User Guide

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BANKING AND YANKING, PART 2
We’ve entered our spins via a gradual deceleration - but
we’ve also learned that an airplane can be stalled at any speed. Is
the same true of spins?
Yes, it is - and although the 172 isn’t cleared for aerobatics,
there’s at least one situation that approximates the entry into an
aerobatic maneuver called a “snap roll.” For those of you who are
flying in the real world, I should point out that this is very hard on
the airplane - so, for once, “Kids: go ahead and try this at
home…but not out in the real world.”
Every airplane has, published among its limitations, some-
thing called “maneuvering speed.” This speed changes with air-
craft gross weight, and is the maximum speed at which you can
“make full or abrupt control movement.” Unlike stall speeds,
maneuvering speeds are higher when the airplane is heavier, and
there’s a relationship here: the maneuvering speed is set such that
if you apply full pitch control at or below the maneuvering speed
appropriate for your weight, the airplane will stall (and hence
unload itself structurally) before it can pull enough “G” force for
permanent damage. This also means that it can hit the maximum
probable gust without any structural damage.
Let’s demonstrate this, once again at altitude: slow the air-
plane to a maneuvering speed appropriate for its weight; in the
172, this varies from 81 knots at light weight to 99 knots at gross
weight. We’ll use 90 knots for this demonstration.
Now, without slowing any further, briskly apply full up ele-
vator. You might get a very brief shriek from the stall warning
horn; what will happen is that the airplane will pitch up, hard,
and snap a wing down equally hard (most likely to the left).
Basically, you’ve “snapped” it into a spin - but since it still has sig-
nificant forward speed, the spin goes forward instead of down.
Hold the controls fully back long enough, reduce power,
and the initial snap will progress into a normal spin. Neutralize
the controls, and the airplane will recover - but as to its attitude,
your guess is as good as mine. Figure out which way is up, roll in
that direction…
Exciting, isn’t it? But not really that scary. Climb back up to
altitude and try another. This time, things won’t seem to be hap-
pening quite so fast. You’ll have time to look at the airspeed indi-
cator; notice that it stays pretty low during the whole spin, and
doesn’t jump off its peg and start indicating again until you’re into
the recovery. Take a quick look at the turn coordinator, too: if you
ever enter a spin at night, or in cloudy conditions, and don’t know
which way you’re turning, it’ll always tell you.
Let’s try another confidence builder: climb back up to alti-
tude, make a clearing turn or two, make sure the airplane is
trimmed for 100 to 110 knots level cruise, and start another spin,
this time to the right. At the end of a couple of turns, simply let go
of all the controls, and take your feet off the rudders.
The recovery will be a lot sloppier; it’ll take longer, use more
altitude, and probably leave you more nose-down, with airspeed
building up rapidly. But notice that the airplane managed to
recover all by itself - something to keep in mind if you ever lose
control at night or in the clouds and aren’t sure what to do.
Flight Instruction
Flight Instruction