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RTH Altitude Best Practices

Discussion in 'Pro/Adv Discussion' started by DigitalKnight, Jun 13, 2016.

  1. DigitalKnight

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    I often practice with my P3A at picturesque rocky butte that rises above surrounding hills (Pulpit Rock in Colorado Springs). It's quick and easy to get to, has a large open parking lot, unobstructed line-of-site, and usually not many people around when I go.

    I usually set my RTH altitude to 40m, but I'd say the highest point of the butte is roughly 360 ft above the parking area, so I always take the bird up to 400 ft to easily clear it.

    Recently I was trying a POI "orbit" around the butte at 400 ft, and as it passed behind the bluff the angle was just barely enough to obstruct direct line-of-site, so I lost connection and it initiated RTH. The "oh $#!+" moment for me was picturing the bird dropping to 40m above its take-off altitude and flying straight into the butte. Fortunately, the video shows it completed enough of the orbit to where I had full line-of-site again (I assume it orbited far enough during the 3 seconds before RTH kicked in), and didn't move back toward the home point at all. All I knew at the time was that it was doing RTH, and then I was able to cancel it and regained control.

    Long story short, the questions I have are:

    1) Will the P3A descend to the RTH failsafe altitude when initiated before moving horizontally toward the home point? If so, I'll have to set it to 400ft when flying above or near the butte.

    2) Will the POI orbit continue for the 3 seconds of disconnect before it stops? It sure looked like it from the video, but I can't say for certain.

    Thanks in advance for the feedback.

    Rocky Mountain Phantom

    Sent from my LG V10 using TapaTalk for Android.
     
  2. msinger

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    No. It never descends. If already above the set RTH altitude, it'll return home at its current altitude.

    That makes sense since Failsafe RTH is automatically initiated 3 seconds after the remote controller connection is lost.
     
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  3. MPPilot

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    I always have my RTH height set to 400 feet as a "just in case" measure. While I'm sure there are no 40 story trees or power lines around here I figure better safe than sorry.
     
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  4. SONIC

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    It won't go down, it will come home at any height above the RTH altitude you have set.
    That being said, I say set RTH higher than you think you need it. If you're comfortable flying at 400 ft why is your RTH set at 120? Set it above all obstacles, you never know when you'll need it. Some idiot in a huge truck could pull in front of you while you're flying and kill your connection, i prefer to keep the RTH well above anything it could hit.
     
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  5. tcope

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    Once it looses the connection with the controller it does take a few seconds for the RTH to kick in. Most likely because it will sent the error to the app which will then give the option to cancel. No cancel and it will initiate. So there would be a slight delay.

    I have my RTH set at 60 meters and will increase it to about 20 meters higher then the tallest obstacle if needed.
     
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  6. DigitalKnight

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    Good feedback, thanks. I haven't had to set the RTH altitude above 40m because I haven't flown anywhere with objects that tall and won't fly behind obstructions. The top of the butte just barely clipped my line-of-site, which surprised me. To quote The Who... I won't get fooled again.


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