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AV-20-S


PT20J

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Check to see if it has the sensorless AOAi still…

That aspect wasn’t working when MSers first got the device…

The AV30 had other issues that were more serious… precession related.

Really fuzzy PP memories…

Best regards,

-a-

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3 hours ago, FlySafe said:

Im very happy with mine, using as a backup AI for G5s, TAS agrees with nav computer, AOA not so well, love the timers for tank switches etc

I bought one of the first ones produced (S/N 30), before they were acquired by uAvionix.   The TAS and AoA are both wrong.  Contacted manufacturer and was told that AoA  won't work in Mooneys, and that there is a bug in the TAS calculation.   The line about the AoA and Mooneys is bunk.  I don't think it will work in any aircraft .   I've e-mail uAvionix several times about a firmware update for the TAS bug.  Silence.

When did you buy yours?   The stuff that works- automatic flight timer, timers, OAT, V, backup AHRS AI, I really like.  I just wish that the TAS readout was accurate.  Anybody else get a firmware update?

Thx

-Fred

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7 minutes ago, 0TreeLemur said:

I bought one of the first ones produced (S/N 30), before they were acquired by uAvionix.   The TAS and AoA are both wrong.  Contacted manufacturer and was told that AoA  won't work in Mooneys, and that there is a bug in the TAS calculation.   The line about the AoA and Mooneys is bunk.  I don't think it will work in any aircraft .   I've e-mail uAvionix several times about a firmware update for the TAS bug.  Silence.

When did you buy yours?   The stuff that works- automatic flight timer, timers, OAT, V, backup AHRS AI, I really like.  I just wish that the TAS readout was accurate.  Anybody else get a firmware update?

Thx

-Fred

I haven’t bought one yet. I’m thinking about it as a low-cost ADI tie breaker in case there is confusion between the G3X and G5 I’m about to have installed. 

I don’t have high expectations for the AoA. I’ve never been able to get the Aspen derived AoA to be accurate. 

I’ve seen other comments about the accuracy of the TAS calculation. I note that they don’t claim much accuracy: +/- 20 kts. Seems lame.584067928_Screenshot2021-07-26at7_39_06PM.thumb.png.81a401a471311bc3e36b329ed052f592.png

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1 minute ago, PT20J said:

I’ve seen other comments about the accuracy of the TAS calculation. I note that they don’t claim much accuracy: +/- 20 kts. Seems lame.584067928_Screenshot2021-07-26at7_39_06PM.thumb.png.81a401a471311bc3e36b329ed052f592.png

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I hope to never see negative airspeed . . . . or groundspeed!

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38 minutes ago, bluehighwayflyer said:

I’ve seen negative ground speed before in a C-175 at night in a climb.  This was before GPS and only the lights on the ground gave it away.  

I’ve just about decided that I am going to install an AV-30 as a backup attitude reference and turn coordinator replacement.  Thanks for that info, @PT20J.   In that case I would probably just not even bother displaying TAS.  

I stopped paying attention to the TAS.   The automatic flight timer really comes in handy for fuel tank switching.   I usually keep it on the AI when I'm flying on an IFR flight plan.

The FBO where Iearned to fly was never a dull place.   One March day with ~steady 40 knot northerly winds, the two brothers who ran the place with their dad got a group of us to help grab hold of their Champ and manually move it out of the big hangar and onto the ramp.  One brother jumped out after the other started it up, advanced the throttle, lifted off, and proceeded to fly with negative ground speed at about 5 ft AGL.  He flew about 100 ft backwards, advanced the throttle to return to the starting point.   Then he retarded the throttle, landed, applied brakes and killed the engine as we all grabbed onto it as it was skidding.  Like Kitty Hawk in reverse.

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I find it hard to reason…

Using a device with known programming challenges… and no updates…

Would have me continuously wondering if there were more pressing unknown programming challenges…

 

Its only the tie breaker…

But, a tie breaker that leaves you unsure of the answer…

The AV30 sure looks nice…. :)

 

How do you guys… wrestle with this logic?

I’m at least a year behind where you guys are today…

Best regards,

-a-

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I find in odd.  I guess the consequence of swimming in the NORSEE end of the pool.  It's a timer, with lots of lagniappe.  Nobody fixes broken lagniappe?

Calculating TAS is not computationally difficult. 

 rho= P/(RT)

The device measures P, T.  R varies slightly with the partial pressure of water vapor in the air, typically less than 1%.

Maybe their pressure measurements are not very accurate.

If programmed to do so, it could also have altimeter and VSI added to its suite of lagniappe.

As @PT20J noted, their use of a 20 knot error bar width means that the instrument doesn't require fixing.  I admire their appropriate use of wide tolerance to minimize their risk.  Didn't notice that before I bought.   The parts that work are fine though.

21 hours ago, carusoam said:

I find it hard to reason…

Using a device with known programming challenges… and no updates…

Would have me continuously wondering if there were more pressing unknown programming challenges…

 

 

Edited by 0TreeLemur
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I have had mine for ~2 yrs. The AI is solid as compared to my g5 AI and i trust it more than my foreflight AHARS for backup in an emergency.  that said, the foreflight AHRS display with a stratus 3 is pretty good. i must be lucky, my TAS display is matching up well.

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1 hour ago, FlySafe said:

I have had mine for ~2 yrs. The AI is solid as compared to my g5 AI and i trust it more than my foreflight AHARS for backup in an emergency.  that said, the foreflight AHRS display with a stratus 3 is pretty good. i must be lucky, my TAS display is matching up well.

If tas reads high, we’d all say it matches pretty well!!!:P

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16 hours ago, 0TreeLemur said:

Yep- I fly a 155 knot C!

I just wish that Garmin would fix the TAS software in the 430W.  It reads low.

Edit:  I must have been sleep deprived to miss your humor.  I’m sorry!

Interesting, why do you think it reads low?  I’ve done lots of speed testing over the 6 years I’ve had my plane.  I use the 3 way gps method and plug in the numbers after landing.  Usually while I do it I use the 430w to give me an estimate.  As long as I use CAS instead of IAS, my 430w has always been within a knot of my calculations.

Are your temp and airspeed indicators accurate?

Edited by Ragsf15e
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17 hours ago, FlySafe said:

I have had mine for ~2 yrs. The AI is solid as compared to my g5 AI and i trust it more than my foreflight AHARS for backup in an emergency.  that said, the foreflight AHRS display with a stratus 3 is pretty good. i must be lucky, my TAS display is matching up well.

I agree. I have had mine for about a year now and multiple times compared my TAS with my analog speed indicator adjusted for temp: they match. Pretty happy with it. I mainly use the OAT (I have it in F and keep the JPI in C...), timers and TAS. AI seems ok, once in a while I browse around to see the Gs and the other stuff. I do not use the AoA. I installed it in place of the old mechanical useless clock. Great backup little gauge IMHO.

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Lagniappe…. Similar to lasagna…. No logic behind the spelling or pronunciation…  :)

True to MS style… we get a word of the day and a spelling lesson along the way…

 

TAS calculations…. I couldn’t get very accurate results from my ship’s calculators….  TAS is very dependent on OAT… my OAT gauge is analog and precision isn’t its strong point…. It’s accurate, just not precise…

 

Best regards,

-a-

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5 hours ago, FastTex said:

I agree. I have had mine for about a year now and multiple times compared my TAS with my analog speed indicator adjusted for temp: they match. Pretty happy with it. I mainly use the OAT (I have it in F and keep the JPI in C...), timers and TAS. AI seems ok, once in a while I browse around to see the Gs and the other stuff. I do not use the AoA. I installed it in place of the old mechanical useless clock. Great backup little gauge IMHO.

Did it need another temp probe installed just for the av-20?

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8 hours ago, Ragsf15e said:

Did it need another temp probe installed just for the av-20?

Yes, as advised by the other pilots and the documentation. I actually like to have 2 OATs (one in F on the AV20 and one in C on the JPI). I forgot to mention I also like the density altitude reading.

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4 hours ago, FastTex said:

Yes, as advised by the other pilots and the documentation. I actually like to have 2 OATs (one in F on the AV20 and one in C on the JPI). I forgot to mention I also like the density altitude reading.

ditto.  I've got one from the JPI900 installed in the port cabin air intake nacelle, and the one for the AV-20-S installed in the first outboard inspection panel on the stbd side.  Of course the AV-20 temperature probe is more accurate being less influenced by engine heat.  Did that on purpose for TAS estimation.  Ha.  At least I can input that temperature into the GPS TAS calculation page...

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