Flying RC Paper Model

Discussion in 'Aircraft & Aviation' started by PaperEngTech, Dec 19, 2005.

  1. PaperEngTech

    PaperEngTech New Member

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    My current design project is a radio control card model. The wingspan is 91.4 cm. (36 inches) with a fuselage length of 56.5 cm. (22.25 inches). My goal is to attract more attention to our great hobby by designing a model that flies and is powered by an electric motor. My first design is a rather plain looking remote control trainer. It currently weighs 22 grams as shown in the pictures. It is constructed using a slot/tab method with a lot of edge glue joints. The emphasis is on strong underlying structures that can take the flight loads and the occasional mishap. Future flying models will be of a scale nature, not having the box like appearance. If there is any interest in this type of card model, please let me know and I will continue to keep you updated on my progress and design/build methods. My inspiration comes from all the amazing card models and expertise that I read about on this and other sites. Also, is this the correct forum for this post? Thanks to all for the inspiration!

    Bob

    Attached Files:

  2. Rick Thomson

    Rick Thomson Member

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    I for one, would be interested in how your project turns out.
  3. Gil

    Gil Active Member

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    Are you aware that the RC modelers are using paper models as templates for RC models made out of sheet styrofoam? They've gotten some fairly decent results and great looking card, ur, sheet styrofaom models out of the deal. Corrugated cardboard has been used for some time now by RC modelers and the models seem to be pretty tough. They thin cheap polyurethane with paint thinner by about 3 parts thinner to 1 part urethane soaking the cardboard in the mixture and let it dry for two days before using. It becomes very stiff, works like wood and is waterproof.

    Keep us informed with lots of photos in any case and good luck!

    -Gil

    P.S. You do neat work.
  4. k5083

    k5083 Member

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    I will be following your project with interest as well. I have been working off and on on a similar project for some time. I originally started building some RC models out of sheet foam using paper kits as patterns, as Gil mentioned that many others have done, but I was never happy with the way the fuselages turned out. I prefer to build smaller park-flyer types with 12-inch to 24-inch wingspans, and for that size, I have decided that the same cardstock that we use for our regular models should be adequately strong. I am using foam for wings, tails, bulkheads, and internal structure. I have one bird ready to install its engine and guts, and am just waiting until I prang my store-bought plane so that I will have engine and guts for the paper one.

    For me the ideal thing would be about a 20-inch warbird comparable in size and weight to the foamies from Cox in the 2nd column of this web page:

    http://coxmodels.com/

    I would put the same hardware in it that one would put in one of the Coxes. With a lithium polyer battery the cost of the on-board components would be about $80 per plane.

    I am also working on some 12-inchers designed to take the gear from a Wattage Micro Flyer:

    http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHSW0&P=FR

    These have much more limited control but the price is right and it would just be fun to see some of our favorite paper model designs flitting around the sky. Besides, the RC companies will never issue foamie park flyers of a lot of the subjects that we can build.

    August
  5. lizzienewell

    lizzienewell Member

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    I am interested in your work. I started thinking about cardstock as a strong lightweight material when I was selling Nordic skis. The very most expensive and lightweight Nordic skate skis have a core that looks exactly like cardboard soaked in polyurethan. The rep of course claimed it wasn't. But it is still some sort of flat fiberous stock glued together and soaked in some sort of resin. It is strong durable and lightweight.
    The cheapy skis have foam cores. They don't last as long and have inconsistent flex characteristics.

    I think we are on right track with the best materials for strong lightweight construction. Fischer claims the heighest strength to weight ratio in the ski industry.
    Here is the link to fischer's image of their Aircore.
    http://www.fischerskis.com/upload/p...chnology_big_b90be64648e07c236f54f4748062462f

    Here is their website.

    http://www.fischerskis.com/en/

    Yesterday when I showed a model to someone they wouldn't believe it was made of paper or that paper could be so strong.

    Here is the interior structure of my model. I think that building with solid bulkheads makes a stronger structure than buildng a stick frame. If I were going bigger I start cutting holes in the bulkheads to reduce weight.

    Take a look at Fischers Airchannel core for another way to build light and strong.

    Here is an early version of my aircraft structure. I've since doubled the number of bulkheads, changed the propulsor design, and removed the sideways gluestrips from the edges of the bulkheads. I've kept the front to back furring strips and the glue-strip parts on the edges of the tail and keel. I glue the skin to the furring strips. The bulkheads create the shape and the rigidity. I think that building the fussalage as a single beam might be better than building paper into sticks. Paper can be used in much thinner members then wood can be. I'm no engineer though. I design by eyeball and gut feel rather than by equation. I expect that a cylindrical fussalage will be stronger than a square fussalage. The tubing of bicycles is round not square. And the newer fischer skis have a curved topsheet. Maybe my bulkhead construction allows curves. I do this all by gut feel.

    The design has stood up to kids throwing the models.

    I do want to see how the RC model goes. I like thinking about trying it but the propulsors that I want don't exist and probably wouldn't fit with an off the shelf RC unit.

    Attached Files:

  6. PaperEngTech

    PaperEngTech New Member

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    It's really exciting to see interest in building strong structures out of cardstock. Am a bit nervous getting replies from elite, extreme and supreme vetrans though, they have been card modellers a lot longer than this newbie! If I post anything that seems inaccurate or if there is a better way, please correct and let me know. Lets move forward together and show the world what can be made from paper!

    The reason for the 'stick' type construction is light weight and the box structure is for easy building. I agree that cylindrical structures will be much stronger, next design will use them. An even distribution of stress/strain is the goal. I was once told that the best aircraft construction material is air (love paper though!), its lightweight. All of the fuselage 'sticks' are single thickness 145 gm/m2 (67#) stock with no coatings to keep it light. Weight is important since plane damage is kept to a minimum with a low gross weight and lower inertial mass results in quicker responses to control inputs in flight.

    To make the frame I apply a piece of plastic food wrap to a thick piece of glass. Then using repositionable glue stick, a single sheet fuselage side is attached to the plastic wrap surface. The now vertically oriented 'web strips' are then edge glued to the perimeter. After that, the top fuselage side is carefully recessed into that assembly until tabs engage and fit into slots that assure an even width when completed and 'trap' the load bearing sides between them. The edges are then glued around the perimiter by using tweezers to pull the vertical web flanges outward until the glue is applied. Light pressure is used to reseal the joint. When dry, the part is removed, the underlying tabs are glued then trimmed and finally the 'web' flanges are trimmed (ultimately traps the main building material - AIR). I can post pictures of the construction sequence if requested. Also could make a pdf available for a wing rib or fuselage side if anyone would like to try this.

    Could everyone do me a favor, if you post a picture of an aircraft structure could you please weigh the part and post the total weight associated with each picture. We can all learn a lot that way.

    This project is not just about a flying cardstock airplane, it is the craft of extending paper modelling design and building techniques that can be applied to any type of model increasing their durability and adding functionality. I am just disappointed that this leaves little time for me to build cars, mechs, buildings, ships, spacecraft and scale plane display models etc. Love them all!

    Lizzienewell, I lived in Alaska for two years, what a beautiful place, I miss it. Can also appreciate the amount of work you have put into your model.

    Thanks,

    Bob
  7. lizzienewell

    lizzienewell Member

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    I'm fascinated by efficiency. I've been working more for the appearance of efficiency and high strength to weight ratio than I have been working for the actuality of this goal.

    I think this is why I'm interested in airplanes. I also interested in human powered vehicals and in sports that put a high primium on efficiency. I do Nordic skiing, kayaking, and bicycleing. If we applied the thinking involved in HPV design to all of our machinery we could easily solve the "energy crisis" and global warming.

    I'll check on my weight. With fully extended wings my craft has a 9.5 inch (24 cm) wingspan. The fusalage is 4.25 inch (10.5 cm) long. It weighs an ounce. I'm sorry I don't have a gram scale.
    I could cut the weight a bit but my scale wouldn't be accurate enough to give the difference.
  8. Gil

    Gil Active Member

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    You might want to obtain a copy of Jack Lambie's book, "Composite Construction for Homebuilt Aircraft" published by Aviation Publishers and distributed by Motorbooks International. Chapter 5 is titled "Paper/Fiberglass Kit Planes". It covers Molt Taylor's "Taylor-Paper-Glass" method of building aircraft structures. Instead of polyurethane he uses polyester resin thinned with polystyrene monomers to "soak" the paper followed by glassing the outer envelope of the part. You will suprised by the strength of these composite structures and they are just about the lowest cost for for their strength that you'll be able to find. I regularly soak paper with thinned instruement lacquer to achieve strengthening and to water proof paper structures. It has little or no effect on inkjet inks and enhances the sandability of the paper.

    -Gil
  9. PaperEngTech

    PaperEngTech New Member

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    Instrument Laquer

    Gil, could you give us the brand of instrument laquer that you use and where to purchase. Most interested in waterproofing specific parts, thanks for the information.

    Bob
  10. Gil

    Gil Active Member

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    A more common name for instrument lacquer is Nitrate Dope and can be found at well supplied hobby shops. Sig is a popular brand. It can also be purchased from chemical suppliers as a dry powder which can be "wetted" with acetone to the desired consistency. Use acetone to thin the dope with as purchased at the hobby shop.

    -Gil
  11. goney3

    goney3 Member

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    *adds to Amazon wish-list*
    That looks like a great book, thanks for posting this suggestion!

    Cheers,
    Keith
  12. mbauer

    mbauer Cardstock Model designer

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    RC SR71s Caution: Hot Rodding Paper Airplanes IS Addictive!

    Hi Everyone,

    I too am working on a cardstock RC model. The retracts are the hardest, but I think the problem has been fixed! The white one was a concept model! GWS edf75-4a Lipo 2400 mAh 12.3 volt 16c (2 each) Proto weighed in at 38-ounce.

    Soon, real soon!

    I like yours it is a beauty!

    The inventor of the Jetx series of model jet engines originally used cardstock for his models. Cheap and the prestressed "skin" was his strong points of why he used it!

    Best regards,
    Mike Bauer

    BTW Ihave test different card stock. Wausau 110 is easiest but weakest, while Springhill 110# index is the strongest! I use Springhill Tag 125# printed on 24" x 36" sheets!

    The books I used to design these models helped greatly. One is super hard to find while the other has a 4th edition the last I looked on eBay. Titles: Model Aircraft Aerodynamics by Martin Simmons -lot of technical stuff, lots of math, but great airfoil plot lists if you know how to use them; Design & Build your own R/C Aircraft ByKenneth L. Smith cright 1984- this book explains how to use the other book! Real easy and only 85 pages!

    Attached Files:

  13. mbauer

    mbauer Cardstock Model designer

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    RC SR71s Caution: Hot Rodding Paper Airplanes IS Addictive!

    Hi Everyone,

    I too am working on a cardstock RC model. The retracts are the hardest, but I think the problem has been fixed! The white one was a concept model! GWS edf75-4a Lipo 2400 mAh 12.3 volt 16c (2 each) Proto weighed in at 38-ounce.

    Soon, real soon!

    I like yours it is a beauty!

    The inventor of the Jetx series of model jet engines originally used cardstock for his models. Cheap and the prestressed "skin" was his strong points of why he used it!

    Best regards,
    Mike Bauer

    BTW Ihave test different card stock. Wausau 110 is easiest but weakest, while Springhill 110# index is the strongest! I use Springhill Tag 125# printed on 24" x 36" sheets!

    The books I used to design these models helped greatly. One is super hard to find while the other has a 4th edition the last I looked on eBay. Titles: Model Aircraft Aerodynamics by Martin Simmons -lot of technical stuff, lots of math, but great airfoil plot lists if you know how to use them; Design & Build your own R/C Aircraft ByKenneth L. Smith cright 1984- this book explains how to use the other book! Real easy and only 85 pages!
  14. John Griffin

    John Griffin Member

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  15. John Griffin

    John Griffin Member

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  16. Gil

    Gil Active Member

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    Composite Construction Technique

    Hello All,

    I've been experimenting with using depron and paper to construct static and flying card models. Depron is a sheet styrofoam commonly available in Europe and imported here for use in model making. It is the same sheet material as is used for meat trays in the supermarket.

    A simple airfoil mold is made out of cardboard into which a depron wing blank is inserted and clamped. This is then baked in a 270 degree Fahrenheit oven for about 20 minutes. The depron yields to mold clamping pressure under the heat and conforms to the mold. Tacky glue is then spread on the molded depron wing surface and thinned PVA is spread on the printed paper cover before the paper is folded over the depron wing blank. The assembly is then wrapped in a thin layer of foam and reinserted into the original mold and left to dry. Kind of low tech vacuum bagging technique. The resulting assembly is then removed and areas of high curvature (wing tips) is then coaxed into place by careful trimming and burnishing down to the rounded depron surface with a burnishing tool.

    Wings made in this manner are light and strong and have the look like molded plastic with paint and detailing. I've also experimented with horizontal and vertical stabilizers using the same technique with the same great results.

    -Gil
  17. Gil

    Gil Active Member

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    Composite Construction Technique

    Hello All,

    I've been experimenting with using depron and paper to construct static and flying card models. Depron is a sheet styrofoam commonly available in Europe and imported here for use in model making. It is the same sheet material as is used for meat trays in the supermarket.

    A simple airfoil mold is made out of cardboard into which a depron wing blank is inserted and clamped. This is then baked in a 270 degree Fahrenheit oven for about 20 minutes. The depron yields to mold clamping pressure under the heat and conforms to the mold. Tacky glue is then spread on the molded depron wing surface and thinned PVA is spread on the printed paper cover before the paper is folded over the depron wing blank. The assembly is then wrapped in a thin layer of foam and reinserted into the original mold and left to dry. Kind of low tech vacuum bagging technique. The resulting assembly is then removed and areas of high curvature (wing tips) is then coaxed into place by careful trimming and burnishing down to the rounded depron surface with a burnishing tool.

    Wings made in this manner are light and strong and have the look like molded plastic with paint and detailing. I've also experimented with horizontal and vertical stabilizers using the same technique with the same great results.

    -Gil
  18. mbauer

    mbauer Cardstock Model designer

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    John Griffin

    Wow, what a build! It is truly beautifull!

    Mike Bauer
  19. mbauer

    mbauer Cardstock Model designer

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    John Griffin

    Wow, what a build! It is truly beautifull!

    Mike Bauer