Tag Archives: wing ribs

Aviation, DIY

Knowledge tests done

Stearman wing rib jigOn Monday, June 4th I went down to Ocean Air Flight Services with my classmate Rob where we took our General and Airframe knowledge tests passing them both handily. With that behind us the next step is to head out to Byron Airport, again with Rob, and take the practical for General and Airframe which we already have scheduled for Tuesday, June 12th.

Today I took the day off from studying, got side tracked by a little “work”, then got to take a few hours of mental relaxation and headed down to the shop to work on the Stearman wing rib jig I started working on back on May 29th.

Working on the Stearman wing rib jigI started off by trimming the blocks I milled the other day down to the right size. After trimming things down a bit, I gathered the rest of my materials. With brass tack nails, glue, and a couple of hand tools on the jig board I got started nailing the blocks into place.

After a few hours of tacking and gluing the blocks in place I had almost all of the inside blocks in place and nailed down. There are just a couple of blocks left on the interior to install then I get to extrapolate the nose-block and figure out how to block the furthest aft vertical truss piece. That last item is going to be interesting because there is no room to block in the piece with the gussets in the way on the sample rib I have.

I learned a few things while doing this today; the most important of which is to not hold out on the good lumber for the jig blocks. Another thing is that lots of small blocks is much better than fewer large blocks. While your at it, if you use a good medium/hard wood, take the time to pre-drill the blocks. As it is, there are 73 blocks on the inside (or will be anyway) and I am estimating 60 blocks on the outside, that’s a total 133 blocks for this wing rib jig.

Were I to start over on this one, I would take a lot of time to pre-cut, pre-drill, sand, and set nails in 250 or more 3/8″ x 3/8″ x 5/8″ long blocks of Douglas Fir. In fact, I am sure I will be doing another jig sometime in the near future so I think once this jig is done, I am going to prefab a box of 500 or more jig blocks. Of course to fabricate that many blocks I will need to build a jig-block jig to make all of them. 😉

☮ ♥ ✈
~FlyBoyJon

Aviation

Airfoils

Airfoil RibsThe last few days have been a bit of a blur. I am shaking off the last remnants of a frustrating head cold that lingered for way too long. This week was also the first week of an early class at SJCC before my spring semester classes begin on the 31st. With the cold and classes I haven’t gotten much of anything done at the day job and getting into the workshop was near impossible.

As a consolation, I managed to get in a bunch of pseudo-shop time in by working on the airfoil templates. All totaled up I put in 11 hours marking up the templates on contractor’s paper and cutting out the finished templates. It is surprising how much time can be spent on laying out even the smallest airfoil. Over 30 measurements are used to lay out the basic shape, and you still have to round everything out for a smooth form. Science and art in one operation.

The picture above shows all seven of the airfoils laid out on the kitchen floor. On top is the wing with its 58″ chord. Below the wing is the stabilator, and below the stabilator are the five airfoils that are stacked to form the rudder. There will be 30 copies of the wing rib, 8 of the stabilator and only on each of the rudder ribs. There are a total of five variations of wing rib and two variations for the stabilator, but they are all based of the basic forms. I will post more about the jig and duplication process when I get back to the airfoils. For now, since I am feeling much better, I move back to the bulkhead construction portion of the project.

This last week’s diversion to the airfoils is a good example of building flexibility into your project schedule so you are able to take advantage of available time when life strikes.

Until next time, blue skies and tail winds.
~FlyBoyJon