Hatz Biplane Association

YouTube has a video of Mehlin Smiths exquisite
Classic at Brodhead. The comments refer to an
8" fuselage extension, I guess to compensate for
the additional weight of the Warner radial.

Anyone on this forum know where Mehlin added
the 8" i.e. which station interval was stretched?
As I'm considering the same stretch (for the same
reason), for me it would make sense to add it
between the front and rear seats.

Thanks !!

Bill Rusk is the current owner of Mehlin's Hatz CB-1 and can answer most any question regarding it.

I spent some time w/Bill at his hangar going of the the changes Mehlin made and with regard to the fuselage extension, the entire 8" extension is all aft of the rear 'pit. It is evenly distributed across the remaining stations between the rear 'pit and the tailpost. The fuselage dimensions from the firewall to the back of the rear 'pit is standard CB-1.

I would not change anything between the front and rear seats as this could drive changes to the wing and landing gear attach points and possibly change the wing stagger which leads to changes in the struts, flying wires, control linkage, etc., etc. Lot's of potential impacts to a change of that nature. Not saying it can't be done, but I wouldn't tackle it unless you are prepared to deal with any redesign/re-engineering issues that may accompany it.

And the reason for 8" as opposed to more? According to Mehlin, it's what would fit in his garage where he was building it.

Exactly!

OK, that helps. Is Bill Rusk out of Broadhead too, or has the aircraft moved now?
I'm a couple of hours away in Lake County IL.

I did read on the archives that there was a longer, fatter Hatz Classic fuselage out there, that the owner was comtemplating selling on. I think it was dated sometime in 2010. Did that fuselage ever fly, to anyones knowledge?

Yes, I'm longer and fatter also - but will typically only fly solo.

Mike

From the sounds of your question, it's not clear to me if you are familiar with the CB-1 and Classic differences. Let's make sure we're talking apples & apples here.

First, Mehlin's Hatz is a CB-1, not a Classic.

Second - What are the differences? That's been asked a lot and someday I hope to compile a complete list, but for now here's some of the high points:
Fuselage Length: same as CB-1
Cockpits: Front - Pedals moved forward 2" and seat moved back 2" and more reclined; Back - Pedals moved forward 3" and seat moved back 4" and more reclined.
Stringers: more stringers were added to give the fuse a fuller, more rounded shape.
Gear Legs: lengthened approx. 3"

GW increase to 1700lbs.

There are several other differences, but we appear to be concentrating on the fuse so I've kept it to that.

The Classic was designed by BIlly Dawson. Jeff Shoemake (Makelan) sells the plans and also produces sub-assemblies including the fuselage.

Bill is out of Poplar Grove. Mehlin's Hatz migrates between Brodhead and Poplar Grove.

Hope this helps.

Hello Doug,

I'm aware of the CB-1 / Clasic differences - it's well documented on this forum, and other sources.
I'm referring to a one-off Hatz fuselage, brief details for which were posted here.
The latest owner was not confident of his ability to complete the project, particularly as it was his first build. He did state the the fuse was TIG welded.
I'll go back and do a search on the keywoord 'TIG', so I can be more specific with my question.

Thanks also for answering the location question.

Mike

OK. I'm not familiar with that one-off fuselage you are referring to. If you find anything out, post an update. I'd be interested in learning what was done.

Hello Doug - I found the thread - Here it is...... (and I've PM'd the author)


Re: Hatz scaled up?
by jdgleitz » Tue Jun 29, 2010 6:36 pm

I have a enlarged Hatz fuselage that I will not be using. It is made to comfortably seat two in the front cockpit. It was designed and built by someone else. It is TIG welded and done very well. I decided for my first homebuilt, I had better stick to the plans. I would think a 220 Cont or similar engine would work well on it. Right now it is hanging in my hangar, but I would much rather it go to someone who might finish it.

JDjdgleitz

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Report this postReply with quote Re: Hatz scaled up?
by jdgleitz » Wed Jun 30, 2010 6:50 am

The fuselage is lengthened as well. It also has enlarged tail surfaces completed. The original builder had a builders page on the Hatz homepage. http://www.hatzbiplane.com/723.html

Interesting. I've often wondered what became of that project. I didn't realize he had changed the fuse... I thought he was just redesigning the wings for a Taperwing look.

I think a person really needs to think about what they are going to change on a Hatz (not directed at you Mike... just thinking out loud here). As homebuilts go, it's on the large side and not all that much smaller than a Waco. In fact, I have some Waco QCF drawings and you be surprised to see how much they have in common and how close some of the Hatz dimensions are to a full scale Waco. If I were to go much larger I think I'd just say "the heck with it" and build a full size Waco.