Built Up Ribs II

[Gil]

Tutorial on Making Built Up Ribs

The following is a tutorial on a method to make small aircraft built up ribs from card stock. The rib modeled is a 1:33 scale main rib of a Piper Cub J3 aircraft.



Cut out the strut sheet and emboss fold lines on one side using the scribed acrylic panel technique.



Use a pin or needle to mark the opposite side locations and emboss the lines on that side.



Finished strut sheet ready for folding.



Crease the folded seams.



Folded, creased strut sheet.



Flatten the strut sheet and slice off several sections. The third or fourth in should be pristine enough to serve as strut zig-zags.



Place the zig-zag strut assembly into the bed of nails jig. The jig holds the struts in position for final assembly.



Cut out two cap strips. Glue them together with thinned PVA glue (white glue). Wrap them around the cap strip form and let dry.



Cap strip removed from the form.



Trim the tails off the cap strip and place it on the bed of nails jig for final assembly.



Apply glue carefully to all strut to cap strip joints and let dry. Dry brushing with a natural bristle paint brush is used to reduce the amount of glue on individual joints. Remove the assembled rib by carefully cutting between rib and and jig. Gently pry it off the bed of nails jig.



The finished rib.

I'll let your imaginations be the guide for other related applications of this technique...,

Best regards, +Gil

[Leif Ohlsson]

Great! And you used double-layered paper for the cap strip, which I, too, thought would be very good for strength.

I'm still thinking in terms of a sort of "female" mould for the capstrip, slightly elevated section inside the capstrip outline for making the framework slightly thinner than the capstrip.

I notice, too, that you made a double layer vertical member in the middle, just like I would have done.

Remaining problem is the aileron ribs. But I'm thinking 1/16 so that will be less of a problem.

Very good to see this method is working. I'll copy it unashamedly (with full credits to you).

A final note: People should think about using wood-coloured paper (some suitable brownish/yellow shade). Perhaps different shades for the framework and the capstrip, just to enhance the built-up look. I hope that will be most effective.

For the spars, I think you will have to go for a full wood-texture, to replicate the wood structure.

Leif

[Don Boose]

An excellent tutorial, Gil.

I must make one of those grooved pieces of plexiglass. It is clearly a very useful piece of equipment with a variety of applications.

Don

[dansls1]

Gil,
I appreciate this - great tutorial!
Unfortunately I've now lost the pictures loading from imageshack (may be my work internet or computer - not sure).
Would you mind if we add this to the 'articles' section as a tutorial? If you don't mind, I'll convert it over - hopefully the pic's will show back up for me to downoad this weekend.

[Gil]

Great! And you used double-layered paper for the cap strip, which I, too, thought would be very good for strength.

I'm still thinking in terms of a sort of "female" mould for the capstrip, slightly elevated section inside the capstrip outline for making the framework slightly thinner than the capstrip.

I notice, too, that you made a double layer vertical member in the middle, just like I would have done.

Remaining problem is the aileron ribs. But I'm thinking 1/16 so that will be less of a problem.

Very good to see this method is working. I'll copy it unashamedly (with full credits to you).

A final note: People should think about using wood-coloured paper (some suitable brownish/yellow shade). Perhaps different shades for the framework and the capstrip, just to enhance the built-up look. I hope that will be most effective.

For the spars, I think you will have to go for a full wood-texture, to replicate the wood structure.

Leif

Leif, Yes, the cap strip is two layers. It might be wise to use a thinner paper to laminate a third or fourth layer. I also thought of making a "T" section mold by making a mold of three pieces, two larger sections on the outside and a smaller in the middle. A layer of paper would then be embossed into the trough before additional flat layers are laminated over it. I decided this was a bit too anal at 1:33 but would certainly be workable at 1:16. I think 1:16 is about the right scale for a cutaway model like this. One last thing is that the Cub's ribs are made from aluminum. I had incorrectly assumed that they were built up from spruce. A little investigation on the internet proved this wrong. Might be the reason so many Cubs are still flying...., Paint them zinc chromate yellow.

An excellent tutorial, Gil.

I must make one of those grooved pieces of plexiglass. It is clearly a very useful piece of equipment with a variety of applications.

Don

Thanks Don. It's kind of fun to play around with the embossing method. And you're right, consider it another tool in the card modelers box of illusions.

Gil,
I appreciate this - great tutorial!
Unfortunately I've now lost the pictures loading from imageshack (may be my work internet or computer - not sure).
Would you mind if we add this to the 'articles' section as a tutorial? If you don't mind, I'll convert it over - hopefully the pic's will show back up for me to downoad this weekend.

dansls1, Imageshack seems to be acting a bit strange (It's currently calm and accessible).

Please add it to the article section as a tutorial and feel free to convert it over. I am also glad that you appreciated it. That's what makes writing them rewarding.

Best regards, +Gil

[Leif Ohlsson]

Gil, that is one great photo of the Cub wing - just what I needed. Any chances of more like that, a link or so? The photo unfortunately ends before the rear spar ending can be viewed in full, which is a part I've been wondering about.

The spars were spruce wood, except 1946-47 models which were "Nicral metal" - if I've interpreted Paul Matt's drawing correctly. I mistakenly remembered this note as pertaining to the ribs. I'll remember that now.

Many thanks again, Leif

[Gil]

Leif,

The following sites are a great high resolution resource:

http://www.j3-cub.com/index.php?opti...ery2&Itemid=62

http://www.primeportal.net/hangar/da...er_j3c-65_cub/

+Gil

[Leif Ohlsson]

Brilliant! Can't thank you enough. Will be immersed in this for some time...

Leif

[RyanShort]

So does the rest of the plane follow? With a tutorial for how to build tubular fuselages out of paper? That'd be fun to build for the museum our squadron's would eventually like to build.

Ryan

[Gil]

Leif,

I've already spent many hours immersed in those high resolution photos. I've been reserving bits and pieces in a file.

Ryan,

Don't really know yet. All the necessary techniques have mostly been developed. There are some that need to be developed such as a highly detailed Continental A-65 engine.

A 1:16 scale Cub is the most likely candidate for something like this...,

+Gil