If it is heated there will be a switch to do so. But you obviously have more capability than a plane without the TKS system. You form your own view but that must be fine for transiting an icing layer.
Clearly deicing fluid is needed if there is a risk of refreezing as it is made to adhere and then blow off as the aircraft accelerates for takeoff.
I may have overlooked something obvious, but why do we actually need the deicing fluid to be blown off once airborne? If it affects the aerodynamic performance of the airfoil, it certainly does it less than ice, and the effect itself would probably be less important on a slow piston aircraft than on a jet airliner. Furthermore, even a very diluted fluid would provide at least some protection - even a tiny fraction, like 1%, of alcohol or glycol in water would change the manner it freezes: instead of a progressively growing layer of solid ice, you'd get slush with a relatively little adhesion to the surfaces. If my reasoning is correct, it could actually make sense to use type II or type IV fluid on piston aircraft with an explicit intention of letting it remain on the wing in flight and giving you at least a few minutes to climb out on top. Please correct me if I'm wrong.
I know nothing about the Saratoga but what I hear from TB20 owners with full TKS is that the system is extremely effective and much more effective than rubber boots.
The downside of TKS is that eventually it gets used up while boots keep working... until the ice builds up too much on other parts...
You should have an AFMS for the system. If not, it's possibly an unapproved installation in which case - while it will obviously work just the same - it might bite you if you want to sell the plane.
Ultranomad - Yes I think so. TKS is something (from vague memory) 20% glycol and 80% water, or perhaps the other way round. So it's no rocket science to mix something up.
Re deicing fluid, as you say there are commercial (jet) requirements for different types, designed to stay on during taxi and until you are airborne. There are different specs called "holdover time", with the highest spec one (which is not very liquid) designed for the most severe ground icing conditions. But I don't think any of them are meant to actually stay on at 150kt for any length of time.
I did get a sample of a brown fluid a while ago (I think I posted a pic of the label here) from Germany. Reportedly it is used by military pilots there who paint it onto the leading edges, and it lasts "just long enough". I never tested it...
I have two stall warning vanes (one for flaps 0-10° and one for 25-40°). One of them looks like it could be heated, but I am not sure and also find no reference in the AFM.
The fuel tank vents are definitely not heated, but I assume they don't ice over.
I'll take a picture of the stall warning vanes...
Why not try them on the ground? If they are heated it will be with the pitot heat.
I may have overlooked something obvious, but why do we actually need the deicing fluid to be blown off once airborne?
To prevent surface irregularities a la the ice you are trying to avoid. The type 1 stuff is for deicing. The type IV is meant to go on to prevent ice/snow accretion until takeoff. It is very viscous and shears off c.100knots. If you are airborne before that you have an unpredictable airfoil shape.
To prevent surface irregularities a la the ice you are trying to avoid. The type 1 stuff is for deicing. The type IV is meant to go on to prevent ice/snow accretion until takeoff. It is very viscous and shears off c.100knots. If you are airborne before that you have an unpredictable airfoil shape.
My point is that airfoil shape will indeed be somewhat unpredictable, but much less than in case of severe icing, nor will it gain the extra weight of ice. In other words, it could make sense to consciously compromise the airfoil performance a little bit to avoid a much worse impairment.
But it is not a wet, deicing type product and its effect would be unpredictable.
Ultranomad
I suspect that for all common GA types the performance with ice accretion has been experienced, if not officially tested, and does not cause major issues. People soon get to know which aircraft have aerodynamics sensitive to icing, e.g.the Challenger.
If you put on type 4 fluid I suspect you would be blazing a new trail, I have never heard of it being used on a piston aircraft before.
In any case it's ferociously expensive and some of the fluids are put on hot (not sure about type 4), so you have to get the chaps with the de-icing rig to come and spray a few hundred litres about, some of which lands on the airframe, but all of which you are charged for.
I know nothing about the Saratoga but what I hear from TB20 owners with full TKS is that the system is extremely effective and much more effective than rubber boots.
Well, that is what I heard too. But I have never tried in real world ;-)
The downside of TKS is that eventually it gets used up while boots keep working... until the ice builds up too much on other parts...
True, but I have about 2hrs on normal, 1hr on high. That should be way enough for "inadvertent" icing.
You should have an AFMS for the system. If not, it's possibly an unapproved installation in which case - while it will obviously work just the same - it might bite you if you want to sell the plane.
It is a factory installed option (PIIPS, Piper Inadvertent Icing Protection System), so I do have a part in the AFM on the TKS system. It doesn't mention anything regarding a heated stall warning. Althought they both look different.
Why not try them on the ground? If they are heated it will be with the pitot heat.
I will try to figure that one out. But I assume it has some other reason, that one looks different. Because in the AFM there is a section on stall warning, which states that one cannot rely on stall warning indications in icing conditions.
I will try to figure that one out. But I assume it has some other reason, that one looks different. Because in the AFM there is a section on stall warning, which states that one cannot rely on stall warning indications in icing conditions.
Might this be because in icing conditions the lawyers cannot guarantee the shape of the wing is correct, so the stall warner may not work at the intended AoA?
