If you want to find out if your glider is going to fold up in flight fire up
your Acrobat Reader and read the Preflight Procedure section of any Wills Wing
manual (RTFM) and actually follow the instructions (like nobody 'cept me and
Rob does) - whether or not you have a Wills Wing glider.
"While pushing up on the leading edge between the nose and the crossbar
junction, step on the bottom side wire with about 50 - topless / 75 - kingposted
lbs. of force. This is a rough field test of the structural security of the
side wire loop, the control bar, and the crossbar and may reveal a major
structural defect that could cause an in-flight failure in normal operation."
Upon breaking down Sunday evening it dawned on me that this is an even better
postflight procedure - gives you the next week to make the repair or buy a
new glider.
on-ground structural failure
Moderator: CHGPA BOD
-
Flying Lobster
- Posts: 1042
- Joined: Fri Feb 25, 2005 4:17 pm
Pre-flight
There's also the Ellis-Test.
*** No, not the one where you lend her your glider and if it comes back in one piece it's structurally sound :)***
She was once setting up her glider and one of the DTs broke free of the upper connection at the keel. One of the aluminum DT connecting plugs at the keel had fractured. There is no way to visually inspect this piece. And the stomp on the side wire check won't reveal any problems at the upper DTs. So Karen and I always do a gentle pull and hold and a quick tug on each downtube (yes, Brian, a gentle pull and a quick tug) while the glider is still upside down in the bag on the ground. Remember, pull UP on the downtube.
Matthew
*** No, not the one where you lend her your glider and if it comes back in one piece it's structurally sound :)***
She was once setting up her glider and one of the DTs broke free of the upper connection at the keel. One of the aluminum DT connecting plugs at the keel had fractured. There is no way to visually inspect this piece. And the stomp on the side wire check won't reveal any problems at the upper DTs. So Karen and I always do a gentle pull and hold and a quick tug on each downtube (yes, Brian, a gentle pull and a quick tug) while the glider is still upside down in the bag on the ground. Remember, pull UP on the downtube.
Matthew
on-ground structural failure
I regularly perform that test.
Brian Vant-Hull
301-646-1149
On Thu, 30 Jun 2005 TadErcksn@aol.com wrote:
>
> If you want to find out if your glider is going to fold up in flight fire up
> your Acrobat Reader and read the Preflight Procedure section of any Wills Wing
> manual (RTFM) and actually follow the instructions (like nobody 'cept me and
> Rob does) - whether or not you have a Wills Wing glider.
>
> "While pushing up on the leading edge between the nose and the crossbar
> junction, step on the bottom side wire with about 50 - topless / 75 - kingposted
> lbs. of force. This is a rough field test of the structural security of the
> side wire loop, the control bar, and the crossbar and may reveal a major
> structural defect that could cause an in-flight failure in normal operation."
>
> Upon breaking down Sunday evening it dawned on me that this is an even better
> postflight procedure - gives you the next week to make the repair or buy a
> new glider.
>
>
Brian Vant-Hull
301-646-1149
On Thu, 30 Jun 2005 TadErcksn@aol.com wrote:
>
> If you want to find out if your glider is going to fold up in flight fire up
> your Acrobat Reader and read the Preflight Procedure section of any Wills Wing
> manual (RTFM) and actually follow the instructions (like nobody 'cept me and
> Rob does) - whether or not you have a Wills Wing glider.
>
> "While pushing up on the leading edge between the nose and the crossbar
> junction, step on the bottom side wire with about 50 - topless / 75 - kingposted
> lbs. of force. This is a rough field test of the structural security of the
> side wire loop, the control bar, and the crossbar and may reveal a major
> structural defect that could cause an in-flight failure in normal operation."
>
> Upon breaking down Sunday evening it dawned on me that this is an even better
> postflight procedure - gives you the next week to make the repair or buy a
> new glider.
>
>
Re: Pre-flight
I always pull Down on the Up tube.
Matthew wrote:There's also the Ellis-Test.
Remember, pull UP on the downtube.
Matthew
-
Flying Lobster
- Posts: 1042
- Joined: Fri Feb 25, 2005 4:17 pm
I've read this in the manual too, and was wondering why nobody seemed to do it (stepping on the side wire). Some people say "It'll wear out your side wire," but isn't the point that the side wire---if in good condition---should be able to handle this test?
My question is, how do we know how much is 75lbs of "step force?"
Scott
My question is, how do we know how much is 75lbs of "step force?"
Scott
on-ground structural failure
I try to keep my weight at 150, and step on both side wires at the same
time. Each then gets 75lbs of force.
~Ralph
================================================================
from: Scott (07/01/2005 07:16)
================================================================
I've read this in the manual too, and was wondering why nobody seemed
to do it (stepping on the side wire). Some people say "It'll wear out
your side wire," but isn't the point that the side wire---if in good
condition---should be able to handle this test? My question is, how do
we know how much is 75lbs of "step force?" Scott
time. Each then gets 75lbs of force.
~Ralph
================================================================
from: Scott (07/01/2005 07:16)
================================================================
I've read this in the manual too, and was wondering why nobody seemed
to do it (stepping on the side wire). Some people say "It'll wear out
your side wire," but isn't the point that the side wire---if in good
condition---should be able to handle this test? My question is, how do
we know how much is 75lbs of "step force?" Scott
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
on-ground structural failure
Yeah, Scott - bullseye. It's all or nothing. If there's nothing wrong with
the wire it suffers no harm (including "wear"). If there is then you really,
really, really, REALLY, want to finish harming it before you're in a situation
in which it matters.
People don't do it because it seems counterintuitive. I confess that my
initial reaction was the same as everybody else's and it took more years than I
want to admit to before my brain finally kicked in and I said, "WADE-A-MINUTE!
Maybe the manufacturer folks really DO know what their talking about." and
decided to stop depriving myself of this really excellent safety check.
(Sometime ask me to show you the frazzled kingpost end of the top side wire I managed
to pop in the back yard a couple of winters ago.)
I discussed this issue with Rob at the competition last month and the
question you posed only went on my to do list after he was out of range. I don't
know what 75 pounds looks and feels like either and want us to watch each other
so's I can get it right. But I just push until I start getting scared. I'm
quite certain that things are under a lot more tension and compression than
anything they're gonna see in flight and nothing has been harmed by these tests.
the wire it suffers no harm (including "wear"). If there is then you really,
really, really, REALLY, want to finish harming it before you're in a situation
in which it matters.
People don't do it because it seems counterintuitive. I confess that my
initial reaction was the same as everybody else's and it took more years than I
want to admit to before my brain finally kicked in and I said, "WADE-A-MINUTE!
Maybe the manufacturer folks really DO know what their talking about." and
decided to stop depriving myself of this really excellent safety check.
(Sometime ask me to show you the frazzled kingpost end of the top side wire I managed
to pop in the back yard a couple of winters ago.)
I discussed this issue with Rob at the competition last month and the
question you posed only went on my to do list after he was out of range. I don't
know what 75 pounds looks and feels like either and want us to watch each other
so's I can get it right. But I just push until I start getting scared. I'm
quite certain that things are under a lot more tension and compression than
anything they're gonna see in flight and nothing has been harmed by these tests.
on-ground structural failure
I push until I feel the aluminum flexing.
How can it possibly seem counterintuitive?!
Brian Vant-Hull
301-646-1149
On Fri, 1 Jul 2005 TadErcksn@aol.com wrote:
>
> People don't do it because it seems counterintuitive. I confess that my
>
> I discussed this issue with Rob at the competition last month and the
> question you posed only went on my to do list after he was out of range. I don't
> know what 75 pounds looks and feels like either and want us to watch each other
> so's I can get it right. But I just push until I start getting scared. I'm
> quite certain that things are under a lot more tension and compression than
> anything they're gonna see in flight and nothing has been harmed by these tests.
>
>
How can it possibly seem counterintuitive?!
Brian Vant-Hull
301-646-1149
On Fri, 1 Jul 2005 TadErcksn@aol.com wrote:
>
> People don't do it because it seems counterintuitive. I confess that my
>
> I discussed this issue with Rob at the competition last month and the
> question you posed only went on my to do list after he was out of range. I don't
> know what 75 pounds looks and feels like either and want us to watch each other
> so's I can get it right. But I just push until I start getting scared. I'm
> quite certain that things are under a lot more tension and compression than
> anything they're gonna see in flight and nothing has been harmed by these tests.
>
>
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
on-ground structural failure
Seems counterintuitive 'cause you're trying to break your glider.
-
Flying Lobster
- Posts: 1042
- Joined: Fri Feb 25, 2005 4:17 pm
OK--so those of you that are part of the sidewire stepping club--I'd like to ask how often do you reach up inside your sail and check the safety ring and nut atop the crossbar/LE junction plate bolt? If you're not doing that as well, then I'd say the wire walking routine is pretty useless.
marc
marc
Great Googly-moo!
on-ground structural failure
Wouldn't stepping on the wire possibly test the integrity of the bolt and
nut?
Brian Vant-Hull
301-646-1149
On Thu, 7 Jul 2005, Flying Lobster wrote:
> OK--so those of you that are part of the sidewire stepping club--I'd like to ask how often do you reach up inside your sail and check the safety ring and nut atop the crossbar/LE junction plate bolt? If you're not doing that as well, then I'd say the wire walking routine is pretty useless.
>
> marcgot art?
> http://www.marcfink.com/
> wanna fly?
> http://www.downeastairsports.com/
nut?
Brian Vant-Hull
301-646-1149
On Thu, 7 Jul 2005, Flying Lobster wrote:
> OK--so those of you that are part of the sidewire stepping club--I'd like to ask how often do you reach up inside your sail and check the safety ring and nut atop the crossbar/LE junction plate bolt? If you're not doing that as well, then I'd say the wire walking routine is pretty useless.
>
> marcgot art?
> http://www.marcfink.com/
> wanna fly?
> http://www.downeastairsports.com/
I do that for every preflight!Flying Lobster wrote:OK--so those of you that are part of the sidewire stepping club--I'd like to ask how often do you reach up inside your sail and check the safety ring and nut atop the crossbar/LE junction plate bolt? If you're not doing that as well, then I'd say the wire walking routine is pretty useless.
marc
In fact, I check every frickin' nut, bolt, safety ring, cable, tang, nico, strap, etc. that I can possibly see. But your point is a good one!Scott
I once saw a drunken young person jump up and swing from the end of my friend's hang glider. The glider was strapped to his van and extended out a few feet. Evidently, it was an attractive nuisance ...
This prompted me to buy a PVC tube (in the days when I was living in a van) to store my glider.
So, does everybody carefully feel every square centimeter of their leading edges and keel to ensure that it hasn't been dented, bowed or bent? If you have carbon-fiber crossbars - are you absolutely certain that there hasn't been a mid-span impact that would cause an undetectable stress?
Of course you could do all of these things, and still be tumbled whilst flying carefully
This prompted me to buy a PVC tube (in the days when I was living in a van) to store my glider.
So, does everybody carefully feel every square centimeter of their leading edges and keel to ensure that it hasn't been dented, bowed or bent? If you have carbon-fiber crossbars - are you absolutely certain that there hasn't been a mid-span impact that would cause an undetectable stress?
Of course you could do all of these things, and still be tumbled whilst flying carefully
Scott wrote:I do that for every preflight!Flying Lobster wrote:OK--so those of you that are part of the sidewire stepping club--I'd like to ask how often do you reach up inside your sail and check the safety ring and nut atop the crossbar/LE junction plate bolt? If you're not doing that as well, then I'd say the wire walking routine is pretty useless.
marc
Scott
'Spark
on-ground structural failure
Doesn't it stretch the wires? - Hugh
On 7 Jul 2005, at 07:35, TadErcksn@aol.com wrote:
>
> Seems counterintuitive 'cause you're trying to break your glider.
>
>
On 7 Jul 2005, at 07:35, TadErcksn@aol.com wrote:
>
> Seems counterintuitive 'cause you're trying to break your glider.
>
>
on-ground structural failure
So let's admit that none of us feels every square centimeter of tubing
- we just sight along the tubes and look for visible defects and check
fasteners, etc. So are we being suicidal? Did Scott ever get an
answer to his question about frequency of in-flight structural failures
not associated with aerobatics? - Hugh
On 7 Jul 2005, at 20:05, Spark wrote:
> I once saw a drunken young person jump up and swing from the end of my
> friend's hang glider. The glider was strapped to his van and extended
> out a few feet. Evidently, it was an attractive nuisance ...
>
> This prompted me to buy a PVC tube (in the days when I was living in
> a van) to store my glider.
>
> So, does everybody carefully feel every square centimeter of their
> leading edges and keel to ensure that it hasn't been dented, bowed or
> bent? If you have carbon-fiber crossbars - are you absolutely certain
> that there hasn't been a mid-span impact that would cause an
> undetectable stress?
>
> Of course you could do all of these things, and still be tumbled
> whilst flying carefully <icon_lol.gif>
>
> Scott wrote:
> Flying Lobster wrote:
> OK--so those of you that are part of the sidewire stepping club--I'd
> like to ask how often do you reach up inside your sail and check the
> safety ring and nut atop the crossbar/LE junction plate bolt? If
> you're not doing that as well, then I'd say the wire walking routine
> is pretty useless.
>
> marc
>
>
> I do that for every preflight! <icon_smile.gif> In fact, I check
> every frickin' nut, bolt, safety ring, cable, tang, nico, strap, etc.
> that I can possibly see. But your point is a good one!
>
> Scott
>
>
>
>
> 'Spark
>
> http://community.webshots.com/user/sparkozoid
>
>
>
- we just sight along the tubes and look for visible defects and check
fasteners, etc. So are we being suicidal? Did Scott ever get an
answer to his question about frequency of in-flight structural failures
not associated with aerobatics? - Hugh
On 7 Jul 2005, at 20:05, Spark wrote:
> I once saw a drunken young person jump up and swing from the end of my
> friend's hang glider. The glider was strapped to his van and extended
> out a few feet. Evidently, it was an attractive nuisance ...
>
> This prompted me to buy a PVC tube (in the days when I was living in
> a van) to store my glider.
>
> So, does everybody carefully feel every square centimeter of their
> leading edges and keel to ensure that it hasn't been dented, bowed or
> bent? If you have carbon-fiber crossbars - are you absolutely certain
> that there hasn't been a mid-span impact that would cause an
> undetectable stress?
>
> Of course you could do all of these things, and still be tumbled
> whilst flying carefully <icon_lol.gif>
>
> Scott wrote:
> Flying Lobster wrote:
> OK--so those of you that are part of the sidewire stepping club--I'd
> like to ask how often do you reach up inside your sail and check the
> safety ring and nut atop the crossbar/LE junction plate bolt? If
> you're not doing that as well, then I'd say the wire walking routine
> is pretty useless.
>
> marc
>
>
> I do that for every preflight! <icon_smile.gif> In fact, I check
> every frickin' nut, bolt, safety ring, cable, tang, nico, strap, etc.
> that I can possibly see. But your point is a good one!
>
> Scott
>
>
>
>
> 'Spark
>
> http://community.webshots.com/user/sparkozoid
>
>
>
Re: on-ground structural failure
My point was ... even with all the aforementioned checks, you may have hidden damage that would indice a failure, or you may encounter air that will break your glider. i.e - there are no guarantees.
I know of a few in-flight structural failures not associated with aerobatics. I was in two of them. The most recent one I was aware of was Jeff Shapiro's tumble at King two weeks ago. I also have heard that two gliders have tumbled at Hyner - Danny, and Skip, wasn't it.
I know of a few in-flight structural failures not associated with aerobatics. I was in two of them. The most recent one I was aware of was Jeff Shapiro's tumble at King two weeks ago. I also have heard that two gliders have tumbled at Hyner - Danny, and Skip, wasn't it.
mcelrah wrote:So let's admit that none of us feels every square centimeter of tubing
- we just sight along the tubes and look for visible defects and check
fasteners, etc. So are we being suicidal? Did Scott ever get an
answer to his question about frequency of in-flight structural failures
not associated with aerobatics? - Hugh
'Spark
-
Tad Eareckson
- Posts: 304
- Joined: Wed Feb 09, 2005 8:50 am
on-ground structural failure
I'm gonna guess that a 3/32-7x19 side wire won't stretch - it'll break at 920
pounds (and is not limited by the nico). (That never seemed like a whole lot
to me but that's not what fails during aerobatics so I guess the
manufacturers understand the loading better than I do.)
A good crash can distort thimbles which would result in an insignificant
elongation of the cable assembly but the preflight testing doesn't seem to be
having any effect.
pounds (and is not limited by the nico). (That never seemed like a whole lot
to me but that's not what fails during aerobatics so I guess the
manufacturers understand the loading better than I do.)
A good crash can distort thimbles which would result in an insignificant
elongation of the cable assembly but the preflight testing doesn't seem to be
having any effect.