Wooden Propeller Blades
I had a question regarding the use of wooden propellers in the IJAAF/IJNAF.
The standard painting methods seem to not apply to them, yet at the same time, a consistent color is also not clear...
I have not seen one with any warning strips either.
The use of them in trainers is clear, but also on early seaplanes. They range from a dark color, possibly stained wood, or perhaps even painted in the brownish color late war metal propellers were... But then at the same time, lighter colors exist, such as the K5Y with a grey looking one! In all cases, the metal leading edge is still clear, either lighter, or darker, but always distinct from the propeller color.
If painted, what colors would they be? Were there any standards for wooden propellers, and was the leading edge made from metal, or brass, like earlier aircraft propellers?
It's an interesting thought that I've not seen brought up before... Most modellers simply paint them the "standard" look, but I have seen some in nice wood, to simply black overall.
Any insight on this would be great, thank you for your time! -NJ
Answer:
From the Taisho era through the early Showa era, Japanese wooden aircraft propellers were crafted by laminating and gluing high-quality lumber—such as mahogany, walnut, and cherry—and then shaping the resulting blocks using tools like hand planes. Prominent manufacturers included companies like Yamaha, known for musical instrument production, established on October 12, 1897 as Nippon Gakki Seizo Co., Ltd. In 1921, at the request of the Imperial Japanese Army, began manufacturing wooden propellers for military aircraft, and in 1931, began manufacturing metal propellers.
The wooden propellers were covered with "urushi"*, and had metal tipping to protect them from damage from rain, pebbles, and runway debris.
The attached photograph shows the scene of propeller manufacturing at the factory of Nippon Gakki Seizo K.K. (now Yamaha Corporation) in Hamamatsu City, Shizuoka Prefecture, around 1921. On the left, workbenches are lined up, and one can see artisans carving propeller shapes out of stacked wooden boards. In the background on the right, men in business suits and Army personnel are observing the work.
Nippon Gakki began manufacturing propellers in March 1921. Why did a company that made musical instruments come to produce equipment for military aircraft? The answer lies in the propeller manufacturing methods of that era. Propellers at the time were made of wood; creating them required artisanal skill to glue together hard, difficult-to-work boards—stacked at an angle to match the propeller's shape and then carve them down using a hand plane. Consequently, Nippon Gakki, which possessed advanced woodworking expertise gained from manufacturing wooden organs and pianos, was ideally suited to produce aircraft propellers.
A propeller manufactured by "Nippon Gakki" from Yamaha's official site.
An inscription on the side reads: "Manufactured by Nippon Gakki Co., Ltd., November 1925." Serial No. 155; Material: Walnut.
The propeller of a Type 13 training seaplane or Yokosuka K1Y.
A propeller attached to an Army engine used for training purposes.
A wooden propeller for the Navy's Type 90 Crew Trainer or Mitsubishi K3M "Pine". It measures 2,750 mm in total length and weighing 17.04 kg.
IJNAF propellers and struts from the collection of Kojima-san.
The propellers of the trainers.
Initially the propellers of the Tachikawa Ki-9 "Spruce" and the Yokosuka/Kawanishi K5Y "Willow" were made from wood with metal tipping. Note the interesting and quite unusual propeller on this "Willow".
The propeller of this K5Y2 seaplane is closer to the standard dark brown seen in the previous photos.
The propeller and the skeleton remains of a K5Y at the "Tsukuba Kaigun Kokutai Kinenkan"
The propeller of the sole complete "Willow" survivor in Indonesia. I'm not sure if the propeller is original though.
Initially the propellers of the Tachikawa Ki-9 "Spruce" and the Tachikawa Ki-17 "Cedar" were made of wood with metal tipping similar to the propeller of the "Willow". But very soon they were treated to the "case hardening" or "encapsulated" method. This was devised by the German company Schwarz during the late Taisho and early Showa periods; to prevent damage from pebbles, ice, and the like, the propeller surface is encased in a celluloid coating reinforced with wire mesh. The wire mesh consists of 0.2mm-diameter brass wire, and the coating is a cellulose nitrate-based finish approximately 1mm thick. Additionally, a 0.5mm-thick brass strip—known as a "tipping"—is attached to the leading edge of the blade using wood screws or nails.
The propeller of this Ki-9 Koh in the attached photo could be an early wooden example without the "case hardening".
On the other hand, the propeller of this Tachikawa Ki-9 Otsu has been most probably "case hardened". Note the single white band on the edge of each tip.
Another "Spruce" propeller, this time with two white bands.
As can be seen in this "Spruce" photo, at some point, the metal tipping was discarded.
A photo of a Tachikawa Ki-17 "Cedar" with the propeller lacking tipping.
In this color (not colorized) photo of a "Spruce" that served with the Korean Air Force after the end of WWII, the propeller has most probably been repainted with the same paint used for the top surface camouflage. Note the lack of tipping.
A "Spruce" propeller still exists and is displayed in Japan, but some sources indicate it has been repainted, so the color seen in the photo is not the original one.
Some Japanese sources mention that the color of the "Spruce" propeller was either beige or light green depending on the celluloid coating.
HTH
*"Urushi" refers to the sap collected from the deciduous tall tree of the Anacardiaceae family, Toxicodendron vernicifluum (Urushi, scientific name: Toxicodendron vernicifluum), found in Japan, China, and the Korean Peninsula is a natural resin paint and adhesive primarily composed of urushiol. In addition, in Southeast Asia such as Vietnam, Myanmar, and Bhutan, there are natural resins commonly called lacquer, though their compositions and uses differ. Crafts made from lacquer are called lacquerware, and especially Japanese lacquerware, due to its high quality.
The traditional colors of lacquer as a paint are black and vermilion; black is used as pigments such as iron oxide powder and soot, while vermilion lacquer uses pigments such as bendo and cinnabar. It is also sometimes done using black and vermilion lacquer to distinguish the coat.

































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