Hatz Biplane Association

I am ordering (most) of the rest of the wood I will need this month (wicks, 15% off… hey, I’ll take what I can get). I am going to be ordering a 4x8 sheet for the fuel tank bottom… so I only want to pay that shipping cost once! Some things are easy, but I have a few questions:

Leading edge… I am going with 1/16" birch… but do I want the 45 or the 90? (I understand the 45 allows you to bend easier… but is it needed on the leading edge?)

Mahogany bow--- it says to use Mahogany, and I would like to use Mahogany… but what kind of Mahogany?!!? I would love to have some 1/3 Mahogany boards, but there is nothing like that. So I am thinking maybe they are talking about using 1/16” Mahogany ply? The other issue is the domestic Mahogany is Mahogany and Poplar…. And that is not going to work well when sanding it down. I have seen a lot of people use different things I think someone even used pine… but any suggestions from someone who did use Mahogany.

Pretty much the same question for the wingtip bows… what wood did everyone use for this?!

Thanks,

Tre’

Tre'
I used Pine and Poplar for both. I planed them to 1/8 inch and epoxied them in a former. I was very happy with the results but it doesn't have the look of Mahogany. The only piece of non aircraft plywood on the plane is my center section floor. I got a piece of 5 ply from a local cabinet maker to save on shipping. I have to say that the quality is as good as the aircraft version if not better. I used Birch Plywood for the leading edge and I was very happy with that also. All the plywood that I ordered was in 4 x 4 sheets since shipping is much cheaper. I scarfed the 1/16 leading edge pieces together, even with 4 x 8 you will still need at least one joint. I forget if I used 45 or 90 on the leading edge, it bent nicely but I wouldn't say easily.

90 deg. leading edge. There are no compound curves till out at the tip bow, so 45 deg. is only used there. Even with 45 ply I couldn't get my leading edge ply to completely comform to the leading edge tip bow/ spar/end rib triangle so I glued the triangular piece of ply to the leading edge following the curvature of the tip bow ply, to the rib at the beginning of the tip bow, and to the spar as it works it's way from the leading edge wing tip up towards the end rib (forms a triangle). Halfway between last rib and where the spar meets the tip bow, I cut a wedge slit in the ply to get rid of where the skin wanted to pooch out. Cutting out that triangular slit allowed the skin to lay flat to the spar then I glued a piece of ply to the underside of the slit area and, after the glue set, I sanded through the top ply skins and into a bit of the bottom ply I glued on underneath. That allowed me to "round" out that last bit of compound curve that I was trying to get out of the ply. Sort of faking it. Hope this paints a picture that you can see in your mind. Hard to put into words, but, hope it helps.

No, that helps a lot. I was going to go ahead and use 90 degree, but I feel better about it now. I will order a smaller piece of 45 degree for the outboard portion.

Thank you,

Tre'