Author Topic: TE adjustment  (Read 1924 times)

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Evan Ludeman / T8

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Re: TE adjustment
« Reply #15 on: June 25, 2020, 08:57:43 AM »
The IAS indicated is a function of pitot and static pressure, independent of TE compensation selections and adjustments.  If it showed values significantly at odds with your ASI, then that might provide some clues as to what is going on. 

"Electronic" TE is very sensitive to errors in the pneumatic sources.  Errors result from 1) non-ideality in the source location (under wing statics...), 2) excess capacity and flows in the system associated with mechanical instruments (the static side of a mechanical ASI is a problem for sure, the pitot side less so, but still noticeable), 3) leaks, whether intentional (say, for a mechanical netto vario) or not, 4) timing differences between pitot and static due to location, parasitic capacity differences, impedance differences. 

Except in the case of unshared, probe mounted pitot and static, it's generally best to use a TE probe.  The only problem here is that sharing a mechanical vario with a pressure transducer vario on same TE probe raises hell with the electronic vario.  I realize this is intensely frustrating... I've been down this road myself! 

One final long shot: are you certain the whole system is dry?  Accumulated moisture in any of the pneumatic lines can and will cause some very strange behavior (personal experience). 
Evan Ludeman / T8


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Re: TE adjustment
« Reply #16 on: June 25, 2020, 10:14:05 AM »
Water in the tubes would also cause problems when set to use the probe, or so I would think.

No other vario, just ASI is shared and when taken out of the system there was no change.

Under the wing static is no good? Great, the manual says there are problems with the nose statics, history has shown the boom static hates water, and I always fly with water.

I understand electronic TE is more sensitive to installation, but this much? I made the video to emphasis just how whack it is when set to electronic TE.

Looking back it would have been better just to buy another ADC and give it the old “remove and replace”. Then if it acted the same, go through the installation.