Hagamos un F3B -going stronger than ever -

[chetosmachine]

Hola,
i have some free time and the molds ready, so i'll make a plane and show how i do it. I have some skills, but i'm not a pro yet :o

This is not the first f3b i make, but it will be the first i do this way. The wings will not have the traditional glass-herex-glass skins, but they will have glass-UD carbon-glass sandwich. I hate preparing the herex, (i don't think balsa could work for me as i am allergic to balsa dust!), so if this wing shows to be good, i'll skip some hours of a work that i totally dislike.

Day1.
Wipe the dust off the molds with compressed air.
I have had some demolding failures on the past, so this time i'll go on the safe, and 6 layers of demolding agent are applied (just like new molds). I use Frekote 770 NC, which gives plenty of shine :D

·Time spent: 3 hours.


Chets

[ShredAir]

Great Chets. Please continue keeping track of time spent building this model.

Dieter Mahlein, ShredAir

[chetosmachine]

Day 2= painting

I use 2K car paint. I believe there are some laws changes that will make this paint unavailable next year, so on the future, i don't know which paint i'll use, because new paints will be water based and the Frekote hates water :mad:

Some masking tape (not the 'paper tape', but clear packing tape), and ready for it. The weather is hot and sunny, so i paint outside and use the sun as a heater. This way i can go faster :cool:
The Frekote needs a special painting technique. If you try to spray much paint at first, ther will be "fish eyes" everywhere. You need to make a first very thin layer, then another, and when the surface is almost covered (the mold does not shine anymore), then you can go with heavier layers.
And the masking tape need to be removed as soon as you finish to paint, or the edges will get awful. I made a mistake, and let the paint dry too much before i removed the mask of the model's name, and got rewarded with a far from perfect work :(

·Time spent: 4 hours
·Total time spent: 7 h.

Chets

[chetosmachine]

Day 3: Preparing fabrics and 1st laminate.

The lay up i'll use is simple:
80g glass
80g UD carbon
80g glass
a patch of carbon at the root and a patch of kevlar where the wing joiner is.

For cutting the fabrics, i use a heavy,soft, rubber matt as base and a fiskar rolling cutter. It cuts almost everything (kevlar excluded) like butter :D
I've cut the fabrics for both wing extremes, not for the center panel yet.

·Time spent: 1h
·Total time: 8h


Then tonight instead of watching TV, i thought i could make the first laminate....
I worked both molds on parallel. First, some resin + microballons on the LE. Then i add some 3mm fiberglass to the mix for the wing root edges.
I put the first layer of glass, put some resin on it with a brush then work the fabric with a plastic squeegee. Uhmmm, do you know guys why molded wings have the fabrics at 45º? Engeeners may want to argue and convince you tha't because the wing works in torsion and is better to have the fabrics this way. That's true, but the true thing is that it is 10 times easier to put a fabric at 45º and work any wrinkle out of the laminate :cool: and you can adjust the fabric width much better!
So i put the first layer of glass, then work on the carbon.
UD carbon(at least, this kind of UD) has a plastic foil on 1 side. It is very user friendly... until you have to cut. When the fabric does not have the original width, it's a bit of a nightmare as the carbon tows start to spread on the edge :o
Fortunately, a bit of resin keeps it in order and there's not much to say. I use a brush to impregnate this fabric, then put it on the mold, peel the plastic and push a bit with the brush, so it is well impregnated. I put the carbon patch, and the kevlar, then finish with the inner glass layer.

I put a plastic foil with plenty of little holes, then 3 layers of kitchen paper, some masking tape so it does not move when vacuum is made.

My vacuum bag is simple plastic pipe, sealed at both ends and with an entry hole for the mold. I seal it with packing tape. It works great!

·Time spent: 2h
·Total time: 10h

This post shows the work i made the last 3 days, so until i do some more work.... no more photos ;)

Chets

[gingin]

very cool - where do i get some molds with my favorite wing section.

[samotage]

Great stuff Chets!

I like the silicone plug, that stuff is great for getting things to go in tight places. I have a silicone squish for my servo cover mold :D

I will be interested to hear how the wing comes out, as you said in my thread that the layup of the 80gsm with the carbon in between 80 gsm glass turns out stiffer (and cheaper) than 200gsm!

Also, it seems your UD carbon comes off the roll much nicer than mine...

Sam,
who has subscribed.

[OVSS Boss]

Thanks for showing us your efforts, look forward to more posts.

Marc

[markStockton]

Very nice thread. I'm going to watch this one carefully. I'm very interested to see how torsionally stiff the wing's come out with this lay-up.

Keep up the good work.

[infopimp]

Subscribed. Great thread!

[jofo1]

subscribed...

[Dbox]

This thread is very CONTAGIOUS ,my hands starting to eatch. :D
Yuri.

[caligulin]

GOOD JOB!!

Excelente Chetos, "ere un artista picha!"

[oteinRc]

Congratulations Chets.

You are doing a GREAT job. These lay up can be the best.

I see you in the workshop... :D :rolleyes: :rolleyes:

[Alvaro Silgado]

Moooola! Good work!


Al.

[Daryl Perkins]

What a great thread! Nice job

dp

[chetosmachine]

Thank you guys!
I rekon this will be longer then estimated, because the hot weather we are having makes the swimming pool sooo tempting :D
Soon, another post with more picts, i promise!
Chets

[chetosmachine]

Day 4: Painting stabs and fuse

But first i opened the vacuum bag just to see the wing skins. Everything looks OK :)

So here i am again with the masking tape on one hand, and the scissors on the other. Very easy to do, but time consuming :o
These stabs won't be used on the new plane, but on the one i'm flying now, whose stabs have seen some abuse(mainly from getting the plane on the car).

The fuse mold gave me some headache, i oversprayed so i had to wait for the excess paint to dry before i could spray a new coat. With Frekote, there's a simple rule: much paint= muy malo!

·Time spent for this task:3h
·Total time:13h

[merengue]

Olà from Italy!
Very interesting thread -- just subscribed!! :p

[chetosmachine]

Day 5: Making the stabs

The Vector has a 2 piece V-tail, so to make the stabs is the easiest task of the plane. It is also one of the fastest tasks.

Firts, i cut the 25g glass, and 4 pieces of 1'2mm, 75kg/m3 herex. I use a paper template and the roller to cut everything. The glass is cut a it "wide", while the herex is cut very tight. You need the herex to be a bit smaller, or the TE will be too fat.
I also shape the contour of the herex, so there's a nice transition and not a step.

First i put epoxy+microballons on LE, put the first glass layer, a patch of glass and the peel ply that will act as hinge, add the herex and glue it with a bit of 5min epoxy so it does not move anymore, add the last layer of glass, plastic foil, paper, vacuum bag and tomorrow i will know if everuthing went well ;)

·Time spent: 2h
·Total time: 15h

[loki]

Good job chetos.

I'm very interested in your layup results.

Saludos
Fernando

[chetosmachine]

Day six: Closing 1 stab

I could have closed both stab molds if i had enough clamping devices, but since my father is using most of them, i only had 5 so only 1 mold was closed.
But i let prepared everything so the other one will be fast to finish.

I marked the hinge, cut out the herex at the hinge line (4mm gap), then made the spars. Rear to front: balsa, foam + carbon-kevlar braid, foam + carbon-kevlar braid.
Carbon-kevlar braid is a 'rare' item. I chosed it because it's light, and stiff enough for the stabs. It also provides such a cool look :cool:
Then mix some epoxy, soak the braids, glue the spars with 5 minute epoxy (not the balsa, it was glued before with ciano, add microballons and close. No big deal here, as i said, the stabs are the easiest part of the plane.

·Time spent: 2h
·Total time: 17h

[target]

Great stuff Chets!

I like the silicone plug, that stuff is great for getting things to go in tight places. I have a silicone squish for my servo cover mold :D




Can you guys elaborate on the silicone plug? What particular silicone is used? Is the plug good for multiple uses, or does it get replaced every time?

I have some servo cover molds that I would like to make also.

NICE THREAD, CHETS! :)

Target

[chetosmachine]

I use silicone for molds. 2 components, well in fact 3 because i used a thickening agent. I mixed it, poured on the mold then waited. I had to cover the mold with packing tape, because i don't know how silicone and frekote interact and didn't want to ruin the molds (nor the plug).
I used silicone because i have it at hand; i could have used epoxy+microballons as well, but i guess the elastic characteristic of the silicone is a plus.
Today i opened the mold of the stab just before going to the slope (damn! 80 minutes of unstoped f3f training :D :D :D ), it released sooo easy :-)
It looks good, feels good and the weight is ok: 40g.

Chets

[target]

I see.
So then you used a product for making silicone molds, used packing tape in the wing mold to insure a release.
The mold that I'd like to use this on is too detailed to use the packing tape on/in...
I'm sure that there is something that can be used to skip the tape, maybe PVA?

Thanks Chets,

Target

[miguelonete]

reallly good job, but...

¿que co#ones haces poniendolo aqui antes que en miliamperios??????????

anda que.... muy buen curro si señor!!

[chetosmachine]

Target,
i used the packing tape to protect the frekote.
On other molds, where i use wax, i also made silicone plugs and had 0 problems. The silicone does not adhere to anything, nor does anything adhere to silicone!
I'm sure you could even skip the pva to make the plugs, but do a test on a small piece before just in case ;)
Chets

[target]

Thanks, Chets.
Stabs look nice.

T

[samotage]

Hey T, What Chets said mate. Silicone will release beautifully from your mold, and epoxy used later in contact with the silicone won't stick to the silicone either.

Hey Chets,

When you put the stabs under the bag for the first cure, you used perforated plastic sheet. I assume this is for debulking under vac to remove excess resin? I am wondering why you would not use peel ply instead? Is this because removal of the peel ply could pull the skin from the mold?

Sam.

[chetosmachine]

Yes Sam,
peel ply gets really bonded to the laminate. I had to pull much less then you can think to release the stab from the mold and i'm sure if peel ply would have been used, it would have released.
On the other hand, i ran out of peel ply and only have a bit that i use to make the hinges.
I like it, and when used, i could remove more excess resin than with the plastic foil i use now, but the plastic is cheap, reusable and reliable so i'll keep using it.
Chets

[chetosmachine]

Day seven: busy!
Before lunch, i closed the second stab mold.
Also, i cleaned the LE of the wing. I should have had a bit more care, because i made a hole in the wing, i may fill the hole with some epoxy, but it's a shame i was so careless.
I prepared the spar, cuted the carbon, cuted the balsa, glues the balsa blocks, sanded them round. I need to work on the sub spars so i can be ready to close the mold. I still did not decide how i will make them.
Before dinner,I layed the other wing. Everything went good so i guess it will be ok.

·Time spent: 4h
·Total time: 21h

Chets

[Dbox]

Your drawing looks like a wing without aeleron to me.
Planes crasy Yuri.

[infopimp]

Next time I hear someone complain about the cost of a moldie, I will refer them to this thread. Carry on. :)

[samotage]

T,

Here are some shots of my squisher.

Sam,
who believes assembling a ready made moldie is like going on holidays.

[ShredAir]

Next time I hear someone complain about the cost of a moldie, I will refer them to this thread. Carry on. :)
That is exactly why early on I asked Chets to keep track of his time spent building.

Dieter Mahlein, ShredAir

[blewis01]

Can you guys elaborate on the silicone plug? What particular silicone is used? Is the plug good for multiple uses, or does it get replaced every time?

I have some servo cover molds that I would like to make also.

NICE THREAD, CHETS! :)

Target

Here's what was reccomended to me, it works well and we have made 6 or 7 servo covers with each plug. After the 2nd or 3rd, it started showing a weave pattern - probably because we used 5.7 oz carbon, but the final results are still good. It makes it so much easier, probably cuts 20 minutes off the layup time. Just wet the cloth out on some wax paper, lay it over the mold, remove the wax paper, put the silicone plug in and clamp it.

Tap molding silicone (http://www.tapplastics.com/shop/product.php?pid=61&)

Mix it up, put it into a plastic bag, cut the corner off the bag and let it dribble into the mold. No PVA required, I waxed only.

Bruce

[chetosmachine]

Dbox, wrong answer :p

Day eight.
Not much work today, just the nose cone and radio tray.
I cut all the fiberglass in advance, but didi a last time change on the layup of the nose cone, because the last layer of fiberglass was becoming a bit rebel, and i thought i would not get a great seam, so i took another kind of fiberglass.
The layup is:
nose cone, 3x163g + 1x 200g glass
radio tray, 3x 110g glass

I could have used kevlar, carbon, carbon-kevlar.... but i have yet to see one of my nose cones to break :D

·Time spent: 3h
.Total time: 24h

[target]

Dbox, wrong answer :p




Is it the outline of Spain? :eek:


Target

[target]

Here's what was reccomended to me, it works well and we have made 6 or 7 servo covers with each plug. Tap molding silicone (http://www.tapplastics.com/shop/product.php?pid=61&)


Bruce


And has anyone tried successfully to use just one-part silicone caulk for this "press" part?

**********************************************

Sorry to hack your thread AGAIN, Chets...

Your plane looks like it is coming out very nice. You are lucky to have access to the molds for this....
Even though you are showing many hours of work, I think that it is worth the extra time to get material where you want it.
Keep the picture coming!

Target

[zero-zero]

I could have used kevlar, carbon, carbon-kevlar.... but i have yet to see one of my nose cones to break :D

Why? do you look the other way when they do? :p

Hurry up, Chets, my birthday is in 12 days and at this pace you won't have the plane ready for delivery! :cool:

Seriously, lovin' it. Great idea keeping tabs on the time spent. Good luck!

[chetosmachine]

Is it the outline of Spain? :eek:
Target

RIGHT! :D ;) :p

[samotage]

mmm, an advanced seaming instrument...

[Jose E Bruzual]

Nice job, watching...

Jose

[jirvin_4505]

QUOTE=chetosmachine]..
Not much work today, just the nose cone and radio tray.
..snip..[/QUOTE]
Chets really enjoying what you are doing here.

Like the idea of precuring -trimming and then laying in the wet seam layer.

I usually lay all layers in creating the lip for joining as I go - I do have some problems with voids along the seamline I can see how you process would eliminate this.:)

Found a video describing the system I use:
http://www.valegliders.com/Workshop%20videos/Wet%20seam%20layup.mp4
from this page:-
http://www.valegliders.com/Wet%20seam%20layup.htm
- this all probably should be in Samotage's wet seam thread!

Things I found to help with the seam:-
I lay the low side cloth (cut to pattern) below the joining lip - then don't have to trim that side. I am carefull to see that the high side has enough to cover down onto the low side cloth.

I have started spraying 3m77 onto loose weave cloth to tie it together - helps with handling and cutting- picked this up from the Phil Barnes video.

cheers Jeff

[jirvin_4505]

mmm, an advanced seaming instrument...

Like the effort you went to to make a special tool.

I have settled on 1-2cm wide strip of flanelet (spelling) cloth (torn up pyjamas) wrapped araond a carbon rod. The cloth seems to smoooch:) down the seam cloth well without picking it up.

Have always wanted to make a hitek seamer that has the attached torch:)

cheers Jeff

[samotage]

This is an example of a retarded seaming instrument.

[chetosmachine]

Hi,
"Advanced", in my posts, is just plain irony ;)

My seaming rod should not by so round. but have a flatter profile. I may sand it, so it does spread pression aver a large area and the seaming is easier.

I may not have been very clear. Once i get everything trimed, i put the last layer, which is flush on one side. I don't get mad if some tows are over the flange, when i wet the cloth i put them under the seaming line.
The glass i used on the nose cone is not my favourite one, so i did not hesitate to pull it out and use another kind of glass. I cut all the cloths with an oversized paper template, because it's easier to cut excess than to put extra glass (but i reckon it is easier to put extra kevlar than to cut the excess!).

I had seen this vid, it's a great vid! But i keep doing the fuses "my way"; it may take longer, but i still prefer having only 1 layer of cloth at the seam. If i had internal inflatable plugs, balloons or something that gave perfect seams everytime, i would lay it this way, but since i don't... ;)


Sam, i like your roller! It's an advanced technology instrument at least, like mine! :p ;)
Your wet seams are great because you paint the fuses aftermoulding, so the seam just disappears!

Z-Z, i won't have the plane ready in 12 days, i'm so sorry! You should have told me that before! I'll do my best so i have it ready and shipped ASAP. Just remember to send me the funds this week, or the next one :D


Chets

[chetosmachine]

Day nine.
I started by preparing the sub spars.
I take measurements of the height with the plasticene trick, then cut all the foam (white, very light and easily crushable) a few mm oversize, so when the wing is closed, it is crushed and the braid attaches both wing skins.
They're made of foam + carbon braid in front of the hinge.
Rearwards, usually i use a plastic straw, but since i don't have herex sandwich, i can't use it on all the lenght, so a mix of foam+plastic straw + carbon braid of another kind is used.

I also made a foam rib with a glass braid just after the servo, i cut a patch of 160g carbon to reinforce the servo area, and add a foam+glass braid where the spar ends to join it to the rear spar.

Then i mix epoxy, and laminate the carbon of the spar.
I mix some more epoxy, and wet the braids.
I use 5 min epoxy to glue the sub spars in place so they don't move.
Then a mix of resin+microballons, on the TE (both), then add more microballons, and spread the LE and a bit on the spar, and finally add some chopped glass and make a solid rib on the wing root. Close the mold, clamp it and i have to wait until tomorrow to see if everything went fine.

·Time spent: 4h
·Total time: 28h

[Daryl Perkins]

I've been molding models since 1992. It's always nice to see how someone else does it. I learn something every time.

Thanks for doing this. I was planning on doing the same thing on my website, when it's up. Going all the way from masters, to molds, to model, and to first flight and model optimization. I don't think the average modeler has any idea what it takes to engineer a "toy airplane." Maybe they'd stop complaining about price... ;)

Keep up the good work.

dp

[infopimp]

Daryl - don't let the fact that this thread is here stop you from showing us how you do it, too. :)

[target]

Daryl - don't let the fact that this thread is here stop you from showing us how you do it, too. :)


Here, here! I second the motion! :cool:

Target

[samotage]

I'm loving this Chets.

Sam,
who just voted 5 stars. :cool:

[chetosmachine]

Thanks guys for your kind words;
DP please don't give up showing us your work :)

This morning i released the wing from the mold. It was easy! The molds are intact, which is always a good thing.
The wing is the most beautiful one i've ever done :)
Weight: 282g.

Unfortunately, it needs to be re-made, and not only that, but i also stopped my plans to close the other wing today. :(
This layup, which in a 10*10 cm sample, looked good, is not up the task.
The wing skin is too soft between the LE and the spar.
I can crush it to almost touch both wing skins :eek:
That's bad.
I thought i could use it in a thermal plane. So i tested the spar.
Crack!
That's what i heard, while i saw the whole wing buckling :mad:
I made some reverse engeenering, and i've seen i didn't glue it properly. I must have done some mistakes when measuring the height, or when cutting the balsa. Next time, more microballons will be used to consistently glue the spar to both wing skins. It's the first time i make this mistake, though.

The carbon braid used on the aileron is not good with the foam spar, since it opened his threads a too much. With the plastic straw, it works very well, as expected.

I have plenty of UD carbon, and i know it works great on sandwich skins, so i will make the center panel of the panel in a more traditional way, with a 80g Glass+80g ud Carbon, herex, 50g glass. I know this combination works well, so i don't expect to loose more time and materials.
I still have to decide what to do with the wing skins i have already laminated.... but it all points to the bin, and remaking them.
I don't have much pictures of the carnage i made to the wing.... it just made my motivation go down :(

·Time spent: 30 minutes
· Total time spent: 28.5h

I won't add the time i spend to re.make those items to the total time amount because it wouldn't be fair.

Chets

[target]

Sorry to hear that, Chets.

T

[chetosmachine]

Day ten.
After the failure of this morning, i don't want to get stuck, so in the afternoon i layed the fuselage.
Lay up is 1*105g glass + 1*120g kevlar +1*163g glass. a 163g glass patch on the tow hook area, and 4 carbon tows running along the fuse.

First i mixed some microballons+chopped glass to fill the edges under the wing and on the stab root, then i mixed more epoxy and with a new brush (the old one was really old) started with the first layer, wiated a bit, put the kevlar, waited 1/2 h, trimed the glass, put the last layer flush on one side, added epoxy, put the patch and the tows, waited, trimed the seam to size, added a bit more resin, closed and done.
Today was really hot, so the fast resin became super fast resin :D not bad, i usually spend 2.5h and today i only spent 1h 45min :)
Tomorrow i will know the result, i estimate a 180g piece, but since i did not weight the cloths, i'm not sure.

·Time spent: 2.5h
·Total time: 31h


BTW, here is how i trimed the fuse. I call this a good timing, since the glass was at the exact point: not too stiff, not too soft :-)
http://www.youtube.com/watch?v=aK1Z2sX396Q

[Daryl Perkins]

Nice job, Chets! Way to keep going. Sorry to hear about your wing. One of the neat things about having our own molds is that we can play with layup schedules, different materials, etc....

Keep up the good work!!!

Thx

dp

[chetosmachine]

Day eleven
More work on the fuse. Fisrt, i demolded it to make sure it is good. It is. Very good! 135g, hard, good seam :)
Once i get rid of the flahing over the seam, i take my cordless driller, the 8mm bit and do the holes for the stab joiners.
Then with the 4mm bit, i do the 3 holes for the wing mounting.

Next, i do a "rib". I tried to make from depron, but it did not work. From extruded foam, did not work. From very light expanded foam. Didi not work. From dense expanded foam.... it worked! This rib is inserted from the rear of the fuse, and is my microballons retainer. Then i put my steel wing joiners, and pour epoxy+microballons+chopped glass to make the proper stab's joiners seat. (could anyone tell me how it's called in english? I have troubles from time to time to explain what i do:o )

On the nose cone, there's a lip to be made, so i clean the mold, wax it and add some epoxy+microballon+chopped glass and close it.
Tomorrow i will have the fuse almost complete.

·Time spent: 1h
·Total time: 32h

[Chad Sullivan]

Chets,
Sorry about the wing. Are you going to do wipers? that's what holds me back from trying this myself. I can't figure out how to make the wipers for the ailerons and flaps. I bet it's the simplest part. But it's kickin my butt.
Five stars man.

[samotage]

Chets,

That is a brilliant seam on your fuzotage. Now I know how you do it I think I will attempt a pre-painted one for your Merlin... How long do you leave the resin to cure before trimming the flange back with the knife?

Sorry to hear about your wing too mate, that is a bummer. I guess though another lesson, thanks for sharing it with us. Did the skin not have any herex in there? Also, have you discovered how you ended up with the spar thickness error, or was it just too short on splooge?

Sam.

[droydx]

Wow Chets,
Great thread, can't believe I missed it till now. Keep up the great work, thanks for sharing the ups... :) and the downs :( . That is real building! You are helping all of us that love to make something out of a million pieces.... fly, and fly well.
Andy

[chetosmachine]

Thnaks guys for your support :)

Chad, yes i'm going to do wipers. I do a silicone hinge on my wings, so the first step is to cut the aileron/flap from the wing, then i do the wiper, and finally do the hinge.
I know there¡s a post in slope forum, from Joe Manor and his 120"+ dinamic, where he shows how to do wipers.

Sam, try a prepainted fuse with a simple glass layup (no need for more as a test piece), and see if it is worth for you.
As for the time i let the resin cure, i used 20 min pot life resin, and had to wait around 1/2h until i could cut it like in the vid. You know the right time arrived because you can cut it with a knife. Important, you must put resin on the excess fiberglass that is over the flange of the mold, otherwise you won't be able to have a clean seam as you will have lots of tows laying around.
I know i did a measurement error because the wing mada "crak" and bucled at the first compression test, and i could actually put pressure on the skin over the spar and it would flex. It's a measurement error; i put very little resin on the spar because if i had measured it right, it would have been enough, but clearly it wasn't. I don't like to put globs of microballons on the spar, but may be i should err to the safe side next time...

The wing skins have no herex at all. I know some people do planes like that (pcm erwin series, daniel lesky 's pace series...) but i reckon they use plain or twill 160-200g carbon, while i tryed to simulate this using glass and UD carbon.
For the other wing tip, which is already lamianted, i'm talking with my composites teacher what i should do, another subspar between LE and spar, or several ribs....

Chets

[jirvin_4505]

Hi Chets,
feel ypur pain on the wing:eek:

My first go at molded Europhia wing using the club mold was unsuccessful:censored:

I didn't prime the balsa core appropriately or just too dry a layup:confused:

Skin bubbled and separated from core when it came out of the mold.

The wing sacrificed itself (after a few Coopers Ales) to sheck my techniques - lots of small mistakes!

Keep up the good work
cheers Jeff
who must get his second eurphia wing into the air for F3b this weekend!

[Hutch]

Chets,

That is a brilliant seam on your fuzotage. Now I know how you do it I think I will attempt a pre-painted one for your Merlin... How long do you leave the resin to cure before trimming the flange back with the knife?

Sam.

Agreed, my seams just do not come out that nice. Nice work!

So Chets, it looks like you trim all of the glass flush with the fuse mold. I assume that you add a separate length of glass tape to seam the fuse when you join the mold halves? Are you waiting till they cure to join them or are you doing it when the epoxy is still green?

-hutch

[Daryl Perkins]

Must have been the weekend for failures. I made a mistake putting my center panel in the bag. This is only the third center panel out of the molds, so I'm still experimenting just a bit. I'm using pre-preg spar caps, and bagging them into the molds with the skins. I always experiment with saving weight. The surface cloth must have been too dry, as just on top of the caps, there was a few bubble delams. Had to poke a few holes, wick some Cya, smooth with a bit of polyester filler and repaint, but it'll never look the same. I'm popping the tips today. Unfortunately, I used the same methods, so I expect the same issues.

At least the part is super strong. I'm tipping the scales at about 240 right now, and I can sit on the center panel when supported at each end of the panel, with maybe an inch of flex. I expected it would be strong, but not that strong.

I'll let ya know how the tips come out.

dp

[chetosmachine]

It's good to know you are getting such strong wings, Daryl. And light! "40g wing tips is light!
What kind of layup are you doing?

As for the fuse, i lay the 1º and 2º layers of cloth, trim both sides of each mold, then add the last layer, flush on one side; i wait gor the resin to get a bit stiff, trim the seam to size (~5mm), add a bit more resin and join the molds taking care not to break the seam. I push it gently, and all i have to do is to wait.

Today i pulled the fuse of the mold, it's ready to get some holes for V-tail linkages (4mm carbon rod).
The nose cone did not come out good, the lip did not adhere to the cone and i could pull it with my nail! I suspect a too dry mix, so i repeated it with a more liquid mix.

I made decission, i will pull the wing skins of the other wing tip and get rid of them. I don't want to loose more time on something it may not work, the le was soft, the aileron was soft.... no way it would work.
The centar panel will have a light glass layer+UD carbon 100g, 1'2mm herex, glass layer.
The spar will be laminated at the same time.
I hope to get it done this week.

Chets

[Daryl Perkins]

LOL!!! No Chets, I don't have 40g wing tips. My body weight is very heavy, at 240 lbs, or 108 kilograms, and I can sit on the center of the center panel. My center panel weighs 22.6 ounces, or 640 grams out of the molds. That's pretty light considering I used heavy 3.5 ounce carbon skins, 1.5mm rohacell, and .7 innner skin.

I expect the tips to be about 9 ounces, or 255 grams. I'll weigh them and post, even if they turn out bad. I can save some weight on the skins, and even probably on the spars, but the model is turning out so light now, and I really like stiff.

Chets, that's a smart decision on the other wing panel. There's no point in wasting more material or more time.

more to come

dp

[chetosmachine]

:o Damn english! :o
("40g is what i writed, 240g is what i wanted to write, now it all makes sense).
i hope your tips come OK!
Chets

[target]

Hi, DP-

If you can, please post some pics for us. You know what they say about a picture being worth 1,000 words!

I'm interested in your skin/sparcap layup. So, then what are you doing for the spar between the top and bottom skins exactly?

Thanks,
Target

[target]

:o Damn english! :o
("40g is what i writed, 240g is what i wanted to write, now it all makes sense).
i hope your tips come OK!
Chets


Your english is FINE! and way better than my ZERO Spanish! :rolleyes:

Keep posting. ;)

T

[chetosmachine]

Just a couple of picts, of the failed lip and how will look my wing tips when i remake them.

[Daryl Perkins]

Just as I expected, the same issues exist on the tips, but not as bad. I used the same materials and techniques, so it was expected. The parts really aren't that bad, just not a production quality part. I'll go ahead and build it out and fly it.

To eliminate the problem going forward, I'll put a thin slurry of epoxy/microballoons on the spar cap prior to placing in the molds. I did that on the second center panel, and it turned out really pretty. You couldn't even see the spar, and maybe adds 1/2 ounce for the panel.

By the way, the weight for each tip ended up at 9.6 and 10.1 ounces, or 272/286 grams. My tip panels are quite large, so I can certainly live with anything under 10 ounces. The nicer one was the heavier one. Imagine that.

Having slightly screwed up parts gives me a good opportunity to try some new things for finishing out the model. I'm learning a lot, and it's finishing out quite nicely, blemishes and all.

Keep going Chets. Very pretty paint scheme!!! Can't wait to see it all done.

dp

[samotage]

Hey Chets,

How about a floc mix for that ring around the nose cone? Looks like the brittle nature of the microballon filler 'aint up that that task.

Sam.

[jirvin_4505]

Hey Chets,

How about a floc mix for that ring around the nose cone? Looks like the brittle nature of the microballon filler 'aint up that that task.

Sam.

Hey Chets - the way the splodge (balloons mix) broke away from the nose cone looks like an incomplete bond to the cured resin of the cone?

When using a dryish balloon mixture I apply resin to the surface that is being bonded to. Lately I put epoxy onto 80grit sandpaper and rub that into the cured epoxy - gives a much more secure surface prep.

As Samotage suggests some flock may help however I feel the test was beyond what the nose cone may experience - unless you tread on or runover your nose cones - vey possible -- ask me:eek:

The nose cone on my Calypso Cobra uses a dry mix of balloons to create the ledge.

cheers Jeff

[chetosmachine]

Thanks for the cotton flock tip.
The second microballon lip was succesful, and i don't think it will break. Anyways, i am "calibrating" the mold, as it need a few layers of tape to get the correct thickness, so when the right nº of tape layers is known, i will lay some kevlar to increase the thoughness.

A bit more work has been done, the stab molds are painted, the wing tips are 1/2 painted, but this work time will not be counted.


Day twelve
I started the day by cutting all the fabrics and herex (for the complete center panel).
The layup, is 25g glass, 100g UD carbon, 1'2mm herex, 50g glass.
There's a patch of carbon where the servos will go.
The carbon spar was laminated at the same time, and is made of 6 layers of 300g UD carbon, 20 mm wide.
I didn't have the camera, so no pictures...

· Work time: 3h
· Total time: 35h

Tomorrow we'll know if everything is ok.

[chetosmachine]

Day thirteen

The laminate came ok. It looks good!
The herex just moved 1mm from the marked hinge line.
I layed the other panel half, i changed my wetting technique of the UD carbon, now i use the sqeege and it's so fast!

·Work time: 2h
·Total time: 37h

[chetosmachine]

Day fourteen

I took the mold out of the vacuum bag. Everything went ok, so i'm ready for the next step.

I took the plasticene, put small blocks along the spar, then closed the molds. Then i measured the height and translated to the the balsa, marked, cutted and glued with ciano. To verify that i have the correct height, i used some plasticene. The spar is now ready!

I also draw the hinge line, then pull some herex in front of the hinge line on the upper wing skin so the flaps can go upwards too. I marked the place of the sub spar that go in front of the hinge line (balsa+fiberglass) and backwards the hinge (plastic straw + carbon braid).

We are having wind these days, so i can't paint :mad: I hope to finish the wing tips and stabs soon!

·Work time: 1h
· Total time 38h

[avago]

Hi Chets,
So this is where you hide out:-)
I've only just found this thread ,thanks for shareing all of your excelent build info.

Cheers
Tim

[chetosmachine]

Days fiveteen and sixteen,
I want to have an end grain balsa sub spar, so i need to prepare it. I chose 4mm balsa, and 110g glass. Cut to shape, cut some acetate and let it glue properly in the vacuum bag. While i waited for the balsa, and given that it was windy (no painting), i put the stabs joiners (8mm carbon glued with 5min epoxy) and did the holes for the centering pins.

Today i first played with the plasticene to measure the sub spar height, the cuted the balsa, and closed the molds to confirm the measurements.
Then i prepared everything needed to close the mold:
-epoxy
-lots of microballons
-cabosil
-patience
-5min epoxy

I started with the carbon braid over the plastic straw that closes the flaps. I impregnated it then glued it to the herex with 5min epoxy.
Then i glued the balsa sub spar with epoxy+microballons on 1 side, glued it to the mold and glued to the small balsa blocks with ciano.
On the upper side, i put some epoxy+microballons+cabosil.
Next, i glue the spar to the upper mold with epoxy and microballons
Then, i prepared a lot of resin, so i could put on the upper side of the spar, and on all the perimeter to close the molds.
Pictures speak better than me.

·Work time: 4h
·Total time: 42h

[oteinRc]

Chets your are doing a PERFECT job............and without me!!! :rolleyes:

Congratulations. I want to see the new Vector in the sky.

Best regards.

[chetosmachine]

L,
i work great without you, but that's because i can focus more on what i do and spend less time talking ;)

Day sixteen,
A long day. Long, because i spent 20h waiting for the resin to cure! Then i had a bit of christmas feeling mixed with terrible fear because of the spar....
The wing did not release too easily, but the center panel never does! It may be because of the shape of the panel, with dihedral and 3 holes for the wing bolts. When a piece does not release well, a layer of acetate does real magic.
I'm so happy!
I'm so :censored: because i screwed up the letters!
I'm so happy, the spar seems well bonded.
I'm so :censored: , if i had the complete wing i could have the plane ready for next f3f race in Portugal (28-29 July, @Lisboa).
I'm so happy, the plane will look so nice! :)

The weight is 723g. It is the lightest center panel i've ever made. And i know where i can save some grams on the next one :-)
Now i really want to finish painting the tips and the stab!

·Work time: 1/2h
·Total time: 42.5h

[infopimp]

daaaaaaaaaaaaaaaaang that looks good buddy!

[samotage]

Great stuff Chets! Looks jsut beautiful!

I see that carbon sock is for the aileron facing. :D.

Sam,
who also dislikes painting outside in the cold and rain...

[jcosta]

I'm so :censored: , if i had the complete wing i could have the plane ready for next f3f race in Portugal (28-29 July, @Lisboa).



Chetos

Better not, our slope is not good for new and shiny planes. Right now we have no grass and a few loose pebbles that tend to scratch or dent shiny new planes...

Like La Moo in the summer. The advantage we have is that we are finally repairing the irrigation system and we will have new grass in a few months.
The slope (well not the slope itself, the surrounding facilities - parking, stairs, assembly tables, etc) has been grossly neglected for a couple of years and we are putting it back in shape as fast as we can, but also not in time for the race...


Great work!!!

[zero-zero]

L,
i work great without you, but that's because i can focus more on what i do and spend less time talking ;)

Aaaah, so the owner of the foot in the 4th pic does not talk? it's not yours... :)

[chetosmachine]

jajaja,
Z-Z you concentrate too much on everyone's feet, but not enough on your planes batt's :cool:

Today i did minor work, i finished painting the molds so i will do the wing tips soon, and started to put the fuse together.
Now i'm trying to figure how to do a good tow hook; on my other plane i have a fixed hook but for this one i would like to have an adjustable one....
I also cleaned the leading edge of the center panel, made the holes for the wing screws and nothing more.

Joao, since the slope is far from being in perfect shape, i guess i'll fly with the vector DS, which is thougher than any other plane i own. See you soon!

Chets

[jcosta]

Now i'm trying to figure how to do a good tow hook; on my other plane i have a fixed hook but for this one i would like to have an adjustable one....


Chets


You will save a lot of grief if you buy a ready made tow hook.
But I have done one with a blind nut, a standard nut, a partially threaded L-hook and a piece of hard wood.

Cut a slot in the fuselage. On the inside insert the piece of wood with the blind nut, already drilled. Insert the standard nut on the L-hook and thread this on the blind nut, tightening with the sandard nut. To adjust, release the standard nut a little bit, move the hook (and the piece of wood inside the plane) to taste, and tighten the nut again.

[zero-zero]

It tested 100% prior to flight, durnit!

Found a delamination in the right wingtip just as I was about to declare repairs finished, so my chances of flying this weekend have gone down the drain. At least there's an airshow on Sunday...

Back to our normal programming now.

[robert zeeland]

Nice work C! Thanks for showing all this and taking the time for pictures, you know these are the kind of threads we all like hombre :)

robNZ

[chetosmachine]

I have not had much build time lately :( so no true advances.
I managed to get a pair of servo covers that loose the paint :eek:
I tried to make some silicone plugs to get better servo covers and the silicone is taking too long to cure(2 days), so i suspect the harder was in bad shape. I used the slow harder; when i made the plugs for the wing root edege, i used the fast harder and everything came OK.
Now i know how i will make the winch, it will be a bit more fashinoable than i thought at first (and will take pictures, of course).
Now i'm spending more time in the shop trying to get my current f3f's in shape for the race in portugal than anything else.
Chets

[RookieOne]

Pishaaaaa, eres un moztruo.
¿Se podría hacer de balsa?
A mi es que me da cosa trabajar con fibra.

Keep on with the good job Chets. Looks like a real ship. :D :D

[samotage]

Hey Chets,

I feel your pain with the servo covers. They are pesky things, I am on to my 3rd set of Merlin covers at the moment, this time I have revised my silicone plug, using peel ply and paper towell to get a nice "cover" part. I am molding from carbon, so no need to finish "black" afterwards.

My silicone I used for the squish went off in 45 mins, so praps your silicone was a bad batch.

Sam.

[chetosmachine]

I throwed away the plug. It should cure in 24h, it's been 36h, it's warm, and it's still tacky. It was my last 3g of hardener, so i need to buy more hardener to use the silicone that i have. I will buy the fast hardener, which has a 6 minute work time and allows demolding just 1 hour later.
I will wait until i come back from Portugal to do the new plug. May be today i lay another wing tip skin....

Sam, may be if you laminate the carbon on an acetate, wait until the resin is green, then put it on the mold, put the plug and do pressure (weight), well, may this could work.... It's just a guess! I've never done it that way!

Michele, you can try to do it from balsa if you want! And i could make you a fuse if you want.... now that you have more building time, it would be an interesting project.

[Lubos Pazderka]

Do not make it like main job!You need a lot of practice with GFK.....

[samotage]

Sam, may be if you laminate the carbon on an acetate, wait until the resin is green, then put it on the mold, put the plug and do pressure (weight), well, may this could work.... It's just a guess! I've never done it that way!


That is a totally rockin' idea chets! I will try this next time :D

Sam,
hoping to open up nice servo covers tonight ;)

[chetosmachine]

Hola!
I'm back from Portugal (i finished 16th from 23 pilots) and ready to continue my work on the plane.
I've made a tow hook wich looks great! It's made from aluminium, brass and some steel. More important, i have enough material to make more than 20 tow hooks :D

I've made a big hole on the fuse end, so the 4mm carbon rods will have plenty of clearance. I'm making a silicone plug so the hole is made by molding, and not like on this one by using a big drill.

I'm preparing a "composite" plate. It's made from 1'2mm ply and 1 layer of 160 g carbon. It makes the wing seat stronger, and allow me and easy way to put the nuts.

I finished laying the wing tips, and the stabs, so this week i'll finish the plane, i just need to close the molds, then finish the fuse.

[target]

Welcome back.
I wondered if I was going to find you in the ocean on one of my boat trips...

T

[samotage]

It's ok T, you could have jsut PM'd wind and currents who would have organised the Sea Otter to go save him... ;)

[caligulin]

Good work!

Congratulations for your good race!

Abrazation desde Cádiz

[jcosta]

Hola!
I'm back from Portugal (i finished 16th from 23 pilots) and ready to continue my work on the plane.
I've made a tow hook wich looks great! It's made from aluminium, brass and some steel. More important, i have enough material to make more than 20 tow hooks :D

Yep

I didn't fly the last 2 rounds just to let Chetos get ahead of me :D
(Or was it because my sunglasses were not appropriate and I couldn't see s... with the plane against the sun - just bought a new pair in Barcelona this weekend. Anyway, I was well ahead of him when I decided to stop flying...)


Now on a serious note, for his second F3F race he did great, even more because it was his first outside his usual slope.

And the tow hook interests me a lot. Can you show us some pictures of how you made it?

[chetosmachine]

Hi,
i have a slow build rate, i have some exams in September so i spend more time studying than in the garage.

I finished the stabs.
I glued the plate with the nuts on the fuse.
I closed 1 tip panel, and released it this morning. Everything is Ok, the wing tip weights 273g.
Tomorrow i'll close the other wing tip mold so the molding will be finished.

Work time: 1h
Total time: 43'5h

That's how my mold sounds when i open it!
http://www.youtube.com/watch?v=BziJgsgKAk4

[target]

Great progress, Chetos!

Target