I am very new to the AHA and this is my first experience with your forum. It seems to be a very good way for Hatz builders to share info. I am trying to decide on what my next project will be. I have seen several Hatz airplanes over the past several years and have always admired their beautiful lines. I would appreciate one of you folks taking just a minute of your time and explain the major differences in the Hatz Classic and the CB-1.
Thanks much
Chuck Lambert

I wouldn't call myself an expert at Hatzes (or at anything for that matter) but I too was smitten years ago by the beautiful lines of the Hatz. It was only a matter of time before I began building one. I'm building what I suppose is a Classic in that I'm using an 0-320 and am enclosing the engine completely. This causes the fuselage to be wider at the firewall to give a smooth line to the sides of the fuselage as veiwed from the top.

The classic and the CB1 are the same structurally, I believe. The front of the fuselage has more of a build out of the skin supporting structure at the front of the fuselage and more side and belly stringers to give the mid and aft fuselage more of a rounded look.

A difference that's of importance to some is that this extra build out adds weight. Hence more power is wanted (needed), and more fuel for the extra power is needed. It just keeps adding up. A plans built CB1 will weigh in the nieghborhood of 850 to 900 lb. A Classic can weigh up around 1050 lb. or more.

Dave and Carol Newbury up near Toledo had two very pretty Hatzes. A HIS and a HERS Hatz painted alike in butterscotch fuselage and cream wings. His was 160 H.P. with full electric. Hers was an 0-290 and no electric. I flew the 0-290 Hatz and it was a real treat. Dave said there was a big difference in the handling between the two. He said the lighter Hatz would turn circles inside the heavier one, the heavier one stalling out and buffeting in high bank turns. Not that everyone wants to do high bank manuevers, there are people who enjoy the ride with a heavier wing loading. I don't know the empty weight of Dave's 0-320 Hatz. It may have outweighed the Classics by some measure. Other replies to your post will undoubtedly have more details on the Classic's weight and construction variances.

I'm building mine off of the original CB1 plans, but with an 0-320. I'm trying to build it in between a CB1 and a Classic. For example, I'm using more than one side stringer as called for in the plans, but I'm not using five as used in many of the beautiful Classics. I'm using three. I'm using a lightweight starter and I'm keeping the instrumentation to a minimum for class B airspace flying.

Your right. This forum is a great place to get answers. And not only by asking questions, but sometimes by answering them. Sometimes an attempt at answering someones post brings on a reply from someone else with more knowledge in that area and we all learn.

Good to have you on board. Hope you give the Hatz a good look see. It's a great little bird.

If there's anyway I can help, shoot me a note at hatz493@hotmail.com

Later,

Mark T #493

Mark has given a great overview. I'll add just a few additional thoughts.

The first Hatz biplane was built by John Hatz, a flight instructor and mechanic in Gleason, Wisconsin. It is my understanding that John owned a Piper Cub and also a Waco 10 biplane; clearly the Hatz has Waco lines, and there is more than a little Cub in the airplane as well. John's airplane is called "Happiness" and those of us who are building our own Hatz biplanes all agree that the name fits perfectly. His airplane captured some special essence of an earlier era of flight and was greatly admired. It caught the imagination of Dudley Kelley, who had been a commercial aircraft draftsman, I believe at Convair. Dudley worked with John to draw a set of plans based on John's airplane, which has evolved somewhat over the years but continues to be known as the "Hatz CB-1." Interestingly, there are quite a few differences between "Happiness" and the CB-1 as drawn by Dudley (chord of wings, certain fittings, aileron design,etc)--I don't know if these are John's or Dudley's changes.

Over the nearly twenty years since the plans were first published there have been many variations of the "Hatz CB-1." In the 1980s several exceptional examples won awards at Oshkosh, including Rick Hansen's "Tizzy Lish," and Frank Pavliga's beautiful blue and cream biplane that captured my own interest. Dale Severs'Rolls Royce powered green airplane is another addition to this long line of wonderfully crafted CB-1s. There have been many others, too, that are special but are not as well known. No two CB-1s are alike. Each is unique, with various engines and many special features such as Randy Brook's aluminum ribbed "Bratz" and Lorin Wilkinson's Friese-aileroned, LOM-powered "Snooty." Many of these builders are frequent contributors to this site.

The Hatz world changed forever, though, with the many contributions of Billy Dawson of Sequin, Texas. Billy built or helped build a number of special Hatz biplanes...first his red airplane in the mid 1990s, and then his green airplane that was grand champion at Oshkosh in 1997. Billy pressure-cowled the airplane, rounded the fuselage, stepped up to the O-320, changed the centersection and gas tank, shortened and metalized the ailerons, faired the wingtips, curved the inboard trailing edges of the wings, perfected the headrest and windshield shapes, and called all of this the "Hatz Classic." Billy also worked with Jeff Shoemake to develop a kit for the Classic through their company called Makelan. Most airplanes being built now incorporate some of Billy's innovations even if they are still being plans-built as "CB-1s."

This year at Oshkosh three Hatz biplanes received high honors. Two were Hatz Classics (Henry Foote and Walter Cwian) and one was a CB-1 with many "Classic" lines (David Guillot).

Which should you build? It doesn't matter. It's like my children. I love every darn one of them!

Paul Uhlig

Randy Brooks

Chucki: This Randy Brooks the builder of the Bratz CB-1. My airplane has quite a few changes:

1. .049 longerons, 2. Front of fuselage modified to use a 15 gallon fuel tank, 3. All fittinga are .015 thickness on wings, 4.Fuselage fittings are made of rectangular steel tubing 5. Wing tips changed, 6. Aluminun ribs, 7, Ailerons on lower wing only-Frieze type, 8. Lower wing dihederal 4 degrees, 9. Stagger adjustable, 10. Dual compression struts in center section, 11. Stablizer adjustable, 12. Upper wing raised 2", Landing gear lengthen 3", 13. Toe brakes both cockpits, This just a few of the changes, look in builders pages Bratz S/N 535. I have a interplane strut drawing in the construction link and W&B procedures. The aircraft is now five years old and still flies as good as ever.

I started mine the following month, finishing it in June of this year. I took it to Oshkosh and was rewarded with the Gold Lindy for Plans Built Grand Champion. My plane is pretty much like Billy's green hatz, except that my engine is a true 160 hp, as it is an O320-H2AD high compression unit.

I think the plane performs very, very well. True, it is heavier than a CB-1, but the extra horsepower compensates for that. Flight characteristics are very honest, it feels like a heavier, more stable airplane but without the sluggishness. Mine grosses at 1080 lbs, cruises at 105 mph, stalls at 38 mph and will do aileron rolls from straight and level flight.

Hope this helps with your decision. Mike