cracks around wing seat on mouldie, best way to fix? - RC Groups
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Aug 11, 2008, 05:37 AM
AKA Cactus
Phillybaby's Avatar
Discussion

cracks around wing seat on mouldie, best way to fix?


yes, i know, holes are a little too square, and it doesn't help i made the larger hole for the wing plug, then realised it's in the way of the push rod and had to move it.
this is the result of flying with an extra 16oz of weight yesterday and a slightly rough landing in the turbulence, flew it after with no trouble and only saw it as i packed away.

there are carbon tows between the front and rear bolt holes but nothing around the edges.
figured i'd give the cracks some pink cyno, then epoxy some carbon tows down in the corners of the wing seat, maybe even patch up and fill the hole with more tows

getting in there will be fun now with the ballast tube in place.
be nice if the nose cone was removable.
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Aug 11, 2008, 05:58 AM
Taranis Tyro...
MattyB's Avatar
Those holes are so big (relative to fuse size) and the corners so square, reinforcing them with tows might not be enough in the long run. I'd be inclined to join them up and take out enough material around them so that you've got good access to the underside of the wingseat (for preparation) and a nice clean, rounded edge. Then work out where you need the actual holes, and a make some ply or epoxyboard pieces to rebrace and strengthen the structure, securing them with tows and epoxy as required. Another layer of glass over the whole wingseat might help too after you've done this (no need for a concourse finish, just sand back the gelcoat plenty to get a good key then wet out with epoxy or thin cyano).

Matt
who thinks cracking of the wingseat should be named "Banana-itis"...
Last edited by MattyB; Aug 11, 2008 at 10:41 AM.
Aug 11, 2008, 06:02 AM
AKA Cactus
Phillybaby's Avatar
well the lower hole was a total muff up, it's where i first had my servo connector, but then found it was too far forwards so had to move the hole back, THEN worked out it fouled the pushrod ( DOH!!! )
the new hole is just about right to get the multiplex connector through if i want to remove the wiring loom.

plan was fill the larger hole in, then make the smaller one an oval
Aug 11, 2008, 06:38 AM
You must die! I alone am best.
slopetrashuk's Avatar
That is a messy build.
Aug 11, 2008, 06:44 AM
AKA Cactus
Phillybaby's Avatar
yep, started off with good intentions, then by the time i got here and things wern't lining up i kinda just thought sod it, the wing will stop any flexing.

the radio bay's much better
Aug 11, 2008, 06:48 AM
Biting ankles since '53
I did the same to the wing saddle on my Bird so I sanded it back cyano'd the cracks, added some carbon in side and then stuck two layers of carbon twill on the saddle, added a release layer of Profilm backing sheet. Then I covered the saddle area of the wing with covering tape (as a second release film) and bolted the wing in place until the resin went green.
Here's how it looked before the repair and before cleaning up and painting.


Aug 11, 2008, 07:01 AM
AKA Cactus
Phillybaby's Avatar
carbon cloth is the one thing i don't have, got some glass ( only thin stuff ) chopped mat, or carbon tows.
i do have scraps of carbon plates
Aug 11, 2008, 07:36 AM
Registered User
miniphase's Avatar
drill a small hole at the end of each crack to stop them spreading further before any additional beefing up
Aug 11, 2008, 09:05 AM
Taranis Tyro...
MattyB's Avatar
Quote:
Originally Posted by slopetrashuk
That is a messy build.
Isn't it great when one of our leading aeromodelling lights offers such outstanding help and guidance...
Aug 11, 2008, 09:08 AM
Born Again Idiot
MooSey-UK's Avatar
If it was done properly in the first place............................
Measure twice, cut once etc etc

Only pulling ya string Phil
You can get carbon twill cloth off of the bay for a tenner.
Aug 11, 2008, 10:25 AM
AKA Cactus
Phillybaby's Avatar
don't worry matt, i'm used to it

just been out to cfs and got me a meter of 50 and 100mm wide carbon tape
together with the tows this should see a good fix

only issue now, is how the hell to get in there
Aug 11, 2008, 10:50 AM
isoaritfirst
isoaritfirst's Avatar
Quote:
Originally Posted by Phillybaby
don't worry matt, i'm used to it

just been out to cfs and got me a meter of 50 and 100mm wide carbon tape
together with the tows this should see a good fix

only issue now, is how the hell to get in there

you could always cut another hole
Aug 11, 2008, 10:58 AM
AKA Cactus
Phillybaby's Avatar
what would be nice is the big hole you get before the nose gets glued on.

i'll have to see what tows are already in there, then cut more away, fix the edges, then put in a fixing plate
Aug 11, 2008, 11:02 AM
Stay in it!!!!
I would use thin CA to fix the crack that actuallu goes over the edge of the saddle. Use a clamp to get it back in place before it cures or before kicking it. Then make those two square holes into one big oval hole. The take about 100K of carbon tow and run it down the inside top corner of the saddle. Then take the same amount of tow and bridge the two sides going around the front and rear edge of the new hole. Dont forget to remove your wires first.
Aug 11, 2008, 11:05 AM
You must die! I alone am best.
slopetrashuk's Avatar
Quote:
Originally Posted by MattyB
Isn't it great when one of our leading aeromodelling lights offers such outstanding help and guidance...
He knows better. Imagine trying to get that past a showline scrutineer Phil....


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