Hatz Biplane Association

To get the gap to 1/4", I'd have to move one bracket 1/8" or move both 1/16" and I'd have to move the two holes in the brackets to line them up. I'll take a look at that now. Back to the garage!

I'm back....looking at sheet 10, the wing bracket hole is shown right on the edge of the spar. If I move that bracket 1/8" to the left, it'll match sheet 10 and give me 1/4" gap between spars. The edge of the hole will be about 1/16" from the spar edge.

I just want to make sure the brackets are in the correct location as it affects compression tubes and flying wires. I see I can move one or both brackets, or leave brackets where they are and move just the holes where they join.

Thinking now to just move the wing bracket 1/8" to the spar edge. I think the rest is OK.

The plans show a 1/4 in gap a Doug mentioned but i built mine with a 1/8 in gap to get a tighter fit. I am hoping that it will be enough room for the fabric.

I don't have my plans handy at the moment, but a couple comments:
1. The drawing of the gap between the centr section and the top wing is to scale. If you measure it with an architects scale i believe it is 0.25 inches.

2. The top wing spar roots are mitered to acheive a 1.5 deg dihedral and keep to end ribs vertical.

Can anyone tell me if I'm on the right track? These photos are looking at the front of the (practice) spars, wing on the right and center section on the left.

CONDITIONS:

1/4" sticks between the spars represent end ribs and then I have one on top and bottom of wing to represent rib; wings would line up with CS on top and bottom.

There's a 1/8" space between the end ribs. Not sure how large it should be.

The dashed lines on CS bracket would align with end rib and spar bottom.

On the center section piece, I left 1/4" on the bottom to represent CS floor.

Can't see it here, but tops are beveled to shape of wing.

The wing bracket is raised 1/4" from plans.

CS bracket holes are 1" from bottom of CS spar.

That bolt hole (CS bracket) that sits on the bottom edge of the wing spar is a bit low (1/16") compared to drawings. Not sure why.

QUESTIONS:

Are bracket holes in correct locations, or did you move any?

Are the aft spars a problem also?

Anything here important as to attaining proper dihedral?

[img]http://photos.imageevent.com/hatz/problem/huge/spar5.jpg[/img]

[img]http://photos.imageevent.com/hatz/problem/huge/spar4.jpg[/img]

[img]http://photos.imageevent.com/hatz/problem/huge/spar6.jpg[/img]

[img]http://photos.imageevent.com/hatz/problem/huge/spar7.jpg[/img]

Just for the record, I drilled both spars for the top left wing today and moved both wing attach plates up 1/4 inch. This causes the first compression strut to be at the same elevation as the second and third or all at 1.75 from the base of the spar. After drilling, I slid all the ribs into position and mounted the compression struts to the spars. There is no interference to the drag / anti drag wires going through the wing with this dimension change. The wing also lines up perfectly with the center section.

Ed:

You go on ahead. I'm enjoying the journey ! ;)

Jeff,
Thanks for the reply, it is quite timely as I will be drilling the spars today.
I noticed Scott's interference and the fix in his pitot picture but I don't know if he also moved the plates up. It is puzzling me because in the dimensioned drawings on page 9 it is clearly shown at .75 but if I measure the 1/2 scale dimensionless spar at the bottom of the page it is 1 inch. The other issue is that the first compression strut is shown at 1.5 inches but strut #2 and #3 are at 1.75. If I move the plate up then at least struts 1,2 and 3 will all be at 1.75.
I noticed you posted some new pictures and I like the "slide rule", too late for this wing but I think I will steal it for the other wings.
Sure wish I had a nice warm basement to work in :D
I took your tip earlier on the Dremel Saw Max and agree, once I started to use it I found it to be very handy.

Thanks, race you to the end.
Ed

[url]http://www.edwinwhite.com[/url]

I sent an email to Jeff Shoemake this morning (3/16) asking for clarification on this.

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

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.