Gliding risk....

2G wrote on 12/6/2019 1:53 PM:
On Friday, December 6, 2019 at 3:15:05 AM UTC-8, Terry Slater wrote:

Tom

The inspections were performed with an endoscope, and the full length of
the spar bonding was inspected visually. SH issued a very comprehensive
guide to the process.

Terry

Yeah, I read their TN 396-08 that covered the process. This required cutting several holes in each wing for access by the endoscope. Of course, these holes had to be repaired and refinished. It would have been so much easier and cheaper to have done this inspection by ultrasonic NDT.

If the SH wing is constructed like the ASH26E wing, there is a layer of foam
between the outer skin and inner skin that is glued (hopefully) to spar. I suspect
ultrasound would not be effective, so what would kind of NDT would be used?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.

On Saturday, December 7, 2019 at 2:09:19 AM UTC-8, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.

The biggest safety risks have been, and continue to be, pilot error.

Tom

On Saturday, December 7, 2019 at 3:09:19 AM UTC-7, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.

Regarding the rogue thermal comment... they can occur. I came VERY close to becoming a statistic a few years ago while thermalling about 1500 ft. agl and wrote a feature article for SOARING MAGAZINE dealing with it. Rather than stalling an inside wing in a thermal turn (as one would expect if you happened to fly too slowly), while thermalling at about 10-15 kts above stall speed my INSIDE (lower) wing suddenly was pushed up and over, resulting in a steep dive / spiral. Subsequent research showed that some thermals can have strong down cores inside of overall lift, and if a glider happened to hit the sheer boundary, with suddenly one wing in the up air and the other in the down air, your day could quickly end.

See https://www.danlj.org/~danlj/Soaring...b_Thompson.pdf

and Dr. Dan Johnson had a good one, too https://www.danlj.org/~danlj/Soaring...Jan-p12-15.pdf

There are 2 books I referred to in my classes that have some pretty good info, too, although they are mostly intended for business folks:
1. Will Your Next Mistake Be Fatal? by Robert E. Mittelstaedt, Jr. for example - on page 160 - Insight #29 - Culture is powerful - what creates success may kill you. Think about this one seriously, for a long time! What you, or others, have gotten away with for a number of times can lead to complacency... and you becoming a statistic... that you couldn't tell anyone about ... from the grave. I recently attended a "celebration of life" for a friend that I suspect may have either lost his life due to his prior successes or rogue air.
2.Why We Make Mistakes by Joseph T. Hallinan

On Monday, December 9, 2019 at 4:10:16 PM UTC-8, Bob T wrote:
On Saturday, December 7, 2019 at 3:09:19 AM UTC-7, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.

Regarding the rogue thermal comment... they can occur. I came VERY close to becoming a statistic a few years ago while thermalling about 1500 ft. agl and wrote a feature article for SOARING MAGAZINE dealing with it. Rather than stalling an inside wing in a thermal turn (as one would expect if you happened to fly too slowly), while thermalling at about 10-15 kts above stall speed my INSIDE (lower) wing suddenly was pushed up and over, resulting in a steep dive / spiral. Subsequent research showed that some thermals can have strong down cores inside of overall lift, and if a glider happened to hit the sheer boundary, with suddenly one wing in the up air and the other in the down air, your day could quickly end.

See https://www.danlj.org/~danlj/Soaring...b_Thompson.pdf

and Dr. Dan Johnson had a good one, too https://www.danlj.org/~danlj/Soaring...Jan-p12-15.pdf

There are 2 books I referred to in my classes that have some pretty good info, too, although they are mostly intended for business folks:
1. Will Your Next Mistake Be Fatal? by Robert E. Mittelstaedt, Jr. for example - on page 160 - Insight #29 - Culture is powerful - what creates success may kill you. Think about this one seriously, for a long time! What you, or others, have gotten away with for a number of times can lead to complacency... and you becoming a statistic... that you couldn't tell anyone about ... from the grave. I recently attended a "celebration of life" for a friend that I suspect may have either lost his life due to his prior successes or rogue air.
2.Why We Make Mistakes by Joseph T. Hallinan

A thermal may not be your standard British thermal, but a confluence of several, competing mini-thermals. I have seen up to six, or more, dust devils converging to make a single thermal. However, in 40 years of flying, much in the very dynamic high western desert, I have never been upset in the manner you describe. This is not to say it can't happen, but I think the typical glider accident is much more mundane and the direct result of poor airmanship.

Tom

Le mardi 10 décembre 2019 07:31:14 UTC+1, 2G a écritÂ*:
On Monday, December 9, 2019 at 4:10:16 PM UTC-8, Bob T wrote:
On Saturday, December 7, 2019 at 3:09:19 AM UTC-7, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.

Regarding the rogue thermal comment... they can occur. I came VERY close to becoming a statistic a few years ago while thermalling about 1500 ft. agl and wrote a feature article for SOARING MAGAZINE dealing with it. Rather than stalling an inside wing in a thermal turn (as one would expect if you happened to fly too slowly), while thermalling at about 10-15 kts above stall speed my INSIDE (lower) wing suddenly was pushed up and over, resulting in a steep dive / spiral. Subsequent research showed that some thermals can have strong down cores inside of overall lift, and if a glider happened to hit the sheer boundary, with suddenly one wing in the up air and the other in the down air, your day could quickly end.

See https://www.danlj.org/~danlj/Soaring...b_Thompson.pdf

and Dr. Dan Johnson had a good one, too https://www.danlj.org/~danlj/Soaring...Jan-p12-15.pdf

There are 2 books I referred to in my classes that have some pretty good info, too, although they are mostly intended for business folks:
1. Will Your Next Mistake Be Fatal? by Robert E. Mittelstaedt, Jr. for example - on page 160 - Insight #29 - Culture is powerful - what creates success may kill you. Think about this one seriously, for a long time! What you, or others, have gotten away with for a number of times can lead to complacency... and you becoming a statistic... that you couldn't tell anyone about ... from the grave. I recently attended a "celebration of life" for a friend that I suspect may have either lost his life due to his prior successes or rogue air.
2.Why We Make Mistakes by Joseph T. Hallinan

A thermal may not be your standard British thermal, but a confluence of several, competing mini-thermals. I have seen up to six, or more, dust devils converging to make a single thermal. However, in 40 years of flying, much in the very dynamic high western desert, I have never been upset in the manner you describe. This is not to say it can't happen, but I think the typical glider accident is much more mundane and the direct result of poor airmanship.

Tom

In 39 years of flying, I have once been upset by a thermal (entering at a speed of 130 kph, 300 m over the rocks in the central Alps, 4 m/s climb after recovery).
A second time such an upset was caused by a rotor (vertical speeds varying between -12 m/s and +12 m/s, trying to work it at 150 kph), but it didn't really come as a surprise.

I have been literally thrown out of thermals and rolled partially inverted by rotor while flying a very light (1-26) ship multiple times in NV . As a previous poster said, not much of a surprise, i think the “death-by-unusual wx condition� scenario is somewhat overblown. If flying on an extremely gusty day or with rotor condx or in monster thermals, a guy needs to factor that into his margins. If he does’nt then he’s setting himself up for an “unexpected� issue where in reality, it should’nt be unexpected at all. As 2g says, its just another part of proper and proactive airmanship.

Tango Whisky wrote on 12/10/2019 6:03 AM:
Le mardi 10 décembre 2019 07:31:14 UTC+1, 2G a écrit :
A thermal may not be your standard British thermal, but a confluence of
several, competing mini-thermals. I have seen up to six, or more, dust devils
converging to make a single thermal. However, in 40 years of flying, much in
the very dynamic high western desert, I have never been upset in the manner
you describe. This is not to say it can't happen, but I think the typical
glider accident is much more mundane and the direct result of poor
airmanship.

Tom

In 39 years of flying, I have once been upset by a thermal (entering at a speed
of 130 kph, 300 m over the rocks in the central Alps, 4 m/s climb after
recovery). A second time such an upset was caused by a rotor (vertical speeds
varying between -12 m/s and +12 m/s, trying to work it at 150 kph), but it
didn't really come as a surprise.

In 45 years of flying, I've never been upset by a thermal. I attribute that to
lack of exposure, as I rarely thermal below 1000' over mountains and ridges, or
below ridge top. That's where the "rogue thermals" exist, and where you are so
close to the ground that even a very capable pilot may not recover in time.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

Here's an article written by JJ Sinclair about a mountain phenomenon that is not that unusual:

https://www.dg-flugzeugbau.de/en/lib...k-the-mountain

My father's name is at the top of the list.

Mike

I've been upset as described, but it was rotor, not a thermal.

There's no substitute for training...

On 12/9/2019 11:31 PM, 2G wrote:
On Monday, December 9, 2019 at 4:10:16 PM UTC-8, Bob T wrote:
On Saturday, December 7, 2019 at 3:09:19 AM UTC-7, krasw wrote:
Reading this forum, sounds like biggest safety risks in gliding a

- Any glider or radio that has had an AD in it's history
- Rogue thermals
- Mysterious medical symptoms that occur only when flying

Other that that, we are pretty safe.
Regarding the rogue thermal comment... they can occur. I came VERY close to becoming a statistic a few years ago while thermalling about 1500 ft. agl and wrote a feature article for SOARING MAGAZINE dealing with it. Rather than stalling an inside wing in a thermal turn (as one would expect if you happened to fly too slowly), while thermalling at about 10-15 kts above stall speed my INSIDE (lower) wing suddenly was pushed up and over, resulting in a steep dive / spiral. Subsequent research showed that some thermals can have strong down cores inside of overall lift, and if a glider happened to hit the sheer boundary, with suddenly one wing in the up air and the other in the down air, your day could quickly end.

See https://www.danlj.org/~danlj/Soaring...b_Thompson.pdf

and Dr. Dan Johnson had a good one, too https://www.danlj.org/~danlj/Soaring...Jan-p12-15.pdf

There are 2 books I referred to in my classes that have some pretty good info, too, although they are mostly intended for business folks:
1. Will Your Next Mistake Be Fatal? by Robert E. Mittelstaedt, Jr. for example - on page 160 - Insight #29 - Culture is powerful - what creates success may kill you. Think about this one seriously, for a long time! What you, or others, have gotten away with for a number of times can lead to complacency... and you becoming a statistic... that you couldn't tell anyone about ... from the grave. I recently attended a "celebration of life" for a friend that I suspect may have either lost his life due to his prior successes or rogue air.
2.Why We Make Mistakes by Joseph T. Hallinan
A thermal may not be your standard British thermal, but a confluence of several, competing mini-thermals. I have seen up to six, or more, dust devils converging to make a single thermal. However, in 40 years of flying, much in the very dynamic high western desert, I have never been upset in the manner you describe. This is not to say it can't happen, but I think the typical glider accident is much more mundane and the direct result of poor airmanship.

Tom

--
Dan, 5J