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Phantom 3 Flight Capability Quiz

Discussion in 'Pro/Adv Discussion' started by huntjock, Nov 30, 2015.

  1. huntjock

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    Time for a little quiz...


    Which of the 9 hypothetical flights shown and described below are possible with P3P/P3A quadcopters? A simple "Yes" or "No" is good enough. You may explain your answer. Should be easy, right?

    First, some assumptions and parameters:

    • Stock P3P with latest firmware/software updates
    • DJI GO app or any 3rd party app - OK
    • Autonomous flight or pilot-controlled - OK
    • Battery fully charged
    • No wind
    • No obstructions along flight path
    • Flights are in the U.S.
    • Flight paths are not in any NFZ (No Fly Zone) or any other restricted area
    • Home points are at the point of takeoff
    • As many waypoints as needed (if autonomous)
    • Rise vertically to flight path at takeoff, landing only after the flight has completed

    Black lines represent the Ground Level; points A, B and C should be interpreted as points along the flight path.

    Red lines are flight paths

    The 3 figures, not drawn to scale, are ground level or horizontal views.


    Please let me know if you need any other info or if I need to clear up any ambiguities.

    figure 1:
    Flight path is 400m above ground level
    #1. (A to B to A) Starting at point A flying to point B then returning to home (from B back to A) along the same flight path

    figure 2:
    Flight path is 50m above ground level
    #2. (A to B to A) Starting at point A flying to point B then returning to home along the same flight path
    #3. (B to A to B) Starting at point B flying to point A then returning to home along the same flight path


    figure 3:
    Flight path is 30m above ground level
    #4. (A to B to C to B to A) Starting at point A flying to point B then to point C back to B and finally returning to point A along the same flight path
    #5. (C to B to A to B to C) Starting at point C flying to point B then to point A back to B and finally returning to point C along the same flight path

    #6. (A to B to A) Starting at point A flying to point B then returning to home along the same flight path
    #7. (B to A to B) Starting at point B flying to point A then returning to home along the same flight path

    #8. (C to B to C) Starting at point C flying to point B then returning to home along the same flight path
    #9. (B to C to B) Starting at point B flying to point C then returning to home along the same flight path


    DJI Quiz 3.jpg
     
  2. msinger

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    None of these are possible if using the DJI GO app. You could probably get pretty close with figure 1, but it would be hard to follow the exact flight path on the way home.
     
  3. huntjock

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    Using apps other than the DJI GO app, which flights are possible?
     
  4. bobmyers

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    figure 1
    Point A to Point B with the flight path turned on, you could fly the same line back-- at the same altitude but not exact. May be possible to set up in FPV Mission Planner-- I haven't used mine that much yet-- but I think the settings are there to do it.
     
  5. huntjock

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    Ok - instead of saying "returning home along the same flight path" let's just say "returning home in a fairly close proximity to the same flight path (+/- 10m)"

    With that, which of the 9 examples is the P3 capable of flying?
     
  6. huntjock

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    Answer: The P3 can apparently fly only 4 of these 9 flights - you may be surprised at which of the flights the P3 is incapable of...

    Here are my answers with some explanation. Let's see if there are any disputations, controversies, or absurdities. In other words, please feel free to dispute/argue/contend. [​IMG]

    Disclaimer: I have not flown or attempted to fly any flights/missions similar to these.

    #1. Yes. This is a straight line flight/mission above level ground. 4km (~2.5 miles) is fairly long distance, but we have all seen flights that exceed this distance. And, 400m high (above ground AND above home point) is higher than I have been, but within the 500m limit allowed by the P3 firmware.

    #2. Yes. This flight/mission is similar to #1 except that the ground slopes upward at approximately 6 degrees (very slight upward slope). Staying at 50m above ground level (AGL) for the whole flight the answer is YES. However, the flight could NOT be accomplished at the same height as #1 (due to the DJI height limit implementation). Also, to continue the flight at the same gradual slope while remaining at 50m AGL, the P3 would crash into the ground at approx 4.5km (just over 3 miles).

    #3. No. The reverse of #2 cannot be done. The P3 may not crash, but would not be able to continue its flight beyond approx 1.6m (~1 mile) from takeoff. Why the P3 can takeoff from B and fly to A, but CANNOT takeoff from B and fly to A...is rather absurd. But, that is the implementation of limits built into the P3 firmware.

    #4. Yes. This mission can be done - as an autonomous waypoint mission. 2 interesting things here are: 1) continuing from B to C puts the quadcopter beyond visual range (BVR), and 2) the distance of ascent and descent over the course of the flight. The distance of the flight is not really a factor in this flight. I will be trying something VERY similar to this soon. I will admit that the BVR factor does make me a little nervous.

    #5. No. Although this is the reverse of #4, the P3 cannot make this flight. I won't go into it, but it is quite absurd - for the same reasons as other P3 flights that cannot be done are absurd.

    #6. Yes. This is just the first leg of flight #4, which is essentially a shorter flight #1. This was a "gimme" but a setup for the subsequent flights below.

    #7. No. This is the reverse of #6, which is essentially a shorter flight #3.

    #8. No. Although this flight is similar to #6 and #2, and EVEN THOUGH the P3 flies ONLY 30m AGL, the P3 firmware keeps it from rising above 500m above the home point. I am not sure if this flight would crash - probably not; it just won't go beyond about 1/2 mile away from the home point. The slope is about 11%, so not steep. Did I say that the P3 never exceeds 30m above the ground? Absurd?

    #9. No. Again, even though this is a flyable leg in the #4 waypoint mission, by itself it cannot be flown. Why not? Because the P3 cannot descend by more than 200m from the home point. Absurd? I hope that the question of such absurdity is rhetorical by now.

    Which of the above missions do you think the P3 should NOT be allowed to fly, if any?
    I was going to add my conclusions here, but I would ask you to draw your own conclusions. As you do, be careful using the word "safety" if you want to rationalize the inablity of the P3 to fly ALL of these missions.
     
    #6 huntjock, Dec 3, 2015
    Last edited: Dec 10, 2015
  7. GadgetGuy

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    Good summary, but a little hard to follow, especially with the hypothetical and diagrams separated from your answers by several intervening posts. I had to keep scrolling up and down.

    A few corrections are in order:

    1. #4 cannot be flown as an autonomous waypoint mission, because no waypoint may exceed 500m from the launch point, which is my biggest complaint about waypoints, in addition to the total 1500m limitation of the mission, and the 200m descent limitation, and 500m ascent limitation!

    2. Also, even flying manually in #4, as soon as you are below the below the peak of the hill on the far side, you will lose all signal because you no longer have the clear LOS required for transmitter control, which will force a RTH after 3 seconds.

    3. Even if DJI didn't impose a 500m radius limit on all Waypoints, you still would not be able to fly #4 as an autonomous waypoint mission because you can't first fly it manually, as is required to set it up, because of 2. above (loss of transmitter signal, once over the hill top).

    So, you needn't be at all nervous about flying BVR or BVLOS, because you can't, when you also have no clear LOS. The transmitter knows best. It wants you to remain calm, while it relinquishes full control to the bird, so it can fly using the only preprogrammed autonomous mission with no distance limits, cleverly called RTH! :) Ain't that grand? :cool:
     
    #7 GadgetGuy, Dec 10, 2015
    Last edited: Dec 10, 2015
  8. huntjock

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    Great responses! Always open to corrections.

    #1. "no waypoint may exceed 500m from the launch point" Really? Ouch!! I thought the 500m limit with waypoints was the max distance between any 2 successive waypoints, not max distance from the take off point. I could swear that I've seen some videos of wp missions using Litchi (on android) where the furthest point away from launch was well beyond 500m - perhaps even 2 to 3 km out there. Now, I am going to have to go back and check again. This may explain an error I was getting when testing the new Litchi for iOS beta the other day. Either that or I may have been running into the 1500m flight limitation - my flight was 3.4km.

    So, flight #4 is completely impossible no matter what. Sigh.

    Difficult for me to comprehend that with so much potential and capability, DJI has placed so many seemingly unnecessary limits on it. Yes, grand.

    I am seriously considering selling my P3 due to these unreasonable flight limitations. No skin off of DJ's nose, I know.
     
  9. stealthbomber

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    If a train leaves the station at 90klms an hour and has to travel 327 klm's how long..........
     
  10. ScopeTech

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    From a newbies perspective I believe Litchi can accomplish most if not all of the scenarios you've presented here.
     
  11. n6vmo

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    I believe Flight #4 is possible with Litchi. Using the "AIRCRAFT" settings tab in the Litchi app, set "Minimum Selectable Altitude" to any altitude below -150'. That will allow you to program way point C to -150 below Home Point altitude. This setting is capable of being set to a maximum of -656' below Home Point altitude.

    Screenshot_2015-12-10-11-59-47.png
     
  12. GadgetGuy

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    Litchi warned that updating the aircraft to 1.5 would impose all DJI SDK restrictions such as the 500m (1640 ft) altitude increase limit and 200m (656 ft) descent. Not sure if the F modes in DJI GO such as Waypoints are part of the SDK for developers, which would likely impose the same 500m radius on Waypoints, too. I hope not. I don't yet have Litchi myself to test, as it was just released for iOS.
     
  13. GadgetGuy

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    Unless you update to 1.5....:eek:
     
  14. huntjock

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    Thanks, jscope. Your comment is actually helping to make the point - that Litchi (and ANY 3rd party developer for that matter) *should* be able to accomplish all of these scenarios. ALL of them.
     
  15. GadgetGuy

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    No so fast...only if you never update to 1.5 or higher, according to Litchi, as I understood it.

    Q: Can Litchi (either before or after updating the aircraft to 1.5) preplan and then fly a mission that takes it where it is beyond transmitter control (out of range horizontally, over the back side of a hill, or behind a large building), without triggering RTH?
     
  16. huntjock

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    Are you suggesting that with the 1.5 "upgrade" the RC and the bird need to remain connected, even in an f-mode autonomous flight? That would really be clipping the bird's wings!

    I will ask Litchi and then post their response.
     
  17. huntjock

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    Sorry - my response was not clear. I should have said:

    "...DJI firmware should ultimately support Litchi (and ANY 3rd party developer for that matter) to be able to accomplish all of these scenarios. ALL of them."
     
  18. TheRealNick

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    You can not fly 200m below home point? I did not know that...
     
  19. GadgetGuy

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    That's not going to happen. DJI writes the SDK used to communicate with their aircraft and makes it available to the developers. If DJI, in their infinite wisdom, decides to restrict the flight of the aircraft in any manner, they will certainly impose that limit in the SDK that the developer apps require to control the bird. They already have, with the last FW update. Litchi will now have to operate within the SDK limitations imposed by DJI, whatever they are now, or are changed to.
     
  20. GadgetGuy

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    Please do. Surely, they are the best ones to answer this question.