Wings

[Kamcoman77]

Your printed nose rib looks great, but looks like it could be half as thick on the inside. The bottom piece is probably not even needed considering how stiff the arch portion is. I used aircraft grade 1/4" ply for my end nose ribs and 1/4" "hobby ply" (Midwest brand) for the interior ribs. I used 1" wide extruded foam with a crosspiece for my added ribs. After mockup, I decided that I only needed one foam rib between the ply ribs, except for the outer bay where I used two foam ribs. I used 1" thick foam because I wanted more support for the 0.8mm nose ply. Used T-88 for all joints. The nose section on my 1st wing feels very strong.

[Brock]

These nose ribs that I have were 1/8" too long.  So I cut them down.  But cutting squarly the ends of a hoop is a bit of a challenge.  3D printing to the rescue.  I made this jig to help guide each rib through the table saw.  Now they are all exactly the same length, and the length that I want.  Next is to draw and print up a jig that will hold them while I cut the stringer notch.

While I'm talk'n about 3D.  I did a  T88 glue test with the LW-PLA test cube.  T88 stuck to that foamy surface better than nails.  I eventually destroyed the cube and it was still stuck.  Too bad PLA can't stand the heat of sitting on the dash of my car (measured 153 degree today).  This is my test standard.  The PETG test sample did just fine but that is not yet made in foaming formula (LW-PETG).  So I have some LW-ASA on order to test out.

[Kamcoman77]

I made my nose rib notch jig from some scrap plywood. Ran the ribs through my table saw three or four times to get the 5/16" wide by 5/8" deep notch.

[Brock]

My nose ribs were not as carefully made and none of the holes lined up so I needed to remake them else have a different solution.  Here is what I printed up to hold the ribs for cutting.

The print had another hour to go but I got impatient and pulled it out early.  It was fine this way.

[Kamcoman77]

Nice looking jig!

[pappyadkins]

I agree... wish I had my printer back then... love this idea....

[Brock]

With the nose ribs all cut (except for some I hope to print) there was no longer any reason to delay working on the second wing.  So work I did.  Got it all assembled for trial rib fit and the gussets are all marked up where they need to be cut for things like compression ribs.  Sure is easy the second time around with most of the sub assemblies already finished. 

I better get on the phone and order that Oratex.

[Brock]

After printing and glue testing the (Light Weight) LW-PLA I was encouraged that 3D printed nose ribs might work.  But PLA can't stand the heat (I knew that).  So I ordered some LW-ASA, which is made for UV and more heat.  I printed a test cube and glued (T88) it to some plywood.  The next day I was very disappointed when I was able to easily pop it off.  See left side of the pic below.  Not wanting to give up so easily I tried again.  This second atempt (with the same cube) I lightly sanded then wiped with alcohol.  Seems that did the trick.  I broke the cube pulling on it and couldn't remove the stuck end by prying on it with my pocket knife.  Looking forward to printing a dozen or so of these.  They take over 2 hours to print but only about 4 minutes to start and walk away.  Is this what it means to "work smart not hard"?

[Brock]

Progress on the second wing is going at a blazing pace, as expected.  I did have one little oops today when I realized that I closed up both ends of the aileron before installing the aileron-spar-web.  Was saved with a (more than) bit of bending and some twisting to boot.  I thought the plywood would buckle but it didn't.  Whew!

[Brock]

The other day I cut loose the ailerons from the wings.  Now I am working on the aileron nose-ribs.  I had 7 (need but I really was not very fond of the ones I had.  So to the drawing board.  First I took a picture of one of the ribs along side two rulers and imported them to the drawing program (shapr3d) then drew out the image as needed.  Next, imported to the slicer and printed with LW-ASA.  End resuld was a way to make all the ribs I want with consistency and at half the weight.  cool!

edit (I typed "(need '8')" above with out the ' ' and it spit out a face.

[pappyadkins]

Love to see more & more 3d prints... I haven't played with any of the LW stuff - just got my CF Nylon parts & filament in... Haven't tried them yet...

[Brock]

It has taken me quite a bit of thinking to decide what to do about the aileron cove.  Here is what I've decided and a question too.

Really the pictures say more than I'll type.  The .016" aluminum when wraped around a 1-5/8" pvc pipe springs out to about the right diameter.  The 1mm x 1.5" ply will go on top of the aluminum to make things a bit smoother.  I tried putting it under the aluminum but that didn't look very well.  Also the bend in the aluminum edge will add structure to the ply on the trailing edge.  The 1/4" square will add structure to the leading edge of the ply (held up just for the picture).  I read that T88 will bond to properly prepared aluminum, so that is what I have planned.

Now for the question.  My HF brake is only 36" long but the aluminum is 48" and I don't want to shorten it.  So do any of you folks have any ingenious ways to make the bends in the second picture?  I might be able to find and borrow a larger brake, looking into that.

[BradW]

EDIT --- ( I just realized that the plywood strip is called for already, with the 1/4" reinforcing strips along the edges between ribs, so you really don't need to put the folds on the aluminum, unless you just want to eliminate the 1/4" strips. Or you could make the folded edge longer (to reach up to the 1/4" strip) and eliminate the plywood, too. This whole area has always been a little iffy to me.)

I would like to suggest that you just skip the folded edge altogether. You are only trying to close the empty space, and the fold complicates that and adds weight, expecially with the extra plywood strip. The 0.016 will likely be stiff enough once you roll it to do the job for the span between the ribs. You could try a short piece to see how stiff it is once you roll it. As long as you don't over-shrink the fabric it will probably be enough to give a good fabric edge. But maybe a little testing is required to see.

Or - if you think the fold is still needed for stiffness, you could also just fold a tab in between the ribs, instead of the whole length (not over the top of the ribs). Cut a space or gap of about a 1/2" to 3/4" wide out of the edge that will be folded, at each rib to clear the rib, and just fold the 13-14" tab over in between each to stiffen the edge. That way you can do one at a time by hand, bending them on a short piece of wood.

To fold a longer piece, you can get two long oak boards to clamp the sheet at several locations, and use a hammer to fold the edge. Takes a little more time, and a little finesse, but once you get the fold started it's easy to tweak it with seamers, or more hammer work. To fold more than 90 degrees, you can bevel the bottom clamp board as needed to get a deeper bend. Cutting this bevel on a table saw is pretty easy, then round the edge with a sander or hand plane. The aluminum will spring back some, but the idea is to get the fold done in a straight line, then you can fit it by hand.

One other idea. Make shorter pieces to fit your brake, and rivet them together at the ends.

[Brock]

Solution!  My neighbor rolled over this relec of a brake yesterday.  48" wide, just as the half sheet of 016" I have.  Hope to use it today, after some clean up.