Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other other light aircraft.
Issue link: http://experimenter.epubxp.com/i/81495
to see. Look for the month and two-digit year of manufacture; the age of some "new" mounts may surprise you. However, if they have been properly stored, they'll retain their new qualities for many years; but check. Some mechanics swap engine mounts rather than replace them. Remember, though, especially if you have mounts at the rear of the engine, that the bottom forward mount is in compression, as is the top rear on each side. When you swap them around, remember that their "set" is not random. Some engines are the exact reverse, so make sure they're installed correctly. Make sure your mounts are isolated from excessive heat, with proper airfl ow and/or heat shields. If you notice your mounts getting hard or suddenly shiny, they may be cooked. Replace them. Rubber parts on aircraft that live in very hot, very dry, or very sunny areas tend to deteriorate faster. Paul Snyder, account manager for aerospace products at Lord Corporation, says that some of the worst things we do to our mounts are done with good intentions. "The efforts we put into the cosmetics of our engine bays can backfi re on us," he warns. "Many cleaning fl uids strip away the wax coat, and then can permeate the rubber, helping the mount to rapidly deteriorate. Petroleum products—from WD-40 and penetrants, to anti-corrosion fl uids, to brake fl uids, gasoline, Jet-A, and lubricating oils—none of these should be left on the elastomeric parts of the mounts. If you fi nd them there, wipe them off as quickly as you can. Although gasoline evaporates fairly quickly, some of the penetrating oils can really get in there and stay. That can do damage quickly, and you won't see it." The worst offenders among us are often those who have the most immaculate engine bays. "Some of the engine degreasers are extremely powerful," Snyder notes, "and they can attack the elastomer." T ere is a mount for everything. T e trick is to understand which one is the one you need. Mounts that look alike can have very different performance characteristics. Check the molded-on part number to be sure you are using what you want to be using. In the certifi cated world, mounts are usually changed at overhaul time. For our experimental aircraft the annual condition inspection is a great time to check mounts, but you might also consider inspecting them when the airplane is put away for the winter, giving you time to order new ones before fl ying starts again. In the spring, after the aircraft has sat for a while and time has added to deterioration is another good time to check them. Even if you never run your engine, the engine mounts are carrying the full weight of the engine. Special thanks to Paul Snyder and Lord Corporation, www.Lord.com. Tim Kern is a private pilot who lives near Indianapolis, Indiana. He has written for more than 40 different aviation magazines and also provides writing and marketing services to the aviation industry. He was key builder on two aircraft and has earned the title of Certifi ed Aviation Manager from the NBAA EAA EXPERIMENTER 31