repair / build thread

[tom in tennessee]

just thought i would share photos and some of my repair / build techniques. maybe you can learn or teach me something since i have a list of things that need to be done. wish list => in no particular order. photos when i get to it. t3

1. repair of a foam core composite wing crunched from shipping
2. removable wing with 15 pin connector
3. fuse mold 101
4. making a ds sloper out of your beater sailplane

[relaxnfly]

Tom,
I'm interested! You're like a build/repair machine!....maybe  leaning a little more towards the repair. Pics please

Michael

[tom in tennessee]

show me what your working with. 
1. mds wing as shipped. wing= thinner than ds-19 airfoil, hiload 60, 6oz carbon/6oz glass

where to start. only concern for this is the delam in the back where there is no join between the skins. everything else if pretty straight forward to me...well i think.

sand the paint off. tried to skip a few steps and use a dlg technique of steaming the dink out. uh, this skin is way stiff, i did reduce the crease but did not take it out. then to add to my repair list i tried a redneck repair and use gorilla glue to puff up the dent. uh, still to stiff. now i have to clean the glue up poo. ive never liked gorilla glue.
so im going to try something else. because the crease is above the servo cutout, in my mind is the weakest area on the wing, it must be perfectly flat on top.

if you didnt know, steaming foam will take out wrinkles and restore the shape. using a soggy cloth and wifes iron as hot as it will go. steam away them dents. careful! if cloth quits steaming soak it again or you have a new problem. try on scrap first til you get the hang of it, (works on eps foams, not sure of depron or epp)

so next - im going to hog out the foam from under the crease. replace foam taken out with a shaped hardwood block. wood will lift the crease flat from under the skin (hopefully pictures will clear this up) fill it up with epoxy and microballoons. t3

[tom in tennessee]

so tonight im going to cut the block out.

and if all goes well i may start the glassing tomorrow depending on how well the block levels out the dent. im going to leave it in overnight and get pics in the morning. t3

[Blue Note]

using a soggy cloth and wifes iron as hot as it will go. steam away them dents. careful! if cloth quits steaming soak it again or you have a new problem.  t3

And if your wife finds out you know your way around an iron, you may have yet a bigger problem on your hands.

Good stuff , Tom.

BNC

[tom in tennessee]

moving along.

got the foam cleared out and a block cut. block fit and happy. concidered leaving block in but, since i want a tight bond between top and bottom ill just use it as a prop to hold up the dent while i epoxy some more glass on top. hopefully when i remove the block after epoxy cures fix will stay flat until i get some epoxy in the hole.

now figure a way to push up inside the servo hole while i lay up the glass. stack of quarters will work! nope, i looked everywhere and all i could come up with is a button battery and a dime. so i got something that i had laying around that fit, to the next step.

all i have on hand is 2oz glass so im using it and it has a good finish look. 3 layers 90deg, 45, and 90. bottom is a tad bit smaller than middle and top bigger. hope its strong enough.

i put epoxy on with my gloved finger. im sure everyone has their own way but this works for me. i can move epoxy around by tapping wet spots and moving it to where i want it, just helps me control how much i put on and not have to blot with a rag after.

glass on and looks flat. but i wont know till its cured. also keep the mixing cup just to see how hard the epoxy got, since i just compare drops of part a to b method. ive found that finishing resin seems to be more tolerant of unbalanced mixes. it always seems to cure hard. t3




 

[tom in tennessee]

thread is moving on.
ok glass is laid. cured and i even filled the void with my slurry mix.
project = easy
skill level = 1
tech. application = not so good. spent more time typing / trying to figure out the attachment prob. than it took for me to complete so far. t3

[tom in tennessee]

on hold. reason, going flying with mike and little buddys want to go outside. t3

[tom in tennessee]

glass on top is reasonable, i may skim it one more time with epoxy and 3/4 oz after all is done.
next step is to fill the front.
tools needed. epoxy, choppers, cup, toothpick, micro balloons, and carbon.
dont forget to mask the area off, and filler up.
i guess one step i forgot before i filled the back up is to wick some foam safe ca all around the edges to reconnect the delamed areas but i didnt have it at work so i just skipped that step (hope i dont regret that later)

[tom in tennessee]

epoxy mix in the cup. carbon trimmed to 1 mm or so, i want this to soak all the way down. in most cases i would leave it a little longer since epoxy has very little strength. 3000k carbon tow i think.
now i pull the block out and fill. let sit overnight, hope the heat generated from this one does not deform my foil.
large batches of epoxy especially fast cure get really hot. 45 may not get hot but may warm enough to loosen skins, lets hope not.

im sure there is a step that i could do to prevent this but im impatient and come to believe anything will fly, even a warped airfoil. t3

[tom in tennessee]

whew. just escaped a 250$ purchase on RCG's. watched RTS buy that 100" waco while i rode the fence. stay focused Tom....
 
where am i - since im making things for the faster, im going to epoxy all sides with about a 1/4" all around the servo cutout. make sense?
also - where ailerons were cut free there is no connection between the skins so i will add either a flat carbon 1/4" rod or tubular tow strands.
im leaning toward the tow but ill make a decision when i see the fit. t3

anyone got some quality 45min epoxy? almost out

[tom in tennessee]

ok, started out with... 8a
i got a new blade w/flaps wing from an RCGer for 100$ bucks. yes! cheaply because he tried to ship it and tips got crunched. easy fix. well, i open the package and.. guess what. dude still dont know how to pack a wing! arrgh! only one tip got more damage to it.
but, like i told the RCGer thats the price i have to pay to get a good deal here to TN. so here's some pics. no biggie but a little more extensive than it would have been.
then the story continues. at aprox. 9am
my wife says i need to pick her up. uh oh. and this is what i saw. nobody hurt but my wifes ride. doh! out of 4 vehicles someone has to run into the one thats not paid for

[tom in tennessee]

i try to forget. so i buy some stuff to keep on task.
15 pin d-sub connector for a wing harness.
my lucky day, they only had male ends. great :|
here is my set up with the connector. i think its pretty trick. 

and back to the wing.
i now scarfed out some more foam around the servo pocket so i can add epoxy and carbon chop all around. and also to the trailing edge.
i was thinking i would add somthing, usually there is a piece of balsa for a te joiner. but just to keep things simple im just going to add some more epoxy and chop. i do have some short pieces of carbon rod that may fit perfectly in the slot.
but we shall see, they are at work and im not. t3

[tom in tennessee]

i did find something that i was not a fan of.
testing the fix,
one tip on the ground and the other in hand and bend it in the middle. no foolin. its going to be right since im ds'ing this above my head over 150mph. i dont want a renegade fuse and a taco wing at that speed. 
i noticed that the non injured side had a serious dimple in it when i deflected at the root.
it turned out to be the servo pocket on the other side that let the skin dip. so i sanded the paint off and going to add 3 layers of 2oz to this side as well to stiffin the skin up to my liking. t3

[tom in tennessee]

ok wing is under way. now i need a fuse to put it on.
since this is a repair thread, ill repair a fuse since i have a head of steam going.
pic of wing that didnt make it. 2 major crash and in the trash. ds'ed to death.
fuse on the other hand, balance lead ejected like a bullet, fuse stuck in the ground about half way up the nosecone. after removing the earth this is what was left.
not to bad. just reshape nose and couple of layers on top of nosecone and done.
after a few drops of ca, its off to repairs.