Your Longest Litchi Mission with a Phantom 3 Standard ?

[Billie Nelson]

I've been flying Litchi missions for a couple of months now, and have logged over 300 miles cumulatively. Most of the missions are long enough to assure signal loss shortly after departure, but with each successful return to base, my confidence has grown, and thus far 30% charge capacity is about the average remaining battery power left by the time the drone returns.

The technical performance spec sheet of the Phantom 3 Standard shows 25 minutes of flight time as the maximum battery duration possible. I note, however, that Litchi tends to estimate flight time of its Mission Hub flight plans as being on average 5 minutes LONGER than the actual time taken for the drone to run the entire course at its nominal cruise speed of 17.9 miles per hour. Due to my being aware that a flight slated to take 25 minutes, generally ends at the 20 minute mark, I have been gradually pushing the envelope, by programming incrementally longer flight times, with my longest thus far being a 5.4 mile round trip that was estimated to take 24 minutes in the Litchi Mission Hub, but which actually saw the P3S returning to base at the 20 minute mark, with 35% battery capacity remaining.

Like a 'Vegas gambler that doesn't know when to stop, I have now created a couple of flight plans that are 5.8 miles long, round trip, with an estimated flight time of 26 minutes. As I mull over whether or not to roll the dice and launch one of these ambitious missions, I thought there'd be no harm asking fellow P3S pilots how long they have dared program Litchi missions, bearing in mind the generous overestimation of flight time that the Litchi Mission Hub applies to each flight plan. My guess is that very few P3S pilots will ever dare attempt a 6 mile round-trip Litchi mission at cruise speeds, and I suspect that a 5.8 mile round trip, even in calm winds, is most likely the absolute limit of the distance attainable with a P3S flying under Litchi control.

So, let's hear your record trip distances and durations, fellow gamblers, and if anyone actually lost their drone while going for a distance record, I am all ears, and ready to learn from those fatal errors.

 

[John Locke]

If you're familiar with @DirtyBird , he's the expert for Litchi flights with P3S IMO. He's done some phenomenal flights around Baltimore with incredible flight accuracy and distance. You can check out some of his flights here.

 

[Billie Nelson]

Hello John. Oh yes I am very familiar with Dirty Bird's astonishing video clips. It was after reading about his preference for the P3S as a Litchi platform, that I realized what a treasure the lowly P3S is, for anyone interested in taking long range flights.

The footage of those drones in aerial procession across cityscapes by day and night, is just mesmerizing to watch, and the accompanying soundtrack heightens the cinematic grandeur of Dirty Bird's exploits. To say I was inspired by those ultra long range missions, would be an understatement. That man is a renegade for sure ha ha.

Prior to the start of my Litchi adventures, signal loss during a flight, was disappointing. Now, I hear that that Litchi announcement "Warning - Disconnected", with a sense of eager anticipation about the footage my drone is capturing while on auto-pilot, well beyond signal reach.

One thing I quickly learned in Litchi, is to review all waypoint altitude settings very carefully, so as to clear trees that may loom taller than they appear in the Mission Hub satellite imagery. Twice while reviewing footage, I watched as the drone skimmed way too close to treetops, so I quickly went back to the Mission Hub and added twenty feet to the altitude at those locations, for a more generous margin of error.

 

[John Locke]

If you're flying that low in your program, be careful you always take off from the same place for the mission you plan. The heights are ONLY relevant to your launch site elevation. The flight altitudes would vary if you chose a different elevation to launch from, such as down in a valley lower than the original flight launch spot. Also keep in mind that barometer measurements from the craft can have an error of up to 50ft altitude (extreme case), and often have errors of 25'. I'm sure you know all these caveats by now, I only mention it for others reading.

 

[Billie Nelson]

This caution about barometric errors probably saved my drone from disaster, John, and I thank you kindly for bringing that error margin to my attention. I did suspect that the altitude of the Phantom 3 Standard was off, particularly when I flew it over a river valley, and noticed the forest was further below the flight path than I had programmed, but I put that anomaly down to the online mapping feature's topography inaccuracies, and not to the craft itself. Now I know better, and will avoid cutting it too close henceforth.

 

[Billie Nelson]

I just successfully completed my longest Litchi Mission thus far. Started out with 98% battery, and the flight time for this 5.8 mile round trip was estimated by the Litchi Mission Hub, at 26 minutes. The altitude ranged from 150 feet over the forest, and climbed to 246 feet over the town, so I could scan for cellphone towers, and mark them on the Mission Hub map.

The drone soared back into view at the 22-minute mark, and when I landed it, the battery level stood at 22%, with the battery icon colored an ominous red, while the Litchi lady's voice prompts issued one dire battery warning after another. The recorded 2.7K footage took up 3.85 GB on the memory card, and there were no close calls to speak of during the entire flight.

Looking at the 22% battery level on landing after this 22- minute flight, I decided to ensure that all future flights do not exceed this 5.8 mile distance, on calm days like today, and no more than 5.6 miles if there is any appreciable wind blowing in the area. All in all it was a successful test, and my next flight along this course will be at a lower altitude, now that I have mapped out the pair of cellphone masts that lurk along the route.

 

[Billie Nelson]

Never satisfied with good enough, I created a flight plan in the Litchi Mission Hub, whose duration was listed as 27 minutes, for a 6 mile round trip over the course of a river's rain forest canopy, with the drone tackling a light headwind on the way out, while benefitting from a helpful tailwind on the return leg.

Knowing that my Phantom 3 Standard generally shows up five to ten minutes before the time estimate provided by the Litchi Mission Hub, I was confident that the battery life would be adequate for this new distance record. Still and all, I did breathe a sigh of relief when the Litchi flight commentary resumed as the drone headed inbound on the return flight, 1,200 feet away. It landed safely with 21% battery left, and exactly 4.0GB of video stored on the memory card.

So there you have it, fellow Litchi users. On a calm day, it is indeed possible to program a 27 minute Litchi Mission Hub flight, for a Phantom 3 Standard, whose maximum flight battery duration is stated as 23 minutes. Litchi's routine 5-minute over-estimation of flight times for all programmed missions, makes this impossible feat, feasible.

 

[shuggins]

Late to the party...but just discovered this thread. Fantastic. As a huge phantom 3 standard fan, I love it when people figure out ways to push their p3s's far beyond stock. Great stuff, Billy!

 

[LZJ]

Would you expect the same 5 minute Litchi mission over estimation with a P3 SE? Would like to hear about users distance experiences with it. I'm out to only about 1.5 mile missions so far with trepidation. Great thread! Thanks.

 

[Billie Nelson]

Would you expect the same 5 minute Litchi mission over estimation with a P3 SE? Would like to hear about users distance experiences with it. I'm out to only about 1.5 mile missions so far with trepidation. Great thread! Thanks.

Flying the same Litchi missions using my Mavic Pro1, I noted the arrival time to be pretty much the same as that of the Phantom 3S, so it is likely that for all flight plans with estimated flight times over 15 minutes, Litchi does overestimate the length of the flight by 5 minutes. Conversely, Litchi missions having an estimated flight time of fewer than 15 minutes do not include that added error margin, meaning the drone shows up on time, and not before, for those shorter flights.

 

[LZJ]

Flying the same Litchi missions using my Mavic Pro1, I noted the arrival time to be pretty much the same as that of the Phantom 3S, so it is likely that for all flight plans with estimated flight times over 15 minutes, Litchi does overestimate the length of the flight by 5 minutes. Conversely, Litchi missions having an estimated flight time of fewer than 15 minutes do not include that added error margin, meaning the drone shows up on time, and not before, for those shorter flights.

Very helpful! Thank you. I'll expand my horizons and will keep you posted with the SE.

 

[LZJ]

Very helpful! Thank you. I'll expand my horizons and will keep you posted with the SE.

One more variable to consider I've velcro'd a gps tracker to the top of my P3 SE out of paranoia for possible future loss as a back up, so I've just got to factor in the payload decremental affect for duration of battery life too.

 

[Billie Nelson]

It will be interesting to learn how much flight time was lost due to the weight of that GPS tracker. I bought one a while back, but never actually used it because I was concerned about the resultant decrease in flight time. That said, DJI drones constantly evaluate the remaining battery power against the proposed flight path so as to terminate waypoint missions and make a beeline for home if onboard calculations determine that completing the Litchi flight path could result in the battery running too low before completing the entire mission.

This ingenious safeguard has seen my drone head home early at least a dozen times over the past year, and the low battery RTH kicks in regardless of whether or not the drone is within signal range. Unexpected headwinds aloft are less of a worry with this feature working in the background during autonomous Litchi waypoint missions.