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3.3 Miles on Stock Antennas - Watch Out for Wind Speed!

Discussion in 'Pro/Adv Discussion' started by IOIIOOO, Sep 1, 2015.

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  1. IOIIOOO

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    Yesterday evening was an interesting learning experience for me. I live in a fairly wide-open area - golf course behind my house continuing north to a series of fields (mostly crops), a school, a small neighborhood, and then fields for 10+ miles north. My home is somewhat elevated so good LOS north from my deck.

    I decided last night to test the range on my P3P while heading north. The plan was to head north until either signal was being lost or I hit 65% battery remaining, whichever happened first.

    Surface wind speed was pretty low. 4mph or so heading north. I took off, ascended immediately to 400 feet, and ended up at 3.3 miles / 17,500 feet out when I lost video and remote signal was 1 bar. Hit RTH, it showed RTH initiating, and then lost RC signal. At this point I was at 75% battery and was 4.5 minutes in.

    Waited about 2 minutes and I got RC and video signal again. The surprising thing - it was barely south of where RTH started and moving SLOWLY back. For the first time ever, it showed the home spot on the battery meter to the RIGHT of the battery remaining! By the time I reached the school (which is about 1 mile north of my home) I was at 35-40% battery, so I decided to land it in a small grassy field behind the school rather than risk it being forced to land in the crops or golf course between the school and my home - or making it back with a battery depleted to a damaging level. I descended to about 200 feet, pointed the gimbal down for a moment to make sure I was indeed over the field and not the road, then initiated a land. At about 80 feet up I lost signal (likely due to LOS loss), and I BOOKED IT over to that school. Phantom was in the field where I expected it, blinking its lights at me.

    Reviewing logs, what I didn't notice at the time, was that I was getting a speed going north of 45+ mph, and coming back between 18-20mph. My guess is that at 400ft there was a much greater wind heading north than I had on the ground.

    Lesson from this? Be aware of elevated windspeed. Does anyone have a good way to gauge this? Because the P3 is so good at keeping stable in higher speeds, the wind speed didn't appear to be higher up above from a flight perspective - it all seemed very stable. Or is it more a matter of watching your speed? Also keep an eye out for good safe landing spots if it comes to that when doing distance and battery seems insufficient for a return.
     
    #1 IOIIOOO, Sep 1, 2015
    Last edited: Sep 1, 2015
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  2. D4T_PoM

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    uavforecast.com

    Use this, its very helpful.

    I use it verytime before I fly my P3
     
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  3. rmfa

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    You should have held forward on the right stick while in RTH. You will increase you speed. Every little bit helps. You can also consider going into ATTI mode when you get a little closer. This will further increase your speed. BTW, smart move on landing in the field!
     
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  4. RoyVa

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    Higher wind speeds are hard to judge. Good rule of thumb they can be 25 mph higher aloft and could be headwinds depending on you direction.
     
  5. IOIIOOO

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    I use this as well - every time before I fly. I don't believe it shows altitude wind speed though. Anyone know of a site that does?

    I thought this might be the case so I switched from RTH to control once I had signal back to hold the right stick fully. Still wouldn't get above 18-20 mph. I assume it was just too much windspeed against the drone.
     
  6. rmfa

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    You have complete control of the craft while in RTH mode. You don't have to take it out of RTH. Just hold the left stick and it will 'steer' back home for you.
     
  7. suck it up

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    Take off and go to altitude. Switch to atti mode and see how fast and what direction your bird starts to drift. Then start off in the opposite direction, and put it back in GPS mode. You will be surprised at the difference in wind speed and sometimes even direction!
     
  8. PinesPhantom3

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    Thanks a lot sharing this link. I've always wonder if there was a reliable source for this data. Is this reliable ?
     
  9. PinesPhantom3

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    Thanks a lot sharing this link. I've always wonder if there was a reliable source for this data. Is this reliable ?
     
  10. Meta4

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    If your Phantom is registering 45+ mph going out that should have been a big clue to start with.
    The top speed in still air is 16 metres/sec (35 mph).
    So doing 45 mph shows you have a 10mph tailwind that can take 10 mph off your return speed.
    Plus .. when you let the Phantom RTH without your control, it comes back slower than when you fly it.
    RTH speed is 10 metres/sec (22 mph) - before you factor in what is now a headwind.
    It's a good rule to never attempt a distance run with a tailwind out.
     
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  11. AL T

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    It's under WIND ALTTITUDE just under the SEARCH & USE MY LOCATION Boxes at the top. I find it very accurate flying here in Nevada
     
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  12. D4T_PoM

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    Has not let me down so far and does tell you wind speed at altitudes which you can set on top next to search bar
     
  13. Evel_Knievel

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    Took the two recommendations right out of my mouth. Follow these and you will NOT go wrong. Always make sure the wind is HELPING you get back. Don't trust a forecast, measure wind speed and direction with ATTI mode. 65% percent battery to start returning is a good number. That's 35% used to get out 35% to return and you should still have 30% when you get back. Monitor battery details often and adjust accordingly if you see anything concerning. Lessons learned the hard way!
     
  14. bracKopter

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    Full speed with the p3 is 30-35 mph. If you are booking away faster then that then you have a tail wind. If you are going slower a headwind. Pretty easy. :)
     
  15. flyNfrank

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    You made the comment about Surface Wind Speed, I thought Hey we finally have someone who is wise about winds being different from the ground surface to the jet stream. But then you had to ask.....The Question. lol!

    I have mentioned this many times, one of my favorite hobbies with my P3 is doing Top Speed flights. I have a decent weather station with a Anemometer on the roof of my house that I use as a reference when the wind speeds are up to my likely before going out. Let me tell it now that winds vary by altitude. I use to do all my flight passes at 200ft altitude. But then found the wind speed increased the higher up I go. I now make each pass between 275-350ft depending. The wind in the higher range is more constant, as in it is never steady like ground levels.

    The best way to check the speed and direction is by switching into A-mode. Just let it drift until you see the mph reading become consistent and then use that info to help keep things safe.

    I've noticed on the P3 the RTH speed is around 20mph which is terrible.
     
  16. Ed209

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    I usually get a feel for winds before doing distance runs... I get up to my cruising altitude and switch to ATTI and see which way I drift. Helps a lot :) Also, some practice runs going in each direction so I know what speeds to expect. Then next battery go for the gusto!
     
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  17. Darmie

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    You can type in the altitude and it will change wind speed as you update the wind altitude.


     
  18. Erik Somoroff

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    Great Site and useful info ! Thank You :)
     
  19. Michael Collins

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    I've seen this too. While returning from. Distance run at 150-200m in altitude, I hit a wall and started crawling home.

    I dropped to 60m and bam! Picked up speed again. Moral of the story is so what you did.. Check your horizontal speed.
     
  20. Erik Somoroff

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    Very good practice ;)