Quetzalcoatl high-performance all-paper glider

[Leif Ohlsson]

http://www.papermodelers.com/forum/attachment.php?attachmentid=26547&d=1254210804

In the downloads section for aircraft you will find a kit for the "Quetzalcoatl" glider (http://www.papermodelers.com/forum/downloads.php?do=file&id=280). It is a trial version developed to get a grip on the technique of designing and building all-paper, high-performance model aircraft, which I did not believe was possible until now.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26548&d=1254210804

You will find that the model is very colourful, with colours sampled from the Quetzalcoatl ("Winged Serpent") mythological figure of Mayan origin reproduced in the wing roundels. Reproduced on the tail fins is the Resplendent Quetzal, Guatemala's national bird.

The design features a Jedelsky profile, double-surface wing with an internal spar, and nine-layered fuselage hollowed out as much as possible. To get the C.G. in the correct position with as little weight as possible added, the nose carries a compact ballast of melted solder inside. The kit provides instruction for how to achieve this without leaving any visible marks on the finished model.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26549&d=1254210804

The kit comes as a six-page pdf, containing a full-colour version requiring reverse printing (on the backside) of one page. The kit contains basic instructions for this, and further tips will be given below. In addition, there is a black & white version for recolouring or test build.

The basic data of the model are:

Span: 375mm - 15"
Length: 300mm - 12"
Weight: 17.5g (including ballast)
Aspect ratio: 7.8 (span / mean chord; 85% of root chord)

[Leif Ohlsson]

It all started with the "Neato gliders (http://www.papermodelers.com/forum/found-internet/4936-neato-gliders.html)" thread started by Outersketcher. In that thread there were tips by others leading to the simple G1 & G4 paper gliders (http://zovirl.com/tags/paper-airplanes/) by Mark Ivey.

I built those, and was stunned by the performance of the simplest G1 glider - it was fast, but seemed to have a L/D performance which astonished me, from what could be determined by living-room glides (a MUCH too confined space for this kind of gliders!).

I then studied the models from the Kobe Wings site (http://homepage2.nifty.com/ytat/). Letting the computer translate the pages from Japanese, I realized this was quite a movement in Japan, elderly men out with their highly-advanced, all-paper gliders, launching them with rubber catapults and achieving flights of quite some duration. The designs seemed very aerodynamically advanced and challenging.

I concentrated on studying several of the gliders found here (http://homepage2.nifty.com/ytat/zumen.htm),and finally chose the "Quetzal" for a number of reasons:

• It was the largest of the models there, and I wished to enlarge it further
• It had a Jedelsky profile wing, which would be most interesting to try out
• There were double fins, which would lend increased rigidity to the otherwise flimsy stab
• The fuselage was simple and constructed in a way that lent itself to easy redesign
• All in all, it could be made into a paper model resembling a classic model airplane glider.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26552&d=1254211314

Here you can see the original Kobe Wings "Quetzal" model in front of Mark Ivey's G1 & G4. They all come as white models, but what attracted me was the possibility of making a very colourful scheme. A quick look for "Quetzal" in Wikipedia (http://en.wikipedia.org/wiki/Resplendent_Quetzal) soon confirmed this, and from there on it was all a lot of fun.

First, the original "Quetzal" download was enlarged to 110 percent, making the fuselage fill up an A4 sheet length. I then "stretched" the wings & stab parts a further 112 percent span-wise. This is how much they could be stretched and still be kept on the same page.

The Japanese instructions didn't come out very intelligible through the computer translation, but I gleaned as much as that tip dihedral was supposed to be 20°, and centre dihedral 2 x 7°. The C.G. marks in the original are centered on 67 percent of the root chord, with a ± margin of 4 percent each way. The original relation between wing & stab angles of attack was carefully kept. This is it as far as design parameters go.

I then redrew the whole enlarged and stretched model, and redesigned the fuselage completely with a more "bulby" front part and pleasing lines (to me). Full use was made of the remaining space on the A4 sheet to lengthen the nose a further 10mm, in order to reduce the amount of ballast as much as possible. Cut-outs in the interior layers were made as large as I dared to save weight.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26553&d=1254211314

A white test-build served to check the viability of the redesign, and to develop the method of using melted solder for ballast (more about this in the build report below). It was also very interesting to make a complete evaluation of weights of the different parts and sections of the model:

Weight distribution (g):

Cut-outs in fuse 1,5
Fuse parts 4,1
Stab 1,1
Fins (2) 0,2

Total fuselage 5,5

Wing supp. (3) 0,4
Spars (2) 0,7
Wing parts (2) 7,4

Wings, no supports 8,0

Wing parts total 8,4

All parts 14,0

Glued sections:

Fuselage with stab & fins 6,2 = 0,7 glue
Wings, no supports 8,5 = 0,5 glue
Complete model, no ballast 15,2 = 1,2 glue (total amount)
Ballast (melted solder) 2,2
Coat of spray fixative 0,1

Complete model 17,5

Cut-outs in fuselage would seem to save ca 10 percent of total part weights, and more than a third of the fuselage weight. This is not entirely true, since cut-outs in the front will have to be replaced with ballast, although less than what the corresponding parts weigh, since the ballast is at the very front. So making the cut-outs is worth the trouble, particularly in the main section under the wings (and in the tail, were it possible).

Main weight (more than half of finished model without ballast) is in the wings, so anything that could be saved there would be beneficial. Anything saved at the tail & empennage would save double or more in required ballast. This is why the tail of the original design is so thin. I particularly appreciate the extra thin reinforcement strips of the outer layers - the wider parts at the front cover the cut-outs in the main section of the fuse, and the aft thin stripes add to strength of the tail, with a minimum of extra weight.

A light coat of spray fixative added only 0,1g. Trials showed that a coat of matt solvent-based varnish, brushed on, would add 0.7-1.0g, depending on how thick you lay it on. A sprayed coat of similar varnish would be lighter. It is probably a wise move for weather protection.

[Leif Ohlsson]

The kit is designed for utilizing A4 size to its maximum. If your paper size is US letter, print at 94 percent and you should be alright. In the Adobe Reader advanced print dialogue, there is an option for automatic centering. Make sure this is turned on.

Making the colour scheme was very satisfying. The result of sampling the four main colours from the Mayan "Quetzalcoatl" figure reproduced in the wing roundels, and letting them flow out over the entire model, really stunned me. If you want to enjoy the same result on your model, you'll need to try out reverse (backside) printing. So here's the deal:

• If you want to study the design further for a bit, and read the instructions, print pages 5-6 on ordinary paper. This is the black-and-white version, and every piece of instruction is included in that, too.

• If you want to make a test-build without wasting expensive ink, do the same, but this time use the kind of paper you've chosen for building the model. For the test-builds, I used heavy paper, intended for making business cards (220 g).

• For the full-colour version, first print page 2-3 on the heavy paper. Then turn page 2 over, and feed it same short end first into the printer, and print page 4 on the back of page 2.

If you experience problems with a mismatch between the front and back side, check your actual paper size. The heavy paper sheets I used had shrunk by 1 mm, from 210 to 209 mm width as compared to its stated A4 size. It took me three misprints and numerous attempts to adjust the kit to finally find this obvious source of mismatch.

There was nothing wrong with the kit after all. 1 mm less width of the paper than what the printer believes is the case results in 2 mm dislocation of the backside printing, which is more than the margin I allowed for when making the coloured reversed printing backside.

The solution to this particular problem was to feed the paper in 2 mm away from the main, fixed, paper guide at the second printing.

There should be no major mismatch lengthwise, even if your paper has shrunk in that direction, since you feed the paper in same short end first at both printings.

If you want to recolour the model, the original was made in Illustrator (vector parts), and the pdf file should open in any other vector (recommended) or bitmap program.

[Leif Ohlsson]

The idea behind a Jedelsky profile wing is that the underside is flat and angled like an inverted V, covered by a curved upper surface, glued on flat to the rear flat section, and forming a bulb at the forward half.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26554&d=1254211578

To achieve this, score the underside fold line from the printed (black & white pattern) side (but do not score the corresponding line on the top surface - this line is just for alignment and actually superfluous). Make the cuts at the wing tip front halves, glue in the four-ply spar, and fold the leading edge to a nice rounded fold. Dryfit the two sides so that the trailing edges meet.

To help achieving the correct bottom angle, a simple jig might be helpful. Make two 1 mm sheets 210 x 120 mm. Score and fold each in the middle (60 mm). Tape a 1-1,5 mm wire in the fold to get correct angle.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26555&d=1254211578

Start with the main (centre) section of the wing. Apply glue to the areas indicated, fold and match the trailing edges. Lay the wing down on the jig, and "massage" the leading edge top part so that a nice curved top profile is achieved, while glueing it down to the spar.

An alternative to a jig is to press down the rear, flat sections of the wing to the building mat, while the front halves are bent down toward the table underneath.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26556&d=1254211578

While the wings dry out completely under pressure like this, you could glue up the fins to the stab. Note that both fins and stab have ever so slightly curved profiles. This is to provide increased rigidity, and if you fold the tabs on the stab and follow the glue lines on the fins, they will help each other to maintain their respective curves.

In the photos, I am building two models in parallell, just to be sure at least one would come out right (they were both fine, actually).

http://www.papermodelers.com/forum/attachment.php?attachmentid=26557&d=1254211578

When dry, bend the wing-tip parts 20° (use the template provided in the kit), and glue up the tips much the same way. Unavoidably with the present kind of wing design, there will be a small gap at the front tip joint cuts. This will be filled out by small extra parts.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26558&d=1254211578

When the two wing parts are thoroughly dry, use the centerpiece dihedral template to rig a provisional jig (of sundry wood blocks or whatever) for the 2 x 7° center dihedral. Trim the center joint for a straight fit, and glue them together, taking care that the main part of the leading edge forms a straight line. Add the top center joining piece, to hold it together. When dry, add the bottom center joining strip.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26559&d=1254211592

To complete the wing, trim the tip joint covering pieces to a good fit, and glue them in very carefully. If you wish to make a quick job of it, omit them and fill the gap with some extra glue.

This part of the design comes from the original and it is still slightly unsatisfactory. I ought to try to come up with something a bit better eventually.

[Leif Ohlsson]

There are nine layers in the fuselage. A suggested glueing order is to first make three heaps of three layers each: The centre section with the optional launching hook for a rubber band, and two outer sections, one on each side. Be sure not to glue the forward section of one outer layer (4L or 4R), leaving it as flap to allow for the melted solder ballast later.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26560&d=1254211887

Let the three heaps dry out completely under pressure before glueing them together.

Both wing and stab sections are supported by the folded tabs included in the fuselage parts. Score these already before cutting out the fuse parts.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26561&d=1254211887

Building two models at one go has some advantages - alignment is easier for one thing. It is a good idea to mount the fuselage in a vice between some pieces of wood or thick card when glueing the stab and wings to the fuse. It will make handing easier, and alignment more exact.

When the glued-up model is all dried out, the fun part starts.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26562&d=1254211887

Weighing is fun, if you have one of these small scales. All my three test builds came out at 15.2g, possibly 0.1 g heavier in one case.

Now, on to the all-important balancing.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26563&d=1254211887

Mount a couple of suitable wood or thick card slivers in a vice, and place the model on them so that they coincide exactly with the CG center marks. Then cut a piece of solder and bend over the section of the nose where it is destined. Cut, or add to, the solder piece by piece, until the model balances well at the correct CG position.

Now for some smoke in your eyes.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26564&d=1254211929

Mount the model against a flat piece of metal, and fold up the unglued fuselage side part flap to access the front cut-out inside. Melt the piece of solder you so carefully measured out into that compartment. It looks really horrible, but is virtually harmless. The iron below will suck up most of the heat.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26565&d=1254211929

When you've melted all the solder, it will likely form a blob much to high to fit into the thin compartment. Further careful touching up with the soldering-iron and a suitable piece of wood or card will enable you to spread the half-melted solder evenly within the compartment, so that the flap can be glued up all tight and smooth.

http://www.papermodelers.com/forum/attachment.php?attachmentid=26566&d=1254211929

You're done - if you deem it necessary, spray the model with whatever you prefer, and go flying!

If you've achieved the correct CG some further trimming is possible by carefully bending the trailing edge of the stab up or down just a fraction at a time. My test models flew well pretty straight off the board.

Due to weather being what it is here in the autumn, I have not been able to try them out on more advanced, high-performance flights, or rubber band launches. Any reports of such would be most welcome!

Leif

[airdave]

Not personally interested in building this plane, but still an interesting and engaging project...and, once again, you have presented a detailed tutorial in an intelligent and thorough manner. Thank you very very much!

I will be waiting to see the future test flight results!

[pmbirner]

Thank you very much for this Lief. This looks like a very interesting project. I can't wait to try it.
Phil

[APA-168]

Agreeed, this is a fantastic project and I can't wait to give it a shot!

[birder]

That is so cool!! Nice job Leif, nice art work as well!!

[rmks2000]

Great stuff!

[buffalowings]

I just printed it out, it looks very good and should have great performance, but one question, what glue do you use?

[buffalowings]

also, do you have any other paper airplane links, I find them to be very cool but I can't seem to find other sites sporting these designs

[Gil]

Hi Leif,

Been wondering what you've been up to. Nicely done thread on "flyable" paper airplanes.

This would make a nice piece in the one remaining "stick and tissue" magazine. If you're interested I'll see what I can do.

It's also a good idea to seal the model (read waterproof) with several layers of acrylic spray to prevent the model from "sagging out". Absorbed moisture will quickly affect the models structure and performance.

Do you plan to use a rubber "slingshot" launcher?

Best regards,
+Gil

[shawnr5]

Very cool. Maybe, I can build it after I'm done with my Halloween stuff.

[Art Deco]

Cool idea and wonderful work, Leif ... and very professionally presented as always!

How far do you think this model could glide if launched from my 22nd floor apartment on a calm day?

[Leif Ohlsson]

1. Glue: I always use ordinary white glue, diluted with ca 20 percent water.

2. Other sites: My own trajectory was to explore the links in the original "Neato gliders (http://www.papermodelers.com/forum/found-internet/4936-neato-gliders.html)" thread, then the links given on the Kobe Wings site (http://translate.google.com/translate?js=y&prev=_t&hl=sv&ie=UTF-8&u=http%3A%2F%2Fhomepage2.nifty.com%2Fytat%2F&sl=ja&tl=en&history_state0=) (Google translated), and then other link pages following from that.

3. Water-proofing: I agree on the need for spraying the finished model. Personally, I will explore another route, namely to pre-proof the sheets by painting them booth sides with Future-type floor polish (the brand available here in Europe is called Pledge), diluted with 50 percent water. I believe this might be the same thing as (diluted) acrylic varnish. Do not try concentrated polish, brush strokes and uneven application will be too visible.

This has to be done with the paper taped to a flat surface. I use masking tape and glass plates. The paper will buckle something terrible soon after painting one surface, but drying out over 24 hours it will return to flat. Same procedure with the back side. So there is a 48 hours waiting with this procedure, but I think it is worth it. Haven't tried it on a model yet, but looking forward to doing so.

What you do not want to do is to varnish a finished flying model with anything containing water. That may be alright on an ordinary built-up model (and I have done so persistently), since the double surfaced structure & framework will keep the model straight. But on a flying model, with all those thin, one-layer surfaces, it is out of the question. Have tried it, and it is no good; it warps surfaces almost beyond salvation.

On the many blessings of floor-polish, see this site (http://www.smallflyingarts.com/Current_Content/Article_2/floor_wax.htm)

4. Rubber sling shot: I don't think I have access to the wide-open spaces required...

5. Stick and tissues mag: I'm curious, which one is that, Gil? And yes, please, that would be ever so nice of you...

6. Distance from 22nd floor: Well, Art, that's for me to guess, and you to find out, right? My guess would be at least 600 meters with an estimated L/D factor of ca 10. The problem for you would be to achieve an absolutely straight flight. I deem the possibilities of that as close to nil. Wich isn't a disadvantage, since ordinarily you do wish your model to fly in nice wide circles, right? (Preferably to the left, if you are a right-handed thrower; the launch then will be to the right, slowly straightening up and transforming into a wide left circle without abrupt transitions). And if you feel an urge to try it, please trim out the model by ordinary flights on outdoor ground level first...

Further tips: I've found this page on model aircraft aerodynamics (http://adamone.rchomepage.com/index5.htm) extremely fruitful. The C.G. calc pages, found at the bottom of it, can be saved as a handy tool, and they even include a variant for canards. There is also a pdf on Canards containing pretty much the information used for the CG calc pages, I believe. In addition, a formula for calculating fin size (of canards only, unfortunately).

Right now, I'm busy trying to apply these learning to the next version of the Quetzalcoatl. Some adjustments necessary compared to my initial guesswork...

Leif

[Leyvonne]

Finally a plan in english instead of japanese; thank you. Now I can under stand how to make this model. Nice job on the colors too.

[Leif Ohlsson]

A number of similar gliders, with full instructions in English, can be found at the link in this thread: http://www.papermodelers.com/forum/found-internet/8729-canon-range-high-performance-all-paper-gliders.html#post129387

[Don Boose]

Wonderful stuff, Leif. This all has great potential for some projects with the grandsons.

I'm not sure which magazines Gil has in mind, but this is the kind of stuff that fits the American magazine Flying Models to a T. They do a lot of free-flight articles and like descriptions of innovative techniques. The current issue has a stick and tissue free-flight rubber-powered Fairey Firefly I by a master designer-builder, Tom Arnold, that has a framework made of water-soaked reeds bent around a blue foam core. Once the model framwork is completed, it is dunked in lacquer thinner to melt the blue foam. http://www.flying-models.com/pdf/contents.pdf I describe this just to show the kind of thing that appeals to the Flying Models editorial staff and the readers. This magazine has also had several mentions of paper models, both as models in and of themselves, and also as a basis for scale flying models with the paper model printed out on tissue.

Don

[Leif Ohlsson]

Glad to see you're back from your vacation Don, and hope you and your wife had a good trip!

The suggestion about using blue foam (which I don't really know what it is, but I can guess) which is dissolved, sounds like something Gil would love to get into. I've been thinking about something like that for building spoked wheels.

But then again, there are so many good methods nowadays for doing spoked wheels, so perhaps it won't be necessary.

Anyway, good to hear from you again - your regular comments is an important stabilizing feature of this forum!

Leif

[Don Boose]

Thanks for the welcoming words, Leif! We had a wonderful time in France (it was our first visit to that country).

Blue foam is a dense form of expanded polystyrene (Polystyrene - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Polystyrene)), similar to the stuff that is used to pack electronic devices for shipment and that forms the "core" of Foamcore board (Foamcore - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Foamcore)). I'm not sure what it is called in Europe.

Expanded polystyrene is also used for egg cartons in the United States and there have been many articles in the American flying models magazines about making small hand-launched gliders from egg cartons.

The "blue foam" version is used on a large scale as house insulation and other such applications and has become very popular among craftspeople because it is dense enough to be carved. And it is not always blue. Art and craft stores sell a brown version that has characteristics of a cross between balsa and basswood (linden).

Back to the topic. Once I have policed up the battlefield following the trip to France, I intend to collect all of your material on these hand and catapult-launched gliders for future reference. It is wonderful stuff.

Don

[Don Boose]

Bravo, Leif! Superb graphics and clear instructions. Back in the day, my son and I built many many Whitewings gliders using similar methods.

Don

[Leif Ohlsson]

Six years after the fact I ran into this video, which give a pretty good picture of what these paper gliders look in the air. Note the number of planes in the air simultateously, their high speed, but also their very good glide angles.

fgg2I6saq-s

After watching it I clicked the playlist of the uploader, Yasushi Toguchi (https://www.youtube.com/channel/UCVfUQY7qgoUfiFU_f2HYrPw). There are several videos on the same subject; some of them may be even better than this one. Let's check them out... :)

I should aso include the link to the blogpage where I found the video, Google-translated. The name is kind of intriguing... - "Morning Cafe: Paper Airplane (http://morningcafe-yamcha.blogspot.se/p/blog-page.html)"

There are at least three links on that page that seems worth pursuing:

• Airplane (http://morningcafe-yamcha.blogspot.se/search/label/飛行機)

• Airframe (http://morningcafe-yamcha.blogspot.se/search/label/機体)

• Flight (http://morningcafe-yamcha.blogspot.se/search/label/フライト)

http://www.papermodelers.com/forum/attachments/design-threads/295224d1474050993-quetzalcoatl-high-performance-all-paper-glider-unit-2.jpg

Here's a photo from one of those pages, depicting the author's favourite "Unit 2". This general layout seems to have stuck as the standard design in Japan. It is much like the one I picked as a template for the Quetzalcoatl six years ago, although the building methods and design details are probably much more advanced today. One of the subjects above is about the washout of the "Unit 2", which seems most interesting!

Those notes were written at the beginning of this September, so we are right up at the design front here!:)

- Leif

[ViperPilot]

Thank you for posting this, Leif! Very informative, great Build guidance, and something that looks fun to both Build and fly!

Alan :)

[card modeler]

¡An impressive model in any point of view! Congratulations on doing so beautiful job, Leif!
I has builded many kinds of model gliders on my entire life and enjoyig them, but I want to replicate nice paper model gliders in scale and good flying too, from now on! They must be in 1:10 scale, maybe. It is my personal challenge and pleasure! Cheers!

[Leif Ohlsson]

1/10 ought to be an excellent choice of scale for a flying glider model! Please report all progress, whether successful or not. Kind regards, Leif

[card modeler]

Thanks you very much Leif! Your post encourage me to build that model!
I´ll be in contact

[ashevilleangler]

I have completed a process to translate the instructions of Mr. Toguchi for his two glider designs into English. I if Leif gives the okay, I will post them to this thread. One question that came up for me while doing this work is about the paper Toguchi uses for his models. He says that he uses 225 kg paper. This is obviously a Japanese paper weight convention. I have not found a good reference for converting it to gsm or even some other intermediate card stock weight like bond, bristol or index. I think that it might be close to 110 lb index stock which is fairly heavy, but that's really just speculation on my part.

Anyone here know what 225 kg Japanese paper might be equivalent to in any other paper weight measuring convention?

Curt

[SCEtoAUX]

Found this page that states it is 260gsm:
http://global.rakuten.com/en/store/penshiru/item/4901480794839/

This page from the same online store says it is 0.28mm in thickness:
http://global.rakuten.com/en/store/maruraku/item/683069/

Seems to be close to 300 series Bristol board which is very stiff.
:)

[snowmanX]

Thank you for posting this!

[ashevilleangler]

Thanks Doug! I think that's probably the "right stuff" for these models.

Curt

[Leif Ohlsson]

Hello Curt, you certainly don't need permission to post addition to this thread. I for one am looking much forward to what you've done. - Leif

[card modeler]

Leif, those kind of flyings in the video, are that I want do with my dreamed 1:10 scale card model glider!

This is I´m working for, just now!

[card modeler]

Mucha flying card model317419

317420

[card modeler]

317421

I print this Marek model in B&W on couche cover 250 gams card.

The model needs 3 sheets sized 13 x 18 1/2 inches to print all the parts, resulting in 1:16 scale model, with 37 inches wingspan.

I´ll build this model to test the parts assembly, the stronger the model and the flight capabilities.

Then, I´ll be able to build the same model in 1:10 scale

[Leif Ohlsson]

Looking forward to this. Good luck! - L.

[card modeler]

Thanks very much Leif!
Mucha glider 1:16 scale. The fuselaje parts, I am building this model in my free time.

[Leif Ohlsson]

Nice work with the uncolored parts. - L.

[card modeler]

the fuselage parts

[card modeler]

Making shape to the central beam to reinforce the wings, and the new wing profile for increase lifting, outlined with a pencil.

[card modeler]

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[card modeler]

I maked a triangled shape to the reinforcement beam, instead of incrase de thickness of that part, so it results lighter, but still strong

[Leif Ohlsson]

Seems like a good profile! - L.

[card modeler]

And finally, I glue the modifiend card wig profile to 5 milimeters thickness foamboard to make the better performance wings shape.

[Leif Ohlsson]

Foam is a really good idea. Easy to cut; like butter :) - L.

[card modeler]

Thanks Leif. You encourage me to continue my flying glider proyect. ¿How do you think about the triangled master beam I maked for the wings reinforcement? I do that to get the whole model weight lower. And I want to tell you: The 5 milimeters card board material I have used for making the wigs profile, is NOT an easy stuff to handle. This kind of card, with two thin card faces and the fiber foam between them, is hard to cut in a clean way! You can see the picture. I like not this very much! but I acepted that, because the thin card faces of the resulting part are properly delinied, with the correct wig profile to make up the wings on the proper shape. But yes! this Card Board is a strong and ligth material for the reinforced parts, to get a good flying card model.

[card modeler]

This 5 milimeters Cardboard material, I can found in my stationery shop, is nice to cut it, but you must be quite sure to do this with a sharp cutter in straight way over the desk. So you can do an accurate job. The only disavantage with this material is, when you slide the cutter, you may compress, instead of cut the foam fiber core of the Cardboard, so you can not be able to get a nice, clean cut, every time.

[Leif Ohlsson]

Good to hear about your experience with the 5 mm cardboard material. I was thinking about thinner foam (with no card) laminated to the paper parts you want to cut out. Looking forward to more about the triangular spar. - L.

[card modeler]

I come back!