It is common practice in many amateur-built engine installations, from Rotaxes to Lycomings, to use K&N filters. They do a wonderful job of filtering the air, and they are reusable. However, they only are able to perform correctly if they are properly cared for. They should be cleaned annually at a minimum with K&N filter cleaner and then lightly oiled with K&N filter oil. Without the oil, which leaves a slight pink color on the filter, they will not filter properly. The one in the photo above was not oiled.
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Mel Asberry - 0
Can a former Part 103 aircraft be registered as an LSA? And how is an appropriate Phase I flight-test area determined?
Vortex Generators for Cooling
A simple fix reduced CHTs in a Velocity by 55 degrees. By David G. Ullman.