Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

First night flight, first crash

Discussion in 'Phantom 1 Discussion' started by Fantom2993, Jul 11, 2015.

  1. Fantom2993

    Joined:
    Jul 11, 2015
    Messages:
    4
    Likes Received:
    0
    I'm pretty new to larger drones. For the past year or so I've been practicing flying with smaller cheaper drones. I bought my Phantom 1.1.1 a few weeks back and had a good first flight, it flew perfectly, I got a good 13 or so minutes of flight before I brought it in.

    After seeing a few threads here on night flying, I decided to give it a try. So tonight took it out, had about 7 or 8 minutes of flight, then it happened. As I was bringing it in, it lost power, and started an inverted fall from 75 or so feet. Motors powered back up, and slowed the descent, it fell through a tree and landed in the grass. No damage, not even to the props. Here's a short video clip from my camera which also survived, showing the crash.

    It appears that this crash was indeed my fault. I had the motors set to immediately turn off, and I believe that in bringing it down I dropped the stick below 10%. I'm actually relieved that it was my fault, and not a problem with the Phantom.

     
  2. robsquad

    Joined:
    Dec 4, 2014
    Messages:
    962
    Likes Received:
    422
    Location:
    Wolverhampton, UK
  3. Pilot_FML

    Joined:
    Sep 20, 2013
    Messages:
    189
    Likes Received:
    28
    Location:
    Mentor. Ohio, USA
    Hmm... it's my impression that its pretty hard to accidentally shut down a Phantoms motors while in actual flight

    You have to hold the throttle stick fully down for at least 3 seconds to shut the motors down.

    Did you do that?

    P.S. I doubt that you have a problem with the Phantom but it might be wise to go out (in day light ;)) and verify you can fly normally.
     
  4. Ti22

    Joined:
    May 13, 2015
    Messages:
    259
    Likes Received:
    86
    Location:
    San Diego
    What are your battery low voltage limits? 13 minutes with a camera load on stock P1 is a long flight time IME. You should’ve had red LED low voltage warnings if not auto-land engaging.

    I know you mentioned 7-8 minutes for the crash flight but how’s the battery balance?
     
  5. Deadpilot

    Joined:
    Mar 14, 2015
    Messages:
    80
    Likes Received:
    8
    I generally could fly mine safely for about 12 minutes with camera on board before the low battery warning light came on, using stock Phantom batteries and with some fairly aggressive flying.
     
  6. Ti22

    Joined:
    May 13, 2015
    Messages:
    259
    Likes Received:
    86
    Location:
    San Diego
    I use 220g BLDC gimbal with 100g Hero2 (20-30g heavier than Hero3/4) using 45-90C nano-tech 2.2Ah batteries (slightly heavier 8ga wire) ‘always see 1st LV warning @ 10 minutes. This is very repeatable across several battery packs/bricks.
     
  7. Fantom2993

    Joined:
    Jul 11, 2015
    Messages:
    4
    Likes Received:
    0
    It was set for immediate shut down of the motors, and I remember reading that holding the left stick at anything less than 10% throttle would shut down the motors. After watching the video I did notice that the motors cut out for a second, before I got back into the throttle. Which I think may have been what saved it from serious damage, as it slowed its fall.

    Honestly, I'm unsure of the voltage limits. I may have been a little high on the estimate of the first flight. According to my video I had 12:39 of flight time, and I brought it in when I got the flashing red warning.

    I'm pretty new at this, what do you mean by "battery balance"?
     
  8. Ti22

    Joined:
    May 13, 2015
    Messages:
    259
    Likes Received:
    86
    Location:
    San Diego
    I’m terrible at explaining stuff like this but I’ll try.

    The following graphs illustrate discharge of an 8S RC Lipo battery pack. Although larger (5Ah) cells and higher series count, they’re the same chemistry and voltage of our P1 2.2Ah RC Lipo.

    1-8Discharge.jpg

    A load s applied and drains the battery while we log/graph the voltage of each cell. These are new and good cells so everything’s fine until the very end. In this example load is removed and the voltage swing or floats back up a bit. Nothing is/was damaged or harmed because we were automatically monitoring to prevent OD (over discharge).

    Notice how that lowest cell is the “weak link” in the series battery chain supplying power to our P1? The same amount of current (Amps) is flowing through that cell that’s flowing through the others. If anybody uses Ohm’s law, it’s pretty easy to see how bettery energy begins to be turned into heat.

    1-8DischargeZend.jpg

    In regard to battery balance we’re talking about the cells being in fairly close agreement in capacity to each other. Trouble is, unless we have something logging and/or monitoring the pack and this cells, we really don’t know what’s going on while the P1 is using the cells.

    Some cells are defective and may sag much early than in this example. Or in the case of running a pack low one cell is simply used up before the others. The more you deeply discharge a pack the more out of balance they become so pack health and maintenance can be a very worthwhile effort.

    That’s why many RC Chargers have testing functions and/or it may be worth fabricating a simple battery testing rig in order to be able to apply loads and measure individual cell performance to insure trouble free use and flight.
     
  9. JKDSensei

    Joined:
    Jun 24, 2015
    Messages:
    1,511
    Likes Received:
    658
    Location:
    USA
  10. JKDSensei

    Joined:
    Jun 24, 2015
    Messages:
    1,511
    Likes Received:
    658
    Location:
    USA

    Good save.
    Now go forth pilot and crash no more.
     
  11. JKDSensei

    Joined:
    Jun 24, 2015
    Messages:
    1,511
    Likes Received:
    658
    Location:
    USA
    Another Neb question.....

    In this instance, would he not have had this happen if he had had the Intelligent throttle option (instead of immediate) checked instead?
     
  12. Pilot_FML

    Joined:
    Sep 20, 2013
    Messages:
    189
    Likes Received:
    28
    Location:
    Mentor. Ohio, USA
    So, did you or did you not hold the left stick "fully" down for 3 seconds when your P1 seemed to lose power? .... (see my original reply).

    Until that gets answered, I don't think it makes sense to think there is a problem with your Phantom.

    P.S. For some reason the question of accidentally shutting down the Phantom in mid-air comes up continuously .... and it continuously gets wrong answers whether its possible or not. ;)

    The manual is unfortunately poorly written and leaves a lot up to personal interpretation.
     
  13. Fantom2993

    Joined:
    Jul 11, 2015
    Messages:
    4
    Likes Received:
    0
    I believe that I did, since I was bringing it in for a landing. "I want it to come down, so the lower I hold the stick the further down it'll go" lol.

    I don't think there is anything wrong with my P1 other than it being owned by an inexperienced pilot haha
     
  14. Pilot_FML

    Joined:
    Sep 20, 2013
    Messages:
    189
    Likes Received:
    28
    Location:
    Mentor. Ohio, USA
    You've got a good attitude.... you'll make a fine pilot.;)

    P.S. After you land, take notice of how long it takes you to shut the motors down.
    You'll quickly realize its not something that you can do by mistake very easily.
    Holding the left stick fully down for 3 seconds takes a "very" conscious effort.

    Enjoy your Phantom.... I still do, even after almost 3 years.:)
     
  15. Fantom2993

    Joined:
    Jul 11, 2015
    Messages:
    4
    Likes Received:
    0
    Well, I'll be honest with you, a part of my good attitude is because my phantom came out of the ordeal with nothing more than a couple of grass stains. But, I'm really enjoying it, and if the time comes that I have an real crash I'm sure I'll buy another.
     
  16. Pilot_FML

    Joined:
    Sep 20, 2013
    Messages:
    189
    Likes Received:
    28
    Location:
    Mentor. Ohio, USA
    Couldn't agree more about how rugged the Phantom is... it was one big selling points when I first got them.

    The only damage I've ever encountered on a crash was a broken prop a couple of times.

    Be sure to carefully look over the quad after a crash.... small cracks on the prop hub and near the motor mounts are easy to miss.