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TKS ice prevention


Mark89114

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Got to really use my TKS this morning, just light if anything but I noticed that there is ice buildup on what I would call the point of the leading edge.  The fluid flows back and covers everything adequately just allows this accumulation to build up.  Again this isn't some extreme SLD example and I really wasn't worried, just curious what it is supposed or not supposed to look like.  Sorry about the picture quality, it was the best I could do.  Again looking for a "normal baseline" what is it supposed to do?

Thanks,

 

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Mark,

Were you able to run the TKS before entering the icing conditions?

Had you run the system lately?  

I believe there is a simple maintenance procedure for running it often.

Pp thoughts only, i don’t have TKS...

Best regards,

-a-

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Did you get the system on and up to pressure before entering the icing? Did it ever clear? And, what did the tail look like.  If you don’t get the system on and coat the surfaces early, it can take some time to clear everything.  But you shouldn’t have that residual ice on the leading edge. 

-dan

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15 minutes ago, Yooper Rocketman said:

How old is your deice fluid?  It loses it’s effectiveness after a few years as the alcohol starts evaporating out of the mixture.   

Tom

DO you know the shelf life 

opened?

factory sealed?

 

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FedEx purges their stock after 2-3 years (unopened).   I’ve had decent luck with it longer but DO find I need to run it sooner and longer as it ages.  It still works, but just need to accommodate the usage based on age. I’ve seen what the OP posted on old fluid   

Tom

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4 hours ago, Joe Zuffoletto said:

Mine has always removed all ice from the TKS panels.

Over what time period and at what settings, I believe the OP is asking...

 

i think we we need more info: was the system on the high setting, and primed prior to picking up ice? How long had the system been running? Was the fluid new or old?  

Ive seen it take a few minutes to shed ice, if I hadn’t primed the system and had it running prior to entering the icing conditions.  

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I had the system primed, system was running on "Normal" and seemed to be flowing properly before entering icing conditions at least 5 minutes before entering icing conditions in addition to the priming I did why taxing on ground.  

I wasn't using it to shed ice that had built up, have experimented with that in the past, just for fun in easy to escape icing conditions, doesn't really work.  

Maybe a gallon of the fluid was a year old, just put in 5 gallons of fresh brand new stuff a couple of weeks before.

Again just the leading edge was built up barely.  The airplane is filthy, it gets used a lot, maybe there were bugs that allowed ice to accumulate build up.  Just speculating.  

I will contact the CAV guys and let everybody know what they say.

 

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Mine has looked like yours a couple of times when I did not purge it with sufficient time ahead of the icing encounter or when I had not used the TKS for a while in my plane. I have since added that step to my pre-takeoff checklist (the purging part) no matter what the expected conditions are and avoided this little accumulation on the leading edge of the TKS strips. I realize that the alcohol content of the fluid may change a little with time but I doubt that it will be the differentiating factor for your case. If you fly high and descend through weather you will often go through a cloud layer on the way down and can test how well the front pores of your TKS strips are purged (including leading edge fouling from flying through organic material [aka bugs] at lower altitudes and in VFR conditions).

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Hi Mark,

I had an O3 with TKS and I had a LOT of trouble with my system at one point, so I now consider myself an "amateur/expert" with the system.  I spent many days with the boys at CAV Aero troubleshooting, etc.  The issues I had have nothing directly to do with your question, but because of my issues, I learned a lot about how the system is supposed to work (and does work, when everything is actually working).

The short answer to your question is, what you were seeing is completely normal.  You stated that  you were running the system in the "Normal" mode, and then you saw the ice as depicted in your pics.  I would say two things to this: One, you were apparently in icing conditions that were just a little bit more than "Normal" mode could handle as far as keeping ice from forming at all.  And two, the system is designed to actually ALLOW some amount of ice to accumulate, and then let aerodynamic forces peel off the build-up of ice.  So the irony is, what you really needed was some more ice! :-)  I would be willing to bet you that if you continued to accumulate ice with the system right where you had it (i.e. "Normal") and just allowed the ice to build up more, it would have peeled off with no trouble.  You could also try going to the "De-ice" or "Max" mode, and see if that wouldn't clear things faster.  It usually does unless you're in really bad icing conditions.

I'm not advocating that you should cruise in icing conditions just to see if I am correct or not.  I'm just telling you my experience both personally in the plane as well as my discussions with CAV.

Bottom line is, the amount of ice that you were showing there is trivial (as icing goes), but not so much so that you should just cruise in it.

Hope that helps,

(another) Mark

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14 hours ago, M016576 said:

Over what time period and at what settings, I believe the OP is asking...

 

i think we we need more info: was the system on the high setting, and primed prior to picking up ice? How long had the system been running? Was the fluid new or old?  

Ive seen it take a few minutes to shed ice, if I hadn’t primed the system and had it running prior to entering the icing conditions.  

I try to prime the system before I enter the clouds, if at all possible. If not, I start the system on high until the wings are coated, then I back it down to normal depending on the rate of accumulation. It takes about 8-10 minutes for all the panels to start weeping on my Acclaim.

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1 hour ago, Joe Zuffoletto said:

I try to prime the system before I enter the clouds, if at all possible. If not, I start the system on high until the wings are coated, then I back it down to normal depending on the rate of accumulation. It takes about 8-10 minutes for all the panels to start weeping on my Acclaim.

This is what I do, too.  For the OP: the windshield pumps are supposed to help prime the system.  I'd run a few gallon$ of fluid through the system at high just to make sure it flows evenly and well.  Bugs shouldn't be a problem as the slight pressure should be enough to push them back out.  When I hit a bird, the service center, which does TKS installation, technician recommended running it on high until good, even flow showed - else risked dried bird goo in the holes.

-dan

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1 hour ago, CAV Ice Protection said:

Hi Mark,

Thank you for sharing your TKS Ice Protection experience with us.

Please feel free to contact our Tech Support team at (913) 738-5397 or email techsupport@caviceprotection.com

Kind regards,
Joel

Joel,

Thread hijack.... Can you tell me the reason for the high-altitude airspeed restrictions for FIKI M20TN's?

-dan

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4 hours ago, exM20K said:

Joel,

Thread hijack.... Can you tell me the reason for the high-altitude airspeed restrictions for FIKI M20TN's?

-dan

I didn't know there was one! How much of a restriction? Always, or only when the system is activated?

Robert

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7 hours ago, teejayevans said:

Maybe at higher speeds it doesn’t cling to the wing?

I suspect this is close to the reason but more a factor of how long the fluid remains on the wing. Higher speeds will force the fluid aft and reduce the coverage and effectiveness. 

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37 minutes ago, Cruiser said:

I suspect this is close to the reason but more a factor of how long the fluid remains on the wing. Higher speeds will force the fluid aft and reduce the coverage and effectiveness. 

But why, then, decreasing IAS with altitude? It could have to do with ram air pressure on the panels at lower atmospheric pressure- but it’s counter-intuitive: the bladder behind the panel should be more effective at altitude. 

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The flow mathematics/calculus must get pretty interesting as the Airspeed increases...

  • the fluid pumps have to pump against the head pressure of air trying to push on the leading edge...
  • the speed of the air rushing by, affects the flow and distribution of the fluid that is being delivered...
  • real speed of air particles whizzing by, vs TAS that includes a pseudo calculation for air density....
  • does some % evaporation occur in real time use of the product?

As a student of fluid flow in pipes... the air in the pipe mostly got ignored as a force.  It’s viscosity is near nil. It’s speed is usually zero...

On the wing, the flow isn’t even linear, plus it is 3D, the pressure is actually a vacuum, it’s amazing that the fluid stays so well adhered to the surface under those conditions...

Benoulies were brilliant! :)

Best regards,

-a-

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