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Best speed to maximize flight distance

Discussion in 'Inspire 1 Discussion' started by RaptorMan, Dec 29, 2015.

  1. RaptorMan

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    I'm curious to know what the optimum speed is when flying the I1 to get the maximum flight distance. I'm not talking max distance away from the RC but the max total flight distance. I'm looking at a couple flight profiles I may do once I've gained some experience and the total trip distance looks to be 6-7 miles. If I took my time I'd run out of battery on time but if I floor it, although the speed would be higher the power consumption rate would also be higher. As a ballpark I'd guessed someplace between 30-35mph would yield the longest flight distance but any feedback would be helpful.

    Just to reiterate this is a question about total distance and not max range away from the RC.

    Oh yeah, I'm talking about an I1 X5 with T48.


    Brian
     
  2. FlyHighUSA

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    Hey Brian,

    I have been working on this very question. After many flights with my IProx5 I have found the best speed to achieve max flight time is 28 mph. When I cross over into the 30+ range it drops only very slightly but it does drop. Hope this is a help. Good luck
     
  3. damoncooper

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    The FPV Camera app allows you to customize the OSD and you can add real-time voltage and energy consumption readings to find the sweet spot for optimal flight time / performance. Like the real time mileage/consumption read out in many cars.

    You can then use the Autopilot apps' Cruise Mode to set flight parameters based on those optimal settings (i.e. Fly at exactly 76% throttle if that were optimal for example).
     
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  4. RaptorMan

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    Ralph, thanks for the feedback. 28mph is a bit lower than I'd have imagined but that's a good starting point for me. I think I'll start at 30mph and see how it goes from there. So, at 30mph and a planned flight time of 12-14 minutes that would give me a flight distance of 6-7 miles which is right where I was looking at.


    Brian
     
  5. RaptorMan

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    Which app are you talking about -- DJI Go? Is this a customization? The normal Go app displays percent battery charge remaining but I've not seen anything that would display realtime power consumption and that would be a nice bit of data to see.


    Brian
     
  6. damoncooper

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    Two apps (non-GO): FPV Camera and Autopilot. Both in the App Store, yeah.
     
  7. RaptorMan

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    Thanks Damon -- I'm not using Apple so my app selections will be Android based. Not sure if Litchi has such a feature though being able to see real time power use would be a very valuable thing indeed.


    Brian
     
  8. Meta4

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    Whatever hypothetical optimum velocity you work out is always going to vary with the speed and direction of the prevailing wind.
    It's quite complex and there's not going to be a one-size-fits-all solution.
    I suspect that the difference between optimum and other speeds probably won't be enough to really worry about anyway.
    That's something to test if you're interested.
     
  9. RaptorMan

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    Absolutely, one needs to know the wind speed and direction if they're going to be pushing the range. I've seen some videos where the guy is chasing cruise ships and he gets 1.5 miles or more from the RC with pretty significant winds -- you could have 65% charge when you turn to head home and not make it of the winds were unfavorable. It would not be nice to drop $4K work of UAV into the ocean because you didn't take into account the winds.

    My though is that if I do any trips that push the range I will preview the area so that if I have to put it down early I know how to get to it.


    Brian
     
  10. damoncooper

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    I disagree. In case it wasn't clear, the app I listed above (borrow an iPhone or iPad for 30 min if you don't have an iOS device) tells you in real time (updated every second) how much current the aircraft is drawing. In any given conditions, with your particular aircraft, you can see the power consumption gauge.

    I have a favorite interview question I like to ask engineering candidates:

    "Weigh me a particular 747 I point you to. You can't get it wet and it has to be able to fly the next day. Walk me through the steps and your thought process to get as accurate as possible."

    I've gotten some incredible answers to that question, but the one that I will always remember is the guy who said "walk up to the cockpit and look at the gauge - they have to know exact weight for takeoff".

    You see my point.
     
  11. RaptorMan

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    OK, what do you disagree with? Flying into the wind is going to eat more energy than flying with the wind to cover the same distance and knowing that is better than not knowing it. Having a current gauge and knowing what normal values are I guess you could guess something about the wind based on the speed and current indications.

    As far as knowing the weight of the 747 without knowing all there is to know about a 747 the cockpit gauges would give you a ballpark, but how's that going to tell you how much the passengers and baggage weighs. I presume there's secondary ways of confirming fuel load but again, no experience with that AC.

    While in the USAF I worked on B52G's and KC135's and the fuel quantity system used capacitance probes with compensators in the tank. This was well before digital and the probe was connected to the fuel gauge with coax. If the coax had a problem the gauge would rotate CW or CCW and do so continuously. During the Viet Nam war, a bit before my time I should add, it was not uncommon for a Buff to have several fuel gauges rotating in circles leaving the pilot with uncertainty in fuel load. I guess they would transfer from a questionable tank to a good one when possible.


    Brian
     
  12. damoncooper

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    Read the gauge. No need for wind speed analysis, fuel quantity systems, etc.