GARMIN. GAP 26 location

Anyone have some inputs as to the best location for the AOA PROBE. THE G3X manual says no further than 25% of chord but the "standard" location right behind the main spar puts the probe tip at about 29% of chord. Has anyone installed one at this location? If so, how well does it function?

Welcome to VAF... since no one is stepping in to answer I'll give you my few cents on it. I'm using the Gretz mast in a typical location.



No clue how to measure the Chord % of where it is but this mast allows you to use washers to adjust it up or down accordingly. I'm under the assumption once I get the wings on that there will be some adjustments made to get it to the correct position.

Have seen other builders use this same location without issues.

Thanks Justin. The chord is the distance from the lead edge to the trailing edge and for the RV-10 it's about 57 inches. According to GARMIN the tip of the pitot/AOA should be no more than 25% of chord or 14.25 inches back from the lead edge of the wing. The location you are using puts the tip about 15 to 16 inches back from the lead edge or about 29% of chord. I was just wondering if anyone new how critical this is or if they've installed and flown and have any experience with this location.

Kupde said:

Thanks Justin. The chord is the distance from the lead edge to the trailing edge and for the RV-10 it's about 57 inches. According to GARMIN the tip of the pitot/AOA should be no more than 25% of chord or 14.25 inches back from the lead edge of the wing. The location you are using puts the tip about 15 to 16 inches back from the lead edge or about 29% of chord. I was just wondering if anyone new how critical this is or if they've installed and flown and have any experience with this location.

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Hello Kupde,

We saw your original posting. We are sure an RV-10 driver will come along and share their experience, but we wanted to comment on the installation guidance.

The GAP 26 probe has been installed on lots of different aircraft, and we have learned a few things along the way. One of the things we learned is that the AOA measurement may suffer if the probe is mounted too far aft on the wing, hence our present guidance which recommends the probe tip be mounted no further back than 25% of the wing chord.

We used to think that more aft installations were fine, but after running into a couple of aircraft where a probe mounted farther back than 25% of the cord length didn't perform well, we revised the guidance to where it is now.

Similarly, we used to provide guidance for a minimum setback from the leading edge, but now we allow the probe tip to be up to 2 inches forward of the leading edge.

Having said this, it probably works fine on an RV-10 in this position since we aren't aware of any reports that it doesn't, and someone will likely share their experience and confirm this.

Thanks,
Steve

So let's hear it guys...

So I have already mounted my GAP 26 but have not run the AOA line. Somebody please post on this location in the -10. If it is not going to work, I won't even bother running the line. Definitely NOT moving the pitot...

The bigger problem is my pitot is mounted as previously posted. You end up about 2" or so too far aft. If you were to move the pitot forward, it would need to be mounted forward of the spar which would tend to move it too far forward.

Guess I just won't bother with the AOA. As a side note, is anyone flying with a Dynon pitot with AOA in the normal location (aft of spar), and how does it perform?

My Dynon is located just inside the Bellcrank at the Van's specified location and the AOA works just fine with the Garmin G3X system. Garmin had not come out with the GAP26 at the time of my build. The front of the pitot mast bracket is behind and against the main spar.

Kupde said:

THE G3X manual says no further than 25% of chord but the "standard" location right behind the main spar puts the probe tip at about 29% of chord.

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Hello Kupde,

We checked with Van's to get the exact chord length and pitot tube position for the RV-10. Based on our calculations, mounting the pitot mast immediately aft of the RV-10 main spar will put the tip of the GAP 26 at approximately 25.8% of the wing chord, not 29%. This is close enough to our recommended location that it should be no cause for concern. Build on!

- Matt

Thanks!

Not the OP but thank you! I was hoping to use the aoa feature so I am glad it will work..

Thanks to all who replied. Thanks Matt. I will mount at the recommended location.