Originally Posted by
JD-EE
sensor_validation, I get the impression that one of the best improvements for a pitot would be some form of airflow measurement out of the drain hole. If either the probe or the hole ices the airflow through will diminish. With a moniker like yours that's a design challenge for you. Measure the existence of airflow without increasing the chances of the probe icing.
Sorry, I don't fancy designing a sensor to measure multiphase flow through the drain holes - got to cope with climbing through heavy rain just after take-off as well as the current hot topic of high altitude ice crystals.
If you want to know if the holes are open I'm sure it could be done by just listening to audible high frequency noise on the sum of, and difference between analogue measurements of total and static pressure - I've seen the evidence similar (patented) idea worked in a coal fired power station with dust in DP instrument impulse lines. Could also listen out for the mud dauber!
But I feel the current circumstances would be better served by small increments to the Pitot design making the chance of individual 'stuck' failure much lower and hence common mode potential failure even rarer. Should be possible with improvements to the heat transfer to the inner walls and especially the drain hole and/or increasing raw input power. BUT current probes meet current specs, what is needed is a repeatable objective test that encourages investment, and a change in procurement specification. Truth is that Pitot tubes are cheap items with considerable risk in getting a change wrong, 0.1% fuel efficiency target more likely to receive investment!