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Old March 8th 04, 12:56 AM
Frijoles
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Lotsa snip
IMO, the handling differences between the two jets are sometimes
mischaracterized. Both aircraft are very honest. Workloads in the

hover
are very similar, except the first Harriers have neutral static

stability in
yaw below about 60kts -- a not-so-insignificant difference for

transition
flight. The first Harriers also have a much "lighter" control feel.


I've seen it described as being more of a sportscar feel vs. a sedan, i.e.

more
responsive, and some experienced pilots preferred it.


I've not heard that characterization but its a good one. However, in spite
of the heavier stick forces, in conventional flight the H II is generally a
much more maneuverable aircraft.


Due
to the stronger stability augmentation on the H II, it is slightly more
forgiving of inattention to sideslip generation in transition flight,

and
protects the less experienced pilot as he (or she) ventures near the

edges
of the envelope.


This would be the area where yaw-induced intake momentum drag rears its

ugly
head, especially in the first generation a/c?


Intake momentum drag is a factor, but usually pilot action (overly
aggressive roll inputs) or inaction (don't center the vane) are usually the
biggest contributors to sideslip issues. Biggest change for most jet guys
is learning to use their feet for something other than brakes and nosewheel
steering. Particularly important factor in the first jet since the static
margin in yaw is less than the H II.


However, due to the different wing and its associated
high-lift devices, at higher winds over the deck and while using the
aft-most spots on the ship, you have to pay more attention to roll
excursions.


I suspect FBW will take care of that sort of thing in the F-35B. Of

course,
development to get the software to that point can be prolonged, as the

MV-22 has
been demonstrating. They seem to have gotten the uncommanded roll in the

hover
half over the deck and half not, and on the deck behind a helo, tamed at

last.

Any idea how the throttle logic is being implemented? AvLeak had an

article a
couple of years ago on the different approaches being pursued by Boeing

and
LockMart. IIRR one of them was planning for the throttle to control RoD
directly in the hover, as opposed to controlling thrust directly. So,

with the
throttle in a hover position (with the computer providing whatever thrust

is
needed to achieve that), pulling the throttle back x amount would command

say 3
fps RoD, y amount 5 fps, pushing it forward from neutral z amount would

command
2 fps ascent, etc.


Not sure what LM uses. I thought the Boeing arrangement was TOO automated,
but that was based on very limited exposure in the sim. I know both went
through many iterations.

ISTR the other company was planning to use it to control hover height, but

my
memory of the article is very hazy.

Guy