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Phantom 1 question.....lifting off

Discussion in 'General Discussion' started by Monte55, Jan 15, 2015.

  1. Monte55

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    I have mentioned this before but never seem to get a response. I am posting it here because the Phantom 1 part of this forum doesn't seem to get much activity. I have a Phantom 1 purchaced April 2014 and got another one on 1/13/15. They both fly fine. Haven't flown the newer one much. The problem, as I see it...is giving it full throttle for takeoff is sluggish. The spool up of the motors is too slow in my opinion. This leads to tip overs. On the first Phantom, I have the S1 bottom switch set to manual. When taking off, I drop to manual, props spool up great and it lifts off fine. Then immediately go to gps and fly. These are stock Phantoms. I have not changed gains and don't plan to. Just cramming the throttle up, in gps, is slow to react. Manual spins up fast with a good lift off.
     
  2. 4wd

    4wd

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    Maybe the newer one is on more recent firmware and the gains are set differently?
    You could connect to the software and if there is a difference, in which case try setting #2 the same as #1
    Make a careful note of how it is now though so you can change back.
    You can download defaults from DJI somewhere too
     
  3. kitari

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    Sounds perfectly normal to me. Granted I have the FC40, but when I take off in gps/atti mode, the props will spool up for about 3 seconds before actually lifting off, no matter how much throttle I give it, but manual mode will launch it into the air like a slingshot. My old fc40 did the same as well.
     
  4. Monte55

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    The problem I have is that I might want to have S1 lower position set to failsafe. But since normal takeoff sucks I have it set to manual to use the faster spool up of the props. Normal takeoff is slow and lame. If not for prop guards, I would have gone through a few I'm sure from tip overs. Still on first set since April 2014. New Phantom acts the same way. It's set for failsafe but I'll probably change it.
     
  5. Monte55

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    So back to the original question. Why don't the props spin up fast at full throttle? Both the Phantoms act the same way. I see many videos of Phantoms taking off quickly. It acts like I'm advancing the throttle slowly. Only on my first Phantom with S1 set to manual will it briskly take off.
     
  6. lake_flyer

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    My FC40 started to do the same thing suddenly after a few months. And I always thought I changed something in the settings that I should have left alone. My P2 always jumped straight into the air as soon as I moved the throttle. Yesterday I flew it without any issue, motors spun up fast as always. This morning suddenly it is the same as the FC40. Slow spin up and nearly tipped over. Had to give it full back pitch to lift it up.

    I wonder what causes this. I didn't do a calibration, didn't hook it up to the PC, it didn't do this yesterday.
     
  7. J.James

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    Have you tried changing the idol speed of the motors in the naza assistant? Go to the advanced tab then the tab that says motors
    there will be a slider that says motor idol speed and some settings like low, recommended and high. if your spool up speed is to slow set the setting higher if your taking off too fast with out havering to give it much throttle then you can lower it.

    here is what it even has on that page in the naza assistant about idol speed.
     
  8. Monte55

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    Thanks for that info. Both of mine are set on recommended. When my props start at idle, they are slow and quiet. I will try a higher rate and see if that helps.
    Nick
     
  9. lake_flyer

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    nice advice Monte55 but have you ever tried this yourself?
    I would strongly suggest against messing with the motor idle speed. I tried different settings once and the result was that the phantom started to hover straight after starting up. It tipped over very hard, even while holding down the throttle, it seemed to take forever before the motors finally shut down. The spool up time is not influenced by changing these settings at all, so I found out. In fact, I tried everything with gain settings, advanced calibration, software reistall, different firmwares, but nothing changed this back to normal.
     
  10. Monte55

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    Did you ever come up with a solution? I was wondering if higher idle speed would cause a problem at landing.
     
  11. The Editor

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    This is simply because when you are flying in either GPS or Atti mode you are not actually flying the craft - the flight controller is. What you are seeing is that throttle stick input does not correlate to linear throttle response because the FC is taking care of everything (as it should do in these modes).

    You are not restricted in manual mode and have a linear throttle curve from zero to 100% thus the more responsive and nimble take off.
     
  12. Monte55

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    I just tried lifting off with the idle set one step higher...no help at all. I start up in gps, have throttle a little over halfway, drop S1 down to manual and it takes off great. No delay or tilting etc. As soon as it shoots up about 5 feet, I go back to gps or atti. If that what I have to do is have manual for a good lift off, then I can't have a failsafe other than turn off tx.
     
  13. ElGuano

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    Idle speed shouldn't need to be changed on a Phantom, the motors/props don't present enough resistant to warrant a change.

    For manual flyers, it may very well be that you're used to the linear response and ability to run immediately to 100% versus GPS/ATTI modes, but it's hard to tell without some quantitative data. Not too many people pop up with true 100% throttle, but I agree takeoff speed is different between the modes.
     
  14. Monte55

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    I might add that manual liftoff does not take full throttle at all. If I had it at full throttle at liftoff and manual, it would shoot up like a rocket and be a few hundred feet up before you know it. I wish they had a separate switch for failsafe.
     
  15. ElGuano

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    If it took 100% on manual to take off, you wouldn't be in the air for long, and you wouldn't be able to control attitude or maneuver :) Ideally, you should be able to take off in manual just over 50% throttle, and be able to hover just at 50%. On some of my heavier Phantoms, it's still easily controllable at 70% throttle hover, but above that it feels like trying to fly in molasses!
     
  16. Monte55

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    The slow spool up is not as bad in calm air. But when you're trying to takeoff any breeze can blow you over a bit plus being in the turbulent air close to ground doesn't help. If the quad was on a pole and not in ground effect it would probably be fine but a bit slower.I aint carrying no stinken pole.
     
  17. lake_flyer

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    I don't really mind the differences between various modes.
    I mind the difference with yesterday! How come the flight controller behaves differently as of now?

    I never found the solution for my FC40 and I doubt I ever will for my P2.
     
  18. Monte55

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    I don't quite understand your first sentence. Why would you not be in the air for long?
     
  19. ElGuano

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    Putting details aside (endpoints, gains, etc.), manual mode requests linear throttle. 100% throttle on manual is spinning your motors as fast as they'll go for the given voltage provided. That's the full 600-800g/axis. If you needed that much thrust to take off, you have nothing left to maneuver or maintain attitude/altitude (slowing down any of the motors to turn or move would cause you to drop).
     
  20. The Editor

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    See my post above..... Manual gives you linear throttle and will take off circa 50% (depending on AUW of your craft) whereas half stick in GPS or Atti DOES NOT equate to half/50% throttle... It is whatever the FC wants to give the motors given any set of parameters. Do not confuse GPS or Atti mode with actual 'connected' flying.... you are merely giving the FC an input (in this case throttle) which it then decides what to do with dependent on it's programming.

    Altering idle mode will have nothing to do with how your Phantom takes off - It is there to alter the speed at which the motors will sit at idle at to overcome inertial forces from different weight/size/pitch props (and in some cases can overcome timing sync issues between esc's and motors).