Environmental baggage is driving the military toward the possible use of polymer films instead of paint to cover aircraft exteriors.
A ``paintless airplane'' segment of the Joint Strike Fighter program has tested an F18-B at Naval Air Station Patuxent River in Maryland under a one-year program that began in October.
The effort ``has afforded the Navy the opportunity to take a proactive role in finding new ways to reduce hazardous materials disposal costs,'' Robert Pirie, acting assistant secretary of the U.S. Navy, said in a press release.
Units of Boeing Co. and 3M Co. have shown the feasibility of replacing paint with a patented class of thin polymer films backed by pressure-sensitive adhesive. The laminate film, known as an appliqué, applies easily, is waterproof and weighs less than accumulated coats of paint.
Generally, the multilayer film composites on a military craft include a fluorochemical exterior, a polyurethane matrix layer and an acrylic copolymer adhesive base, according to Steven Speech, program manager in the aerospace department of 3M's adhesives division in St. Paul, Minn.
The film could reduce the toxic paints and solvents used to strip coverings from military aircraft. Painting, stripping and repainting is expensive, requires elaborate painting booths and accounts for much of the hazardous materials associated with aircraft.
In the past, now-banned methylene chloride was used to remove paint. Now, blasting with plastic beads or starch granules generates a lot of waste.
``We think the Boeing/Navair program has shown the feasibility and demonstrated the life-cycle cost,'' Speech said, but there is a ``significant amount of work to do'' to qualify appliqués for broader military use.
3M and Lockheed Martin Co. applied polymer film to a Navy S-3 reconnaissance aircraft operating from Jacksonville, Fla., in April, and on the front half of an Air Force C-130 cargo aircraft operating from Biloxi, Miss., in June.
In addition, Lockheed Martin has been testing polymer film on military aircraft in Fort Worth, Texas. Boeing and Lockheed Martin are building prototypes of the Joint Strike Fighter for a scheduled fly-off at Patuxent River in less than three years.
Airbus Industrie and an airline installed several hundred square yards of a 3M drag-reduction film on an Airbus A340. Since October, the craft's Cathay Pacific Airways Ltd. flights between Montreal and Singapore have used less fuel. Fine parallel grooves reduce drag in the air, Speech said.
For three decades, 3M has sold aircraft-marking film, usually polyester-based, on which signage shops use screen or inkjet printing, or toners to create logos and markings with ultraviolet-colorfast inks.
Aircraft use another 3M film of 14-mil polyurethane to protect the leading edge of wings and tail structures and as a boot to cover radomes.