Hatz Biplane Association

Hello all.

I have an early set of prints (SN85) and I do not have a drawing that depicts the size, material or a grid diagram of the firewall. can anyone help me out with a grid diagram of the standard Classic firewall?

I know that I could make one on my own, but I am basically lazy I guess!

If there is one out there already, I would like to have it for review.

I saw some earlier posts on the Forum that gave me ideas on the material and thickness, but any additional info on what folks with completed aircraft have used would be most appreciated!

Thanks!

Rick
HC85

Hi Rick, Everything you need is on page 25 of the plans. If you don't have page 25, I suspect there are other pages you are missing as well. Like you , I have an earlier set of plans (s/n 93) and there were pages missing when I received them several years ago. I contacted Jeff Shoemake and gave him a list of what I DID have and he sent me all the missing pages. I strongly suggest you get in touch with him and get whatever you are missing.

FYI, the firewall page specifies 24 gauge stainless. I can send you a pic if you want, but you'd be better off with a copy of the drawing.

Hi Doug, Yea, I am missing page 25. I have asked for the pages before from Makelan, no go. I would buy a new set of plans if I could... I have a friend in Florida still waiting on his. I have had a pair of windscreens on order for a couple years now lol!

I was able to get some of the other pages at Brodhead the year before last, I didn't realize at that time I was missing this info too. Maybe a pic would give me enough info if it were clear enough.... Wouldn't hurt to try!

Thanks for the reply!

Rick

Let me see about getting a copy made.

If you are going with the Rotec then the firewall grid on page 25 will be almost useless. It would be nice to have all the pages though. If i remember correctly the fuselage formers are also on that page and they are useful even if using the Rotec. I can email you a pic if that would be helpful.

Ooops, Boy am I embarrassed! I found that two of my pages were stuck together! I have the firewall page after all. Duh

I would like pics tho Ed.. So, you don't think that shape would flow so good to a round one behind the Rotec? Pics would be much appreciated!

Thanks everyone!

Rick

Hi Rick
I made my firewall as per plan using .018" stainless from aircraft spruce. Any aircraft that I've built or seen uses .016-.018" galvanized or stainless with stiffeners or bead rolling where required. I've just finished shaping the .040" 3003 aluminum cowling firewall forward to the R3600 exhaust ring and it blends in nicely.
Regards Steve SN162

Thanks for the info Steve! Good to know.

I'm looking forward to seeing more pics of your plane too!

Rick
HC85

Rick,
I am sorry, I wasn't thinking about using a speed ring when I suggested that the firewall pattern would not be helpful. I am building a complete cowl like the Waco YMF and as such my firewall will be closer to round. I used foam board mounted in place of the firewall and then projected lines onto it and it came out close to round but it also located the holes for the mount. I have moved my engine up two inches which also affected the firewall. I guess I should have indicated that for me the pattern wasn't helpful. Something that I recently realized. I rounded the fuselage just a little from the plans by making the formers for the stringers a little rounder. After mounting the stringers I noticed that the bottom two stringers will interfere with lower wings. At this point it is an easy fix but it is something to consider if you also want to round out the plans.

Hi Ed, No problems!

I also thought about doing the YMF, UMF style of cowling, but ended up where I'm at with the speed ring or nothing, because I was not looking forward to the re-design like you are tackling now! I doubted my abilities to do the necessary metalwork, or fiberglass mold work, with good enough results. My "Hatz" off to you for doing so!

I have followed your project, and have used your construction ideas, and photos to help my project along. I would bet a few folks are looking forward to seeing your work! Please post when you have it in a good place to do so! Can't wait to see it!

Rick
HC85