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Ride the Wind: Practise in ATTI Mode!

Discussion in 'Phantom 2 Vision Discussion' started by rotordan, Mar 1, 2014.

  1. rotordan

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    This is about sharing my personal experience and not about beliefs or religion. Other related experiences welcome!

    I find that flying in ATTI mode in windy conditions both improves my flying and makes for great stable footage. The GPS mode is a great tool and I do not want to miss it at all. Being cogniscant of what it does for me makes me a better pilot. With GPS mode it is just too easy to totally forget about the wind and I consider that a bad habit for anyone flying anything in the air.

    After I had flown about 15 hours I decided to take the plunge and change my P2V to NAZA mode. This is described in the manual and in other posts. It can be un-done just as easily as it is done. I have configured it such that the S1 switch 'down'' means 'Failsafe'. I do not intend to set that to 'Manual', ever. I did not buy my P2V to do aerobatics. I use a simulator for that. But I digress.

    The advantages of flying in NAZA mode for me are:
    * Ability to instantly switch between ATTI mode and GPS mode
    * Better LED feed-back about GPS reception during start-up
    * Ability to switch on 'Failsafe' without switching off the transmitter
    * Ablitiy to instantly and positively switch out of 'Failsafe' at any time
    * IOS Home Lock Mode for recovering 'lost sight' manually without the aid of down-link
    * Much more stable footage in high wind conditions in ATTI mode

    Flying in NAZA GPS mode is just as flying in P2 mode with green LEDs. There is no difference. Just make sure your S1 switch is all the way up. I make that part of my periodic 'scan' of things. It becomes a habit, just like flicking it up when things look wrong.

    Here is what I did before changing that switch to ATTI for the first time: I went to a very very open field under a blue sky with about 10 knots of surface wind. Something like this where I practised yesterday:

    It is important to check the weather and pick the right time. Note the front approaching on the right. It was blue skies with ~12knots wind when I practised. An hour later it was no-fly with rain and high gusty winds. Also notice the nice straight line features of the terrain, great for practising precise control.

    I took off in GPS mode with 10 sats, did my usual figure 8 and hover close-by to confirm GPS stability. Then I took it up to about 100ft and flew up-wind from my position and let it hover. Then I switched to ATTI and watched it drift without any control inputs. Of course the wind was stronger up there and it took up quite some speed, much more than I had expected. I let it drift a short way down-wind from me and switched back to GPS. It stopped and hovered almost immediately. After repeating this a few times at different altitudes and noticing the wind shift I started to fly it in ATTI mode. I brought it in close to be 100% sure about its orientation and first tried to return it to my position. Depending on the gustiness of the wind it can be tough. Whenever I got uncomfortable I switched back to GPS and re-positioned up-wind again. Gradually I improved my skills and I will continue to practise for a long time to come.

    Besides the better footage I get when it is windy this practice gives me confidence that I can handle a situation where GPS suddenly becomes unreliable or some other bias appears. I feel that it changes my instinctive reaction to something unusual from freezing and likely releasing the sticks to actively flying the aircraft against the bias. I consider this a good habit. Hopefully it will give me enough skill to recover from the infamous 'fly-away' if and when. Staying in the GPS comfort zone will very likely not prepare me.

    This is my experience. Your's may vary.
     

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  2. Mossie

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    I agree. I'm a rookie but I can't see myself going back to Vision mode. You have so many more options in NAZA and yet with the S1 switch up ,it's just like Vision mode any way.

    Home lock saved me the other day when I let it get too far away and I lost orientation with lost wifi signal. Also part of my initial check is to let the copter fly about 30 mtrs away and then S1 switch full down to initiate fail safe and check it flies back to its home position.

    The LEDs are more logical when you realise that there's TWO sets of flashes, the first relating to the position of the S1 Switch.

    The only thing you've got to watch and which nearly had my copter flying into some trees is, if you are flying in ATT and you take your hands off the sticks when it is moving ...IT WILL KEEP GOING !
     
  3. Pull_Up

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    Great post, rotordan, and I heartily approve of this bit:

    You have obviously got a good handle on aircraft control, pre-flight and post-take-off checks and flight manoeuvres, and assessing and keeping orientation at a distance (and nice to see someone else who enjoys a bit of met ;) ). That is great time to have a look at NAZA mode, because the actual flying bit, and the knowing what your aircraft is doing bit, is now almost second nature.

    Mossie, all I'll say is in your Home Lock save, what would you have done if your sats had dropped to 5 (been a lot of solar activity lately, for example) and Home Lock wasn't available? It's why I always just caution people a little not to lean on HL too much at the expense of the mk 1 eyeball, but try to always know your orientation so that in the absence of any of the extra features, for whatever reason, you've got a plan B.

    Having said all that once you feel you're ready and have switched it very quickly becomes second nature, and I enjoy the level horizons that atti mode brings to pics and vids (and will continue to do so until my gimbal arrives ;) )
     
  4. pawnmeister

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    +1 Great post.
     
  5. Mossie

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    Yeah I know, if I'd lost satellite cover I would have been up 'Shxt Creek without a paddle ' !!

    Just one thing for the experts. I've had a couple of tip overs on landing due to being not positive enough with the power. Both times luckily it has been in soft ground but two of the props have jammed in the grass and stopped rotating whilst the other two have continued rotating until I could power off. I presume the motors are sturdy enough to cope with that sort of thing ??

    Sorry Rotordan for hijacking your post !!
     
  6. pault

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    Hi Mossie :)
    I do not qualify as an expert as I have only had my P2V for 6 weeks but in my early days I had the exact same issue as you (tipping over on landing)
    Imo, it is worth practicing hand landing - I do this all the time now and it really is so easy. Just park it in the air in front of you and walk forward and grab one of its landing struts. The other point is how you stop the motors. At first I used the same technique as starting (sticks in and down - there is a word for this but have forgotten :)). This also caused a tip over so I now just pull vertically down on the left stick.
    I cannot comment on your question regarding the motors but I should imagine it certainly does not do them any good. It is not only the motors to be concerned about, it may also damage the ESCs.
     
  7. Bigbells

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    Excellent topic. I hadn't really given any thought to practicing in ATTI mode, but now I will. I also hadn't realized there could be any benefit other than being a better pilot. Steadier videos is a good thing.

    After too many rotor strikes on the ground caused by tip-overs following perfectly good landings, I have gone to "hand landing" most of the time. I also use the "left stick straight down first" method mentioned by pault to stop the motors, because it seems impossible to use the "corners" method without having a momentary power surge that may cause the quad to tip if there's any wind at all. With solo hand landings there aren't enough appendages available to move both sticks to a corner anyway. Since I usually fly without a co-pilot, I can do hand landings but not hand take-offs. On take-offs from ground level, I give it full throttle quickly to make sure there's not a tip-over.
     
  8. pault

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    The other advantage to hand landing is that you need not have any concerns over how flat the ground is. For take off you only need a tiny patch of flat ground or even use your flight case or bit of cardboard etc. The field I use to practice has no flat ground - it is all covered by low growing vegetation so I just couldn't fly there if I had to land on the ground.
     
  9. Pull_Up

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    Also good if the surface is dusty - there's lots of holes in that camera unit and a cooling fan. I takeoff from the case and hand land when it's windy or when the surface is rough, muddy, wet or dusty. Sorry, off topic! :)
     
  10. Mossie

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    Just flown it again and it seems fine, BTW what are the ESCs ?

    Regarding switching to ATT, I have just done a really crap video showing mine 'riding the wind'. Don't laugh it's my first YouTube video and first attempt at editing !

    http://m.youtube.com/watch?feature=em-u ... 9MUBE4r0G4
     
  11. pault

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  12. pault

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    And it looks really cool - always gets the attention of passer bys who cannot believe the P2V just hovers on its own !
     
  13. nhoover

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    Nice post - my experience is pretty much the same. Flew about 15 hours, then enabled NAZA mode wo/manual. I started trying out ATTI mode and loved the footage. When I was doing some speed runs (trying to hit 50mph for the Flytrex challenge), I realized I could use ATTI mode to measure the wind speed at altitude - that works perfectly. Then it turns out she flies so much faster that way! My first couple of runs were at 57-59mph and that was only in 7-8mph of wind. Seems like almost 10mph faster than GPS mode. Although at full speed it is not actually able to hold altitude, so make sure you start at say 2-300' or whatever if you're trying this. I also like how it performs turning etc with ATTI mode. The more I use the more advanced features of NAZA the more I am impressed with it. HL and CL work perfectly for me and are very useful.
     
  14. rotordan

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    no probs about 'hijacking' thread.

    hand landing: we do little else these days. when doing it solo, i catch with the right hand and pull the left stick fully down with the left hand until the motors stop. the right stick is not needed to stop the motors. works for me as i am right handed. my son is left handed and he can do it too. it is important to keep the rotors well above one's head and clear of bystanders. i make contact with my arm stretched uwards from almost under the skids. i also observe hovering for a couple of seconds to detect possible downdrafts. we always do it well clear of structures and obatacles.

    -----

    about when to start flying in ATTI mode: this is a claasic dilemma. as long as the support technology works there is no incentive. to the contrary: practising without the support introduces significant additional risks. on the other hand the consequrnces of the support failing on you when you are unprepared are significant. so it is an individual trade off mainly determined by your assessment of:

    * the risk posed by training without support, e.g. your skill level, the environment, any help you may have
    * the risk posed by failing support, e.g. likelihood of it happening, the consequences of it
    * your asessment of how the training mitigates the above risk

    without any well quantified experience on a large fleet this comes down to personal judgement. the point of my post was to relate my experience with training and to encourage people to reflect and make their own judgements. of course i have not been able to be 100% neutral when describing my own conclusions and expeience.

    and all this neglects the fun factor of learning something new and the satisfaction of feeling a better pilot. ;-)

    -----

    using support, e.g. home lock: when i am in trouble i use all the support i can get. period. i agree with pullup that we should give serious consideration to the risk of the support failing and have a plan b. i never fly out of visual range intentionally. but it has happened to me a number of times unintentionally. most prominent cause is to take my eyes from the aircraft for whatever reason. re-spotting it at a distance is hard! I also had unexpected but foreseeable changes in the background clouds make me loose it, the sun suddenly breaking through a solid cloud layer was a memorable one.

    i mitigate the risk of failing GPS support by limiting range and altitude according to the number of sattelites available. in essence i do not fly far away unless i have 9 sats, 10 or more makes me very comfortable. i bring it back closer when the downlink tells me the number of sats is 8 or less. so far this happened exactly once, when i started out with 9 in a spot that was bordered with high rises. i will try to gain altitude to re-aquite satellites. most of the time this works. but it makes me very cautious.

    i would very much like to see a precision estimate (hdop) even if it means dropping the sat count. also an audible warning for this would be useful. does anyone have experience with effectively getting feedback to dji?

    enough typing on the tablet ....

    my experiences (and some opinions), yours may vary
     
  15. Mossie

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    I flew mine today for the first time from my back garden. Previously when in the middle of a field I would get 10/11 sats and it was rock steady in the hover, even in strong winds. Today in the back garden with only 6/7 sats, it was definitely 'hunting' in the hover and landing was definitely a lot trickier. I think if I do it again from the back garden it's going to have to be a hand landing.
     
  16. coloradosky

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    Great post Rotordan. Great disclaimer also- sometimes the feedback is a little rough!

    Thanks for the post. :)
     
  17. Bigbells

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    I've been practicing Atti mode, due mainly to reading this thread. It's challenging, fun, and I feel like I'm learning something.

    It is nice to know that GPS mode is just a flick of the S1 switch away. I'd have had a heck of time landing today without GPS due to the very lively winds. My practice included a good 5 minutes just doing my best to hold position, which is pretty tricky with the gusting winds, and requires quick reaction and good anticipation or else the quad is suddenly 75 feet away from the point where I'm trying to hold it.

    I'm looking forward to a calm day so that I can try manual mode.
     
  18. havasuphoto

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    Here's something else you should know about the difference between GPS mode and Attitude mode; GPS mode limits the maximum forward/rearward tilt to 25 degree's. This tilt, while maintaining altitude, with no wind, yields around 12m/sec speed.

    In Attitude mode-it does just that, it maintains the attitude you set. Not Altitude. Also, the tilt limit now becomes 35 degree's. This increase in tilt will yield speeds upwards of around 15m/sec-again, without wind.

    I know this because I have FPV and iOSD-so I can watch the number of degree's nose down, and see the difference when I change from GPS to atti mode.
    I use the "drift technique" for filming. I start upwind, tilt the camera, and get an idea of what I'm going to shoot. Then I flip Attitude mode, and Home Lock....I can then yaw the aircraft towards the subject, while holding back stick-just a little, and let the wind carry the aircraft back. IOC still works in Attitude mode. So, if you learn the combination of flying in attitude mode, using the wind to your advantage, and IOC(either course lock or home lock)...there's very little you need to do to film. The less you touch the aircraft, the less movement will be in your footage.

    Now while describing it, and reading it sounds easy-it isn't. It takes a lot of practice, and it only practical for certain types of shooting situations.
    But, take the time to learn the handling and flying characteristics of your aircraft in both modes,and with both IOC modes.

    Also, lean how Fail Safe works. That works beautifully smooth, if you subject is between you and the aircraft. But, realize in FS mode, you won't be able to tilt the Zen gimbal-so frame everything first, set your flight return path, flip fail safe-and just watch the aircraft fly back on it's own-while filming. It's an auto-pilot, and it fly's very smoothly.
    One more thing-the max speed in fail safe that I've seen, is around 10m/sec. It's not fast. So, if you hit fail safe, and you have a strong wind, the aircraft may not return all the way, before the battery runs out.

    For real long distance situations-get the shot, then hit Atti mode, and Home Lock, pull full back on the stick, and maintain altitude with throttle-you should hit around 20m/sec!!! We call that the "back turbo".