Hatz Biplane Association

by **mmarien** » Mon Mar 11, 2024 6:06 pm

I ended up buying the fiberglass bump cowling from Rotec. I think I'm going to do the boot cowling in fiberglass. It's been my goto material lately.

by **scsmith** » Sat Jan 13, 2024 6:28 pm

This thread seems to have died out. Does anyone know how to contact Dick Hartzler? Is he still making spun aluminum cowls. I want to use it for the boot cowl (behind the engine) just as Ed White did.

Did anything come of the effort to do a group buy for speed rings? Does anyone have a source, or care to make one?

Steve.

--About to pick up a partially completed Hatz Classic from Nicholas Boughen in B.C. I don't know the serial number yet. I've built and fly an RV-8.

by **mmarien** » Fri Dec 16, 2016 8:01 pm

I've been watching this thread closely. I'm not anywhere near thinking about ordering parts for the cowling. But the pictures go a long ways to solve connecting the cowling to the airplane. Looks like in either case, bump cowling or speed ring, they are both held in place by squeezing them tight to the engine valve covers. No framework required. Thanks for the pictures Steve.

by **Bitshifter** » Fri Dec 16, 2016 4:53 pm

Thank you for the pics.
If I understand correctly there is nothing but the bumps holding the bump cowl in place?
That sure would make it easy.

by **ssearle** » Thu Dec 15, 2016 8:09 pm

Last picture of the speed ring mounting

Note that nothing holds the ring on except pressure against the engine rocker covers.
Steve

by **ssearle** » Thu Dec 15, 2016 8:06 pm

[quote="johnkerr"]Doug, could you post some information on the Waco mounting method? Per Ed's comment and the decision chain Hans & Sam have followed it appears that mounting is a larger issue than obtaining the "ring".
So far, all I've come up with is spiderweb of braces attached to the motor mount.

Hi John and Ed
Here are some pictures of mountings for Waco engines - both cowl styles with 300 hp Jacobs engine.
I have one more picture to come.
Read the picture comments for details of what each picture shows.
Hope this helps!
Steve SN162

by **stearmoth** » Tue Dec 13, 2016 6:44 am

Hi Rotec Hatz buffs!

We received a new inquiry for a Rotec speedring (also from USA) and I thought, I might spread this theme:

Just to let you know, that there still is an opportunity for manufacturing Speedrings with mounting hardware for attachment to special rocker covers (these could also be made available).
The goal is to catch at least 6 orders for a production run for the rings. The earlier given price of about $ 1800.00 is meant for a fine grid sandpaper finished (ready for polyshing and ready to mount including mounting hardware except the special 4 rocker covers needed.
Of course, it would also be possible to supply just the raw spun speedrings without fine sanding and some of the mounting hardware for less money. In this case the builder has to attach the mounting hardware himself. That price has yet to be determined if anybody is interested.

How many prospective builders would be interested in that Aeroplaneworks speedring?

Looking forward to any replies....

Hans & Sam, H.C.#78, Switzerland

by **dougm** » Mon Nov 21, 2016 6:23 pm

The rings provided by Dick Hartzler are intended to be used as the front portion of a full cowl, not a speed ring. The shape is very different. As Ed points out, it is probably possible to modify the ring and turn it into a speed ring, but that would require a fair amount of metal working. I don't have those skills and I would like to find a source where we can get consistent copies made. Incidentally, the company that produces Dick's rings is the same one I've been in contact with about making the speed rings.

by **Bitshifter** » Mon Nov 21, 2016 5:57 pm

I used the 34" dia. 4" radius as a cowl for behind the engine and in front of the firewall. My plan was to use the 34" dia. 8" radius as a blank for a bump cowl, pushing it back until the valve covers stuck through the 8" radius. I was then going to make 18 covers that would be the bumps where the valve covers came through. I changed my mind and decided it would be easier to make the bump cowl out of composite but I also toyed with the speed ring idea. I think that the 8" cowl would work as a speed ring but it would need to be cut along the front side and then rolled back. This would be hard but not impossible. The cowl comes rolled from a solid sheet so it looks like a 34" bowl. To be useful the flat section in the center needs to be removed. I made a form and cut and rolled a hole in mine to clear where the engine mount comes through. it took a few days to make a wood form with two pieces of 3/4 inch plywood and a router. To use as a speed ring the section removed would extend into the radius section so the wood form would need to be much bigger.

: HatzCowl2.jpg (66.84 KiB) Viewed 4219 times

by **johnkerr** » Mon Nov 21, 2016 1:14 pm

30” diameter, 4” radius, 5” deep $70

34” diameter, 4” radius, 5 ½” deep $80

34” diameter, 8” radius, 10” deep $100

39” diameter, 8” radius, 10” deep $120

42” diameter, 8” radius, 10” deep $150

This is the pricing for "standard" rings from Dick Hartzler. The 34" diameter, 8" radius seems close.

What is the difference? Wire wrapping inner circumference, folding rear edge?

Hatz Biplane Association

Speedring Cowl for a Rotec - Possible Group Order?

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