A “glow-in-the-dark” safety coating system—originally developed under a U.S. Naval Air Systems Command (NAVAIR) contract as a joint development between Sherwin-Williams Aerospace Coatings and Defense Holdings Inc. (DHi) for use on aircraft on naval carriers—is now available in the civilian aviation market.
AfterGlo Photoluminescent Paint Kit AG110 is applied to the tips of aircraft propeller blades, helicopter main and tail rotors, and other rotating objects, making them visible in dark and low-light operations. Increased visibility of such objects—whether stationary or rotating—can in turn help personnel in hangars, airstrips, helipads, and repair facilities to avoid inadvertent contact with those components.
The photoluminescent (PL) layer of the three-part coating system essentially absorbs the sunlight and can deliver a steady, 8-h glow that is visible from up to 40 ft. The coating—typically applied using a high-volume, low-pressure (HVLP) gravity feed gun—is also said to provide excellent hardness and impact resistance.
“Challenges included determining the right phosphor, determining the right level of phosphor to use to obtain the glow level, and developing a system to maintain the photoluminescent look while also handling the rigorous environment of an aircraft propeller,” DHi President Richard Martin explained to AEM.
DHi developed the PL pigment, and Sherwin-Williams Aerospace developed the paint process and manufactured the product. The system includes a white polyurethane basecoat, followed by the PL layer, and then topped with a clearcoat.
“During nighttime operations, when propeller-planes prepare to take off, flight-deck personnel on Navy aircraft carriers often are unable to see or hear the rotating propellers because they are potentially distracted by noisy, high-tempo flight operations,” said Martin. “The Navy charged small businesses through its Small Business Innovative Research (SBIR) program with developing a product to increase rotor and propeller visibility and ensure sailor safety on aircraft carrier decks.”
He noted that the paint does not affect the use of night-vision goggles.
DHi won the Navy’s sole contract for its PL paint in 2004, and by 2005 the company was working with Sherwin-Williams—already a qualified supplier to the Navy—to manufacture the coating on a large scale. After years of lab and flight-testing, the Navy adopted and certified the paint in May 2008.
Introducing AfterGlo to the civilian market made sense, according to J. Marc Taylor, Sherwin-Williams Aerospace Director of Sales, because the technology has “much potential” to improve safety at airports and helipads.
“While it does provide a visible safety mechanism when the aircraft is on the ground, the glowing propeller tips do not interfere with pilot visibility in the air because the glow is visible only from distances less than 40 ft away,” Taylor said. “This plays an important role in military applications, too, as it means enemy planes cannot see the paint glowing while the aircraft is in flight or on the decks of a carrier.”
Although the coating system is already approved and in use for military aircraft, bringing the technology to the civilian aviation market has not been challenge-free, according to Martin. “Obtaining each specific OEM qualification has proved timely,” he shared.
AfterGlo is currently in testing at several OEMs and OEM propeller companies. “Numerous fleets are anxiously waiting to add it on their aircraft,” he said.
The patent for the PL paint covers any rotating object—not just aircraft propellers and rotors.
“Most definitely” was Martin’s response when asked whether AfterGlo could find application in other transportation segments. “In fact, DHi has discussed the use for markings and stripes on combat vehicles, antennas, winglet tips, as well as novelty or safety markets.”
The paint’s applicability for wind turbine blades and industrial fans is also being explored.
List price is about $800 per kit, which covers about 600 in2 of area.