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Wooden propellers are popular collector’s items among aviators and non-aviators alike, and many people even use wooden propellers for home or office décor. However, correctly identifying historic aircraft propellers can be a complicated and time-consuming process. At Hartzell Propeller, we regularly receive messages, calls, and emails from people seeking to discover the origin of vintage propellers they’ve found or collected. While it’s not always easy to positively identify historic propellers, we’ve gathered a few tips to help you get started.

Do you have an early or modern wooden propeller?

Historic wooden propellers can be classified as either early or modern wooden propellers. Early wooden propellers are usually longer than modern wooden propellers at eight feet or more, while modern wooden propellers are only six to eight feet in length. Early wooden propellers also typically have eight bolt holes and use darker woods such as mahogany or walnut. By contrast, modern propellers tend to have just six bolt holes and are made of lighter wood like ash or birch. One of the best online resources to compare historic propellers is woodenpropeller.com, which includes a wealth of information from many different propeller manufacturers as well as a helpful photo gallery.

Other types of propellers

It’s not uncommon to come across a wooden propeller that isn’t an aircraft propeller at all. For example, airboat propellers are often mistaken for aircraft propellers. These props are characterized by wide, flat blades with square ends, and were used for slowing airboats powered by automotive or aircraft engines. Some people also find test club propellers, which were used to test engines from the ground. Test clubs are typically shorter and don’t have a twist to them like aircraft propellers.

Identifying by serial number

While some propeller manufacturers used special identifying numbers on their propellers, Hartzell doesn’t have a serial number system for our early wooden propellers. However, some Hartzell props used by the Army Air Corps used “contract numbers,” which are characterized by two digits (standing for the year the contract was awarded) followed by the letter “K.” Most of these types of propellers were used on service aircraft.

Determining the value of a propeller

There’s no hard and fast rule for determining the value of historic aircraft propellers. In general, factors like rarity, current condition, and the type of aircraft/engine the propeller was used with can help assess the value of the propeller.

Do you have questions for the Hartzell technical team? You can reach us at techsupport@hartzellprop.com