Why We Use…

Non-adhesive Trim Seals

The difference between the quality automobile and a low-cost counterpart can be perceived in just a leaking door seal. In small aircraft, it’s the same, with annoyance as the quiet pleasure of flight is defeated by the constant high whistle of the wind rushing past, water leaks in, and the doors rattle and buzz.

Cirrus Design is a relative newcomer to the small-aircraft marketplace. After fifteen years of development, their doors opened in 1998 to present the world with an elegant, high-performance composite small craft. The single-piston-engine airplanes quickly found an audience, and by 2002, the company could boast of being the second largest manufacturer of vehicles of this class. According to the company, “Because we design with the mind of an engineer and the heart of a pilot, we build planes that are both sensible and exhilarating.” They are “focused on building not the most advanced general aviation airplane in the world, but the safest general aviation airplane in the world.” Crumple zones on the airplane sacrifice the machine in favor of passenger safety in the event of an accident, while the wing design minimizes low-altitude stalls and inadvertent spins, and a TKS-based weeping wing ice protection system reduces icing problems. One unique safety feature introduced by the company is the Cirrus Airframe Parachute System (CAPS), which uses a small solid-fuel rocket that can deploy swiftly a parachute capable of supporting the entire aircraft to a safe landing, in the event that an extreme emergency occurs and all other landing methods are unavailable. The company also provides transition training at its Duluth, MN, facility along with each airplane purchase.

Aircraft are the product of many hours of critical design with CAD and drawing board, but the details are often resolved by insight and experience. Marcel LaFond, interior design engineer for Cirrus, relied on past work with marine vessels when he selected non-adhesive trim seals for the cabin and luggage doors. Based on this experience, his first choice was for a vinyl carrier spine with an EPDM bulb to act as the seal, but he later switched to a silicone bulb for better performance at temperature extremes. The seal is simply unrolled from a reel, cut to length and installed around the door-opening flange on the fuselage. LaFond notes that, at present, the ends of the trim are butted together, but that the company is researching gluing the ends to create an unbroken 360-degree seal.

Having a reinforced self-gripping seal means time is not expended during production in preparing, applying and, possibly, cleaning up adhesive from the aircraft fuselage. The cost of the seal used by Cirrus is no greater than the expenses incurred by using a seal with an adhesive.

LaFond’s marine experience also served to recommend TrimLok, Torrance, CA, for the trim material. With Herb Dillon, Cirrus’s assistant purchasing manager, LaFond examined the company’s off-the-shelf catalog, but elected to explore a custom solution. Says Dillon, “TrimLok generated several iterations for us to examine, and kept the lead times down when we went into production.”

TrimLok produces a wide range of seals, gaskets and decorative trims, in EPDM, PVC, neoprene and other materials. Built-in metal clips reinforce a gripping edge, and there are product lines with or without peel-and-stick adhesive. Applications have also included cars and trucks, and trim for upholstery.

—RM

TrimLok
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