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Old November 2nd 03, 11:59 PM
Karl Striedieck
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An article appeared in Soaring Magazine a few years ago titled "Attitude
Problems" dealing with ways of dealing with an unconnected elevator control.
Pilots of flapped ships can use flaps, spoilers and bank angle to adjust
pitch, standard ships the last two.

Gliders using a tow release in the nose will be more easily controlled on
air tow than those using a cg release, but, if an initial zoom up after take
off can be controlled, the latter can be controlled sufficiently to allow a
high tow and possible bailout as well.

As pointed out in an earlier contribution to this discussion, trying to
simulate a disconnected elevator by allowing the stick to move freely in
pitch won't create the same degree of instability, but it is still a useful
exercise.

Varying the bank angle to arrest phugoid zoomies is very easy to accomplish
(steepen bank to lower nose and vice versa). When a bailout is not an
option, use of this mode alone will result in the glider coming to back to
earth tangentially at a reasonable speed.

Anyone interested in a copy of the mentioned article can contact me.

Karl Striedieck








"Andy Blackburn" wrote in message
...
I would not suggest that loss of elevator is anything
but the most serious of mechanical incidents. However,
if it should ever happen, instead of throwing your
hands into the air and resigning yourself to a certain
fate, there are controls that you might be able to
use to maintain some measure of control - namely speedbrakes
and flaps (if you have 'em). Will it be a pretty
landing? Unlikely. Nevertheless, it beats the alternative.


I recommend practicing this rather than trying to figure
it out in real time in an emergency. I have practiced
flying without the use of each of the controls for
this reason.

Doug's right on UA 232 - the gear hit before the right
wing. The earlier comment was that the crew were unable
to control pitch with thrust. More precisely, they
were not able to adequately control pitch or heading
to make a good landing. If they had totally lost pitch
authority there would have been no survivors - which
I think was the main point. Use whatever control you
have.

9B

At 17:12 01 November 2003, Doug Haluza wrote:
I think it would be difficult to overstate the severity
of a total
loss of elevator control. It is possible to damp out
the phugoid with
spoiler (and/or flap) but this won't help much close
to the ground.
Deploying spoiler on the down part of the phugoid will
reduce your
forward speed, but it will increase your vertical speed.
The rate of
descent at impact is the real problem. It may be theoretically
possible to do something that could later be classified
as a landing,
rather than a crash. But you only have one chance to
do this, and the
probability of doing it exactly right on your first
try is not very
high.

United 232 did not dig in a wing and cartwheel. The
aircraft hit the
ground with a high descent rate (1850 fpm) slightly
right wing low.
The right main gear broke through 12' of concrete,
and the wing broke
off along with the tail section on impact. The rate
of descent, and
loss of the wing, was a direct result of the phugoid
mode.

P.S. For a very interesting first hand account of Flight
232 from Capt
Haynes see: http://www.panix.com/~jac/aviation/haynes.html

Andy Blackburn wrote in message news:...
Doug overstates the case a bit. Even without elevator
control it is possible to damp out the phugoid mode.
I tried this on a BFR recently and I encourage the
rest of you to give it a try as well. Since the phugoid
is a function of airspeed/pitching moment coupling,
you can damp it out by applying speedbrakes at the
bottom of the cycle. This take a bit of thinking ahead,
but it can be managed with practice.

The United 232 crew was able to control pitch through
pitch/thrust coupling. They applied collective thrust
to adjust pitch and differential thrust for directional
control. It was crude put effective enough to get
to
the runway threshold. Unfortunately, the dug s wing
in on landing. It was not directly a result of the
phugoid mode, though I suspect all the different modes
conspired a bit.

At 00:48 01 November 2003, Doug Haluza wrote:
(nowhere) wrote in message
news:...
Yes, according to Peter Garrison's 'Aftermath' column
in the November
issue of 'Flying' you don't need to connect your
elevator
control! I
quote: 'the NTSB report does not comment on the fact
that a
disconnected elevator does not make an ASW-20, or
for that matter any
other airplane, unflyable. The situation is aerodynamically
no
different from what occurs when the pilot removes
his hand from the
stick.'

I think I'll start leaving the elevators off my
ASW-15
now. Imagine
how the reduction in drag will improve the performance!
Not having to
worry about pitch control will certainly cut down
on the cockpit
workload as well. The benefits are endless!

Well, it may be flyable, but not landable! The stick
free phugoid can
get pretty dramatic, even with the mass and friction
of the stick
attached to provide some damping . If you have not
tried this, you
should. Keep hands completely off and keep the wings
level with
rudder. Let the phugoid fully develop--it's a real
roller coaster
ride. Close to the ground, it's a crap shoot whether
you would land or
crash.

There was an accident a few years back in a DG-800
that had a loose
nut on the elevator control. The pilot hit on the
down
part of the
phugoid and crashed wings level. He lived, but never
flew again.

The same thing happened to United Flight 232, the
DC-10-10,
that
crashed while attempting an emergency landing at the
Sioux City
Gateway Airport, Iowa, in 1989. After losing all hydraulics,
they had
no movable flight controls. They were able to fly
the
aircraft with
differential thrust on the two wing engines, but they
could not
control pitch on final approach.

I have not seen the article, but I'm surprised that
a knowledgable
person would suggest that elevator control is optional.