Lessons learned today: Take heed and enjoy

I was on a survey job for the Sacramento Kings new arena and I discovered a few good tips.

• Set your RTL at %30 of battery drain.
• Carry good electrical tape

• Buy a backup Iris+

• Get a lens guard for your GoPro.

I decided to allow my unit drain to 20% and RTL. I was 60m up and only around 100m away. The Droid lady said "Low battery, returning to launch" Sounds good to me. As it's decending I notice I'm well off the mark and headed into oncoming traffic. It's a tight quarters job and you gotta be ready. I begin to nudge it over the K rail and I hear the motors begin to decelerate. I hit hard left and, well watch the quick video.

The gimbal plate cracked in half but I was able to use electrical tape to finish the job. I had a Mobius on there for shits and giggles and the GoPro was the survey unit. You'll see it fly. Gotta hand it to GoPro. That's one tough unit. I did have a CPL filter on there, but if you can use a cheap 3D printed hood, do it. That filter saved my lens.

So if you're ever unsure out there. Trust your gut and RTL.


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    • Ahhh shucks, now I'm sorry I said "stupid stupid". Hug? :) Look, putting your story up is good - it creates debate and people learn from it. Task accomplished. 

      I forget the number of things I have done that with hind-sight you think "You're lucky you got away with that". 

      As for "what to put for mAh" - I really do not know. I have a fundamental distrust for Adrucopter to accurately report mAh used / remaining.

      Some basics:

      You have a brand new 5100mAh battery. Do you know it is 5100? Have you drained it and charged it and checked? You've told MP you have 5100 and you would like to "protect your ass" at, let's say, 1000 remaining.

      What happens if your battery was not actually 5100 when you bought it? 

      What happens if you have hurt your battery by over-discharging? 

      What happens if there is a small error in current measurement? The cumulates over the 15 minute flight time.

      I go by voltage (which is shown on my Tx). 3.8V is roughly 40% remaining. So when it beeps at 3.8V I know it's time to think about coming home. If I am near I will fly some more. If I am far out, I'll head back. I normally fly with 10000mAh (2x5000mAh)

      Getting every last drop out of the battery is bad for a number of reasons. 

      You ruin the battery. 3.3V under load is getting near empty. What if you can't make it home?

      I have returned home to find I cannot land. There was an Alsatian hell bent on eating my heli for lunch. He refused to move and was barking at the heli with a ferociousness which would scare a rabid dog. Damn thing stood there for two minutes while the owner wondered over and put it on a lead.

      I have had to stop coming home because a group of walkers stopped in my flight path to stare at my heli. Being on a job I am not supposed to fly over them. I had to hover for a minute or two before the moved.

      All of the above are good reasons why you should have ample reserve if you're working.

      I don't know much about the Iris but would the sx260, weighing in at 287g, and a 5100 lipo not be putting the Iris over what it can carry? My 5000mAh 20C (Lower C = lighter battery) weighs 877g. That's over a kilogram you're asking the Iris to carry. Not convinced it'll work well. I may be wrong though.

      Off topic alert:

      I have a sx260 which I converted for IR. How are you joining all the images and retaining the gps data? I will be attempting that soon. Currently not interested in the GPS details but will be soon.


    • Sorry, did not realise the Iris is a 3S - the battery I was weighing is a 6S. Your's would be half the weight then :)

    • Crispin,

      I have a plaque on my office wall that says: "Lord, guide my words this day that they may be as sweet as honey, for tomorrow I will probably have to eat them". ;)  But, I frequently fail in that endeavor, as well as many others.

      To clarify, the IRIS+ has a load rating, over and above the full up stock bird, of 400g, but that can be pushed a bit by using 10X4.7 props in lieu of the stock 9.5X?.


      I have been limiting missions to about ten minutes and still watching the battery voltage closely. I really like the verbal updates provided by Tower. I am just getting started flying mapping missions, mostly over trees where I don't want any unexpected landings of any kind! I am a tree farmer planning to use the IRIS+ to look for problems in pine plantations, and I use small wildlife plots for launch and recovery. No need to worry about people or traffic.I try to have the bird home with plenty of battery to spare. Then when it starts its RTL descent I switch to Stabilize mode and use the remaining battery to hone my "two thumbs" flying skills.

    • Jack,

      I am also in the process of completing a fixed wing with a S100 to study pine plantation.  I am located in the middle of the pine belt here in MS where all we have is pine trees and logging.

      I am using a Penguin air frame and I would love to trade notes with you on what your doing.

    • Ken,

      Sorry I haven't replied before now, house guests for the week! I am just getting started with the S100, add to that I am a VERY senior citizen (albeit engineer) and very new to this technology, so what can you expect ;). I have not tried fixed wing. How much room do you need to launch and recover (considering trees)? I went with IRIS+ for its VOTL capability, I don't need much clear area for launch and recovery. I will be happy to share whatever I learn, mostly the hard way, though this forum has been a great help.

      PS: I am in SE Louisiana, north of BR. Consider a PM.

    • Ken,

      I'm just south of you in New Orleans. I have several ongoing projects, one is capturing imagery for a new Gulf Course being constructed. Several old trees are being removed and I am recording the progress. I am also starting to experiment with the DYI NIR method and calculating the NDVI ranges for a citrus trees.  I have access to a citrus farm down here and the owners have given me access to fly there farm.  

      I've owned a Penguin, but now use a FX-61. I find wings do a better job of "slicing" through the wind. I also find they also have fewer possible points of failure (less servos, less control services, etc). I currently using a S100, SX260, and a SD780 (NIR).

      I recently presented at the New Orleans Maker Faire and put together this overview of mapping with sUAS. You can see some of my set up in the video. http://www.dv-proj.com/data/?p=409  

      Other then doing consulting for a few surveying companies down here, I don't get to talk shop. Feel free to drop me a line if you have any questions.


      Overview - Using sUAS to capture high resolution imagery
      This video is an overview of the processes used to plan, launch, recover, and process aerial imagery for orthomosaics and 3d reconstruction. *sUAS –…
    • The dealer is going to take the "lens error" camera back and send me a S110. Thoughts? 

    • Any good guide on Tower? It is similar to MP2 but I couldn't find the survey settings. Granted I haven't really looked that hard into it. 

    • As for surveying there's really nothing mind blowing about Tower...

      1. Go to Editor 

      2. Tap the squiggly icon, tap it again (this should bring a menu off on the side)

      3. Choose Survey

      4. Follow the prompt, draw you area of interest

      5. Tap the survey waypoint icon at the bottom (this will bring up the survey options). In my case it was the 2nd way point. 

      6. The rest should self explanatory...

      Good Luck


  • It amazes me how people rely on a last-resort safety feature to bring the expensive machine home. Stupid stupid.

    It's like me relying on the anti-crash feature on my car to hit the brakes when the car in front of me stops. 

    Turn off the battery fail-safe, fly with a bit of concentration, know your situation and stop ruining it for the rest of us.

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