Hatz Biplane Association

Get your self some soft aluminum, shot bag and a nylon hammer and try making something. I was shocked with the air scoop, it's far from perfect but I never made anything like that before.

I was thinking of making it in parts. The bump cowling I bought has three parts to it. It also needs access panels and maybe some louvers. They would probably be aluminum covers. I haven't worked with fiberglass much so this would be a major project. I'm working on the turtle deck and stringers so the cowling is probably be a year away. I'm way ahead on the planning and drafting because the COVID-19 is keeping me close to home.

I did have a look at your cowling on your web page. I like your air scoop. I'll probably do something similar but with fiberglass. Great to have web sites to research like yours and Hans and Samuel in Switzerland. I almost visited them a couple years ago when I was in France but I ended up not having enough time.

I made something similar out of aluminum and was pleasantly surprised that it was not that hard.
Remember that you will need access to that area and if it is one piece that you may need to pull the prop to get it off.
Of course if you make it out of glass it will be smooth and look much better than mine.

It was a steep learning curve going from 2D AutoCAD that I used at work to 3D. The airplane is a couple years of slowly adding pieces.

I had a conversation with the mechanic next door today. He came over for something and noticed my bump cowling. I bought mine from Rotec. He was saying the speed ring was better for cooling. Something to consider in a warmer climate.

I was thinking of doing the cowling forward of the firewall in fiberglass. I just have to figure out how to go from the drawing to a mold to make the real thing.

Looks good, I wish I had your Acad skills.
A friend used the model to create a bump cowl in Solid Works. I still haven't decided if I am going to use it.
It limits access to the lower plugs and drains which I feel are important to have easy access.
It also limits oil drainage if it comes out the plugs.

Thanks Ed. That works. AutoCAD imported it no problem.

You might try this, its an IGS file of the R3600 engine. It is just an external model but it should work. I don't remember where I got it.

It's not complete. I draft parts as I build them. Probably spend more time drafting than I do building when it's tooo cold in the winter. If you want a copy that you can have printed poster size let me know what view you want. Some samples below. I'll send you a PDF file. Staples will print a 24"x36" for about $20. They can do larger.

I can put on a speed ring rather than the bump cowling if you prefer.

Does anybody have the 3D engine? I asked Paul for it but never heard back. It's not on their site that I can find.

Holy Cow "Some Drafting" indeed!
Did you draft the whole Hatz?!?!
That would make for a good shop-art poster.

orchardair wrote:I found an old thread in the CB-1 section where the exact question was asked - I should have searched before asking.
I made mine 0.090 as well, but will wait before I weld them on since there was a concern that the length is not sufficient.

I read that also and was a bit concerned but did some drafting. The fabric at the back comes down from the stringers and wraps around the bottom longeron. The stringers at the back are nearly in line with the top and bottom longerons so if the lug sticks out at all from the longeron there shouldn't be a problem.