Today's Message Index:
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1. 12:12 PM - Thoughts on flying at the edge of the envelope (flylightning)
2. 07:27 PM - January 2011 Lightning Newsletter (N1BZRich@AOL.COM)
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Subject: | Thoughts on flying at the edge of the envelope |
I have thought about this for a few days and if I should share this or
not, but I think it will provide an experience to think on. We hear
pilots talk about the edge of the flight envelope in movies and tv
shows, and think it sounds really cool but what does it mean? Each
aircraft has a flight envelope based on several factors, speeds, G-load,
weight, configuration like flaps, ect. One I would like to think about
is Maneuvering speed or Va, and what happens if you over G the aircraft
below it? We all know a plane can stall and any attitude and any
airspeed as long as the critical angle of attack is exceeded. When at
or below Va a full and abrupt control movement results in the aircraft
reaching it's load limit, it will most likely stall, or at least they
are designed to, several things are happening here but the long story
short is if below Va the plane will stall before exceeding the load
limit and breaking. The lightning is a responsive aircraft in all
control axis but stable. The wrong control movements can result in the
above at an unexpected time.
I became aware of an instance recently with a Lightning that experienced
this. The pilot flying the aircraft was not familiar with the aircraft
but was flying it with no problems during normal flight, there also was
a check pilot onboard. The aircraft became dangerously close to another
in-flight, a near mid air. The pilot flying (not check Pilot) promptly
pushed the stick full forward while in normal 80knt or so climb out. The
resulting pitch attitude was unexpected and undesired as you can
imagine, the pilot than abruptly pull the stick full to the up stop.
What happened next correlates to the discussion above. The aircraft
shuddered hard than pitched down, the pilot did not change the stick
input but kept the stick full up at the stop. Several oscillations
resulted until the check pilot neutralized the stick. Neutralizing the
stick unloaded the aircraft, decreased the angle of attack and allowed
the wing to fly again.
After this happened I was told that I needed to check the design over
for a flutter problem because that is was the shuttering and pitching
was about. Clearly that is not what happened, had it been truly flutter
we probably would not have gotten to talk about it with the pilot as
they would have heard a high frequency vibration followed by a nice
quite sound as the control surface departed the aircraft. That is a
discussion for another time, but considering the pitch system is a push
pull tube, and the related components do not allow any slop in the
system, and the flight testing done prior to release of any kits, makes
flutter very unlikely.
The pilots aboard experienced a high speed/ accelerated stall. The
pitching was a result in lost tail down lift and the aircraft attempting
to correct the pilot induced condition. The vibration or shudder that
was felt was a stall buffet.
The POH explains that proper stall recovery is to relax the stick
pressure not to pull or push the stick to the control stops.
The designed Flight envelope kept the aircraft in one piece, this
happened below maneuvering speed and resulted in a stalled condition
instead of an in-flight break up. The Pilots of the aircraft got to
experience the edge of the flight envelope, thankfully it was not the
other end.
Nick Otterback
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Subject: | January 2011 Lightning Newsletter |
All,
The January 2011 issue of the Lightning Newsletter, and the last that
I will be responsible for writing, was sent to the websites that carry our
newsletters on Tuesday, 28 December. This issue should soon be posted on
the sites that carry the newsletters .
Here are the sites where you can read the latest "Hangar Talk" newsletter.
_http://www.flylightning.net/_ (http://www.flylightning.net/)
_http://www.greenlandings.com/_ (http://www.greenlandings.com/)
(http://www.flylightning.net/)
_http://moonshineaviation.com/_ (http://moonshineaviation.com/)
See a synopsis of the January issue's contents below:
Featured in this issue is the results of the voting for Lightning of the
Year for 2010.
Next is a "Great News for the Lightning" article that I think you will
enjoy reading. It will also give you an idea of what will be keeping me busy
in the near and distant future.
There is also an update article on the first Lightning being built in
Germany. Gerd Nowack sent us a great report and some excellent photos on how
his build is going.
The News From the Factory Section had an update on Lightnings and kits
sold from Mark Stauffer. Arion had a very good year in 2010 and 2011 is
looking even better.
There are also some good inputs in the other various sections - News from
Builders and Flyers, Technical Tips, etc. Thanks to all of you that sent
things for the newsletter.
In the Safety section this month I cover a review of AOA, stalls, and
particularly, accelerated stalls. You will understand why I felt the need to
cover this after you read the article.
Remember, unless someone steps up to "take the stick", this will be the
last issue; certainly the last issue that I will write. I have written the
newsletter for 3 years now and I feel it is time for someone else to take
over to provide new leadership and new energy. I will still be occasionally
writing for the newsletter, but will leave the leadership of the
newsletter up to the new editor. Who will that be?
Please let me know your thoughts on this, and all other past issues of the
newsletter. Do you think it has been helpful and informative? I'll pass
your comments to the next newsletter leader. And remember to continue to
send articles to the newsletter. Without your inputs, it would not be as
useful or informative. Thanks for your support in the past.
Blue Skies and happy flying,
Buz Rich
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