Well Today is day one...

I have printed out a wing rib and am starting to cut a template from 1/8 alum. Maybe When I get it all cut out and duplicated for each end of my stack I'll Post a picture. Being out of building aircraft I do enjoy working with metal and wood.

LAST EDITED ON Jul-17-06 AT 09:24 PM (CST)
 
Hey as long as you are making templates let us know what you are making . Maybe you could crank out a few sets for the template impaired among us ? What are you making ?

This is very timely, as I'm about to rebuilt a Streak from scratch. Last time I didn't think to make a template, I just drew it out with a pencil.

I've since made ply templates but I find it takes sooo long to get it right that I must be missing something.

The thought of cutting a shape like that in aluminium makes me quake.

What's your method for cutting it out and shaping it?

living in an apt relagates me to using a small saw

Heh heh, and another hour for the 3rd rib? Sounds familiar.

What do people do with their templates? Do you just cut around them on the balsa with a knife, and that's the rib done? I was never happy with the resulting shapes, and it was too hard to put them together in such a way that I could block sand them.

I found it really hard to centralise them so that you didn't end up with one that was sanded too much on one edge and was below the template on the other edge. I ended up cutting them way too large and then sanding and sanding and sanding and....

There has to be a better way. Maybe some kind of key-hole to align them between the templates for sanding. But how to cut it accurately...

For a straight wing (all ribs the same), I stack rectangles of balsa, nail 'em together, trace a rib on the top and cut them out on my jigsaw. Finish-sand them before taking the stack apart.

Many moons ago, my flying buddy and I tried shaping a 4" or 6" thick block (forgot which) to the rib shape, then setting up a fence on a bandsaw and slicing the block like a loaf of bread. Moderate success...at least they all matched.

Hi Ray,
yeah, I was afraid you'd say that I have a hand-held jigsaw, but not a bench mounted band saw or fret saw. There's no way the wife will countanence another power tool so soon after the pillar drill...

Its been a busy week for me....I am in the process of having an engine dropped into my honda and having an overheating problem with my rv.
I think tomorrow I will have that resolved...
Now for where I am .... I could only find 25 inch arrow shafts to use for now...which should work out quite ok for my wing for the .049
My airfoil is a bit think and we shall see how that affects it...
I am most likely going to cut a new templat because I didn't do the best at arrow shaft location and leadout guide location....
But hey Its progressing.
I will take a photo later if I can and upload it. I am no where ready to glue yet and its a bit of trial and error....
I have a name planned for it, but it might give away where I take my inspiration from.

Here is the ribs in place I havent actully tied the jig to my building shelf and its just kind of sitting on the supports...
Because I was a bit too close to the screw holes I used to hold my templats to the ribs I had some problems with the holes chipping out to the screw holes.....
I will see how this works and also make a second set of templates...

Work is moving along nicely, So I am posting a new picture.

Not that I am an expert builder or anything but on the next one you do, I would try you do try to keep the grain of the rib running in a straight line from leading edge to TE. I am not saying the not having the grain that way will hurt, but it is less of a chance for the wood to over power the glue joints causing a warp. Trust me this can and has happend to me.

Robert Storick
AMA 12366

Saint Louis,MO.

The only part of scratch building I never mastered was ribs. I resorted to looking for a kit I liked the airfoil of, then ordered a set of ribs from the manufacturer. Works pretty well.

Here is another photo as I am progressing on my half-A stuntship.
There is a lot of sanding to do and the tips need to be removed and thinned some.

For some, using counter-grade Formica or similar laminate is easier to obtain and work than aluminum.

But the only time I use templates like this is to cut foam.

For ribs, I take the drawing of the rib and make as many Xerographic copies as I need ribs. Transfer the drwn outline with all the holes, spar cutouts, etc to the wood by laying the copy face down on the wood and either: a) heat it with an iron or monokote iron to transfer, or b) the method I use, rub it with acetone rag. The resulting transfer looks like the printing ao a good kit. Identiying numbers, etc are all transfered.

If it is a tapered wing with all the ribs CAD drawn, I just make the copies from the plan set 8" x 11" sheet at a time.

Then I cut them all out with a sharp exacto blade. This goes really fast and a whole set of tapered ribs is done in less than an hour.

If you only have tip rib and root rib for a tapered set, then I guss you need to use the template sandwich method tho.

In my opinion, taking too much time trying to get the ribs perfect is a loss of time. The wing needs to be board sanded to get it just right anyway, so leave a blade-width of the line intact when cutting and then sand with a long bar.

Just for reference, I use 220 or 320 dry on a 36" x 4" aluminum sanding bar for ribs. It only takes a few strokes with the bar to true up any minor cutting errors in the ribs--then the same treatment after applying the caps. Dont forget to lightly break the edges of each cap and LE/TE before covering--this prevents edge-induced sand-throughs of the covering.

Just my approach--your mileage may vary.

Curt

PS: Sparky knows of what he speaks on this.

I picked up a cheap kitchen scale at the dollar store to gee how much my airplane weighed so far. I was supurised that I am presently around 4 ounces. I'll shall see how muct the rest of the body and tail section add to this effort.

Couple or three comments. On wood sizes, weight is the impotant factor, not thickness. I had a bunch of light 3/32 I won at an indoor contest. It was often lighter than any 1/16 I had, so I used it for 1/2A ribs sometimes.

Light weight is important in 1/2A's. I've had satisfactory results with TD 049 airplanes with 32-36 span, 6 inch chord up to about 11 oz. An airplane the size of yours needs to weigh less than yours in going to weigh. On an airplane that size, I would use 1/8 square fairly hard balsa spars with a piece of 1/8 square with tapered ends underneath in the center section. I wouldn't sheet the leading edge. I'd use a piece of 3/16 square for the leading edge. No caps. the trailing edge would be 1/32 sheet top and bottom, D-tubed all the way out.

Another way to make the trailing edge is to use a piece of 1/8 hardwood. Put in a couple of 1/ 16 x 1/8 spars top and bottom and then put in 1/16 sq diagonals to the trailing edge. It will be quite rigid and looks neat.

Your building is high quality and building 1/2A's is an evolutionary learning process. Your next one will be lighter and fly better.

If you are an AMA member you can go to the AMA archives and search for my name. You will find my Cheap Thrill construction article and maybe get some ideas.

I make my rib templates out of 1/16 basswood. I make them in a top and bottom half and sand them to identical and then glue the halves together. For a rod jig like yours, I sink a couple of short lengths of brass tubing in a piece of composition board. I cut holes the template and rib blanks with a piece of sharpened tubing and fit them over the two pieces of brass tube in the board. Then hack away. I have to be careful with the basswood template as it is more cutable than aluminum or formica.

Here is where I am upto. I haven't yet mounted the engine. The top of the wings have been covered and the bottom is still bare. The left wing has 4 coats of dope on it and the colors haven't leaked or bled as far as I can tell.
I will most likely just dope it all and leave it this color till is see how it flys.