Question: K&N filter and flying in the rain

[Lycosaurus]

I have some questions regarding the K&N air filter and how it behaves when flying in the rain.

The K&N is constructed of a wire mesh which supports a gauze, which is cleaned periodically with a cleaner and then an oily substance is applied to to the gauze.

In a carbureted engine, the air filter receives ram air from the front of the plane. If flying in rain, would the oily substance on the filter be washed away and thus reduce particulate trapping effectiveness? Or is this oily substance impervious to water?

[Bavafa]

My experience with K&N filter (on my motorcycle) is that if/when it gets wet, little air can go thru, so if you are in the rain you might want to open your alternate air if you have it.

The oil however does not get washed that quickly with the rain.

[dmaib]

I've flown mine in plenty of rain in the past 500 hours and have noticed no ill effects.

[RV6_flyer]

My SOP for rain is to put the Carb Heat / Alternator Air on as soon as I get any rain. I also pull the prop RPM back to 2100.

[NickAir]

I have flown the -7 plenty in the rain with my K&N air filter. No adverse issues regarding the filter or performance.