Ask anyone what color a Piper Cub is, and you’re likely to get some strange looks. After all, everyone knows that it’s yellow, or, to be specific, some will say it’s Cub yellow or “Lock Haven Yellow.” Or is it? The iconic Piper J-3 Cub is probably one of the most identifiable aircraft general aviation aircraft. From an initial trainer for World War II pilots to a ubiquitous—and nostalgic—platform for modern-day aviators to discover the joys of tailwheel flying, the Cub has earned a special place in the hearts of aviators for more than 80 years.
When you close your eyes and imagine a typical taildragger, odds are that you picture the pert little Cub, bedecked in a cheerful yellow with the signature black lightning bolt on either side. As it turns out, not all Cubs are the same color. The J-3’s beauty lies not just in the eye of the beholder but also in the history of the plane’s finishing and covering. Here’s the straight dope on Cub yellow.
Before the production of the J-3 Cub, the Piper Aircraft Corporation painted most of its aircraft silver with red or black trim. Yellow was chosen because the consensus among pilots was that it was the most visible color, which would make the J-3 Cub easier to spot. Although there was no research at the time, William T. Piper’s intuition was on the mark.
As it turns out, contemporary research indicates that fluorescent yellow green is the color most visible to the human eye. Those pigments weren’t available in the 1930s and ’40s, so yellow would be the best choice at the time. Besides the increased visibility, from a manufacturing point of view, the finish of the yellow pigment was superior to that of the silver pigment used at the time.
What is Yellow?
Piper Aircraft manufactured the J-3 Cub from 1938 to 1947. The earliest models were painted with chrome yellow, so named because the yellow pigment came from chromium, derived from lead chromate. Like most small aircraft of the time, the Cub was covered with Grade A cotton fabric. The aircraft skin gained its strength from multiple layers of tautening nitrate dope, and yellow pigment added to the dope gave the plane its color. Piper finished the original J-3 Cubs with nitrate dope colored with “Lock Haven Yellow” pigment (#M-9521 by Randolph Paint Products, now part of Consolidated Aircraft Coatings), which was a darker shade of yellow with a slightly orangish tint.
The nitrate dope, which had been used since World War I, had several advantages; it was easy to apply and provided strength and a lasting finish. However, there was one major drawback: It is highly flammable.
During World War II, a new, less-flammable formulation was developed: butyrate dope. Butyrate dope had many of the advantages of nitrate dope, but it did not adhere as well to aircraft structures and cotton fabric, as did its more flammable counterpart. However, butyrate did adhere well to nitrate dope. So, aircraft manufacturers developed a new covering process, applying nitrate dope for the base coats, followed by multiple coats of the butyrate dope. This solution decreased flammability but created a new problem for Piper. None of the companies were able to create a pigment compatible with butyrate dope that perfectly matched “Lock Haven Yellow.”
The closest contender was a brighter, purer shade of yellow, which creator Randolph Paint Products referred to as “Piper Cub J-3 Yellow” (#F-6285). Even though Piper continued to call it “Lock Haven Yellow,” all Cubs (and successor models, including the Vagabond, Pacer and Tri-Pacer) manufactured after the change to butyrate in 1946 would be “Piper Cub J-3 Yellow.”
Restoration and Modern Cubs
If you’re restoring a Cub today, you have a number of color options. Traditionalists focusing on historical accuracy still choose butyrate over nitrate dope (albeit on polyester rather than cotton fabric). Randolph Paint Products still offers a choice of “Loch Haven Yellow” and “J3 Cub Yellow.” For those opting for other coatings, PTI provides a range of seven yellows to choose for a polyurethane finish. Poly-Fiber Aircraft Coatings offers three Cub-specific yellows in its spectrum of vinyl coatings: “143 Cub Yellow,” “145 Lockhaven Yellow” and “146 J3 OEM Yellow.”
Modern paint finishes, such as polyurethane or vinyl, yield a sleek, high-gloss finish. These new paint technologies create visually stunning looks, true, but the fact is, there were no high-gloss Cubs back in the day. Dope, whether nitrate or butyrate, yields a duller satin finish. Restorers who prefer modern paint formulations often add flattener to the topcoat to dull the finish of modern paint and give it more of a satin finish, like traditional Cubs.
While it is still possible that there are some J-3 Cubs with the original color and covering from the Piper factory, eight decades of wear and tear and the vulnerability of cotton to deterioration due to mold and UV exposure mean that most Cubs have been recovered, most several times. Many Cubs have been lovingly restored and continue to entice new generations to fall in love with tailwheel flying. The odds of spotting a J-3 Cub at your local airport are good, but it’s fairly unlikely you’ll see many Cubs in the original nitrate dope “Lock Haven Yellow” livery flying today.
How Can You Tell?
For those aircraft spotters hoping to discover a J-3 Cub in true, original nitrate “Lock Haven Yellow,” watch for a darker shade of orange yellow with a flatter finish. Plus, there is one more tell-tale sign. Because butyrate dope does not adhere to surfaces as well as nitrate dope, it was not suitable for covering the boot cowl of the aircraft. When Piper made the shift to butyrate dope in 1946, it switched to enamel for the boot cowl. This forced it to alter the detailing to accommodate the different coatings. The signature black lightning bolt was shortened so that it would fit completely on the boot cowling.