Hans U & Samuel D Gautschi Hatz Classic Project: rotecradial

Hans & Sam Write:

Hatz Classic modified to look like a vintage Waco, by Hans & Sam Gautschi, Switzerland

A life long dream came true when back in the Spring of 2004 my son told me about his strong desire to build an airplane with me. I was delighted as I've always wanted to build a real airplane instead of the many years spent building and flying small scale models.

My Son's suggestion changed thoughts on what I thought could and or would ever happen! After all raising two children, a married guy should have family things to do in the evening rather than building airplanes. Luckily for me my wife Therese supports us in our joint project.

My Son and I have always loved vintage airplanes, especially biplanes, so the choice to build a Hatz was not a difficult one to make. But that really came later as our first considerations centered around a replica Gipsy Moth (mostly for the looks and the ability to fold the wings). The limiting factor in selecting a Gipsy Moth was the lack of a reliable and serviceable in-line engine which made the project unfeasible; so it was that we settled on the Hatz biplane, which despite not offering folding wings, became our choice based on 3 reasons:

1. Another home builder in Switzerland already was building a Hatz Classic and, being an aircraft engineer by profession he did all the stress calculations (requirement in this Switzerland!)
2. The availability of the Rotec R-2800 radial engine and subsequently the R-3600. The Rotec Radial is a natural fit for the Hatz (or is it vice versa?)
3. The Hatz CB-1 is a well proven design and the Classic is an extension of the CB-1 with some beefing up to accommodate a 160HP flat engine. The Classic in design is more pleasant aesthetically and matches the desirable look of the late 1930's Waco biplane in design. The basic Hatz Classic design provides a perfect base which can accommodate small cosmetic and design changes.

Initial discussions about the suitability of the Rotec 7-cylinder radial started a lively discussion about the feasibility of this engine as rated at 110 HP power the concern was it would be under powered for the craft; but the advent of the 9-cylinder R-3600 it solved this concern and we moved forward with our plans and in 2005 and we placed an order for a R-3600 for our "Classic" at Osh05.

Our forward planning and goals were to use the Hatz Classic plans as a base, but undertake the following modifications to achieve a vintage "Waco"- like look:

• New elliptical tail-plane and modified fin design with ground adjustable incidence device. The fin is separated from the fuselage (can be removed). The area between stabilizer and fin is closed with an aluminum panel.
• High pressure "Bendix" wheels and undercarriage streamlined with a wooden superstructure, fabric covered.
• New lofting of fuselage with small "cosmetic" modifications to the ground and side view. This included a new all wood turtle deck with large baggage compartment (post sack) accessible by a side hatch. Rising the front of cockpit decking for a racy, vintage look and better blend for the radial engine. Omitting all but two stringers on the fuselage sides.
• The collector ring will be enclosed within the front fuselage paneling like on a Waco QCF or a Stearman. Carburetor and cockpit heat will be taken from this surrounding.
• Changing the plans for the wing at the tip, center section and lower wing to fuselage so as to follow closely the Waco QCF design. This includes a new wing tip bow design following the skeletal slope of the airfoil.
• Fabrication and installation of a special built speed ring for the R-3600

In the final analysis, we are trying to build a vintage looking 1930's biplane by using modern materials and methods to achieve our goal.

Our thanks go to American Mehlin Smith, who's custom vintage Hatz which greatly influenced our thinking on the project (see picture at left showing a red/cream Warner powered Hatz)

Our efforts, as a father and son team, are towards living our dream, and achieving our dream! In the process we're having a great time!

Stay tuned!

Hans & Sam Gautschi

H.C. #78, SwitzerlandHope page for Hans U & Samuel D Gautschi & RotecRadial

as usual please click on thumbnails to expand the pic...

Early days with Hans & Sam ... and the workshop! ................

Meticulous care and an eye for detail as seen in the first pthographs is obvious...

fuselage takes shape:

. . .
as usual please click on thumbnails to enlarge...

Hans and Sam are currently evaluating the possibility of encapsulating the R3600's collector ring (similar to that in a Stearman PT 17) .

Looking forward to future reports on progress being made.