Nuther SR-22 crash/incident?

T o d d P a t t i s t wrote:
Matt Whiting wrote:


I'm not familiar with the Blanik glider or its aerodynamics so I can't
comment.


Isn't that the subject we are discussing? - whether general
aerodynamic principles are sufficiently well understood that
we can not only predict what happens aerodynamically in the
real world, but also use that prediction to determine
whether we should disregard a pilot report that conflicts
with our prediction?

Sure, but you need to know the specifics of the aircraft in order to
know which principles to apply. For example, a powered airplane at high
angles of attack derives some lift from the propulsion system as the
thrust is vectored downward from the horizontal. This can be a big
factor for powered airplanes, but doesn't apply to gliders. That
doesn't change the underlying aerodynamic principles, it just means you
have to apply the appropriate principles.

Matt

That doesn't change the underlying aerodynamic principles, it just means you have to apply the appropriate principles.

It's not the principles in question, it is one's understanding of them
in the light of apparantly conflicting empirics.

The difference between theory and practice is that in theory, there is
no difference. In practice, there is.

Jose
--
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In article ,
T o d d P a t t i s t wrote:

What I said was that they entered via an "accelerated
stall" and that they brought "the nose well above the
horizon, while slipping ... holding that attitude then
allowing speed to decay." The stick was full back and in
one corner, with the rudder to the opposite side. They
expected from the nose high attitude that the critical AOA
would be exceeded as their initial upward path became a
downward path (as speed decayed) and the attitude relative
to the horizon remained unchanged.

Not to split hairs, but... what you originally wrote was:

"We decided to try an accelerated stall spin entry from a full
slip, bringing the nose well above the horizon, while slipping
with stick full back and left and full right rudder, holding
that attitude then allowing speed to decay."

A big difference in
"...decided to try an accellerated stall spin entry..."
and
"...they entered via an "accelerated stall..."

In article ,
Matt Whiting wrote:

With the stick full back? I'd like to see that demonstration.

Can be done in a Citabria.
When I took my first acro lesson, this was one of the first maneuvers I
was taught. Another was a "falling leaf", where the aircraft is fully
stalled with the stick full aft and rudder is used to keep the nose
"centered", thereby preventing a spin from developing.

In article ,
T o d d P a t t i s t wrote:

In this case, the stall entry was brought about by bringing
the nose up very high at speed in an initial accelerated
maneuver so that the unpowered aircraft was in a steady
climb.

Remember my use of the word "agressively"? You have to force the
accellerated stall (that's why it is called "accellerated"!).
Another name for an accellerated stall is a snap/flick roll.

john smith wrote:
In article ,
Matt Whiting wrote:


With the stick full back? I'd like to see that demonstration.


Can be done in a Citabria.
When I took my first acro lesson, this was one of the first maneuvers I
was taught. Another was a "falling leaf", where the aircraft is fully
stalled with the stick full aft and rudder is used to keep the nose
"centered", thereby preventing a spin from developing.

I don't think that is what was claimed. The claim was going from full
rudder one way to full rudder the opposite side without entering a spin.
Then again, the original claim about entering a acclerated stall
seemed to morph in later messages so I don't know about this claim. :-)

Matt

In article ,
Matt Whiting wrote:

I don't think that is what was claimed. The claim was going from full
rudder one way to full rudder the opposite side without entering a spin.

That is correct.

On 2006-06-16, Matt Whiting wrote:
Then, I'd like to know which model airplane it is. You can always find
odd exceptions, but if this is a Cessna single, then, yes, I think the
pilot is full of it. :-)

Think again!
When I first got my Cessna 140, we tried all kinds of manoevres to see
what was likely to bite and what was not.

One of them was stalling in a maximum effort slip. All that happens is
the plane shakes like a wet dog and develops a high sink rate. No spin.
The yoke was all the way on its back stop and the rudder was to the
floor. Note that something entirely different happens if you try this
from a SKID rather than a slip. At least in the C140, we couldn't get it
to spin from a slip whatever we tried (and the C140 has plenty enough
elevator to properly stall the plane and to enter a spin from a skid).

I suspect that the Blanik L13 (the only aircraft I have access to that
is approved for spins) will do the same if I stall it in a slip - I'll
have to try it and see what happens.

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http://sr22shop.com
Peter Duniho wrote:
"T o d d P a t t i s t" wrote in message
...
But 80 knots isn't "at low speed". That's my point.

I'm sure you will agree that whether 80 knots is close to
stall or not depends strongly on airfoil, wing loading, etc.

Yes, I agree that it does. However, there's no reason to believe that the
SR22 is in that category.

For the SR-22, given that it has a published stall of 59
knots w/flaps, I can't see how 80 knots could be anywhere
near stall.

It's obviously not. Not during a normal approach, that is.

However, I've never flown an SR-22, and I've
learned enough over the years to strongly temper my own
theoretical aerodynamic musings whenever they conflict with
a pilot report.

Well, I *have* flown the SR20, which lands essentially the same (elevator
forces might be slightly higher in the SR22 for a pilot who doesn't know how
to use the trim). I found absolutely no tendency for it to be unresponsive
to an increase in AOA during the approach and flare.

More to the point, the person to whom I was responding also has NOT flown
the SR22 (probably not an SR20 either). He's purely speculating, and in
doing so inventing some pretty odd concepts of aerodynamics.

Pete