Cac Ca-2 Wackett Trainer Prototype

Discussion in 'Aircraft & Aviation' started by paul a, Apr 2, 2007.

  1. paul a

    paul a Member

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    I,m going to try to build this balsa plane out of paper.looks like it won,t be to hard.I figure if they can model card model out of different materials why can,t I do the reverse. so off to the store for some chip board.dbdesigdbureau.buckmasterfamily.id.au/plans.htmshure hope it flys!

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  2. yaniv

    yaniv Active Member

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    good luck my friend :)

    i will look on this trade coz i like to make a paper mdel of jhon p47 into r/C model
  3. paul a

    paul a Member

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    is thatgoing to motorized or a glider?
  4. paul a

    paul a Member

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    the easyest part to start with is the stablizer .I built up the frame with three sheets of 100 lbs stock . cut out the frame then cover it with 20 lbs stock. next will be the rudder.

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  5. paul a

    paul a Member

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    rudder.

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  6. paul a

    paul a Member

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    Tail complete.wings will be next.

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  7. paul a

    paul a Member

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    cut out the wing in the same way as the tail.the ribs are I beamed for strength.the addittion of a leading edge helped with warp and curling issues.maybe I,ll add a stringer in the top.the landing gear wire sets the angle on the wing dihedral.

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  8. paul a

    paul a Member

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    www.bsdmicrorc.com/this is the sight I,m going to get the motor and wheel and stuff if this project works I think paper RC is in my future.
  9. k5083

    k5083 Member

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    Paul

    I admire your build, but I'd be concerned about two things for a flying model. One is strength under compression, cardstock lacking the stiffness of balsa even when laminated. A bigger concern is weight. Are you shooting for a target weight, or weighing parts as you go? Balsa may be difficult to get where you live, but it's a lot lighter for the same strength than cardstock. So is sheet foam, which most small-model builders use now.

    Most of all, why cover with 20 lbs paper stock and not tissue? Even if you're a purist, tissue is still paper and it is very easy and cheap to get. Any greeting-card shop has packs of tissue for gift wrapping, and the office supply stores sell pretty much a lifetime supply (80 big sheets) for under $10.00. It wouldn't be as light as the Japanese tissue that the serious builders use, but so much lighter than typing paper. I'm afraid especially that covering the tail feathers with such heavy material may make it really hard to get your CG in the right place.

    Anyway, it certainly looks great. I'm rooting for you!

    August
  10. paul a

    paul a Member

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    I never thought of weighing the parts. I just weighed the completed tail it weighed a half of a gram I think that might be less than balsa. I find the 20 lbs paper adds strength to the overall build.thank you for your concerns and suport.
  11. k5083

    k5083 Member

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    It might be light enough, especially with the right size electric motor. I look forward to seeing how it comes out!

    August
  12. Darwin

    Darwin Member

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    I can't keep myself from chiming in on this subject, the build string has wandered smack in the middle of my playground (I have been building and flying stick and tissue models since 1955, and seriously investigating flying card models as early as 1985. I think you are traveling down the wrong path by attempting to use stick and tissue construction techniques with cardstock/paper. The difference between the two is like the difference between spaceframe and monococ approaches to building sports cars (you probably had to be an active sports car nut during the 60s to truly appreciate this). Stick and tissue carries strength through the framework, and (at least until carbon fiber) balsa wood has just about the highest strength/weight ratio of all modeling structural materials, INCLUDING CARDBOARD...the model skin contributed a (at least moderately) impermiable surface for airfoils, and aescetics for those who wish models looking more or like the real thing. Card models carry thier strength through the skin, and the framework is only along to maintain a reasonable contour of the skinning surface. Point is, if you want to build a flying model out of card, use cardmodelling techniques. Use 65 pound cardstock, not 20, and don't try duplicating a balsawood framework....for the tailfeathers, a simple spar will suffice for the stab, and the rudder might not need even that. Elimination of the framework largely cancels out the heavier weight of the skin. It will work well for gliders and electric or fizzpower motors. Card, unfortunately, doesn't work worth a tinker's damn for rubber power, unless you cheat and use a motor stick to provide the strength required to keep a quadruple-knotted rubber motor from turning the fuselage into an oversized spitwad.
  13. paul a

    paul a Member

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    what is a motor stick and if it was made out of paper is that cheating?
  14. k5083

    k5083 Member

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    A motor stick would be a wooden shaft that carries the rubber band, like the fuselage of one of those Guillows rubber-powered toy planes (Sky Streak, etc.). You would bury this in the middle of the fuselage.

    I don't think you could use paper for it. It would crumple when you wound up the rubber.

    August
  15. paul a

    paul a Member

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    what if I use a paper tube and ran the rubber down the middle .I could spirel wind the tube in two or three direction for strengh.
  16. paul a

    paul a Member

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    The tube idea worked . the rubber broke with no damage to the tube .now all I have to do is see how thin I can make the tube. this one is at 5 grams.

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  17. k5083

    k5083 Member

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    Good work! The rubber broke?? If you're using contest grade rubber that was quite an achievement! How many turns did that take?

    5 grams is a lot but as you say, you can now experiment with how much you can shave off. I have heard of the tube approach being used before.

    Make sure there is enough diameter for clearance of the rubber; they bunch up quite a lot when you get to triple and quadruple knots.

    August
  18. paul a

    paul a Member

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    135 turns not contest grade.I notice the thump when winding . probly need to concider a cone shape.
  19. paul a

    paul a Member

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    Will work out the bugs over the weekend and see if I can come up with small movie clip .
  20. yaniv

    yaniv Active Member

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    nice work my friend

    i think about making jhon model to a MOTOR 1 not a gileber

    i see once on the fiddlersgreen website some one that do it for a p47

    also on some polish site about some one how make its from the MALY P47

    http://www.konradus.com/forum/read.php?f=1&i=117183&t=117183

    (dont know way we all select p47 hahah)