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Old Nov 24, 2012, 03:24 PM
C4X
Glider Junkie Beyond Help
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Canada, BC, Roberts Creek
Joined Nov 2008
617 Posts
Build Log
Zone v2 Disser build

I am in the beginning stages of building a set of Zone v2 wings (with Edge tails). Nothing revolutionary here. I'm ever thankful for Gerald Taylor's work which allows a fellow like myself to have a solid airfoil and planform to work with. They will be my first foam cores cut with my self made (auto-cut, Tekoa style) hotwire cutter, and the second wing I will have bagged with my vac setup.

My hope is to have this thread to bounce questions off the fabulously knowledgeable RCG members here when I come up against problems that I can't find answers for through searching, or conflicting info renders things 'confusing'. I will also post my progress for other newer users to be able to follow and hopefully benefit from.

So far, I have everything drawn up in ACAD, printed out planforms and airfoil templates, CA'd the airfoil templates onto some Formica and cut them out with my bandsaw. I have yet to finish the airfoil templates, which leads me to my first question (of many to come ): I was planning to finish the top template's LE perfectly following the airfoil, and somewhat round off the LE of the bottom template (to avoid the wire hanging). Is this the standard, or are peeps rounding the top LE template a bit as well?

As for the layup plan: 30psi Foamular (300), all glass with a disser on tails and wings, Kevlar LE's and hingelines. Initially I will use a pod and boom I was sent from DLGJunkyard some time ago (thanks for that ).

Disser question: Is 1k optimal for avoiding bumps on the finished wing, or would 3k be better? I've heard conflicting opinions about this. I am certainly willing to experiment, but funds are tight so I would rather go with good info and let my screwups cost me, not bad design. As well, can I expect decent results from having the disser layer straight onto the mylars, or are they better off under a layer of glass?

As for layup, I was thinking the disser would act as the bias, and I will add another couple of layers of 2.4oz E glass on 90. Any thoughts on that?

Moving forward, any advice is appreciated. None the less, I will post results with as many pics as I can. Standby...
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Old Nov 24, 2012, 03:58 PM
dougmontgomery's Avatar
Glendale,Az.
Joined Oct 2004
3,536 Posts
2.4 ounce is way to heavy, 1.5 ounce at max but I had good results with 2 layers per side of .61 ounce and criss crossing the layers to sort of balance the fg. Of course on the 45


I prefer all 1.7ounce kevlar due to less issues with unbalanced FG.
Good luck.
doug
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Old Nov 24, 2012, 04:29 PM
Hey was that a Thermal ????
Joined Nov 2009
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I may be an oddball hear but I do disser wings a little differently. I had a frame that was large enough to cut two full wing skins. The frame was 24" by 65". I laid up the tow onto the frame and set it aside. Now I spread my glass out on my bench and brushed it nice and smooth. I then sprayed the disser with 3m77 and set it on the cloth. I used a piece of pvc pipe to roll the disser onto the glass. Trim around the outside of the frame to remove the excess cloth. Flip the frame and cloth over so you can now press the cloth to the disser where the roller could not reach. Now carefully cut your disser cloth from the frame. Carefully flip it back over so the tows are top of the cloth. Lay parchment paper over the carbon and hard roll it to flatten the tows and bond them to the glass really well. You can now cut your wing skins and bag your wing.

OK so everyone who reads this is going to go crazy because the glass ends up on the 0-90. Once the carbon is added the glass would do NOTHING for torsional stiffness. The glass is now being used for span stiffness and for dent resistance.

I like 3K for handling but the 1K gives a better wing surface. If you want some 3K I can send you some. I have a BUNCH I wont be using.

Paul
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Old Nov 25, 2012, 04:09 PM
C4X
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Canada, BC, Roberts Creek
Joined Nov 2008
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So to be clear, I could either use 1 layer of 1.7oz Kevlar (0-90) or 2 layers 1.4oz glass (both 0-90) + disser? Maybe one of the glass layers on bias? Obviously any doublers and possibly a d-box are going to help alot.

All shall be clear after the first wing is out of the bag If it's usable, all the better, tho I am fully prepped to see what it takes to break the first one, all in the pursuit of quality of course

I am also guessing with a thin section like the Zone, prefacing the flaperons is a must?
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Old Nov 25, 2012, 05:05 PM
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Glendale,Az.
Joined Oct 2004
3,536 Posts
2 layers of 1.4fg on the same surface will be to heavy, yet a single layer on top and bottom, even on the bias can twist and warp- facing the ailerons will help with flutter and strength of the ailerons but will not help with the warping from the amount of fabric across the top and bottom of the wing that may be unbalanced.

That is why I would suggest, two layers of .61 or 3/4ounce fg on the bottom and the top, the chances of your wing lasting longer without warping will be greater.

Kevlar is a pain to cut unless you have my cutting device- but if you are doing hinges and patches and have kevlar, it is worth the time to cut.

It takes about 30-45 minutes to bag a wing from start to finish once everything is prepped, 3 hours for everything to prep+ materials, I hate to see 3-4 hour wasted on a twisted wing.

kevlar cutting here:
Kevlar Cutting with Laser (2 min 11 sec)
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Old Nov 25, 2012, 07:49 PM
Mark Triebes
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Elk Grove, CA
Joined Sep 2001
868 Posts
Quote:
Originally Posted by The_Builder View Post
I like 3K for handling but the 1K gives a better wing surface. If you want some 3K I can send you some. I have a BUNCH I wont be using.

Paul
Where do you get the 1K tow, Paul? I searched for it a few years ago and had no luck ... haven't looked recently, but would stil love to get some.

Mark
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Old Nov 26, 2012, 02:39 AM
Aussie F3K Pilot
Melbourne, Australia
Joined Jun 2008
499 Posts
Hey Mark,
You can find it here.. http://www.cstsales.com/carbon_tow.html
Cheers,
Marcus

p.s. Thanks for the Spectrum F3B you used to make, I had one for many years and loved it. Thank you.
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Old Nov 26, 2012, 02:52 AM
C4X
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Canada, BC, Roberts Creek
Joined Nov 2008
617 Posts
That laser cutter is sick! Certainly keep your parts looking polished with those fine lines.
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Old Nov 26, 2012, 11:22 AM
Mark Triebes
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Elk Grove, CA
Joined Sep 2001
868 Posts
Quote:
Originally Posted by Machineman View Post
Hey Mark,
You can find it here.. http://www.cstsales.com/carbon_tow.html
Cheers,
Marcus

p.s. Thanks for the Spectrum F3B you used to make, I had one for many years and loved it. Thank you.
Glad you liked it, Marcus ... Yeah, CST has most everything, if you want to pay through the teeth for it ... was looking for a more, well, reasonable source ...

Thanks.

Mark
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Old Nov 27, 2012, 09:53 AM
G_T
Registered User
Joined Apr 2009
5,692 Posts
Try R&G in Germany. 1K is hard to find.

Personally I prefer Kevlar to fiberglass for skins. I do not find it any harder to cut, really. It just takes the proper tools, just like any other aspect of making stuff. The proper (and cheap) tool is Fiskers scissors. Ruin the edges on a coarse sanding belt or disk, at 90 degrees. This makes a fine (but not smooth) sawtooth edge which prevents the Kevlar fibers from sliding out of position when being sheared. Note I said sheared - Kevlar doesn't cut worth a darned, but it shears easily. 1.7 should now cut easily like thick paper.

There are a couple other 'tricks' to working with Kevlar, but they are also no big deal. It is knowledge, not money.

0.8 Kevlar - non-option. Weave won't close as the yarns are twisted.
1.0 Kevlar - nice light wings but hard to work with, requires wax paper transfer methods. A bit pricy.
1.7 Kevlar - nice durable wings. Pieces can be spliced so scrap can be used for skin, so yield is good. Easy to get, not real expensive per wing. Sweet Composites is a good source, though there are others.
40gsm Kevlar disser - nice light enough wings, stiffer in torsion. Slightly stiffer fabric holds shape decently. Notably stiffer flaperons. Me like. Get from R&G in Germany.
1.19 glass - nice finish, light wings, likely easily dented. Not stiff enough by itself. Currently unobtainium unless another production run happens. Thayercraft was source.
1.4 glass - nice finish, unbalanced IIRC. Twisting is an issue. Cheap. Not really stiff enough by itself. Thayercraft. Useful for doublers if nothing else.
2x0.75 glass - a pain IMHO, but cheap. Wings not really stiff enough. Nice on shaped balsa cored tails.
1.6 glass - nice finish, getting more reasonable for stiffness... But not so light. Balanced fabric - Thayercraft.
Carbon of any form - ba bling, ca ching. R&G to save some money (it's a relative thing). Team up for a group order.
Light tight weave S-glass - could be used for the forward section of a D-box if someone wants to experiment. R&G had some last I looked. In light weight, most S-glass is open weave. You want the very tight weave stuff if you go this route.
Light glass/disser from EMC-Vega - reputation as a flimsy fabric to handle. Hard to get it to go straight. Can take a long time to get, but may be worth considering for the experimenter. I've never worked with it so I cannot advise.

One could even strip down some spread tow fabric or ribbon, to make disser. Samurai tows are 1K I believe. Others are 3K or higher. Any will work without making appreciable bumps because the tows are already rolled out thin. But it will up the cost, and the weight a little, just like any disser.

Gerald
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Old Nov 28, 2012, 10:37 PM
C4X
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Canada, BC, Roberts Creek
Joined Nov 2008
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Making progress....airfoil templates are almost done, a tiny bit of shaping left I think (to make them as perfect as they are going to get), then buff them up with a felt tip in the Dremel. I will hopefully be able to start blocking foam and cutting some cores soon, but first I need to play a bit with my power source / bow combination to find a happy balance with the 30psi foam. I am using a 106b iCharger w/ 500 watt computer PSU.

The charger is fantastic for, well, charging things! but the extra bonus function of a 'foam cutting' mode is what initially sold me on it, as I was going to buy a lab power supply specifically to cut foam. In the end, a friend pointed me to the iCharger because of its hidden talents. Initial tests show that it most certainly works for heating up wire, albeit only thus far on some lightweight polystyrene.

My bow, as I mentioned, is self made from plans I found in an online back issue of 'RC Soaring Digest' - November 2008. Its made from Oak to last the ages, the automatic bits as well (though I likely wont use that part for this build, seems tricky to get the thing worked out for proper cuts). I am using 'Surfstrand' braided wire on my bow, which I read once upon a time was decent and strong. Time will tell...

I am fairly clear on the layup now, either (2) layers 0.75oz glass + 1k disser, or I might try (1) layer of 1.6oz glass + 1k disser (plus doublers in the appropriate places). Later on I am all but surely going to aim for the 1.7oz kevlar. It really seems the ultimate solution for my needs, most especially when combined with the disser style. I weigh in at just over 210lbs these days and launch hard, so I have to be sure my wings aren't of the exploding variety.

Thanks for all the advice so far, guys (and the 3k tow offer from Paul).
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Old Nov 29, 2012, 04:49 PM
Aurora Builder
United States, MD, Lusby
Joined Nov 2003
3,418 Posts
C4X,

Welcome to the build group! Your idea of 2x0.75oz glass+1K disser is perfect. Put the glass on the bias and use a 3.7oz piece of uni carbon, 15mm wide tapered to 8mm at the tip for your spar. That will get you a light wing that is plenty stiff. 1.6oz glass results in heavy wings. 1.19oz glass was great but as Gerald mentioned its unobtanium. I suggest reading up on pre-facing flaperons, the methods are straightforward, result in stiff flaperons and beefy hingelines.

I haven't played much with 1.7oz kevlar but the 40 gsm kevlar disser from R&G is really nice stuff and makes a very very stiff wing. I can't get the weights down but that's due to experience, glass is easy to check weight on.

-Sam



Quote:
Originally Posted by The_Builder View Post

OK so everyone who reads this is going to go crazy because the glass ends up on the 0-90. Once the carbon is added the glass would do NOTHING for torsional stiffness. The glass is now being used for span stiffness and for dent resistance.

I like 3K for handling but the 1K gives a better wing surface. If you want some 3K I can send you some. I have a BUNCH I wont be using.

Paul
Nice tips on the disser frame Paul. I went crazy when I read your torsional stiffness comment however. In theory you are right. In practice it works out differently...I've tried both ways with different weights of tow and you still need the glass on the bias when working with such a thin wing. Carbon spar takes all the bending loads. Glass is cheap so putting it on the bias doesn't cost you but time.
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Old Nov 29, 2012, 07:04 PM
C4X
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Canada, BC, Roberts Creek
Joined Nov 2008
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Ahhh, I see. I was thinking the glass would be 0-90, but with the spar handling the spanwise loads, make sense on the bias. It is an awfully thin wing, after all, and likely very prone to twist. Good advice (which of course is actually Doug M's idea, suggested earlier, though not as a bias layer). 0.75oz glass is also too easy to get in quantity, anywhere, for cheap. Would a D-Box with Uni work well, or does that require woven fabric on the bias for it to do an effective job? Without having anything approaching an engineer's background, it seems to me that a centred spar stands a better chance of providing a balanced level of spanwise stiffness than a D-Box would (unless there was a full depth spar). If not, nothing wrong with regular tapered spars in the appropriate place.
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Old Nov 29, 2012, 08:59 PM
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Glendale,Az.
Joined Oct 2004
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sorry, I meant 45 degrees not 90 degrees!!!sorry to misguide you. Glad sam caught that.

Doug
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Old Nov 29, 2012, 10:41 PM
C4X
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Canada, BC, Roberts Creek
Joined Nov 2008
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Originally Posted by dougmontgomery View Post
sorry, I meant 45 degrees not 90 degrees!!!sorry to misguide you. Glad sam caught that.

Doug
Cheers Doug, you guys are keepin my program straight for sure. Saving me alot of wasted effort I think.
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