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Risk Assessment: Litchi Flight Plan ...

Discussion in 'Pro/Adv Discussion' started by Avocet, Aug 3, 2016.

  1. Avocet

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    Hi P3xers ... I was wondering if some of the more experienced Litchi users/Phantom pilots might be able to help me get an idea about planning and associated risks. I have lots of hours in UAVs but am relatively speaking a low hour Phantom pilot. I have a P3P that I intend to use as an introductory video platform, sort of a first step that combines my love of things that break that earthly tether and a way to record same.

    Anyway, I digress. I live on the lovely coast of Maine. Some here may be familiar with one of our real gems, a Gulf of Maine island called Monhegan Island. Magical place in a lot of respects. I would like to start filming it. It provides a number of challenges, most of which I will spare you from.

    My question, however, is, my first Litchi plan is a 17 minute flight. I'm wrestling with wondering if that is stretching the duration limits of the P3P. I really like the plan and want to use it but not if its unrealistic or unnecssarily risky. The island is populated, but not densely. It has sheer cliff drop-offs on most of its sides and is 12 nautical miles out to sea. Recovery of lost UAVs would be interesting, as long as they stay on land ...

    Even more difficult, I (for better or for worse) am not a boat owner. Getting to the island is time consuming and somewhat expensive so maybe 1 recon trip at best would be possible. I have been there a few times before, but never with my mind's eye for the phantom and its camera.

    I'm finding that it stands to reason that the places I'd like to photograph the most are often much more difficult to get to!

    Love to hear your thoughts I would ...

    Screen Shot 2016-08-03 at 10.58.17 AM.png
     
  2. Sagebrush

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    In my opinion yes. If it's windy, your bird may not have enough battery to complete the flight which of course would probably be catastrophic.

    I've been flying Litchi Missions since February. When learning to fly autonomous Litchi missions, I would suggest you start out with a much more conservative mission in a location that you can scout before the flight and be able to observe the bird throughout the mission. Set the flight higher and slower than you've got things figured out. It's probably a good idea to keep your left trigger finger on the mode switch so you can quickly abort the mission.

    Pre-scouting a mission site is important to ensure that there isn't something in the flight path that you can't see or didn't notice on Google Maps. Are there power lines you haven't identified? Is there a new cell tower? How high are those trees?

    Remember, the GPS system is good for about three meters and the altimeter is good for about the same.

    Good luck,

    SB
     
  3. shockwave199

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    I concur with everything that was said. A 17 minute mission can be fine or disaster, depending on winds that day. I have found that my actual mission times come in an average of 2 minutes shorter than the mission estimate. There is a pad of some sort built in, I think. But I always choose the calmest days to fly to avoid problems with higher winds. Don't forget you also eat up battery time preflight as well. I time my missions anywhere from 10 to 13 minutes. For a given area, that's usually plenty of filming coverage. Your mission doesn't look all too exciting in terms of how your flying the bird. I'm sure the area is beautiful but if you're just gonna essentially fly a circle, shorten up the flight time to be safe. Good luck. Post the video afterwards!
     
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  4. Flipsonic

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    This past weekend I executed a Litchi waypoint mission mostly over water. Litchi said the duration is 13 minutes. That's the most I would go for anyway. Where I took off, it was calm winds so I felt good about the mission. But when the bird got up at 200' in the middle of a large body of water, I could see the front pitch down a lot due to heavy oncoming winds. I had it programmed for 25 mph but only went to 15-17 mph. At this time I was unsure and was ready to hit RTH. Halfway through the mission, I see the battery at 50%. But I trusted my instinct and continued anyway. I needed to experience how far I can push it. Luckily on the way back, it caught a jet stream and went back up to 25 mph. I even pushed right stick forward to hurry it up and it went to 32 mph. Then just when the battery alarm (30%) just sounded, I see it coming back to me. The entire time I was almost crapping in my pants. By the time it landed, battery was at 25%. These learning experiences are priceless. Next time, I will definitely be more cautious as I may not get lucky. Hopefully you can get something out of my experience.
     
  5. Sagebrush

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    In the manned-aircraft world there's a saying. There's bold pilots and old pilots but there are no old-bold pilots.

    SB
     
  6. shockwave199

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    Consider using uav forecast. Type that into your browser and it'll come up. There's a paid app but I use the free version. 24 hours is all I consider accurate anyway. At 24 hours I plan to fly the day if it looks good at the location and altitude I'm flying at. By 12 hours if it still looks good I make a definite plan. Within an hour or so if nothing has changed for the worse, I'm off. Uav forecast is a great, easy way to plan for flights and stay safe. Recently, the wind was so calm that I questioned the accuracy of 20mph winds forecasted only an hour later even at 100' up. I went to fly thinking that forecast could not be right. I arrived and I was being blown back just standing there, lol. The bird never came out of the car. Don't fly and get surprised. Use uav forecast to better your odds of a safe and fun flight.
     
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  7. Flipsonic

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    Thanks for that Shockwave. I'll definitely use it in the future. In any case, I'll be ready for anything since you'll never know what will happen until the last minute. Keeping my finger on that mode button at all times.
     
  8. Traveler

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    Lots of good information in the replays. That said, I'll add my .02 cents.
    You cannot calculate a mission on just time. It is more of combination of distance, speed, and wind. You can run a battery down pretty fast In a head wind at full throttle. A lot less time than 17 minutes. So as a new Litchi user who may want to push the limits, I would suggest the following. Start a log to track distance, speed, wind, time and battery percentage or voltages at landing. With this data, you should be have better information for planning future flights. Start small and build.
    Cheers
     
  9. FantomFlier

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    You should also consider testing the wind speed right when and where you are about to start the mission (not only Litchi, but any long range mission).

    Using a spare battery, take the quad up to the altitude/s you intend flying, switch to ATTI mode and let go of the sticks. You will quickly get and idea of wind direction and speed at each altitude. Use this information for planning the final mission.
     
  10. shockwave199

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    This advice is passed on often and not that it's wrong, but that's an advanced approach to it. If you don't know how to fly well, switching to atti in wind can be disastrous. Even if you switch back to gps you can still be disoriented enough to have problems. Only if you have strong flying skills should you switch to att to see how fast the bird is flying away. I would suggest a better approach in general is to simply monitor the wind speeds at the altitude you want to fly in a given location and pick a calmer day. Sure anything can happen in a moment. But having flown a lot of litchi missions, I haven't run into problems with wind causing issue. I know what altitude I have set, I know what cruising speed the mission is set at, I make certain to set maximum cruse speed at 30 mph in case I should have to lean on the stick, and I closely monitor the wind forecast before I head out. Land or water, I've been successful without any extra effort than that. Pick your day wisely and keep missions to 13 minutes for general points of interest filming. As well, keep the bird within 2k' so it's never too far off. I also keep my finger on the mode switch too. Healthy drones sync automatically too with litchi when you set that up. That feedback after a flight can be very helpful.
     
  11. Pharm

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    Also keep in mind that if you set straight lines instead of curved paths (in the mission settings), the AC will stop and start at each waypoint. This stopping and starting will increase the mission time but it is NOT calculated into the estimated mission time that Litchi shows you. If you are set to straight lines and have a large number of waypoints, it might significantly increase the mission time well beyond the estimate.
     
  12. Pharm

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    If I was flying the mission you showed, I'd break it into two parts; the island part and the land part. New battery for each part.
     
  13. theTastyCat

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    Would definitely break it up. I've come to find that though we may think it's cool to shoot 17 minutes of video in smooth, beautiful, artful Litchi style, it's just boring as is could be to watch, even when it's my own footage. I find that a 1.5 to 2 minute video of the highlights, usually 5-10 seconds, is really enjoyable to watch. If I get bored watching it, I know other people will too! There's always exceptions of when shots can be longer and still hold interest, but even when flying towards an object, I find giving the first 5 seconds, then maybe another clip halfway, and another one on arrival gives the same idea without losing people's interest. So fly twice!
     
  14. Avocet

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    Some terrific comments .. thanks fellas! I guess the old adage, "if it looks like a duck, talks like a duck, its probably a duck ... " Mission abort! (Will replan this one, perhaps into segments).

    BTW ... a 200 acre rock 12 miles out in the northern atlantic is hard to be bored by. Post edits will always have an opportunity though. And I agree ... there are more long boring videos made by phantom pilots out there than NOT. :)

    Fly it safe ... :eek:o_O
     
  15. Avocet

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    Hmmm ... if you look closely, you'll see that the 'land part' IS the island part. There happens to be a small island to the left in the pic just off the main island. This looks like a low tide picture so its hard to differentiate between the cliffs edges and the underwater features surrounding the island. Thanks for your comments!
     
  16. Richard Walker

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    I keep my Litchi flights to 12 min or less just in case of issues like wind. Your plan seems long without more experience in that area.
     
  17. theTastyCat

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    Seriously, sounds like an incredible place to get footage!! Would really love to see the finished product.

    And if you have to fly there and back, I'd be nervous as a crack baby when signal dropped on the way there, but when it returns with awesome footage I would feel like a *complete* ninja!
     
  18. Avocet

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    Well, they'll be no Ninjaing on this one. The island is 12 nautical miles off the coast. Boat, Ferry, Helicopter, or powered submersible is the only way there. No airport, the island has 3 pickups, a fire truck and 2 cars last I heard. That's it. About 60 year round residents, 90% fishing for lobstahs ... 3 inns, a small grocer and an ice cream shop/sandwhich shop, 2,455 art galleries with seascapes on canvas, and lot's of wanna-be landscape painters calling the ghost of Andrew Wyeth ... It is singularly a unique bump in the Gulf of Maine though.
     
  19. Mike_in_Letcombe

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    Hi; Miike here. I'm also new to Litchi, with my new Phantom 4. Very experienced with my Phantom 2 Vision + so upgraded to the 4. I am SLOWLY learning Litchi (done one flight, out in the open, away from people and kept well within sight at all times), only a 5 minute flight but it worked fine. But I notice your comment '...keeping your left trigger finger on the mode switch so you can quickly abort the mission.' I wasn't aware of this and am a bit nervous that, once it's off on a Waypoint flight, I have lost control. IF I change over to 'sport' or 'ATTI' mode, will this abort the mission and let me take back control? Can I put it back into 'P' mode (so I have my collision avoidance sensors back on) and still keep control or will it then start the Waypoints flight path again? Sorry to butt in on your conversations but you sound like you know more about Litchi than I do!
     
  20. happydays

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    I have not experienced that in around 60 Litchi flights so far. I often add in an extra waypoint to allow long straight runs as Litchi won't allow the distance between waypoints to be over 1500m (from memory).