On 2023-02-22, Stefan Schreiber wrote:
Maybe it is me who now really would need some crash course in aviation,
Yes.
Is flying in a spiral not something you would do in some intentional
way?
Sometimes you might do it purposely, yes, but no, you typically would
not do that sort of thing willingly. Because it's *highly* dangerous.
Most likely if you go there, you will dive, and then die, with no means
of recovery. You'd crash yourself and all of your passengers.
https://en.wikipedia.org/wiki/Graveyard_spiral
Stefan, lately I've been minding the Mentour Pilot channel on Youtube.
The guy doing that is a Swedish pilot, used to piloting the Boeing 737,
and not so much anything AirBus. He then also takes down *all* of the
disasters which have happened in the recent decades, talking down and
analysing what happened in talk and instrumentation.
I'd thoroughly recommend that Swedish Chef. He's stupendously good,
physically minded, all of it. He knows what he does. In fact, just now,
within weeks, he took upon himself to spin a 737 in a simulator, upside
down, going into an upset and something which could go into a lateral
spin. "Yes, you can do it, but..."
https://www.youtube.com/watch?v=JhzaogGQNFU
Then on the other hand... https://www.youtube.com/watch?v=AaA7kPfC5Hk
Everybody thinks this sort manoeuvre is hazardous. Whereas it isn't: a
barrel roll is just a 1G monoeuvre with pretty much no risk at all. An
aileron roll carries much more risk, and is much more difficult to
execute properly. Flipping a helicopter is harder, but not *much*
harder; these aerodynamics go to superavionics and high control, of the
kind leading to such movements as the infamous Pugachev Cobra (
https://www.youtube.com/watch?v=kcLavSl58yQ ).
Of course, there will be more. One of the things here is active
parametric arrays. To order twenty or more, in military radars, such as
there are in the F-36. Those AESA's work interferometrically just as
would a high order coherent ambisonic rig. They only do so at
VHF/UHF/Ka-band fŕequencies, in radio, at about 2000-6000 closely spaced
"speakers"/transmitters, all of them spaced about a quarter of a
wavelength apart. Each of them doing gigabits per second, and maybe a
50W max. In toto, some continuous 100kW in software defined radio, in
intermittent, fully superfast transmittance and receivership.
Opposite to the spin situation, because this is kind of uncontrolled.
Or you "have to do something".)
I've never flown a plane. Yet I think I could recover a plane from such
a spiral. What you do there is: 1) you push down on the yoke to recover
airspeed, 2) you use ailerons to level off, and 3) if you then have to
go to too much airspeed while descending, you'll spoil your airfoil,
and then apply lift and drag via flaps, while not approching
aerodynamic stall.
So in which sense would you have to "recover" from the spiral?
You need to see which attitude you're at. You will need to put
slight ailerons in the opposite diretion. You'd be falling and you'd
need to follow your airspeed. If too much, you'd have to even spoil. If
not, you'd need to increase thrust in order to gain kinetic energy. In
any case, you'd want to keep yourself at about 160-200 knots of
equivalent speed and so kinetic energy, in order to stabilize the
aircraft, and then level off.
I read this before, btw:
"But whoever cares, really?
We should. Because none of us wants to drive an aircraft into the
ground, or a mountain.
We all know what we're talking about.
I know. Do we all?
Especially when you have to use the instrument in order to deliver
yourself and your passengers from a death spiral."
One of these things really is the death spiral. The thing here is that
you don't *feel* at *all* that you're in it. It's kind of like the
barrel roll, at one G. It's just a manoeuvre or a mistake, which feels
like nothing bad is happening. Yet if you don't follow your
instrumentation, you might be going into a death spiral. (This is why
the synthetic horizon in an airplane *is*. You're supposed, as a pilot,
to follow it, precisely *because* when it isn't level while you feel
level, *then* you're off in your feelings. You might be going into a
dive or spiral, and you're supposed to fly by meters/instrumentation,
not by your seat.
So what is this spiral? A situation when the plane is spinning, even a
stall (interruption of air flow), or what else?
The typical death spiral isn't a stall at first at all. Rather it's a
continuously advancing bank to either side of the airplane. As a pilot,
you won't feel it happening, because the airplane is intrinsically
stable by design. Even if you go into that bank, you'll just feel 1G of
acceleration towards the floor.
However, now the floor might be at 15, 30, 45, 60, 90, and eventually
even 180 degrees from upright. Before you even know it. And when you go
even half there, think about the lift your wings give you:
