Are air filters necessary on Pitot, static or TE lines?

Hey all,
I have noticed some gliders have what look like small fuel filters spliced into the tubing prior to avionics. I imagine this is a safeguard to dust, etc entering the avionics. Seems to make sense eventually what's outside is going to get inside....

However, is this necessary? I see a lot of old gliders without them. No mention of it in the manuals.

I'm redoing my panel with new avionics. Before I install I would like RAS's opinion if some sort of air filtering to my $2,000 variometer or shiny new ASI is good practice?
Thanks!

I put a water filter (fuel filter) in my pitot line after losing the ASI
whilst
cloud flying using the A/H on the Butterfly vario. The thought of water
entering the electronics was enough to convince me it was a reasonable
idea.





At 11:53 12 December 2018, Pete wrote:
Hey all,
I have noticed some gliders have what look like small fuel filters
spliced
into the tubing prior to avionics. I imagine this is a safeguard to dust,
etc entering the avionics. Seems to make sense eventually what's
outside is
going to get inside....

However, is this necessary? I see a lot of old gliders without them. No
mention of it in the manuals.

I'm redoing my panel with new avionics. Before I install I would like
RAS's
opinion if some sort of air filtering to my $2,000 variometer or shiny
new
ASI is good practice?
Thanks!

Interesting. Thanks Mike. What kind of water filter are you using? I wonder if really fine filtration (osmotic, etc) would have any negative effect on the rate of change of air pressure and thus affect instrument reading?

It was actually a paper motorbike fuel filter. The idea that the paper
would absorb any water. I did several cloud climbs post installation
without any issues. Sadly, I no longer own the glider.




At 13:10 12 December 2018, Pete wrote:
Interesting. Thanks Mike. What kind of water filter are you using? I
wonder
if really fine filtration (osmotic, etc) would have any negative effect
on
the rate of change of air pressure and thus affect instrument reading?

On Wednesday, December 12, 2018 at 1:53:18 PM UTC+2, Pete wrote:
Hey all,
I have noticed some gliders have what look like small fuel filters spliced into the tubing prior to avionics. I imagine this is a safeguard to dust, etc entering the avionics. Seems to make sense eventually what's outside is going to get inside....

However, is this necessary? I see a lot of old gliders without them. No mention of it in the manuals.

I'm redoing my panel with new avionics. Before I install I would like RAS's opinion if some sort of air filtering to my $2,000 variometer or shiny new ASI is good practice?
Thanks!

The filters cost nothing and stop water droplets or dust entering your instruments. All gliders I've seen (new and old) have filters on all pitot-static tubes. Hard to imagine any reason to not install them. The water enters easily trough fuselage static ports, too.

What filters are you recommending that cost nothing and work well? I was thinking of going to Autozone and buying small-motor gas filters?
If there is something better I would like to use it.

Depending where you are based will depend on what they are called, but this is about what you are looking for:

https://shop.streckenflug.at/product...roducts_id=475

Cheers

On Wednesday, December 12, 2018 at 12:37:12 PM UTC-5, Ross wrote:
Depending where you are based will depend on what they are called, but this is about what you are looking for:

https://shop.streckenflug.at/product...roducts_id=475

Cheers

Aircraft Spruce has some. https://www.aircraftspruce.com/catal...itotstatic.php

On Wednesday, December 12, 2018 at 11:37:12 AM UTC-6, Ross wrote:
Depending where you are based will depend on what they are called, but this is about what you are looking for:

https://shop.streckenflug.at/product...roducts_id=475

Cheers
Here in Oklahoma a few years ago our club 2-33 had a malfunction of the airspeed, turned out to be a nasty smelling decaying remains of some kind of insect in the pitot tube, could have easily gotten into the instrument. on my own sailplane I have installed small engine paper element filters to minimize the possibility of contaminates getting into my spendy instruments.
Scott

Some are dust/dirt/water filters. In general, the bigger the better so a dirt load is minimal to flow. Keep in mind, some use them to keep out bugs of various kinds.

Also, some are "gust filters" (online sources can define way better than I....). The basic purpose is to limit big changes in pressure in the downstream tubing......thus "gust filters".
You may have a dirt filter as well as a gust filter in the same tubing hose.