M A J O R M I L E S T O N E S
John T. Hartzell opened a sawmill in Greenville, Ohio in 1875. The business prospered, but John fell ill and sold the company to his son George W. Hartzell in 1900. George promptly moved the business to nearby Piqua and expanded operations there. Some time later he moved his family residence to Oakwood, Ohio – some 35 miles from Piqua. As a teenager, George’s son Robert N. Hartzell had a burning desire to be involved in aviation. In 1914 fate brought Robert the encouragement he needed when Orville Wright moved into the newly built Hawthorn Hill mansion the Wright brothers designed, one block from the Hartzell residence in Oakwood. Robert spoke to Orville often about his interest in aviation and Orville, knowing that the George W. Hartzell Company was already supplying high quality walnut lumber to others for production of aircraft propellers, encouraged young Robert to begin manufacture of their own propellers. In 1917 Robert left the University of Cincinnati to follow his dream of being a part of the fledgling aviation industry.
The onset of World War I in 1914 created a problem of immense proportions to the George W. Hartzell Company, but one that would ultimately lead to great opportunity. Up to that time nearly all of Hartzell’s hardwoods were exported to Europe, however, the war created an embargo on these shipments and Hartzell was forced to develop alternative uses for its output of wood. The company immediately began producing gun stocks and supplying lumber to be used in the manufacture of propellers to support the growing war effort even though the United States was not actively involved at the time. When the company began making its own propellers in 1917 the timing was serendipitous as the U.S. had just entered the war and the Hartzell Walnut Propeller Company had an instantaneous and almost overwhelming demand, at first for Curtiss Jennys and later Liberty engine powered Dayton-Wright DH-4s. Hartzell’s success with the war time production of propellers provided much needed experience and was a great source of pride for the company.
They say that "necessity is the mother of invention" and after several years of license production of thousands of metal propeller blades for the U.S. military, the end of World War II created the need for new products to replace this business. Robert Hartzell was quick to recognize this need and hired David Biermann, an expert in propeller research at NACA, to lead the company in development of new products following the war. Biermann and his team began one of the most prolific periods in the company’s history. In addition to developing all-metal controllable pitch propellers followed shortly thereafter by constant-speed propellers this team also developed the following industry firsts:
- The first composite propeller blades
Hartzell had developed a unique fabric-based plastic material for use in industrial fans, dubbed Hartzite. In 1945 the material was used to construct blades for use in Hartzell’s first ground adjustable propellers. A patent for this construction was granted in 1949. The material was lightweight and durable, two of the same features that would be found later on Hartzell’s modern advanced structural composite blades that were (re)introduced in 1978. - The first reversible propellers
Hartzell Propeller has always been responsive to customer’s needs and Biermann’s team was no exception. Responding to the desire to be able to control sea planes while on the water, Hartzell introduced a reversible propeller system for the Republic Seabee in 1946. While the market was limited at the time, it was prescient in that reversing propellers would later see widespread use on turboprop powered aircraft beginning in 1965. - The first full feathering propellers for
light aircraft
In the early 1950’s several aircraft companies were developing light twin-engine aircraft. Until this time multi-engine aircraft had all been large military and transport airplanes with large heavy propellers suited to these aircraft. The light twins being developed required relatively lightweight full-feathering constant-speed propellers previously unavailable until their introduction by Hartzell in 1952 for the Aero Commander 520, followed in 1954 for the Piper Apache, Cessna 310 and Beech Twin Bonanza thus beginning Hartzell’s preeminence in general aviation. - The first practical turboprop propellers
Until the early 1960’s turboprop engines were large and so were their propellers. With the advent of small turboprop engines being developed by Pratt & Whitney and Garrett, there was a need for lighter propellers to go with them. Hartzell answered the call and in 1964 launched a three-bladed steel hub design that was mated to a Pratt PT6A on the first Beech King Air 90. Since that time Hartzell introduced four-bladed and five-bladed versions of that same basic design. Today Hartzell Propellers can be found on almost every general aviation, corporate, utility, agricultural, military trainer and light commuter turboprop application.
In 1986, after a call for help late in the Voyager’s test program, Hartzell’s engineering and manufacturing team built two brand new propellers in less than a week for Burt Rutan’s radical aircraft designed to go around the world without refueling. Metal propellers were originally thought to be too heavy, however, a durability problem with their wood props led the Voyager team to reconsider. Even though the metal props weighed more, the thinner blades were able to deliver more thrust, more than offsetting their weight penalty. The success of this rush program allowed Voyager to maintain its weather critical timetable and in December 1986 piloted by Dick Rutan and Jeana Yeager achieved that feat in just a little over 9 days.
Hartzell helped to set new altitude records for piston (Condor) and turboprop (Egrett) engines through its involvement with these two significant aircraft programs in the late 1980’s. Hartzell’s unique design for Boeing’s Condor UAV program were two slow turning 16-foot diameter, three-bladed composite systems. The Egrett utilized a single four-bladed composite system. Hartzell continues to demonstrate record setting performance today, having just set the propeller driven time-to-climb record to 3000 meters of 1 minute 9 seconds with Wayne Handley in his Turbo Raven.
NASA next generation propulsion programs
Having already been involved in the NASA Advanced General Aviation Transport Experiments
(AGATE), in 1997 Hartzell was selected by NASA to serve as the exclusive propeller system
partner on the General Aviation Propulsion (GAP) program. Other partners include Teledyne
Continental Motors developing a new technology 2-stroke diesel engine, as well as Cirrus
Design, Lancair, and Piper supplying test bed airframes. Major objectives of the program
are to develop the next generation of technologies that will increase efficiency, safety
and performance while reducing noise and cost. Hartzell tested its first prototype in the
latter half of 1998. Results from the new, highly swept blades were very promising.
Further testing with the new Continental engine is scheduled for 1999, with flight testing
to begin in the year 2000.
