Hatz Biplane Association

I built my ribs complete - i.e. including the inner uprights and gussets. I thought about the other method and decided that I'd give this a try. I have yet to assemble the wings, but it seems to me that the following should work:

1. Glue the outboard spar doublers in place on the spars.
2. Drill all spar holes (including the spar root WITHOUT the root doublers at that location)
3. Install all the ribs from either the root end or the tip end as appropriate relative to the outboard doublers
4. Temporarily install the compression tubes to provide rigidity
5. Glue the outboard side of the root doublers in place and, when dry, drill out the holes from the opposite side using the existing holes as a guide (and a drill jig to ensure a perpendicular hole if necessary).
6. Glue the inboard side of the root doublers and repeat the drilling process from the opposite side.

Has anyone tried it this way? This seems like it would be easier than fiddling with installing the uprights and gussets on all those ribs and then having to trim all the gusset material.

I had something in mind similar to Doug,
I have access to machining equipment so I can put the bolt holes in the spars and the doubler plates individually and not have to worry about them lining up later. In theory anyways. I can use a Bridgeport mill or a CNC mill to put the bolt holes in the proper location. I will verify hole locations to the brackets before drilling of course.

I also don't like the thought of trying to add the uprights and gussets on the wing. I am sure the method works fine but like most things there are several ways to wind up with the same results.

I will take another good look at this before I start gluing up ribs.
Later!!
Anthony

Hey guys.

I had no problem adding the uprights and gussets after the ribs were on. It was a very simple operation. Simpler, I would imagine, than trying to drill decent holes through the spars of a partially assembled wing panel. Just my opinion. My bottom wings went together very easily this way, and I plan to do my upper wings also this way.

Nick

It's been many a year since I built my wings, so I'm tyring to remember what I did. I know that my ribs were all built and I slid them into position on the spars. Seems to me, I predrilled the doublers and spars before hand and glued up the doublers to the spars after the ribs were in place using bolts through the holes to ensure alignment of the doublers to the spars.

Another option would be to tack glue the doubler plates to the spars and drill all the holes then pop the doublers loose to add the ribs and assemble the wings. Just a drop of CA at each corner of the doubler would hold it in place to drill the spar and doublers together. This may be the best option even while doing the drilling on a mill.

I received another shipment of vertical clamps today to make the jig for adding the gussets to the 2nd side. I am guessing it will be at least a couple weeks before I see my spruce arrive to start building ribs. Will keep me busy for a little while anyways.
Later!!
Anthony

I received my wood order the other day and I am finishing up the jig for the 2nd side of the ribs. I should be cutting gussets this week and pieces for the ribs.
Later!!
Anthony

Here's a newbie question regarding the option to glue the upright members of the ribs only when attaching the ribs to the spars:

Are the ribs actually glued to the spars? I understand they are glued to the leading and trailing edges, but if they are supposed to be glued to the spars, I don't see how you could glue them to the spar without leaving the upright members off until that point.

I may be missing something, but I can't see spreading glue on the rib upright members and then just "sliding" them into position on the spars, without losing most of the glue. Spreading glue on the spar and then sliding the rib into place will have the same scraping effect.

What am I missing
Amit.

We assembled the ribs to the spars but positioned the ribs just to the side of it's final position, smeared epoxy on the spar and slowly slid the rib into position.
There wasn't a lot of glue squeeze-out. Two nails were used to hold it in position while the glue set up.
I saw a Taylorcraft wing that only had two nails in each rib with no glue.
John Hanson

For the rib nose and tail, 1/4 ply, birch ok or what is the ply of choice? Also I see the mahogany question has been asked but I didn't see the answer yet. 90 deg or 45 deg? Luan core or poplar

Thanks,
John

Naples FL

I used birch because it was cheaper but make sure you skuff up the surface where you glue. The manufacturing process leaves it pretty slick.
As far as mahogony, I would think the 90 degree would be acceptable. I've only heard of people using the 45 degree on applications with a tortional load.. like skinning the wing panel. As far as the core, what ever is available at a reasonable price.
Jeff Moore