F R E Q U E N T L Y  A S K E D  Q U E S T I O N S

About how many employees work at Hartzell?
Hartzell employs approximately 325 people. Employees are non-union and work 3 shifts.

How is manufacturing organized?
Manufacturing is organized by machining cells. The cells generally include a team of 8 – 10 people who not only make a particular part family, but also provide expertise on the best process layout, sequence and equipment.

Hartzell cellular manufacturing is a close grouping of all machines necessary to produce a part family so that the entire processing sequence is optimized in terms of floor space, production time and product quality. Hartzell consistently applies the knowledge of their skilled machinists and inspectors to the critical tasks of process development and continuous improvement.

The cells operate as their own business center. Key Performance Measures for each cell are established and tracked according to planned goals. The result is a true team atmosphere and spirit.

Modern Machine Shop and other trade journals have recognized Hartzell for such traits as innovative process development, cellular manufacturing teamwork and quick setup procedures in articles.

What does the inside of the plant look like?
Picture a white epoxy painted floor with an extremely neat and clean work environment showcasing numerous computerized machines and processing equipment. Visitors are often stunned at the pleasant appearance of our machine shop. It translates into tremendous customer impact during tours and helps create the special pride in our work place.

One might perceive the plant would look like a propeller assembly operation where blades are machined and assembled with purchased components to make propellers. To the contrary, the majority of our time is spent manufacturing highly engineered propeller components other than the blades. Hartzell machinists and inspectors have insight into the entire manufacturing process, including quality control, and understand the critical functions of our respective parts.

What materials are used to make propellers?
Hartzell propellers are constructed from various materials, but the primary structural components in the hub system are high strength aluminum or steel forgings. Blades are made from high strength aluminum forgings or advanced composite materials (Kevlar or graphite).

What types of equipment does Hartzell use?
Hartzell employs a variety of high precision CNC mills, lathes and grinders. Numerous computer-controlled machines perform the vast majority of the component manufacturing. This state-of-the-art equipment operates to tight engineering tolerances down to 0.0001 of an inch (0.0025 millimeter) with repeatable output.

Composite manufacturing is accommodated with a CNC ply-cutter to provide accurate patterns. Hartzell developed special oil-heated press systems to mold composite blades.

Special processes at Hartzell include heat treatment, metal cold working, chemical etching, various plating operations and painting.

How long does it take to assemble a propeller?
A propeller is generally assembled in about 1 to 4 hours depending on the complexity of a given model. Special workbenches and tools aid the propeller builder. Documented inspection is performed throughout the assembly process and final verification.

How is a propeller balanced when it is made?
First the blades for the propeller are balanced together as a set. After the propeller is assembled, it is statically balanced on a sensitive, computer-controlled workstation.

How are composite blades constructed?
Technicians "lay-up" patterns on a foam core by hand, alternating Kevlar or graphite mesh in a specified arrangement to promote optimal directional strength. The raw blades are then press-cured. Blade shanks and leading edges are made from high strength metallic alloys.

How are spinners made?
Hartzell spinners are typically made from spun aluminum. While spinning, a flat sheet of aluminum is forced over a mandrel in the shape of the spinner dome or bulkhead. These raw spinnings then go through secondary operations to create blade cutouts and attachment holes. They can be brushed, ready for painting or polished to a mirror finish.