info. One more, if you don't mind: does the ACLS
tadpole act more like a flight director (like, say, the intersection
point of standard civilian jet ADI needles), or does it simply act more
like supersensitive ILS needles? I know it's the little cue that ends
up (hopefully) on top of the velocity vector, with a dot in the middle,
but am not sure which of the above it actually functions as.


It's raw ACLS data plain and simple. No roll-summed steering or flight
director commands are given. Also, on course/on glidepath are represented
by the tadpole being perfectly centered inside the velocity vector
(concentric circles). Many pilots castle priority to the HUD in order to
get the dot in the VV for reference too.

FYI, I'm also investigating to see if there's a way to record the
deviations from AoA, lineup and glideslope every, say, 10th of a second
or so, and then use statisitcs (root mean square, probably) to
calculate a landing grade. (A kind of mathematical LSO!) There's almost
certainly a way, but I doubt if Microsoft created those variables in a
way that would make it as easy as it seems.


United Airlines used that technique in their fixed-based simulators in the
interview process. It's not entirely accurate. The flaw with the United
sim was that pilots tended to get better scores if they didn't fly it like
an airplane and muscled the jet back and forth above, through, and below the
glideslope then back through to high and so on (and likewise with
courseline). This minimized the RMS errors (less time spent in the
deviation area), but made for a crappy approach that would have made pax
wonder what monkey was at the controls.

You'll have the same problem with your method in the Hornet CV
approach--e.g. no sane carrier aviator would fly from a high ball to a low
ball ON PURPOSE. They're taught to lead that correction in order not to
descend below the centered ball. Food for thought.

--Woody

Thank you all for your input. I just recently uploaded the Hornet HUD panel
to avsim.com, flightsim.com, and simviation.com. I think it turned out
pretty well - very similar "look and feel." Any of you who tinker with such
things, let me know what you think needs improvement. Also, someone was kind
enough to point me to the Hornet's NATOPS flight manual, so of course now
I'm just going to HAVE to model the HUD/vector steering arrow, and maybe the
basic modes of the HSI, also. Thanks again.