Hatz History

Hatz Biplane

The origin of the Hatz biplane goes back 40 years to 1968, when John Hatz from Gleeson, Wisconsin,
was looking for a more economical airplane than his OX-5 powered Waco 10. He designed his own biplane while leaning on the lines of the early Waco design.
The fuselage was a relatively simple steel tube frame with a Piper Cup type landing gear and flat steel tube tail, 4-aileron straight wooden wings and a flat 4 cyl. aircraft engine. That prototype still flies today and more than 200 similar biplanes have since been built.




Hatz CB-1

When Dudley Kelly drew up plans of John Hatz’s original design, his version became the CB-1
Several developments from the basic design have evolved in the past . Power has increased from 85hp up to 180hp on several planes.




Hatz Classic

Billy Dawson from Seguin, Texas, begun building his third example of the modified Hatz.  This airplane, which
differs in many ways from the original CB-1 design, came to be known as the Hatz Classic and the firstflight was 1996.  

Some of the more noticeable differences are: 

  • The outward appearance, which is more rounded or fuller and resembles the style of the grand airplanes of  the 30’s

  • A larger engine fully enclosed in the cowling
  • The use of push-pull tubes in place of cables for the aileron and elevator control linkage
  • Aluminum ailerons
  • Seats are relocated and reclined, allowing more leg room and comfort in the cockpits

  • Modified wing tips and dehidral added

  • Covered gear legs   

Billy succeeded in building an airplane that was above all fun to fly.  It has comfortable seats and a roomy cockpit. 
It has a reasonable fuel range.  With the redefined windshield shape there is very little wind in either cockpit. 
A limited baggage compartment is usually built into the turtle deck, the upper portion of the fuselage directly behind the rear seat. 
The normal cruising speed of 115-120 mph which makes the Hatz Classic comparable to many larger,
more powerful biplanes, the Stearman, for example.

These characteristics make the Classic model suitable for reasonable cross country trips.  It’s low landing speed of around 43 mph makes the Classic right at home on Billy’s 1400’ grass airstrip, located behind his home. 
The 1,000 + feet per minute rate of climb and solid control feel, make the Classic an exciting platform for limited aerobatics.  Maneuvers such as standard loops, barrel rolls, and hammerheads are easily mastered and performed. 
Because the airplane weights over a 1,000 pounds empty and with a gross weight of 1,700 pounds, it has a heavier or bigger feel than many of the experimental airplanes available today. 
The 50“ cord Clark Y airfoil provides good lift at lower speeds.  The influences of the weight, lift and wing shape make the Hatz Classic as manageable as any tail dragger during cross wind landings, and ground handling. 




Hatz MS

Mehlin Smith’s Vintage CB-1 Hatz (MS)

Mehlin Smith from Broadhead, Wi, built on the basis of the CB-1 design, the most beautiful vintage style Hatz existing today.
The use of a vintage 145hp Warner radial engine makes this aeroplane unique.
Mehlin built this marvelous aeroplane over a period of 27 years (!) and the main noticable modifications create
a special 1930’s character:

  • Vintage 7-cyl. radial engine

  • Installation of large dia high pressure Bendix wheels with smooth contour 1930’s style tyres

  • Redesign of the tailplane and fin/rudder with beautiful elliptical shape. Fitting of an aluminum sheet metal covering for the stabilizer/fin fuselage area

  • Increasing the side profile height of the front fuselage portion

  • 1030’ paint scheme consisting of period standard colors

  • Cockpit with period instrumentation and some authentic details as e.g. wooden control sticks and simple

As a consequence of the rel. heavy engine, Mehlin decided to lenghten the fuselage tail arm by 8”.  It is uncertain how much this upgraded the longitudinal stabilty, Mehlin’s Hatz is one of the best performing Hatz biplanes flying today.

Mehlin’s Hatz deserves the tribute, that we have been encouraged to modify the proven hatz Classic design to have the look of a 1930’s style biplane.
The availablity of a suitable radial engine in the form of the Rotec 9-cyl. engine made this possible.

(written: H&S, January 2009)



Hatz Bantam

The Hatz Bantam   is an evolution of the Hatz CB-1 Biplane designed by John Hatz in the late 1960s.  It has been modified to use the Jabiru 3300 120 hp. engine.  To balance the plane with the lighter 178 lb. engine,
the CB-1 design was lightened and dubbed the "Bantam". 
The empty weight of the Hatz Bantam has been reduced to approximately 780 lbs. 
Setting the gross weight at 1,320 lbs. gives the Bantam a useful load of 540 lbs and will qualify it to be a
"Light Sport" aircraft.

Without changing the relative position of the propeller with an O200 engine, as per plans page 26,
changes in the Bantam include:

  • Tail group from Sta. 6 aft (horz. stab., elevators, vert. fin, tail wheel etc.) at over thirty lbs. has been moved forward 4"
  • Wings are moved 1-1/2" aft.

  • Pilots cockpit is 1" forward

  • Fuel tank has been relocated from the center section to the forward fuselage (18+ gal)

  • Each wing panel is 12" shorter

  • Ailerons are on the lower wings only

  • Wing ribs and bracing are pressed aluminum

Using state of the art technology, many new parts have been designed for production using AutoCAD drawings in conjunction with water jet, and CNC milling and turning.  Our goal is to make these parts, and eventually kits, available to Hatz builders. 
Some parts are interchangeable with any model of Hatz and others are specific to the Bantam.

The prototype Hatz Bantam, N. American Flyer z, rolled out August of 2005.




Vintage Hatz

The Hatz Classic is a very fine performing and stable biplane, but for our taste it’s look with the flat engine cowling is a bit to modern. Without loosing some of the fine qualities, we wanted to change a few design features to have it look more like a Waco. With the advent of the new 9-cyl. Rotec radial a round engine is available, which makes this possible.
Taking the Hatz Classic plans as a base, we undertook the following modifications to achieve a vintage
"Waco"- like look:

  • New elliptical tailplane 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 turtledeck 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. Ommitting all but two stringers on the fuselage sides

  • The collector ring will be enhoused within the front fuselage panelling like on a Waco QCF or a Stearman
    Carburetor and cockpit heat will be taken from this surrounding

  • Changing of wing planform at the tip, center section and lower wing to fuselage blend very close to the Waco QCF design. This includes new wing tip bow design following the skeletal slope of the airfoil

  • Fabrication and installation of a special built speedring for the R-3600

All in all, we are trying to achieve a vintage looking 1930’s biplane with new materials just as we like the many designs of the 1930’s aera.

(written: H&S, January 2009)