Propeller Manufacturers

Early propellers were made from one piece of solid wood and later props were made from several laminations of a hardwood, usually spruce or mahogany and then hand carved. Shortly after World War I, the first successful metal props appeared; this was the ‘Reed’ type developed by Dr. S. A. Reed. The props were cut, shaped and twisted from one piece of Duralumin, an aluminium alloy. From 1926 onwards, metal props became more common on high-powered engines, but wood props are still used today, usually on low-powered home-built aircraft.

Ernest G. McCauley (c1885-c1930) founded the McCauley Propeller Company in 1938. Right from the inception of the company, all their propellers were made from metal, starting with a ground adjustable prop they invented and made from solid steel, in 1938. In 1946, they made the first metal props for civilian light aircraft, called a ‘Met-L-Prop’. Metal props are now made from either a single piece of forged Duralumin, hollow steel or a light alloy. Prior to 1930, most wooden propellers consisted of either two or four-blades. A three-blade prop was unusual due to the difficulty of attaching the blades to the prop hub, while still maintaining sufficient strength. With metal props this is of course, less of a problem. One notable exception was the Junkers JU-88 twin-engine bomber. Apart from being the most-produced German bomber of the Second World War, it also had three-blade, wooden, constant-speed props. The Cessna Aircraft Company purchased the McCauley Aviation Corporation in 1960 and operated it as a separate division. The same year saw the introduction of McCauley’s two-blade, constant-speed propeller with full feathering and alcohol de-ice system. Electric de-ice followed in 1967.

As the years progressed, further advancements saw the introduction of three-blade, full feathering props and reverse pitch props for turboprop aircraft in 1977. Next up was the four-blade prop in 1983 followed by the hugely successful

McCauley ‘Blackmack’ series of propellers. In 1992, the five – blade scimitar shaped prop was made for turboprop aircraft of up to 1650 shaft horsepower. The company received a name change in 1996 to McCauley Propeller Systems and it is now the largest propeller manufacturer with over 250,000 props made over the year, operating on aircraft worldwide.

In 1911, Robert Hartzell expanded his family’s Walnut Furniture manufacturing company to make aircraft propellers with the name changed to Hartzell Walnut Propeller Company of Ohio, USA. The name was later shortened to the Hartzell Propeller Company. They concentrated on the high-performance light aircraft and turboprop market; they no longer make fixed-pitch propellers. They were the first company to manufacture feathering propellers and pioneered the use of composites materials in 1945 in propeller manufacturing. Their first composite propeller (and the world’s first) was patented in 1949 and flight-tested on a Republic Seabee amphibian aircraft. In 1978, Hartzell installed the first production run prop made totally from composite materials on the Spanish CASA 212c Aviacar. Composite prop blades are 25-50% lighter than metal blades with the added advantage of higher strength, greater reliability and performance, fatigue resistance and better vibration damping, etc. The blades are made from polyester or epoxy-resin with a fibre to provide directional strength. The fibre may be glass, carbon or a synthetic Aramid fibre such as Kevlar, which is also found in bulletproof vests, amongst other uses. It is also lighter in weight and more expensive than ordinary fibreglass. In addition to using new materials, propellers are still being refined with new designs using ‘Q-tips’, sweptback tips and scimitar shaped blades

The Sensenich Propeller Company was founded in the USA by the Sensenich brothers in 1932. By 1942, it was the largest manufacturer of wooden propellers in the USA and commenced fixed-pitch metal propeller manufacturing in 1947 and later composite propellers. McCauley, Hartzell and Sensenich are the three leading propeller manufacturers in the USA for light to medium size aircraft. So, is it by chance or coincidence that two of the world’s major propeller manufacturing companies, McCauley and Hartzell are located within a few miles of each other in the same city of Dayton, Ohio, the Wright Brothers home town! It was on the request of Orville Wright to his friend Robert Hartzell to make propellers that saw the start­up of the Hartzell Propeller Company.