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Worried about a leading edge crack in the fiberglass wing laminate ofmy PW-5



 
 
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  #1  
Old February 11th 18, 06:20 PM posted to rec.aviation.soaring
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Default Worried about a leading edge crack in the fiberglass wing laminate ofmy PW-5

Hi all.

I own a PW-5. I have a MM Fabrication Wing Rigger I use when put the glider together and take it apart.

Yesterday, a gust of wind caught the wing when it was vertical on the wing rigger, and even though I was holding the wing steady near the spar, the wind force was strong enough to topple the wing rigger and slam the leading edge on the ground (grass). Personally I think these wing riggers need longer wheel bases to provide more moment against moderately strong wind, but that is another story.

An initial inspection for damage showed a 3 inch crack in the fiberglass in the leading edge where it struck the ground. The crack is deep enough to show the square pattern of the underlying fiberglass cloth layer, so it's not just a surface crack. (A PW-5 doesn't have a gel coat anyway. It has a coat of paint over the fiberglass laminate.)

I'm now worried about structural integrity of the wing, of course. Should I be? What should be your next steps? or what would you do next if you were I?

Respectfully,
Charles "Ben" Ethridge
  #2  
Old February 11th 18, 07:12 PM posted to rec.aviation.soaring
chuck[_3_]
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Default Worried about a leading edge crack in the fiberglass wing laminate ofmy PW-5

The crack is deep enough to show the square pattern of the underlying fiberglass cloth layer

If you’re just seeing the outer layer of glass, that by itself might not be a structural issue.
Having said that, if you have a crack significant enough to see the glass underneath I think I’d get a knowledgeable person to inspect it. They might want to remove paint for a better look at the local area. What part of the country are you located?
  #3  
Old February 11th 18, 07:46 PM posted to rec.aviation.soaring
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Default Worried about a leading edge crack in the fiberglass wing laminate ofmy PW-5

Been there, done that..........First off, it's important to place the trailer into the wind and then don't rotate the wing to the vertical position until your lined up into the wind (behind the trailer). If your wing-rigger has lateral adjustment, recommend you restrict the movement by placing a piece of plastic pipe (split on one side) onto both sides of the axle. As for the damage, send me close up pictures of the damage and I'll try and advise..
JJ
  #4  
Old February 12th 18, 04:50 AM posted to rec.aviation.soaring
Steve Koerner
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Default Worried about a leading edge crack in the fiberglass winglaminate of my PW-5

I'm sorry to hear of such a mishap.

As JJ says there is never a need to expose your wing to the wind in a vertical position. You are vertical only when you are lined up with the trailer which is lined up with the wind. All maneuvering is always done with the wing flat. I've disassembled in windy conditions many times -- once in the middle of the night alone with a strong thunderstorm blowing in. If the wind is blowing you have to think it through.

JJ's comment about adding split plastic pipe might apply to an earliest version of sliding axle Wing Rigger before the development of the split cylinder locking clamp. The vast majority of sliding axle Wing Riggers were made (and still are made) with this amazingly effective clamp mechanism which asuredly does not need a plastic pipe helper.

Mark Mocho at MM Fabrication is on top of all this and his build quality is superb.
  #5  
Old February 12th 18, 12:02 PM posted to rec.aviation.soaring
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Default Worried about a leading edge crack in the fiberglass winglaminate of my PW-5

I see your point about lining up with the wind, but our trailers are all relatively permanently mounted blocked and chocked in one area and I would have to rent or borrow a tow vehicle each time, so putting the trailer into the wind is not a no-brainer at this particular field. I will make this suggestion to the field owner though, since others use a Wing Rigger and could suffer the same fate.

I have the later version of the Wing Rigger and I'm not questioning the quality. I'm pretty happy with it overall. I'm just questioning one aspect of the design. What would be wrong with, say, doubling the wheel base length? Wouldn't that at least mitigate the risk of a spill in situations where one can't turn the trailer into the wind?

The only downsides I can think of are that (1) it would add a bit to the construction cost a bit and (2) it would be a bit harder to pack in a trailer with a narrow front door.

  #6  
Old February 12th 18, 12:36 PM posted to rec.aviation.soaring
Justin Couch
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Default Worried about a leading edge crack in the fiberglass winglaminate of my PW-5

On Monday, 12 February 2018 04:20:59 UTC+11, wrote:
Hi all.

I own a PW-5. I have a MM Fabrication Wing Rigger I use when put the glider together and take it apart.

Yesterday, a gust of wind caught the wing when it was vertical on the wing rigger, and even though I was holding the wing steady near the spar, the wind force was strong enough to topple the wing rigger and slam the leading edge on the ground (grass). Personally I think these wing riggers need longer wheel bases to provide more moment against moderately strong wind, but that is another story.

An initial inspection for damage showed a 3 inch crack in the fiberglass in the leading edge where it struck the ground. The crack is deep enough to show the square pattern of the underlying fiberglass cloth layer, so it's not just a surface crack. (A PW-5 doesn't have a gel coat anyway. It has a coat of paint over the fiberglass laminate.)

I'm now worried about structural integrity of the wing, of course. Should I be? What should be your next steps? or what would you do next if you were I?

Respectfully,
Charles "Ben" Ethridge


PW-5s are so lightly built that the crack is probably much larger than that under the bond. Get someone to check it out properly if it's anywhere inboard of the airbrakes.
  #7  
Old February 12th 18, 02:51 PM posted to rec.aviation.soaring
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Default Worried about a leading edge crack in the fiberglass winglaminate of my PW-5

Â*"What would be wrong with, say, doubling the wheel base length?"

if you visit the MM Fabrication website and find the page with WingRigger options, you will see that it IS offered with a wide-track chassis. The bottom tube that holds the hardened chrome axle is seven inches longer and incorporates three linear bearings instead of the two in the standard chassis. The axle is also correspondingly longer. Stability is improved, although few customers opt for this choice. The wide-track is standard on WingRiggers sold for large gliders, but is available for an additional $75.
  #8  
Old February 12th 18, 03:07 PM posted to rec.aviation.soaring
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Default Worried about a leading edge crack in the fiberglass winglaminate of my PW-5


What would be wrong with, say, doubling the wheel base length? Wouldn't that at least mitigate the risk of a spill in situations where one can't turn the trailer into the wind?


Sorry to hear the story. Sounds like a knowledgeable person needs to check the structure.

A bigger rigger wheel base might get in the way when you try to get the wing near the glider to slide it into the trailer and remember, you are trying to keep something that likes to fly from flying in a gust. My guess is there is no practical way to make it big enough to fix the problem.

If the wind conditions are sporty, the tricks I've used are some combination of keeping the wind horizontal as long as possible, turning the trailer into the wind, finding a sheltered location, making a sheltered location with a big vehicle, getting some friends to help, and waiting for a lull in the wind.

I guess this is a part of gliding. To expect one person with any normal rigger to always work without precautions is optimistic. Just like in sailing, the wind is going to get respect one way or the other.

Good luck on the repair.

  #9  
Old February 12th 18, 04:43 PM posted to rec.aviation.soaring
JS[_5_]
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Default Worried about a leading edge crack in the fiberglass winglaminate of my PW-5

On Monday, February 12, 2018 at 6:07:50 AM UTC-8, wrote:
What would be wrong with, say, doubling the wheel base length? Wouldn't that at least mitigate the risk of a spill in situations where one can't turn the trailer into the wind?


Sorry to hear the story. Sounds like a knowledgeable person needs to check the structure.

A bigger rigger wheel base might get in the way when you try to get the wing near the glider to slide it into the trailer and remember, you are trying to keep something that likes to fly from flying in a gust. My guess is there is no practical way to make it big enough to fix the problem.

If the wind conditions are sporty, the tricks I've used are some combination of keeping the wind horizontal as long as possible, turning the trailer into the wind, finding a sheltered location, making a sheltered location with a big vehicle, getting some friends to help, and waiting for a lull in the wind.

I guess this is a part of gliding. To expect one person with any normal rigger to always work without precautions is optimistic. Just like in sailing, the wind is going to get respect one way or the other.

Good luck on the repair.


As others have suggested to the OP: Get the damage assessed by someone experienced in maintaining composite aircraft.

Not necessarily a factor here, but something noticed while riggers are used.. Some pilots like to have very little weight at the spar, so they aren't lifting much. This would be very easy to do with a wing as light as the PW5.
Having little weight in your hands can allow a casual grip on the spar. If there is a bump or a wind gust, this could lead to loss of control.
I'd suggest having sufficient weight at the spar to make you hold on.

I've only rigged a PeeWee the old fashioned way, but perhaps will get a chance to rig one in the next couple of weeks using the rigger kindly donated by Wolf-Dietrich Weber.
Jim
  #10  
Old February 12th 18, 04:47 PM posted to rec.aviation.soaring
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Default Worried about a leading edge crack in the fiberglass winglaminate of my PW-5

I've been solo rigging since 1982 almost every time I fly (originally my LS-3 but for the last 26 years, my ASW 24). I haven't built any WingMates in a while (maybe in the future) but one of the selling points was the ability to use it on any terrain, including plowed fields. It's actually more stable, easier on my body, and doesn't take much, if any, more time than if I'm using a crew.

But...I'm VERY careful in the wind. I use some of the same tricks mentioned plus one or two that are specific to my design (e.g., lowering the wing as far as possible until it's horizontal). But basically if the wind gets too strong and/or gusty, I ask someone to help. They don't have to lift anything! Big point. All they have to do is stand by the wingtip in case the wind tries to blow it over when the wing goes vertical. I've never damaged it in wind but I've had a couple of close calls.

If you have doubts about how much wind is too much, get someone to help. After 35 years of solo rigging, I'm actually more inclined to ask for that quick assist to "just stand there and push back on the wingtip if it starts to topple over" than I used to be.

Chip Bearden
 




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