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Building Tips and technical articles. => Building techniques => Topic started by: Tim Chenevert on February 14, 2018, 07:31:35 PM
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I am using a kit to build my next plane. I am using the parts as templets, tracing around them and then using my Xacto knife with 11 blade to cut them out. Slow process. Is this the preferred way of doing this? This is my first scratch build so I am open to any and all suggestions. Tim
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Solid method there, done by many.
Stacking with templets on either end and something more solid than pins to hold, (bolts or a fine misting of spray adhesive) then gang sanding for ribs is popular. This also works on scroll saws, and allows tapered wings.
There are many good methods.
Phil
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Why not just build the kit?
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For ribs for a straight wing, make a template out of metal, plywood, formica, or other harder-than-balsa substance. Then you can cut out a bunch of ribs without wearing out the template.
For tapered wings, I stack cut.
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I did all this with just an Xacto knife. That's three full Skyray 35 kits.
(https://s5.postimg.org/5ay0nhdxz/DSCN4995.jpg) (https://postimg.org/image/qxd14icib/) (https://postimage.org/)
Mark
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Why not just build the kit?
Some of the ribs split when someone tried to take them apart. This is an old kit from 1960’s. I can also make duplicate kits like Mark did with the Skyray. Bootlegger also wants to build one. The metal Templet idea is great as I am thinking I can lay it down and trace a new one with my knife. Tracing with a pencil then cutting requires a lot of light as my eyes are not what they use to be....Lol! Thanks for all the suggestions, I appreciate it, Tim
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I would try and find a rib set if it's a kit that someone is re producing. For straight wings, like the Twister, I spray glue rib blanks into a pile and glue a paper template on the top and band saw the stack and finish the stack with the disc sander. Tapered wing ribs are done the same only two in a stack.
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Hello Tim
I make the ribs using the stack method. I make two ribs out of 1/8 inch plywood and I mark them to make sure they are in the same position when I use them. I use the holes on the plywood rib to insert wood screws so when I`m marking the outline on the balsa the ribs won`t move. then I screw them together using studs and nuts. I sand them to shape and before I take them out of the stack I place diagonal lines with a marker and use place all the ribs with the marking up. That way I don`t get a bump on my sheeting because I flipped a rib. I place them on the jig as they come out of the stack so they are in the same position they were in the stack. My wings come out straight and I have no problems.
Juan
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I have cloned several kits during my model building years and still do. Yes I make templates of the ribs(tip and root) in case I want to do another one. This way wood can be replaced that is too heavy or too light. Nothing like clumsy fingers and thumb going through the sheeting while sanding. Don't forget to post pictures. H^^
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Tim I am sorry to hear that some of the ribs in the kit are FUBAR...truth is they were so delicate and the wing tip parts already broke out of the plank i did NOT look at every set
Duplicating ribs out of better stock for a constant chord rib set is pretty fast if you floole some of the advice above... mainly a set of two perfect templates of harder material, jig or band saw to close shape, then sand..by hand or on a tool to final all equal shape ---then deal with spar notches with coping saw and purpose built sander
If one want to get real anal there are all sorts of guys who can lazer cut sets.... many already have a inventory of the more popular rib sets... I have not looked at LazeWorks for the Sneeker
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It’s really ok Fred. I have all the ribs cut now using new wood. This weekend I am hoping to have the rest cut out of new wood. I am saving the kit. I like all the ideas for templets and stacking though! Perry do you remember that wing we flew a couple weeks ago? That was a Sneeker and I have decided to build one since that one is so old. I flew 1/2a’s as a child and have just returned to C/L recently. So far I have a Sneeker that was given to me, a ARF Ringmaster, a Twister that I built and now scratch building this Sneeker so I appreciate all the advice I can get. Thanks to everyone, Tim
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Tim there are several ways to do this as others in this thread have stated. At one time, a lot of years ago, I had lots of templates I had cut from plans and kits. I primarily used a #11 Exacto to cut all of these. Sometimes the wood in the old kits is heavy, hard or rotten but you can use the parts to trace, just like you are doing, and build the model. I have cut many many individual ribs out with a #11. I actually had the time to do it and really enjoyed the therapy of doing this by hand. Of course you can stack ribs between two templates and cut and sand them down, nothing wrong with that at all. I just enjoyed sitting down, taking my time and cutting out parts with a knife. Guess I just have a lot of patience.
Mike
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I did all this with just an Xacto knife. That's three full Skyray 35 kits.
(https://s5.postimg.org/5ay0nhdxz/DSCN4995.jpg) (https://postimg.org/image/qxd14icib/) (https://postimage.org/)
Mark
Wow you are one brave and determined soul. And you still have all your fingers? n~
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Wow you are one brave and determined soul. And you still have all your fingers? n~
Peter,
At the time there was a lot going on with my wife's health, so getting away for a while and cutting all the parts from scratch was great therapy. I have two scroll saws, but I decided I wanted to do it by hand. Felt good. And, yes, all fingers accounted for.
Mark
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Without a sandpaper fix, everything I cut looks like I used a chain saw.
I even have to clean up plywood I cut with sandpaper.
CB
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I even have to clean up plywood I cut with sandpaper.
CB
Hi Charles,
How do you cut plywood with sandpaper?
Keith
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Attached freshly taken pictures of a method I've used for decades for constant chord projects. The templates were in a baggie hanging on the pegboard in the shop, and are for a deBolt Livewire "Rebel" 1950's R/C model I built for my brother for Christmas one year.
The templates are 1/32" birch plywood. Pins are pushed through to make tight holes (needle nose pliers!), and then fresh pins are bent 90 deg. and then some zigs and zags bent to make a mechanical flange sorta, secured with either epoxy or baking soda & CA. These ribs were cut out using a single edge GEM blade and a #11 Xacto blade where absolutely required. And I resharpen #11 blades multiple times. If I need to undercut for center sheeting, I would cut all the ribs the same, and then undercut just the few required by hand. Believe it or not, cutting ribs this way...if you're careful...you generally won't need to sand them at all...certainly not if you add cap strips. If you need to sand them, you're not doing it right, or not holding the GEM blade at 90 degrees. Be sure you mark the ribs so that you know which side is which...helps prevent warps if there is a slight difference top to bottom...and there will be. I like to put a mark in the bottom of one of the spar notches with a ballpoint or Sharpie.
I use a slab of crappy old 1/2" balsa for a cutting board to support the ribs and accept the locating pins. The pins keep everything firm while cutting, one rib at a time. This method allows fitting ribs onto the sheet balsa as economically as possible, while keeping the grain as straight as possible. Looking at the picture of the top side of the templates, you'll see that I added a spruce brace across the top of the spar notch on the wing rib template. That wasn't possible with the stabilizer ribs. All these ribs were cut from 3/32" balsa about 8 lb./cu.ft.
For stunt/combat ribs, I'd suggest putting a rough hole where you want the leadout holes to be...then use a 3/8" hardwood dowel with some 320 grit sandpaper...about 1.5" wide, rolled around and glued on at the tip. Use this like a violin bow from the tip end to sand out the leadout holes the way you want them...it's a lot easier and faster than you'd expect. Do it before you glue the wingtip on. You don't have to open up the outboard wing ribs, but may want to make them a little neater...or not!
And yes, I've used the stacking method for both tapered and constant chord ribs. It works fine, but wastes more balsa. H^^ Steve
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Be sure you mark the ribs so that you know which side is which...helps prevent warps if there is a slight difference top to bottom...and there will be. I like to put a mark in the bottom of one of the spar notches with a ballpoint or Sharpie.
With those ribs it'll be more than a slight warp.
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Tim, remind me to give you a good whack on the right shoulder next time we cross paths! LL~ Steve