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Why do the props back off in flight???

Discussion in 'Inspire 1 Discussion' started by flyingclint, Feb 22, 2015.

  1. flyingclint

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    so I just hit the order button last night and my I1 is on its way to me hopefully! I've been hearing all this commotion about DJI sending out prop locks, because users have been complaining of the props backing out in flight! How is this happening? I mean, my P2V+ has self tightening props and this isn't an issue at all, so what is it about the inspire that's causing this to happen? Also, if I just ordered mine last night, do I still need to contact DJI to get my free prop locks, or should they be coming with my inspire???
    Thanks!
    -Clint
     
  2. Kilrah

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    You should be getting locks with your machine by now.
    Many people are flying without them including myself. As long as you make sure your props are really tight it's good.

    The I1 ESCs have dynamic braking, i.e. instead of just letting motors slow down on their own from prop drag when they need to do so they will actively brake for faster response. A fast spinning prop that is not tight may continue to turn and unscrew when the motor brakes.
     
  3. flyingclint

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    Ahhh. That makes sense. I didn't realize that they had hard braking setup on it. I hope they make that an option to turn off at some point! Thanks for replying and giving me the info on it! Much appreciated!
     
  4. The Editor

    The Editor Moderator
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    I doubt it!....... The reverse emf dynamic breaking is what makes the Inspire into the great craft is. The breaking makes it more stable and more nimble.
     
  5. blade strike

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    I agree.. the active braking is the cats meow. . Just put the locks on or get the quick release props when available. You won't have to to even worry about the chance of a prop shot.
     
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  6. flyingclint

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    Sounds good! Thanks guys for the info! Can you explain a little more in detail why the braking is such a good thing? How does it help make the inspire more stable??? Just trying to learn more...!
    Thanks!
    -Clint
     
  7. blade strike

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    The faster you can speed up and slow down the motor on a multirotor, the more stable and agile you can make the craft.

    It's really the best way to control the motors. But to take full advantage of this, this requires bidirectional feedback with motor/esc, only a few fc turly support this.
     
  8. Kilrah

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    Imagine you're driving your car but with a 1 second delay between you turning the wheel and the car actually starting the curve. Would be a mess. Now same with 0.1 second... Would be manageable, but not great. Best is as it is - no delay between you determining what you need to do and that being in effect.
    It's the same thing. The FC is extremely fast at sensing things, determining the best thing to do to react to them and sending appropriate orders, but unfortunately it has to wait a relatively long time for that order to be applied when the motors only slow down passively. Active braking reduces that response time and overall delay.

    BTW this already improves things without bidirectional communication. Bidirectional communication goes even a step further by letting the FC know exactly how the motor is behaving in real time, but improvement from that is less important IMO unless you intend to alter the propulsion setup.
    If you're gonna change motors/props then yes feedback is good as the FC will be able to learn a configuration's behavior and auto-tune itself for best results with that combination. On a "frozen" setup like the Inspire where the characteristics of the ESC/motor/prop combo are known in advance and isn't supposed to change the response can be hardcoded and the point is kind of moot.
     
    #8 Kilrah, Feb 22, 2015
    Last edited: Feb 22, 2015
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  9. flyingclint

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    Interesting! Thanks for the great info! I love learning and good analogy with the car steering!

    Cheers!

    -Clint
     
  10. InspiredOne

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    o_O

    I don't entirely praffle what you forbicated, but I'm confident if they were to moxtanover it, that would furbogas any further issues.
     
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  11. flyingclint

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    :D
     
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  12. InspiredOne

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    I didn't realize one had to be a rocket scientist to do this... Back in the day, at the dawn of flight, I would have been one of those guys who flew by the seat of his pants. ;)
     
  13. gogowanda

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    Can someone shed some lights on the quick release prop? are they from DJI? we're looking into making a quick release prop system but if the OEM is on it then we may have to reconsider it.
     
  14. Kilrah

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  15. Airwolf13

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    Inspire V2?
     
  16. InspiredOne

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    NOTICE: This opinion has been expressed previously.

    I like the original hubs, better. Looks "classy."
     
  17. gogowanda

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    thanks for the link. if it requires a new motor system then we'll keep working on our quick release adapter for the original motors.

     
  18. Kilrah

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    No, as mentioned many times the prop adapters and props will be available separately, just need to screw the adapters on the inspire motors (which are the same as the ones in the set).