Discussion in 'Tips, Tutorials & Tools' started by Jimi, Nov 25, 2004.

  1. Jimi

    Jimi Member

    Could i ask, umm, what's the best method to use for making really small spinners? it's really small.. about 1 cm tall and the diameter of the base is about .8 cm. And what's the cardboard thickness that you guys recommend? Though i made one, it's rather out of alignment as in REALLY out of alignment when spun.. and it has been my 5th try. :( (oh yeah, the spinner looks like this (from a zlin 142).
    oh yeah, out of the topic but since i used an LOM m337CE engine, my cowling also looks like this :D looks weird i know.
  2. yaniv

    yaniv Active Member

    can u please sow us how is the part of the spin looks like?
  3. Jimi

    Jimi Member

    it's the red thingy spinning in front.. :D come to think of it, i used a Ivoprop magnum 2 blade propeller. so, i am using a propeller designed by Ivo Zdarsky (a czech refugee that seeked political asylum some time before) and strapped it to a czech built engine.. huh?!
  4. shoki2000

    shoki2000 Active Member

    Jimi - you are showing the real thing when the problem is with its card representation.
    To help you we woulfd need to see the part you are trying to build :D
  5. Gil

    Gil Active Member


    One way is to make a cone which has the diameter of the spinner as its base (0.8 cm) and is as high (1.0 cm). Waterproof with lacquer, dope or shellac. Use spackle to fill out the contour (make it oversized by a little to allow for sanding to shape later). Use plasticine modeling clay to fill the inside of the cone so a dowel can be inserted to allow "spinning" the spackle to shape. Let the spackle dry completely before sanding to shape.

  6. charliec

    charliec Active Member

    Another technique is to adapt Ron's technique for making wheels (in the article section). Build the spiinner from a stack of 2mm card disks to approximate the shape - glue together with CA gel glue - drill out a hole in the centre of the disks part way through the stack - insert fine screw - use the screw to hold the stack in a drill chuck. Use reasonably low speeds initially - sand down to desired profile. You can put in the location holes for the propeller blades by cutting out slots in the appropriate disks.

    I'll see if I can come up with an image.


  7. Peter H

    Peter H Member

    A papermodel approximation of what you need is a cone. A cone has height and a circular base.
    A cone with zero height is a full circle. As the height increases then
    a fillet is removed. I use an angle to determine the size of the fillet.

    Your cone is height=10mm. and a circular base of 8mm. diameter.


    Using pythagorus the inclined length of the cone is sqrt((4^2)+(10^2)) This gives 10.77mm.

    Looking forward a bit into the construction this gives a pattern of a circle of 10.77mm radius **BUT** the cone would be zero height and it does not have a circular base of 8mm. diameter so to translate all the properties correctly a fillet needs to be removed.

    Ratio of pattern to actual cone is (pi*8)/(2*pi*10.77)=25.13/67.66=0.37

    The angle of the fillet then is 360-(360*0.37)=360-133=227 degrees.

    So with all the math crap done....

    1)Draw an arc of 10mm radius and 133 degrees.
    2)Add a glue tab if you need it and cut a small circular piece out of the centre of the arc (ie. 1mm dia) to allow clearance for the the paper/card to roll to a point.
    3)Check everything and adjust if the thickness of the card affects the final dimensions.

    If someone wanted to get picky (Help Maurice !!) there is bound to be a formal way of presenting this. Also note I've done a bit of approximating numbers since no one except Ron can see the difference in 0.005mm.

    This approximation is just a cone but if you wanted a spinner with a smoother approximation you would then probably develop a conical frustum and a cone. It really depends on how far and small you want to get.
  8. Ron

    Ron Member

    Wasn't there an amazing little cone generating program floating around somewhere? I seem to recall that it did multi-segment cones and maybe even lunes (or maybe I'm a loon?) All that was needed was the base diametre, the height and the number of segments. Peter, you flatter me too much :) My eyes are getting bad to the point where I've upped my favorite 1:33 scale to 1:24!

  9. NOBI

    NOBI Active Member

    Hi Jimi,

    I think best method of doing a small spinner should be as picture below, i also attach u a PDF file (in zip) of spinner u want too (Hight = 10 mm and Diameter = 8 mm).
  10. charliec

    charliec Active Member

    As promised earlier - an image of a spinner made from a stack of card disks.

    It was disinterred from a pile of "failed model" parts so it's a bit bashed around.


  11. Gil

    Gil Active Member


    Are you building the I-16?

    Nice spinner. And I thought I was the only one around that had the bad habit of keeping failed attempts and other test parts around to look at...,

    Best regards, Gil
  12. charliec

    charliec Active Member

    I-16 ? - not any more - decided that aircraft models just weren't interesting enough for me to finish it.

    I always keep bits and pieces - it's a bad habit from writing code - you can always find something useful, even if it's a lesson in how not to do it, in old stuff.

    If there's any interest I'll write the technique up.


  13. lunarhighway

    lunarhighway Member

    i have two other techniques i sometimes use for small spinners. altough they're not "pure" paper techniques :oops:

    With the first, you try to approximate the shape with a paper part, made out of one or more cones (as with a lot of models). if the part is really small a single cone will do. You could make it lightly longer in length, and maybe a little smaller in diameter(?) than what it should be. When buiding, fill the inside with white glue, especially the front. At this point you might also want to add a piece of metal wire of wood, that can later be used to attach the spinner, so it can really spin, but more importantly will give you something to hold on to.
    Let the whole thing dry toroughly (i put it on the radiator in my room) than you can sand the tip to a shape that is more like the real thing (that's why it had to be longer). now comes the difficult part: cover the entire spinner with white glue, and suspend it upside down in a place where the glue can dry. the glue will run down to the tip and if you applied the right amount, it will become approximately the right shape. you can alsways shape the glue a bit with a small tool, and by thinning it in some areas with water. When dry, paint and sand, and apply more glue if needed. you can also build up the shape further by warping small strips of paper aroudn the spinner, and sand smooth again. When finished, paint the right color and noone will see the messy work that went into it :)

    The second will probably not be popular with paper purists :D . it's a variation on heatforming conopies: take a plat piece of plastic, the kind blister packs that cover a lot of products are made of . and look for a paintbrushhandel, or anything else that resembeles the spinner you want to make. Heat the plastic (i've heared ovens, hot water, hairdryer) but personally u use a lighter, kept at a sufficiant distance from the plastic. When the plastic goes soft, quickly pull it over the paintbrushhandel, and there you go. might nog not work perfect the first time, but after some experimenting with heating techniques and plastic, you'll get something the right shape.

    If you use FIRE be carefull!!!!!! don't use it around all that precious paper you have!

    both techniques may look a little messy at first, and work best on small parts (i usually build 1/72) but with care they can both give exelent results imho.

    hope this was somewhat usefull in adittion to the other great tip i read here :)

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