Hatz Biplane Association

Builders,
What thickness did you use for the little tabs which hold the formers: ??

.125"

Thanks Jeff.
That seems like too thick to me, especially since I believe all the vertical posts these tabs are welded to are only 0.035" thick. But I really do appreciate your input!

Agree with you on the thickness. I only reference the size from having them waterjet cut off the CAD drawings available from the HBA, and .125" pieces is what I got. Thing is, those two tabs are all that holds each bulkhead, which all the stringers are attached to. Best to overbuild it I guess.

I see our plan numbers are two apart. 138 vs 136. Build on, brotha!

I made mine .125 also and tapped them 8/32.

That tabs for the spar fittings on drawing 06 were 125. So I just had forty tabs waterjet cut from the same material. Probably overkill. 0.125 seems excessive to hold the formers now that you question it. The wing fittings are only 090 and they hold the wing ??? When I get the 050 material cut I may just have another forty tabs cut from that. If somethings going to fail, it's probably the 035 tubing not the thicker tabs.

It might be over kill but it sure holds them good

Just curious could you use AN742 Adel clamps?
Not to plans but would it work?

I actually thought about that and I can see no reason why it wouldn't. I do think that the brackets are easier though. I have taken the formers off a couple of times and having threads in them is much easier than futzing with Adel clamps and hardware. Remember that you have to fish your hand and wrench in between the fuselage and the formers, squeeze the clamp,line up the holes, get the nut and washer on...

Thanks all.
I think I'll go with 0.050". I have some left over from other parts water-jet cut. You really only need 16 of these tabs.