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What is your thoughts on safety/dependability with 4 props?

Discussion in 'Inspire 1 Discussion' started by The_Duck, Dec 16, 2014.

  1. The_Duck

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    Hello all

    First post for me, thanks all for your interesting input in previous threads.

    I have been looking for information on which drone to purchase, and judging by the initial information (awaiting final judgement when products actually arrives), the Inspire seems to have almost all I want.

    But what is your thoughts on the fact it in fact is "only" a quad when it comes to safety and dependability of the rig? If one prop fails, you much likely will crash the whole copter.

    I am the first to admit my experience in advanced drones is very limited and perhaps prop failures is extremely unique and easy to prevent. Then that is probably the answer. But is that true? I have been looking at other drones like the Walkera Tali 500 that does not have all I want in other aspects, but at least it has 6 props that most likely will not create a fast death of the drone upon prop failure.

    Or am I thinking wrong?
     
  2. Victor22

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    You are thinking wrong.
    People crash for all kinds of reasons, but engine failure is for sure less than 1% of them
     
  3. ultraturtle

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    DJI makes great hexacopters and octocopters, all of which can shrug off a prop or motor failure. They start at about $8,300 for a ready to fly kit with capabilities similar to an Inspire 1, to include a gimbal and camera, but without Lightbridge. As far as reliability goes, you just need to decide whether a single fail operational S900 system, or 3 Inspire 1s are the better value for roughly the same cost.
     
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  4. Paul K

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    When Inspire1 was released, 4 prop only was also my concern ,but on another hand ,you can fly octocopter and a single loos wire can bring it down.
    I thing bad motor will show the problem right away or gradually as the time goes . The motor or prop failure is far less than 1%.I managed land phantom 2 with 1/3 of prop missing due to bad judgement clipping a obstacle. Even the best technology is not 100 % reliable ( look one O-ring on space shuttle lead to a disaster.I am using small walkera Hoten X as a practice quad and with so much stress on so inexpensive motors and so many flights,only one had to be replaced.
     
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  5. skillet

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    Having had the same question about failure resulting in major expenses I still went ahead and ordered... Not a single person in any post could respond with what I would have liked to hear. You need to tell yourself that it is inevitable that you will incur damage at some point, and yes, it is going to be expensive repairs. First thought that keeps coming up is the gimbal and camera in their exposed state...
     
  6. Meta4

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    Driving your car with only 4 wheels gives you the same level of redundancy but you don't find many people worrying about that.
    Motor failure is extremely rare. And just because a hex has six motors, it doesn't mean it can shrug off a motor failure.
    The Walkera Tali 500 may have 6 motors but it has so many other problems. It's a lot better to have a good quad than a bad hex.
     
  7. The Editor

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    It's not the number of rotors on it's own that gives you redundancy but also the algorithms within the flight controller that is able to adjust in the event of a prop/motor/esc failure. The Naza has the logic to allow control (and hopefully a safe landing) in the event of ONE axis failure. Not all FC's have this feature/logic written into them.
    The situation with a quad is that if you lose a prop/motor or an esc goes out during flight you WILL CRASH! - Yes there are experiments with quads that allow them an element of controlled flight should a prop disappear but this is experimental and as yet does not exist in the commercially available world.

    This is one of the main reasons I built a Hex over a quad as well as designing a dual bus power distribution system into my craft so that even if I lose a battery or a a connector or solder joint goes down I still have full power (albeit with reduced mAh) applied to my electronics. Should I have a failure mid flight, I am able to tell via telemetry of a sudden drop in mAh capacity and then land quickly before anything nasty occurs :)
     
    #7 The Editor, Dec 18, 2014
    Last edited: Dec 18, 2014
  8. MrDrone

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    May I ask what Hex frame you used?
     
  9. ringolong

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    I was scared to get one too, but it has everything built in.

    I have a 680 for flights that are too risky with a quad. (Which is not many)
     
  10. lake_flyer

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    Exactly why I modded my P1 to use 2 batteries, mainly using it to fly over water. Not to get longer flight times. Battery power is really the only thing I worry about. Having regular hardware and software checks and doing the proper preflight checks every time, reduces the chance to hardware failure to practically zero. A battery failure however, can just happen to anyone, anytime. I'm very interested in the multi battery experiments for I1 from Damon Cooper for that matter.
     
  11. HanMan5000

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    I crashed my first inspire (minor crash, just a few feet above some grass) that ended up breaking two props.

    I replaced only one of the broken props (I guess I missed how badly the second propeller was damaged because of how shocked I was from the crash) and took off with 3 good props and 1 prop that was badly damaged (I'm talking like 40% of it was broken off).

    Remarkably, even with one severely damaged propeller, the Inspire 1 took off and stayed in the air. You could tell it had trouble balancing, but it stayed in the air until I landed it and realized there was another broken propeller.

    Anyway I replaced it and it flew like new again :).
     
  12. xahhax

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    They are so many things that can go wrong. I have other 1600 flights on electric single or multi rotors. Motors don't fail. But ESC do in my experience.
    And if ESC don't fail, something else will. I had an Hexa, one of the Cell of the lipo died in flight (a first for me), so the DJI flight controller dediced it was below voltage and landed the bird - which ended in a crash as it was quite far from me...
    Therefore I think an inspire is not fundamentally less reliable vs. a custom build hexa/octo where other things can go wrong and the cost difference is all for the inspire.
     
  13. CaptainBadge

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    How did you miss a prop missing 40% of the flight surface?
     
  14. lake_flyer

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    +1
    if there ever is a VERY good reason to check and double check, and go through the whole charade of pre flight checklists again, it is after a crash, ANY crash that is, no matter how light, a crash is a crash.

    The reason why there ALWAYS is a very good reason to run a pre flight check. A prop can also be damaged during transport or storage (bend in a blade for instance).
     
  15. KnightOwl

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    I have been a happy Inspire 1 owner since April but the issue of hexa / octo redundancy shouldn't be swept under the rug or diluted by other factors. IMHO the Inspire's reliability is excellent but in an apples to apples comparison six or more motors / props is better than four. These are complex systems and so many other components besides the motors can fail but that is true for all multirotors.

    I suggest that anyone contemplating this purchase to consider their level of risk aversion. I'm OK with flying an X3 equipped Inspire 1 and though the X5 has some serious improvements over the X3, I'm not comfortable putting that amount of money in the air on just four props. Also I'm just a hobbyist so the capabilities of the X5 are beyond me, but for a professional who is used to spending thousands on a camera they may not flinch at the cost of the X5. Also as a professional this equipment might be insured, so the risk of financial loss is minimized if the Inspire crashes.

    My question for any of professionals out there (or anyone else) that enjoys the RTF convenience of the Inspire 1 + X5, is what thought / impressions do you have on the Yuneec Tornado with GGO4 (basically an integrated MFT Panasonic GH4)?

    KnightOwl
     
  16. Robgunbuilder

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    I had a ESC failure on a Tarot 960 hexacopter while flying a about 60 ft. Altitude and maybe 50 feet away. Cause was a broken solder connection ( invisibly held by shrink wrap on the esc power cables). Bird powered up and took off stable as a rock for 1 minute . Then the ESC failed. The DJI A2 flight controller was UNABLE to control the bird with 5 rotors still running fine. It went in, in a flash and I'm an extremely experienced helicopter and multirotor pilot. I could not stabilize it at all.
    Perhaps a octacopter could stay up with one motor down but 99.99% of you are going to crash with a single motor failure on anything less. Luckily this is an extremely rare occurance but I'm not drinking the cool aid that a hex will save anything in a single motor failure. As they say @&$$&@ happens!
     
  17. ringolong

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    What sw version were you running on your A2 when this happened? I have never tested mine to see if it would fly on a motor or esc loss, but I have seen videos that shows it flies well enough for a safe landing when one of the motors comes completely unattached from the arm severing the powering cables so it was not spinning and just dangling around.

    What was the cause of the broken solder?