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Old December 27th 07, 06:03 PM posted to rec.aviation.piloting,rec.aviation.aerobatics
Angelo Campanella
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Posts: 30
Default spins from coordinated flight



Dudley Henriques wrote:
Todd W. Deckard wrote:
I return to the original question: if the ball is in the middle will
it spin?

If you introduce a climbing turn stall with the ball centered, you might
get a temporary wing drop at the break but unless you introduce a yaw
rate as the stall breaks; no yaw rate...no spin!


There is a possibility that a flip to the outside can occur in a low
speed but large bank climbing turn, since the angle of attack of the
outboard wing is greater than that of the inboard wing. Thus, in a left
climbing turn of 30 degrees or maore bank, the right wing experiences a
higher angle of attack, and will stall first if the airspeed drops low
enough, and especially if an accelerated stall is induced. I have had
this demonstrated tome in a C150. The result is dramatic. The craft
flips to the right, as in a half snap roll, ends up upside down, and one
is obliged to recover by certain mens. My instructor then practiced much
back stick to get back to right side up, managing the zoom safely. It's
a bit more of a thrill and happens quicker than a conventional spin. It
can be done in both directions, plenty of altitude, please....

NOTE: If you analyze angles of attacks in urns, level, descending,
climbing, using a spiral helical surface as reference, you will see that
in turning descent, the inner wing experiences a greater angle of attack
and will fall safely to the inside of the turn, but when climbing the
oppsite wing stalls first. Te flip to upside down is a total surprise.
Hence in climbing steeply out of a takeoff, the speed, turn rate and
bank must all be carefully managed. Usually, the less the turn rate, the
better, the ball must alwys be kept centered and the airspeed must be
kept always at least 1.2 Vso or more.

A further hint is that in a cross-wind condition, especially when
higher level winds are of a changing direction (usually rotates to the
right on ascent in the northern hemisphere), it is best to make the
first turn into the wind; If you take off of RY270 and the surface wind
is from 300, the wind at 200 feet AGL will be from 310 and that at 400
feet AGL will be at 320 degrees, and likely of a higher wind speed. A
gradual right turn (10 degrees bank) will present you with increasing
airspeed and a more rapid rate of climb; wery safe and very efficient.

On descent to landing, opposite things happen. As you descend, the head
wind speed diminshes, and in the northern heispere it shifts a bit to
the left. Here in Ohio, if there is any significant surface wind, I
usually keep about 10 knots extra on early final (if Vso is 60 kts, I
carry 70 or 80 kts. When about a half mile from touchdown, I often see a
5 to 10 konot drop in airspeed with no action on my part. Crosswind
components accordingly dimiish in speed and shift a bit to the left. A
crab angle serves on the first part of final descent. If any significant
crosswind remains below 200 feet, a shift into a side slip, where
fuselage is aligned with the runway while the upwing wing is down is
best for touchdown, often on one wheel for a moment.

Angelo Campanella