Solution 1:  Call the guy back and tell him you'll be happy to open up the rib slots a bit.

Solution 2:  Punch through the line on the paper with a pin, in lots of places.  You'll have a bunch of punched dots on the balsa.  Cut them out.  It'll be tedious and inaccurate -- make them a bit oversized and plan on sanding the wing with an idiot board (i.e., a two or three foot long sanding board).

Solution 3:  If they're not there already, print out the ribs with a really-o truly-o laser printer (if you did this on a big plain-paper copier of the type where the paper comes out warm you're probably there already).  Then turn them printed side to the balsa and iron the back.  Laser printers (and electrostatic copiers) print with plastic dust that melts with heat; you can transfer the print to something else with -- heat.  It'll be slightly less tedious and inaccurate than solution 2, but you still want to make them oversized and plan on wielding your idiot board to good effect.

You can glue stick the paper ribs to the balsa then cut on the lines. Make more copies if necessary. If you use a glue stick, the paper peels off pretty easily.

I'd try to convince Eric Rule to cut a set of ribs and then open up the notches myself.

Apparently there's some programming involved, long story short there's no laser cutting going to happen on this project.

You might take the root rib and tip rib to Kinkos and shrink them to the size you want on paper. Then make a 1/32" ply template of both, and stack carve/sand your new ribs.

I'm not sure that works for geodetic ribs.


I like the glue stick and the ironing board ideas.

MM

Don't know why a sanding block would be called an idiot board but my dad repaired TV's back before PC boards came around. He had an extension cord with one end bare wires that he used for  something in the back of the TV. He called it his idiot killer. We also put two nails in a board and hooked it up and cooked hotdogs. Found the idea in a magazine, different times.

Anyway, I think I'll try gluing the paper ribs to a Cheerios box and cutting them out to make permanent templates that I can trace with a pen on the wood.


MM

Idiot board? Where did that come from?

My dad the car body & paint man.  Skilled bodymen get the short sanding blocks or even get to hold sandpaper in their bare hands.

Anyway, I think I'll try gluing the paper ribs to a Cheerios box and cutting them out to make permanent templates that I can trace with a pen on the wood.

You'll do much better to make permanent templates out of thin plywood, linoleum, sheet metal, etc., and cut the ribs by tracing around them with an X-acto knife.

 
 I'll try this again...

 Go ahead and have him cut your ribs. Then, once you have them, align and stack them and you can file open the spar slots in about two minutes.

I already asked him and he's not going to cut out my 92% ribs with his laser beam machine. Does anyone kit a Thunder Gazer 40 ?

I've had good luck using cereal box cardboard for templates, It's pretty tough. I mean I'm not going into mass production and besides I'm sanding everything with an idiot board  .

MM


P.S. Linoleum??

BTW, I tried ironing the laser copy onto a sheet of cheerio box. Used the highest heat on a monokote iron and the paper was smoking and about to catch on fire. Very little of the ink transferred and both sheets warped allot, still fun.

MM 

1) Around a machine shop, any tool with a handle (i.e., that causes sweat) is an "idiot stick". I can see body shop guys might call a sanding block an "idiot board". A lot of skill involved in sanding, not that I know how to sand on a car body and make those straight peaks and stuff. But I saw the movie once. It maybe have been on YouTube.

2) MM wants to build a scaled-down version of the Thunder Gazer. He didn't say he insisted on replicating the Warren Truss ribs. Straight ribs would make it pretty simple, as I already stated...root rib, tip rib, stack carve & sand.

3) As an alternate scheme, one might make the Warren Truss ribs with strip ribs, add vertical strips about every 2", and sand to match the root & tip ribs after assembly, per Tim's suggestion. Apply cap strips and there you go.

4) I'm pretty sure Patrick scales his plans and parts sheets up & down with his CAD program without any problem. But he could be using a different program than Eric.

  Steve

I have an old version of Profili, which I got for a donation of $10. It costs more now, but still not more than you might spend on a family at a fast food place. It prints out all ribs along a span, including transitions from one root section ('airfoil') to a different wing tip section. I cut them or their rib strips out and use rubber cement to attach them to my balsa sheeting. Then I just cut them out and sand to the line. This is quite accurate and relatively easy. Profili has a large library of wing sections (or at least mine does) and stores all new ones you enter. It allows you to modify them, add spars, lightening holes, etc. Mine is more restricted in these operations than newer versions, but I have found this software well worth the price and very easy to use - no computing skills necessary. Larry sent me his program (Stunt-Rib) before he died, but I haven't examined it, believing that Profili fills my needs. It would do what you want.

Edit: I forgot to mention that the paper pattern just peels off the balsa after the shaping and that the rubber residue just rubbs off like an eraser.

It has been a very long time since I last cut wing ribs from scratch. I lurk more than model these days.  But when I did I sorta like the idea that the "master" for each rib might be made for sterner stuff then light ply or balsa, so...

 I traced and cut the rib shapes out of light 1/4 thick close grained pine craft boards.  Then I drilled wing jig holes at two locations, fore and aft, and bolted the set together as one big multi-layer sandwich.

 This hard stock allowed me to take them to the belt sander and slowly perfect the shapes on both upper and lower rib surfaces to my own desired degree of accuracy.  With the rib set still bolted together I then used ....wait for it....my radial arm saw to cut the 1/4 wide spare slots in the upper and lower surfaces. Yes this took some jigging to handle the taper in the wing from root to tip.  I was also able to cut a 1/4 square space (diamond) in the leading edge to accept the leading edge 1/4 inch stock. 

The light pine is much easier to control the material removal then that of balsa and thin light ply, IMHO.  With these hard rib profiles in hand I could then simply retrace and/or cut around them to produce an accurate reproduction of the rib profile in balsa without the tapered/sanded in cant to the rib surface that some sanding techniques might incur.  I also end up with a real “hard copy” of the rib set for later use if I need or desire.  It sounds rather labor intensive but I take a measure of comfort knowing I’ll only be trashing pine and not balsa should something go amiss.  You can even use the pine ribs to mock up your wing build in a wing jig if you so desire.

Sorry for being long winded, can’t help myself.  On a somewhat related request.  Could somebody post a rib profile of a Geodetic rib and then also post the airfoil shape it produces once the wing is built.  Just curious about  how much longer the Geo ribs are versus the wing profile they produce at builds end.  Thanks

Tony

Eric, see post #17. Maybe it was the wrong kind of printer? Let me know if you cut a Thunder Gazer 40.

Below are the 92% rib templates ready for tracing.

MM

Walt: post #17 said you used a laser print. If what you used was an ink jet system that ink is in a liquid form and is shot onto the paper where it dries into a solid line. As a result it will not transfer to the balsa when you apply heat to the back of the paper.

In order for my suggestion to work you need to use a photocopy machine that uses powered ink. Most photocopy machines use this system but check first. Since the powder is turned into ink lines by means of heat the resulting image can be transferred to another surface by applying heat to the back of the paper.

As far as doing a laser cut of the smaller sized ribs goes I will cut anything a person requests as long as they can provide me with an AutoCAD file of the parts they want cut. If I have to sit in front of a computer and create the AutoCAD file someone will have to pay the costs involved. If I am creating a kit that I intend to sell I absorb the cost involved and hope that I sell enough of the item to cover my costs. In the case of the ribs you asked about it would be a "one time" job and there is no way I could cover the AutoCAD cost involved unless you want to pay for the AutoCAD time.

When all the ribs are shown on the plans I use a ball point pen and trace on top of the plans to make an imprint on the balsa. Yes, it cuts through the paper sometimes but they can still be reused. Then I go over the imprint directly on the wood with the pen to make it easy to see. Cutting is done with a #11 blade and a tad oversize to leave for leveling . After all are cut I clamp them together and sand even.  When only the root and tip ribs are shown I do the hard template (& band saw, electrics etc) thing but I try not to use plans that don't have all the rib outlines.

These plans didn't have the ribs. The tip and root rib it did show were different than the plan view plus, airfoil shape was different than the balsa kit ribs. I think something got lost in the translation. Anyway, I traced the balsa ribs on paper, reduced to 92% then glue stick to Cheerio box and now I have templates see post #25.


MM