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I’m making balsa wood toy planes. I want the tops of the rudders to look fair. Been thinking about using an exacto knife and the bottom of a water glass. Also, I’d like to round the corners of the slim little batten that forms the fuselage and so was wondering if anybody’s used the Veritas cornering tools or Kakuri radius plane?
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I always used french curves to score balsa, then either cut it a little proud with a jeweller's saw, or gradually worked through the curve with successive score cuts (balso tears if you try and cut across the grain too deeply). Clean up with sandpaper on a block.
*I'm with Phill on the French curve. If you are doing a lot of them, maybe it is worth making a template out of pressboard, laminate or 1/8" plywood. Get a shape you like, cut two pieces of the thin material, sand down to exactly what you want. Then sandwich the balsa detween the templates (could be many layers of balsa a once) and use an exacto knife, rotozip or Dremel to cut out many at the same time. Another source of a fair curve would be aviation books at the library. Xerox a drawing or photo you like and xeroxigraphically enlarge it to what you need.
*Or you could just have the tips of the propellors made in some shop somewhere, where they can all be made perfectly the same, and then lag bolt them to your blanks.If you want to go that jig route, you could stack all of them together, and then use one of those big makita saws to just cut them all at once. You'd have to make several passes to get some approximation of the curve you wanted, then use a belt sander to dress them all up before you remove them from the stack...Do you have a 'full-size', of your model ? Could you post a picture ?
*Hope you're not planning to use lag screws...
*OUCH!
*I'm still cooking up designs (approaches really,) for the wings. The other day I was reading an article in the Geographic about the gliders of the forests of Borneo. There is in that piece a really incredible photo of prosimian-looking mammal with its stereoscopically huge nocturnal eyes full of golden flash, its glide membranes extended fully to all its extremities; from chin to wrists to ankles to caudal pinnacle. It struck me very powerfully as a bat specie that never found need of the exigency of gliding UP.Anyway, its glide membranes with such a high percentage of soft, unsupported surface, ie. such large spans between strong, yet adjustable structural elements enabled me to experience visually, the evanescent, but very real, support of dense night air. It is, of course, the work being done by the animal's musculature that allows the membranes to deploy without the punishing amts. of friction that would result were the membranes to flutter... Which leads to my next question: how would you build a wing that would allow the glider to gather speed quickly, and once that speed was reached, deploy, harnessing the just-gained velocity for a maximum flight. I'm thinking of spring-steel wire pierced through the fuselage and kinked either side the body, creating the leading edge of slightly backswept wings. Perhaps then lycra could be attached to the fuselage and sleeved over the wire creating a wing that would self-deploy. The mechanism that would release the wire(s) after an appointed time, or in relation to another parameter is then, question number three.Also, some might ask (or think atleast,) what has this to do with fine homebuilding. To which I'd reply: think of the aerodynamic implications of building a fine home, such as fine summer ventilation, fine flue function, roofing attachment, garage return shearwalls where wind blows and the earth don't shake, prevailing wind and heat loss and sound etc.Someone once said, "there is much profit to be found in toying with the microcosm.. and little expense." Which maybe is why we built forts as kids and the architects the world remembers, build models. As for the 10" Timberloks and that big brown Makita...
*So you are inhaling.....near the stream, fractally...aj
*The problem with getting to these threads late is that you think of a good line as you read, only to find that someone else has beaten you to it....Rich Beckman
*I would think that although you could theoretically launch your "glider" as a missile, any spring extension of wings would act as an instant speed brake and, given the unpredictability of deployment in a model, would immediately cause loss of forward motion, bringing your bird into a dive. Then the wings would take over. But unless you had some way to control the weight and balance and some sort of pitch control after recovery from a dive then either the bird will continue straight to the ground or will porpoise, drastically shortening endurance and distance. The missile effect in the beginning will gain some distance but not, IMHO, the distance you could get with a properly balanced fixed wing launched conventionally.However, it is an interesting theory, and in powered flight it does seem to work.Now, maybe, if you started with a rigid wing, fully extended but on a pivot, with a spring and piston system that would allow the wing to rake quickly backwards during a vigorous launch but still be effectively active - some lift but a lot of missile characteristics - and then after the initial energy of the launch is dissipated the spring overcomes the effect of the piston and smoothly returns the wing to its forward full-lift producing position. It would take a little fine-tuning with the wing angle of attack as it pivots to produce a smooth transition from semi-missile to full glider.Let's get busy. Start building that sucker.
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I'm making balsa wood toy planes. I want the tops of the rudders to look fair. Been thinking about using an exacto knife and the bottom of a water glass. Also, I'd like to round the corners of the slim little batten that forms the fuselage and so was wondering if anybody's used the Veritas cornering tools or Kakuri radius plane?