What temperature is a pitot tube usually heated to prevent ice?
And are pitot tubes always heated to the same temperature, is there any difference between aircraft (say, a C172 and an A321)?
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asked Jan 13, 2017 at 7:27
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1$\begingroup$ According to this article: matronics.com/aeroelectric/articles/Pitot_Heater/… - the internal temperature of the pitot-tube was around 270degrees celcius while the unit was placed in submerged water. This was while operating at 13V and 16A (208W). This is the type of pitot featured in a light aircraft and is most likely similar to those fitted onto C172s. $\endgroup$– andy-mCommented Jan 13, 2017 at 10:08
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2$\begingroup$ @andy-m Why don't you post an answer? $\endgroup$– Noah KrasserCommented Jan 13, 2017 at 10:18
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$\begingroup$ @NoahFisher Because it doesn't answer the question. The question isn't "What temperature are pitot tubes heated to?" but "Are they all the same temperature?" A single datapoint is an OK answer to the first question, but doesn't address the second at all. $\endgroup$– David RicherbyCommented Jan 13, 2017 at 10:58
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$\begingroup$ @DavidRicherby Actually the first was exactly my question until Jamiec changed it to what it's now. $\endgroup$– Noah KrasserCommented Jan 13, 2017 at 11:46
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$\begingroup$ @NoahFisher OK but the comment was posted after that edit. Apologies, though, for telling you what your own question said after it had stopped being your question. I'd not noticed you were the asker or looked at the edit history, and I should have done both. $\endgroup$– David RicherbyCommented Jan 13, 2017 at 12:35
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1 Answer
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This page talks about the Pitot probes that operate at temperature range -65°C to +70°C. They are FAA TSO-C16 and Military Approved. It is probably unwise to heat them more during normal operation. This is not very hot but +70°C would already burn the skin. The probes are used at Pilatus PC-12, Bell 212, Bell UH-1 Special, Cessna Caravan, Diamond DA42, IAI Heron and Quest Kodiak.
This contradicts another source where heater temperatures of 200 °C are reported, and also this industrial Pitot device (while not used on the aircraft) is rated up till the 200 °C, so the design itself allows the temperatures that high. However the heating device is only part of the probe and should be hotter than the tube it is heating up.
This answer says there are significant differences between Pitot heat systems, and some on the light aircraft are rather "anemic". Hence it may be that some models are heated and operate at much higher temperatures. There is also a phrase "plastic cover could melt" there. Plastic melts well over 150 °C.
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$\begingroup$ In which conditions is the temperature measured? And what is the thermal inertia? $\endgroup$– minsCommented Jan 13, 2017 at 17:13
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$\begingroup$ This is not specified, I assume these tubes are not rated above +70°C in any possible conditions. $\endgroup$– h22Commented Jan 13, 2017 at 20:17