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rlborger(at)mac.com
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 Posted: Tue Jun 19, 2007 9:03 am Post subject: Turning Stall |
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Andrew,
You wrote:
"I have learned from experience that stall characteristics are very
specific to each airframe. There are only generic similarities across
the same model. Even in the ubiquitous Cessna 172, the stall
characteristics may appear to be consistent during an imminent stall,
but if you push it deeper into a stall, or an uncoordinated stall, the
characteristics are not at all similar. On an experimental
construction, I would expect these variations to be more drastic than
in production models.
As soon as I heard about this accident, I looked at the google
satellite map of Livermore airport and wondered why he was tempted to
make a 180. If the golf course had people in it that might be one
reason, but it looks like there are quite a few cow pastures slightly
left of course, and some shallow lakes (reservoirs?) further left."
Yes, that's why I limited my comments to only those aircraft in which I had actually performed the various turning stalls. And I explicitly stated that none of them had laminar flow airfoil sections. Those aircraft which I had tested where simple, basic and very well behaved in most situations. (Don't secondary stall an older C-150 with the landing light in the wing unless you have lots of altitude. It snaps to an instant spin.) Even the simplest and nicest have a nasty stall in a slipping turn. Laminar flow sections can be notorious in their stall characteristics. That is also why I will be investigating the stall characteristics of N914XL in straight and level, coordinated and uncoordinated turns, clean and dirty, various weights and CGs, etc. with plenty of altitude and in tiny increments to look for behavior defining the edges of the flight envelope.
I too am baffled as to why a pilot with that level of experience would try to turn back when suitable areas to put it down are available within 30 degrees of the departure heading. All I can think of is that he had practiced the 180 turn to see how much altitude would be lost and had established such a turn-capable altitude. (That attitude seems too be all too prevalent in some comments) Then when the engine quit, he was above that altitude so he turned. Unfortunately, he did not account for the extra weight of the passenger or he did not account for the fact that the turn is in actuality much greater than 180 or different density altitude or some other factor we don't know.
I try to learn from every accident. Learning from Europa accidents has been too frequent recently. My heart goes out to all those who have been affected by the latest accidents.
Good building and great, SAFE, flying,
Bob Borger
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jeff(at)rmmm.net
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| Posted: Tue Jun 19, 2007 10:58 am Post subject: Turning Stall |
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As I'm sure all of us following this tragic thread are... I too have
concerns about these accidents having occurred back to back. My wife
who does not like to fly is asking me why I would want to continue my
adventure. As I have just explained to her these incidences are
completely different and as these friends lost would want us to, we
should all use these to become safer pilots.
As I was turning final at my first Sun-N-Fun in April, I over shot the
turn and had to over correct it with a steeper bank. Had I been slow,
well lets not go there. I was like most caught up in the moment, had an
RV-8 in front of me and a 172 behind. There is no doubt in my mind
that even the most experienced among us (And I'm Not One Of Them) have
the ability to make the wrong decision at that defining moment. I only
know one who was perfect in all his decisions.
For that reason I have followed the advice of my instructor and that is
to keep the speed to where it isn't an issue until I'm on final and
level. Calculating winds, weight, and other issues should be for
another time and not at the instance of when that moment hits as we are
all human. As another Europa flyer showed me once, flaps coming down
are reserved for final and seem to work well that way.
On take off going back was always forbidden in my training and the
best field in front or sides is the only way to go under 1000 feet.
Many times my instructor pulled the power below that and if I didn't,
he pushed the 150 over to get speed before we looked for a field he
did. Lose power get your speed find a field he always said.
I am very saddened for both of these families and want to offer my own
condolences. I'm sure the ones we lost would now be glad to see us
sharing these Ideas and in the same becoming safer at what we love.
Jeff Roberts
N128LJ
On Jun 19, 2007, at 12:01 PM, Robert Borger wrote:
| Quote: |
Andrew,
You wrote:
"I have learned from experience that stall characteristics are very
specific to each airframe. There are only generic similarities across
the same model. Even in the ubiquitous Cessna 172, the stall
characteristics may appear to be consistent during an imminent stall,
but if you push it deeper into a stall, or an uncoordinated stall, the
characteristics are not at all similar. On an experimental
construction, I would expect these variations to be more drastic than
in production models.
As soon as I heard about this accident, I looked at the google
satellite map of Livermore airport and wondered why he was tempted to
make a 180. If the golf course had people in it that might be one
reason, but it looks like there are quite a few cow pastures slightly
left of course, and some shallow lakes (reservoirs?) further left."
Yes, that's why I limited my comments to only those aircraft in which
I had actually performed the various turning stalls. And I explicitly
stated that none of them had laminar flow airfoil sections. Those
aircraft which I had tested where simple, basic and very well behaved
in most situations. (Don't secondary stall an older C-150 with the
landing light in the wing unless you have lots of altitude. It snaps
to an instant spin.) Even the simplest and nicest have a nasty stall
in a slipping turn. Laminar flow sections can be notorious in their
stall characteristics. That is also why I will be investigating the
stall characteristics of N914XL in straight and level, coordinated
and uncoordinated turns, clean and dirty, various weights and CGs,
etc. with plenty of altitude and in tiny increments to look for
behavior defining the edges of the flight envelope.
I too am baffled as to why a pilot with that level of experience would
try to turn back when suitable areas to put it down are available
within 30 degrees of the departure heading. All I can think of is
that he had practiced the 180 turn to see how much altitude would be
lost and had established such a turn-capable altitude. (That attitude
seems too be all too prevalent in some comments) Then when the engine
quit, he was above that altitude so he turned. Unfortunately, he did
not account for the extra weight of the passenger or he did not
account for the fact that the turn is in actuality much greater than
180 or different density altitude or some other factor we don't know.
I try to learn from every accident. Learning from Europa accidents
has been too frequent recently. My heart goes out to all those who
have been affected by the latest accidents.
Good building and great, SAFE, flying,
Bob Borger
Jeff
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Eagleville Marketing Group / EMG
488 Beasley RD.
Eagleville TN 37060
615-355-7575 Office
615-406-8651 Cell
615-534-1082 Fax
| | - The Matronics Europa-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Europa-List |
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