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P2 vs. S900 / A2 Reliability and Stability

Discussion in 'Other DJI Multi-Rotors' started by ianwood, Sep 20, 2014.

  1. ianwood

    ianwood Taco Wrangler
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    I am considering an S900 / A2 / GH4 but I have concerns about the A2's reliability and stability. I am curious to hear the experiences of P2 users who now have an S900 / A2.

    The P2 has some reliability issues with batteries and we had the horribly annoying compass declination J hook which is now thankfully fixed. Losing a P2 to a duff battery would be bad enough, but losing an S900 would be intolerable. I want to be 99.99% certain it's going to stay in controlled flight.

    I am also curious to know if the A2 auto-declinates. Do you rotate the puck? And if so, does it fly arrow straight in high-declination areas or does it hook? Anyone have some GPS plots of an A2 in a high declination area (+/- 12 or higher). With that much money in the air, it had better be rock steady and straight as an arrow!

    I also read about the GPS dropouts and I am curious to know what may be the cause. They could be isolated one offs (bad hardware, install issue) or it could be a common hardware GPS reset causing a cold start. GPS issues would be a deal breaker even if infrequent.

    And why is the A2 banned by the CAA? Ignorance or is there something to it?
     
  2. OI Photography

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    I'd like to hear the same feedback, mainly in regards to the stability/GPS issues. Declination isn't an issue where I usually fly (thank goodness) but I do want to know more about why the CAA and others have issues with the A2.
     
  3. gilmbento

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  5. rilot

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    The A2 isn't banned by the CAA. They are investigating anecdotal evidence of a high failure rate. No action has been taken yet that I'm aware of.
    As far as stability is concerned, my A2 is so locked in on GPS it's unreal. I'm not in a high declination area but if you are, rotate the puck to correct it. This is the official way to sort it out.

    My A2 has been faultless for 100s of flights now. I think a lot of the issues stem from the use of the internal receiver in the A2. I use FrSky Taranis with a receiver connected via S-Bus.
    There were issues with some dodgy GPS pucks but they seem to have all been solved now.

    At the end of the day, if you define the Phantom as "not a toy" then the S900 and A2 is even less of a toy. It's a serious bit of kit and needs to be treated with respect due to the weight and potential for injury.
     
  6. ianwood

    ianwood Taco Wrangler
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    I feel like I've been a beta tester on the P2 dealing with it's idiosyncrasies and defects. If I am going to put several thousand dollars in the air with the S900, idiosyncrasies and defects will not be tolerated.

    So far, my concerns are:

    - Must fly arrow straight anywhere in the world. Rotating the puck is only semi-effective. It should auto-declinate.
    - Reports of A2 GPS warm or cold starts.
    - Gimbal clearance issues.
    - Electrical connectors, durability.
     
  7. rilot

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    Unfortunately, the market is still essentially a hobby market. Things need work and maintenance and work arounds. Even top end copterworx stuff isn't infallible.

    Declination issue:
    It sounds like you should put your money in to something else if you don't like the puck rotation thing. If you're looking to fly pro you won't be flying in GPS mode anyway as you will want as smooth a flight as possible. I only flick to GPS when I need to take my hands off the controls or I want the craft to hover against the wind. For flight I'm always in ATTI.

    Cold starts:
    It's not something I've seen on my own craft.

    Electrical connector durability:
    The antispark connectors on the S900 and S1000 are rubbish. Saying that, most anti spark connectors are junk anyway. The guys I know who are flying S900s and S1000s are using a Y cable with the XT150 on the end that interfaces with the craft, and XT60s on the battery ends. This elimiates the issue of the XT150 soft start messing with the A2. XT60s are fine by the way. My S800 EVO draws about 40A at hover.

    Have you considered a Wookong? They are tried and true and relied upon by many professionals. Yes, they aren't as dialled in as the A2 and you forego some niceties such as intelligent gear retracts, but they are a very well known and understood quantity.

    I will say this though, if you find the P2 tiresome with it's idiosyncrasies then maybe you're in the wrong hobby. These aren't toys and are more akin to racing cars than a family sedan, in that things break and require tuning, time and a lot of effort to get working perfectly.
     
  8. ianwood

    ianwood Taco Wrangler
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    I would consider the WKM if it weren't for the two S900 uncontrolled drops I read about on rcgroups.com. One resulted in an expensive crash, the other recovered before impact. This could be down to older IMUs and incorrect adhesives but I want to see more conclusive results of WKMs flying fully loaded S900s before I'd consider it.

    As for flying style, I am actually doing a lot in GPS mode lately. I used to use ATTI but I've found that unless the wind is blowing from a suitable direction, I end up correcting for it too often. ATTI is great at sunrise when there's almost no wind otherwise I shoot in GPS. With the right gains, GPS gives me a pretty smooth ride. That and declination issues will impact ATTI and IOC flight as well.

    I guess for the A2, I would like to see it an order of magnitude more reliable than the Naza but it seems to be the same thing just with more features. It's not very reassuring considering how much money I am considering putting on on the table.

    Are there non DJI FCs that are better and more reliable?
     
  9. rilot

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    I think it's the same with anything. If you read enough you will get the impression that every product is unreliable. No system is infallible.
    I can only speak from my experience, and that is that the A2 has been faultless.

    If you don't mind moving away from DJI then the XAircraft SuperX is extremely reliable by all accounts.