humpy
Member
Hi,
I have just finished reading the https://www.homebuiltairplanes.com/forums/composites/6953-wood-sheeting-glass.html thread, and am in much the same situation.. I have had previous experience in sometimes quiet extensive fiberglassing of boats on and off over the last 30 years, but in such cases.. weight was never a major issue ...
I am pondering replacing the wing skins on a poor dilapidated old winton ultralight I have acquired with fiberglass, My main reasons for wishing to go down that path rather than simply recover with fabric are to stiffen up and strengthen the wings, as in their current state they seem to be just a bit too easily deformed by any stress placed on them. The leading edge fiberglass sheet is VERY thin, and deforms with only a very light touch and is also starting to lift away from the spars.. The old girl is over 15 years old, and rather dated in construction design...
The wings are 4m long and .22 m at thickest, and 1.4m wide. ribs are spaced approx every 40 cm. each rib weighs approx .48kg.. ( i have a couple loose..)
total current wing weight in its current state is approx 23 kg each,,,,
The sensible option that was suggested to "toobuilder" was to simply start afresh with a full composite wing build to truly gain the benefit of light weight and strength... however, to go to those lengths whilst nice, would put this project way out of my budget and time resources and probably abilities as well... next one ill go nuts on...
this one im trying to do on a budget , whilst still making improvements ... ( all those layinng on the floor still cackling at the use of the word "budget " and "plane rebuild" in the same sentwnce can shush and get up now....)
I have worked out that if I went solid core foam, as was uggested in toobuilder thread, due to the size of my wings volumes at roughly 1.5m3 for both wings it would be way tooo heavy .... at close to 50 kg just in foam... with weight limits, I have approx 50ish kg all up to allocate to to the rebuild, ( thats leaving a bit of weight spare for other things..) ...
so I am leaning more towards simply adding some more foam ribs similar in "toobuilders" original wing he rebuilt, but have had a couple of ideas that may be clever or may be just totally nuts.. i wont be offended if anyone points out that any of these following ideas have major flaws.... I am self taught at fiberglassing, usually oveer engineer any boat project I have had a hand in, i like to err on the "safe side" of things... I so and have never had to 'glass with weight as a constraint in my thoughts before... So i was thinking with skill and budget constraints, to leave wing as is and make the fiberglass pretty much doing a job of "covering only", ala "super stong stits " covering... nothing officially to do with wing strength, but any added strength would be simply a bonus
Firstly, the easier? part of the wing repair...
regarding the current leading edge fiberglass sheet, as mentioned before I feel it is currently way too flimsy to be safe , possibly due to age? or original design? i am not up with whether time weakens fiberglass in such a way.....
I think it is polyester sheet, ... i was thinking of gently removing fully from wing, as it is already halfway there.!.. and then once again adding some foam ribs ala toobuilder's wing , or even go full solid core, as that would only add less than 10kg extra weight, which is not too bad.... and would make the lay-up a lot easier... and then simplu put on a couple of fresh 5oz epoxy layers.
whilst at this point.. what are people thoughts on say 2 x 5oz layers vs 1 x 7oz layer as seems to have been generally recommended as good from reading the forum??
or....another idea... temporarily bond down the current leading edge glass , so its back to normal, then apply mold release to it etc , and use it as a mold to lay up new stronger leading edge over the top, ala a weird take on the "one off method", then remove this fresh leading edge, remove old leading edge, and replace.... ?? that way it would avoid the solid core foam 10 kg added weight and the new glass leading edge should still be strong enough in its own right...?
OR......instead of removing old glass... rebonding back on to spars properly with epoxy,, then simply laying another layer of epoxy and cloth on top of it, to strengthen it to a good level... ( that method i feel seems to have possibly many flaws.. but does seem a nice easy "quick and dirty " method...
now the hard part... the rest of the wing!!
firstly .. the upper wing...
Instead of covering with ply and then a single layer of 7 oz cloth, like "toobuilder" had done in the past.., ( as he was also seeking lighter methods of doing the same process...) i was thinking of putting in possibly double the amount foam ribs in in each section, so that the actual gap between each ribs is less than 6 inches, and laying up with a couple of layers of say 5oz cloth and epoxy, instead of a single 7oz layer,
However, even with the extra ribs, i am sure sagging would still be a major issue, so I was thinking of layering up with the wing mounted in a position that holds it almost vertical rather than horizontal, and perhaps with a light tension evenly spread along the bottom edge of the cloth by an attached rod clipped to the whole edge of clothe and kept under light tension, that way it would keep the cloth tight as it dried, and as a result it should be have very few and only slightly saggy areas that would need filling...?
According to my calculations, that should enable me to cover each wing in glass for less than 20kg weight gain...
The other thought I had would to be to use possibly use say 2 inch urethane foam sheeting bonded between each spar on top of the wing to bridge each gap, and then gently sanded down ( or hotwired if styro used ) to match wing curve, then lay up the 2 upper layers gently on top, then flip wing and do similar for the bottom, ?
note ....the bottom of the wing is totally flat, so if that simplifies the concept please speak up I have vague visions of obtaining suitable prefabbed flat fiberglass sheeting and simply bonding into place for a quick and easy result???
have attached some pics of the poor old girl on the day we picked her up to give an idea of what i am battling with...
I (claim to) have a thick skin, and am seeking enlightenment so please speak freely if i am sounding insane ..
cheers
will
I have just finished reading the https://www.homebuiltairplanes.com/forums/composites/6953-wood-sheeting-glass.html thread, and am in much the same situation.. I have had previous experience in sometimes quiet extensive fiberglassing of boats on and off over the last 30 years, but in such cases.. weight was never a major issue ...
I am pondering replacing the wing skins on a poor dilapidated old winton ultralight I have acquired with fiberglass, My main reasons for wishing to go down that path rather than simply recover with fabric are to stiffen up and strengthen the wings, as in their current state they seem to be just a bit too easily deformed by any stress placed on them. The leading edge fiberglass sheet is VERY thin, and deforms with only a very light touch and is also starting to lift away from the spars.. The old girl is over 15 years old, and rather dated in construction design...
The wings are 4m long and .22 m at thickest, and 1.4m wide. ribs are spaced approx every 40 cm. each rib weighs approx .48kg.. ( i have a couple loose..)
total current wing weight in its current state is approx 23 kg each,,,,
The sensible option that was suggested to "toobuilder" was to simply start afresh with a full composite wing build to truly gain the benefit of light weight and strength... however, to go to those lengths whilst nice, would put this project way out of my budget and time resources and probably abilities as well... next one ill go nuts on...
this one im trying to do on a budget , whilst still making improvements ... ( all those layinng on the floor still cackling at the use of the word "budget " and "plane rebuild" in the same sentwnce can shush and get up now....)
I have worked out that if I went solid core foam, as was uggested in toobuilder thread, due to the size of my wings volumes at roughly 1.5m3 for both wings it would be way tooo heavy .... at close to 50 kg just in foam... with weight limits, I have approx 50ish kg all up to allocate to to the rebuild, ( thats leaving a bit of weight spare for other things..) ...
so I am leaning more towards simply adding some more foam ribs similar in "toobuilders" original wing he rebuilt, but have had a couple of ideas that may be clever or may be just totally nuts.. i wont be offended if anyone points out that any of these following ideas have major flaws.... I am self taught at fiberglassing, usually oveer engineer any boat project I have had a hand in, i like to err on the "safe side" of things... I so and have never had to 'glass with weight as a constraint in my thoughts before... So i was thinking with skill and budget constraints, to leave wing as is and make the fiberglass pretty much doing a job of "covering only", ala "super stong stits " covering... nothing officially to do with wing strength, but any added strength would be simply a bonus
Firstly, the easier? part of the wing repair...
regarding the current leading edge fiberglass sheet, as mentioned before I feel it is currently way too flimsy to be safe , possibly due to age? or original design? i am not up with whether time weakens fiberglass in such a way.....
I think it is polyester sheet, ... i was thinking of gently removing fully from wing, as it is already halfway there.!.. and then once again adding some foam ribs ala toobuilder's wing , or even go full solid core, as that would only add less than 10kg extra weight, which is not too bad.... and would make the lay-up a lot easier... and then simplu put on a couple of fresh 5oz epoxy layers.
whilst at this point.. what are people thoughts on say 2 x 5oz layers vs 1 x 7oz layer as seems to have been generally recommended as good from reading the forum??
or....another idea... temporarily bond down the current leading edge glass , so its back to normal, then apply mold release to it etc , and use it as a mold to lay up new stronger leading edge over the top, ala a weird take on the "one off method", then remove this fresh leading edge, remove old leading edge, and replace.... ?? that way it would avoid the solid core foam 10 kg added weight and the new glass leading edge should still be strong enough in its own right...?
OR......instead of removing old glass... rebonding back on to spars properly with epoxy,, then simply laying another layer of epoxy and cloth on top of it, to strengthen it to a good level... ( that method i feel seems to have possibly many flaws.. but does seem a nice easy "quick and dirty " method...
now the hard part... the rest of the wing!!
firstly .. the upper wing...
Instead of covering with ply and then a single layer of 7 oz cloth, like "toobuilder" had done in the past.., ( as he was also seeking lighter methods of doing the same process...) i was thinking of putting in possibly double the amount foam ribs in in each section, so that the actual gap between each ribs is less than 6 inches, and laying up with a couple of layers of say 5oz cloth and epoxy, instead of a single 7oz layer,
However, even with the extra ribs, i am sure sagging would still be a major issue, so I was thinking of layering up with the wing mounted in a position that holds it almost vertical rather than horizontal, and perhaps with a light tension evenly spread along the bottom edge of the cloth by an attached rod clipped to the whole edge of clothe and kept under light tension, that way it would keep the cloth tight as it dried, and as a result it should be have very few and only slightly saggy areas that would need filling...?
According to my calculations, that should enable me to cover each wing in glass for less than 20kg weight gain...
The other thought I had would to be to use possibly use say 2 inch urethane foam sheeting bonded between each spar on top of the wing to bridge each gap, and then gently sanded down ( or hotwired if styro used ) to match wing curve, then lay up the 2 upper layers gently on top, then flip wing and do similar for the bottom, ?
note ....the bottom of the wing is totally flat, so if that simplifies the concept please speak up
I have vague visions of obtaining suitable prefabbed flat fiberglass sheeting and simply bonding into place for a quick and easy result???have attached some pics of the poor old girl on the day we picked her up to give an idea of what i am battling with...
I (claim to) have a thick skin, and am seeking enlightenment so please speak freely if i am sounding insane ..
cheers
will
