Hatz Biplane Association

The drawing on page 10 seems to show that the correct solution is to have the wing attach fitting hole at 1" from the spar bottom, rather than 3/4" from the spar bottom as shown elsewhere. This would seem to solve it.

Nick

Hi all,

Nick, you just brought it to the point! That is the only change to do! All other on the center section is o.k. We will write this to jeff Shoemake!
For us, we made new front and back spar fittings for the top wing panels with the mounting holes 1/4" higher (z-axis) because we already bored the mounting holes on the spares.
Best regards
Hans & Sam, H.C.#78, Switzerland

I'm glad this came up when it did, as I had just drawn the hole locations for my upper wing spar fittings and was preparing to drill them.

Nick

Good Morning Gents,
I am now laying out the spar attach fittings for my upper spars and have positioned the inboard spar fittings 1" from the bottom rather than 3/4" from the bottom. It also appears that the outboard fittings need to go up 1/4" Can anyone else confirm this? Makes sense, really.

Nick

IN answer to my own question, and for the benefit of others in the future, the answer is no, I do not have to change the position of the outboard spar fittings on the upper wings.

Nick

This is correct: The center section assy is drawn correctly, however, the top wing spar fittings have to be placed 1/4" higher (z-axis) than the 3/4" as dimensionned on the wing plan!

Hans & Sam, H.C.#78, Switzerland

I'm getting to this party a bit late. I am planning to move the inboard spar fittings to the prescribed 1" from the bottom of both the front and rear spars.

My question is, are/did folks also move the location of the compression tube holes at the wing root up from the bottom of the spars 1/4", making them 1" from the spar bottoms as well? Either that is done, or you would rotate the fittings about the compression tube holes as drawn on the plans.

My concern is clearance of the drag/anti drag wires through the ribs. Does moving the location of the compression tubes, and thus where the drag/anti drag wires attach by 1/4" make a difference?

Thanks folks.

Jeff Orear
Hatz Classic #138

Jeff, I did move the compression tubes along with the inboard spar attachment fittings. They all went up by 1/4".

Nick

This Center Section / Wing spar connection thing is really quite frustrating. I followed the center section discussion as best as I could and my center section is complete. I am now fitting my top left wing spars to the center section and it looks like I need to move the attach plates up 1/4 inch from what is shown on the plans. I have the same question as Jeff, the first compression strut uses this wing mounting plate and it will move up 1/4 inch if I move the wing mounting plate up 1/4 inch. It looks like others before me have discovered this same problem and moved the plates up 1/4 inch. My question is will moving the first compression strut up 1/4 inch cause any problem with the drag/anti drag wires and the ribs. I do not plan to move any other compression struts.

Ed:

You and I seem to be at the same spot of of our builds. I moved those fittings up the required 1/4", effectively moving the location of that first compression tube up 1/4" as well. I don't think there will be any interference issues, but if there are, the truss structure of the rib can be modified. If you go to Scott's site, he has a pic of such a situation, not associated with this particular compression tube, where he had to make such a mod to clear a drag/anti drag wire.

Build on!

Jeff