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Will switching to MANUAL mode allow a fast descent?

Discussion in 'General Discussion' started by VoicOfReason, Aug 29, 2014.

  1. VoicOfReason

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    Three questions I would like to have answered without first trying this out and damaging my Phantom 2:

    1. If I switch to MANUAL mode (instead of GPS or ATTI) will this allow me to drop the Phantom more quickly from the sky? I'm pretty sure answer is yet, but....

    2. If I drop my Phantom out of the sky more quickly from higher altitude (why would I want to do this? Phantom 2 descends so slowly, it eats up my battery life) by switching to MANUAL mode and then just letting it fall, can I switch on GPS and have it recover/right itself at some point, even if it happens to flip over while in manual mode?

    3. Has anyone tried using MANUAL mode to descend more rapidly?

    Thanks!
     
  2. gunslinger

    gunslinger Moderator
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    If you're not well versed in MANUAL mode it could allow a descent that's a bit faster than anticipated... :eek: :shock: :oops:

    -slinger
     
  3. VoicOfReason

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    I haven't seen ATTI produce a faster descent. So, has anyone tried this? I can imagine a faster descent would be quite nice (thunderstorm coming, got to run to the bathroom, battery low, etc.)
     
  4. Damon

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    ATTI and GPS have max descent limited to 2 M/S regardless if straight down, circles, forwards backwards etc.

    In theory Manual has no limit, but I don't feel like testing that theory out. ;)
     
  5. locoworks

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    me neither, stressed props and motors isn't the order of the day for me. I find myself wondering if those with puffed up batteries have been flying hard and pulling higher currents for sustained periods and have stressed the batteries in some way?? has anyone taken a static amperage reading with full power and the phantom held down???
     
  6. OI Photography

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    No but I've measured current while in flight and even when at 1400g and laying on the throttle in a climb I can't get it to draw more than ~27A (using E300 motors)
     
  7. VoicOfReason

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    So, who's going to guinea pig the descent issue? Part of the curiosity is stems from the fact that I upgraded from my micro drone to the Phantom because I loved to ascent with my micro drone and then drop like a firework, cutting the throttle, and then recover and zoom in. Phantom isn't as fun when you can't do that kind of thing. I have seen the Youtube video of someone flipping a Phantom over just to see if it can recover and it seems to recover just fine. So, even a free-fall may not be so bad.Probably make any gimbal freak out, thought.
     
  8. neoben

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    ...It beats the other suggestion I've seen for coming down fast, which is to CSC the motors OFF, let it drop like a stone, and then restart the motors with enough altitude left to have the Phantom right itself and come to a stop before hitting Terra...

    Best,

    Ben
     
  9. The Editor

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    Unlikely with new batteries but.... - The Phantom batts are rated at 10C (which is pathetically bad considering modern battery technology but it's probably been done to keep the weight down). In any case, you would be able to draw sustained current of around 54amps and no doubt bursts of 80 - 100amps for a few seconds. The Phantom will not draw anything like this in real flying situations. Assuming people are using standard 9x5 props the max current draw with 4 x 2212x920kV would be around 50amps.

    I think the problem is that many people are flying modified aircraft and do not really understand the relationship between AUW, Prop size/pitch, kV rating of motors and current draw. Just changing the prop to 9.5 x 5 as an example would mean the full throttle draw will increase to nearly 60 amps which (theoretically) is above the packs C rating. Unfortunately some people do ascend for some strange reason at full throttle for a sustained period and this MAY have an adverse effect on the packs. Couple this with the fact that packs internal resistance will increase with age/use and your Lipo's will not give up their charge so readily when asked for high demand.
     
  10. Jayson Hanes

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    I descend in manual mode almost every flight. Anywhere above 300 feet you are good to go by simply flipping the switch into manual.. BUT.. terminal velocity with the throttle at idle will be reached and be unstable (ring vortex/prop-wash issue) WITHIN SECONDS.. so I recommend being prepared to flip back to gps mode BEFORE you are under 200 feet altitude. In fact, I did this yesterday and I bounced it off the grass... I waited too long before flipping it back to gps mode (or giving full throttle).. I was under 100 feet when I tried to full-throttle up but there wasn't enough time..

    I didn't get any damage because this bounce was on grass.. but if it were over water or asphalt, I'm sure it'd have had problems.. lol
     
  11. VoicOfReason

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    And there it is... I knew someone out there has tried this. :)
     
  12. Jayson Hanes

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    If you are quick on the throttle, you can easily get down fast and safe in manual mode -- just keep your thumb off the other stick until you have had a lot of practice! (you WILL flip it if you are not careful! ...if not high enough to recover, that would mean a bad crash..)
     
  13. Happyflyer

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    The only way I would ever allow it to come down as a dead bird would be if someone gave me a thousand dollars so I could replace it when it splattered all over the ground.
    If you are going to fly high, and I have done it, is to check your home location is set and pop up quick with a full battery. That way you will have time to get it down. Waiting until battery is 50% then going up is just nuts.
     
  14. Elginet

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    I just asked someone today if you could do this successfully! I was out in the country months back and had it about 2000' for some good subdivision pics, and then had to wait FOREVER for it to get back down. I wasn't sure if the GPS sensing motion or altitude change would let you shut the motors down to do that.
     
  15. ProfessorStein

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    But wait... if you were already in VRS, and flipped the switch to GPS so the Phantom rev'd up the props to stabilize... wouldn't that just exacerbate the issue and make you fall FASTER??
     
  16. locoworks

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    possibly/probably. moving laterally all the time while descending on still days should prevent VRS, on a breezy day the wind does the job for you and you should be able to descent vertically without VRS becoming an issue. the more wind speed the faster the descent could be as the vortices will be blown out the way faster
     
  17. VoicOfReason

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    Of course, there is another option. Instead of dropping like a bird in manual mode, you could just a faster, but controlled descent.
     
  18. ProfessorStein

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    But the Phantom's descent has always been limited... and is even moreso in the 3.0x firmware. That's the point. You can't really get faster unless you switch to manual.
     
  19. VoicOfReason

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    Yes, that's what I meant. I was just thinking that it sounded like the discussion was saying we could either descend in manual like a rock (full throttle down) or use GPS. I think somewhat controlled manual descent would be nice...

    Anyway, so who wants to post a video of them dropping out of the sky and then switching on GPS mode to auto stabilize? I'd like to see how that looks and what to expect. Someone here already posted that they do it all the time.

    Anyone??
     
  20. Jayson Hanes

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    here you go..
    [youtube]http://www.youtube.com/watch?v=TRYyvTHZrfI[/youtube]

    I was 600 feet up then let it drop.. then went to move forward while forgetting I was still in manual mode... I panicked and just slammed it back into gps.. no problems at all and I was still about 150 feet up above the water!

    and another.. skip to 1:08.. I was about 450 feet up and dropped to just below 200.. and then at 2:00 I did it again above the trees and almost didn't pull out of it :)
    [youtube]http://www.youtube.com/watch?v=zmN2VwopsNI[/youtube]