Sammy Mason on Stalling & Spinning

On 20 Feb 2004 19:48:04 GMT, (BAToulson) wrote:
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A third was in a Bocian, also on a winch when the rear canopy, which slid
backwards on rails, came unlocked, slid back and hit the rear stop. This one
was probably the worst because, a) we were about 100ft and starting to rotate
into full climb, b) in addtion to the "bang" as it hit the stop, there was a
huge, disorientating rush of air, and c) it took a while to work out what had
happened, take over from the pupil, (only his second or third winch take off)
and get the nose down etc.

IIRC Derek Piggott had this happen as well - except that the rear stop
didn't and it took the tail off. He - and his pupil - came down by
parachute.

And Chris Rollings had this happen on Aerotow from Aboyne - with my
future wife in the other seat - and caught the canopy as it went past.

Chris Rowland

In article , Todd Pattist
writes:

The first time I tried this in my Ventus, I was flying along
sideways with full rudder and level wings and heard a loud
"BANG!" After my heart stopped thumping, I figured out that
one of the gear doors had sucked open into the sideways
airflow. :-)

That happened to me once.Scared the hell out of me.

Another scarey bang was in a Puchacz on the winch when the cover, which is over
the rear seat adjustment bar, could not have been secure and flicked down and
hit the side of the fuselage. This was about six inches from my left ear and
was magnified by the megaphone shape of the hollow fuselage.

A third was in a Bocian, also on a winch when the rear canopy, which slid
backwards on rails, came unlocked, slid back and hit the rear stop. This one
was probably the worst because, a) we were about 100ft and starting to rotate
into full climb, b) in addtion to the "bang" as it hit the stop, there was a
huge, disorientating rush of air, and c) it took a while to work out what had
happened, take over from the pupil, (only his second or third winch take off)
and get the nose down etc.

However, one of the the worst I know of these type of incidents was a pilot at
my club who owned a Carmem and lost the complete canopy at about 4000ft agl. It
departing it caught his skull which bled profusely and a combination of blood
and the wind causing his eyes to run, made it extremely hard for him to see.

Once he worked out what had happened, his big concern was what else the canopy
had hit, tailplane for example. He considered baling out but, having checked
all controls decided to ride it down to the nearest field, successfully I am
pleased to say.

The farmers reaction to this bllod covered figure arriving at his door was, I
understand, unprintable.

Needlesss to say, all of the above (except U/c doors) occurred either as a
result of poor take off checks or mechanical faults.

Barney
UK

When turning, the only rotation is about the vertical (earth-fixed) axis.
Then take it to the extreme case of diving straight down (here defined as
the longitudinal axis vertical). In that situation, all of the rotation
will be around the longitudinal axis of the aircraft - i e roll.

Remember, we're talking about Sammy's model. When diving there is no
rotation, about the longitudinal or yaw axis. (There is no aileron
input.) Same thing going straight up. The orientation of the lift
vector (positve values) would rotate the glider about the lateral
axis.


In turning flight with the fuselage level (longitudinal axis horizontal),
all of the rotation will be around the yaw axis of the aircraft.


Again, not according to the model as I understand it. If the aircraft
is sinking, the one wingtip is travelling faster than the other, and
therefore there is a difference in angle of attack, and in model, this
is accounted for as a roll. I'm waiting for the book to show up, but I
suspect that we're all taking this too literally, trying to justify it
in the real world.

As for the train, the only force of importance is the side force on
the rail. There is no friction (or better said, it is unabserved). The
point is that a leaning train looks like a turning train to a sensor
that simply measures force acting in a single direction.