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Compass calibration versus liftoff

Discussion in 'Pro/Adv Discussion' started by SteveJ, May 24, 2015.

  1. SteveJ

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    I have read all the advice about recalibrating the compass any time you launch from somewhere different or update the P3. It is so quick and easy I don't hesitate to do it every time. I have been very careful about not doing it around anything metal or something like powerlines.

    Today I calibrated and set my P3 on the ground to take off. Little did I know, a bit of dew from the grass got on the camera lens and screwed up the video from that entire flight. The nicest place to lift off from is a metal picnic table, which would keep everything clean and dry.

    My question: once you have calibrated the compass, is there any issue taking off from a big metal picnic table?

    Oops, another question: I have been hand catching the P3 for landings. Is there an accepted "hand launch" technique? Seems a little more awkward controlling the remote.

    Thanks.
     
  2. Fplvert

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    Hi Steve, welcome to the forum.

    The best thing to launch from is your case or backpack.

    Definitely avoid ferris metal that will mess with the birds compass.

    Hand catching is a lot easier if you wear a lanyard and pull the throttle all the way down to stop the motors. Don't release the stick until motors come to a full stop (about 3 seconds).

    Hope this helps, have fun!
     
  3. SteveJ

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    Thanks. I am shopping for a backpack, but it looks like there are some issues with the P3 being a bit taller than the P2. Hoping to find something that is a soft pack, but protects well. Seems like new alternatives will be coming out quickly.

    For now, I guess I will drag a little mat with me to launch off of.
     
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  4. Meta4

    Meta4 Moderator
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    Compass re-calibration is not necessary if you are flying in the same local area .. say within 100 miles of where you have successfully calibrated already. The earth's magnetic field doesn't change much over that scale.

    I have taken off from an aluminium picnic table with no effect but if you try to launch from a car roof or a manhole cover, your Phantom will give an error msg saying compass calibration required because the mag field it detects is very different from what it is calibrated for.

    In this situation, you should not recalibrate for the mag field of the steel you are on. Move well away and fly. The distorted mag field has no effect a few metres away.
     
    Andy_in_Sleaford likes this.
  5. F6Rider

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    I have a fold up Aluminum launching pad for take offs, good quality aluminum has no effect on the compass. You could make one from Lexon or plexiglass just make sure the hinges are non magnetic, (take a magnet to the store) an aluminum ribbon hinge would be perfect.
     
  6. louforgiveno

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    I do it every trip reason why and maybe you can correct me on my thought....but i have an Alpine X10 subwoofer in my trunk along with a cap and i worry that there could be some magnetism and so i always do the "calibration dance"
     
  7. TacAir42

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    I would love to launch from the bed of my truck. It has a nice rubber mat to land on! Too bad we can't calibrate then plug in a temporary compass deviation figure to operate there.
     
  8. ATPhoto

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    Steve, if it makes you feel any better I had the same problem with a bit of dew on the camera lens.....so no more launches from grassy areas, unless you're trying to do some lawn mowing at the same trim!
     
  9. Julius717

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    20150521_220925.jpg

    P3 fits fine in a P2 backback.
     
  10. teccer

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    this is my launch platform, also my carrying case, I had to fit a new roof to my conservatory and had sheets of 1/2" polypropylene left over so I made this box, my phantom fits perfectly using polystyrene to drop the legs into without having to remove anything from the quad, plus I've got my spare lipos/box of spares FPV gear and goggles.
    the box is just made as you see with black gaffer tape inside and outside for all the joins even the hinge, notice the foam stuck to the inside of the lid to hold the phantom securely
     

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    #10 teccer, Jun 18, 2015
    Last edited: Jun 18, 2015
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  11. tvckz

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    Is that ducktape?
     
  12. teccer

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    yes just black duck tape, AKA in the UK as gaffer tape
     
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  13. UKFlyer

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    I use a P2 backpack which fits the P3P perfectly including the Nvidia Shield and my Launch pad which is just a piece of flexible type plastic and fits in the Backpack lid pocket.

    [​IMG]
    [​IMG]
     
  14. scott rich

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    Julius -

    Are those black boxes on the left of the picture accessory boxes that fit into the extra battery slots? If so, where did you get them? I've been looking for exactly that.

    Thanks,
     
  15. bbfpv

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