great machine!! isolator question

Discussion in 'ALTA' started by Rolf Ableiter, Sep 25, 2015.

  1. Rolf Ableiter

    Rolf Ableiter Active Member

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    Hi,

    since yesterday i am a proud owner of the ALTA and flew it today with great success :)

    i don''t have any height dropping issues - the ALTA is flying like a jib in the air. Great work freefly!!!! This really is a great working machine!!
    Everything works fine and together with the aero landing kit the M10 is much more stable.
    I didn't change anything and used the default settings for my first flights (2 packs = 40 minutes, wow!!)

    freefly forgot all the parts in my package (wich isn't a big deal and they send it in a second package) and so i have used only the green isolators wich are build in. I don't have the others yet...
    my test camera: lumix GH4 with 1235 panasonic on a M10 with aero landing gear, perfect balanced. nothing more.
    With my cinestar i used the blue O-Rings and didn't have any vibrations. Now i have them. Especially when flying down.
    i autotuned the M10 with the ALTA hanging on a stand (as i always do this).

    what isolators are good for this setup?

    i will post a video of the vibrations (test footage)
     
  2. Rolf Ableiter

    Rolf Ableiter Active Member

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    test footage:



    i didn't see such vibrations since years... :)
    do you think i have to change any setting or is it just the wrong isolator? The ALTA is flying very smooth and i don't think that this is a result of any wrong gain parameter... (all default - i didn't change any setting)
     
  3. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Looks like you need to go stiffer! It appears the entire gimbal assembly is bouncing around.

    Josh
     
  4. Rolf Ableiter

    Rolf Ableiter Active Member

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    or less... i think, the setup is to light for the green isolators...
    it would be nice to hear what others use with the same camera. my problem is: time... i hope freefly sent me the parts as fast as possible...
     
  5. Mateusz Hajdziony

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    You should probably play around with Gyro Filter and Output Filter values on the Movi. If you can see the vibrations on your video feed from the camera you can put the ALTA in position hold mode and play with the parameters on the Movi and watch the results immediately. For lighter payloads (like GH4 with light glass) you should probably go lower with both filters, probably to something around 3.

    Changing vibration isolators should help in my opinion, it looks like you are getting some vibrations from the aircraft and that's what's causing your Movi to vibrate. Maybe even the Movi itself is dancing around on vibration isolators.

    Anyway, keep us posted if you manage to calm down the vibrations when you get the new isolators from Freefly!
     
  6. Rolf Ableiter

    Rolf Ableiter Active Member

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    the output filter and gyro filter are lowered (by 3 for gyro and 4 for output) and the M10 worked perfect with the cinestar 8 and blue o-rings. The MoVI stabilizes better with the ALTA (i think because of the controlled downwash of the Props and the new landing gear) but i get these vibrations.
    may this setting is way to light for the ALTA (M10 is only 2,1 kg with batterie and gear, camera 0,9 kg = 3kg payload for the ALTA) but the flight times are amazing (20 min +).

    my problem is, that i am located in Germany and my first job planned with the ALTA is september 30th...
    Everything is working great, i flew many times with it and feel comfortable with it. i soldered all my batteries to EC5, etc...
    i think freefly sent the forgotten parts but i am sure they didn't do this with express...

    i have many of these blue and red o-rings used for the cinestar
    may i take a closer look at the isolators and change the o-rings by myself (if they are not glued)

    i need a solution... timing was perfect if all the parts would have been delivered :)
     
  7. Steve Maller

    Steve Maller UAV Grief Counselor

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    Maybe you could add some weight to your MōVI?
     
  8. Rolf Ableiter

    Rolf Ableiter Active Member

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    i played a bit and i found out a mistake i made while tuning the MoVI:

    i hanged the ALTA on a stand but i used the handle to hang it and this will eleminate the function of the isolators.

    i changed this and will try a next flight tomorrow.

    BUT:

    when the MoVI is in it's "airborne" majestic mode the batterie plate vibrates like hell... normal?

    i now have a gyro filter of 2 and an output filter of 3.
    autotuned with 50% i'll get stiffness gains wich are quite normal for that light setup (about 10 for tilt, 40 for roll and 75 for pan).

    i really hope to get the isolators in time... there is no way to change the o-rings as in the older ones from the cinestar.

    adding weight could be a solution but this will cost flight time. But if the new setting won't change the behaviour i will try this too...

    what makes me a bit confused: with my cinestar i never had these vibrations and used them from early 2012...
    i changed to the MoVI with no changing at all (blue o-rings). crazy...
     
  9. Aj White

    Aj White Member

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    What batteries are you running? I'm running a close AUW of 22lbs and only getting ~9mins.
    I guess elevation and temp really make a difference.
     
  10. Rolf Ableiter

    Rolf Ableiter Active Member

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  11. Aj White

    Aj White Member

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    I am actually using the black ones... seems to give me the best results. I hope I get your flight times when I get back down to sea level!
     
  12. Rolf Ableiter

    Rolf Ableiter Active Member

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    yesterday i flew 15 minutes in hard wind with 20Ah (2 x 10Ah) tattuu batteries wich resulted in 3,8V/cell.
    i am here about 200m (650ft) above sealevel with 15 degress Celsius.

    9 minutes is very short... where are you located?
     
  13. Pete Maughan

    Pete Maughan Member

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    I've had poor footage using Panasonic zooms with lots of vibes even with their stabilisation off. Try a prime.

    Pete
     
  14. Aj White

    Aj White Member

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    I actually did some testing today and I think I'm just landing way too soon. I tend to be very safe with my batteries but with the voltage sag I was getting in the cold weather I ended up with batteries still at 50% at 9mins. I could have flown longer. What do people normally do with voltage sag?
     
  15. Howard Dapp

    Howard Dapp Active Member

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    AJ i'd keep doing what you're doing! 50% @ 9 mins is healthy and more than enough time to capture multiple takes plus you're not beating up your lipos in the long run.
     
  16. Rolf Ableiter

    Rolf Ableiter Active Member

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    the % ratings made with a lipo tester are just guesswork of the tester.
    if i fly my lipos to 3,7V-3,8/cell i am at 15 minutes with my payload and two 10A batteries. freefly set their warnings at 3.5V/cell wich is pretty low but okay (not the best thing for the lipos but okay).
    i flew 19 minutes and still had 3,7V/cell so now i set my timer to 15 minutes wich is more than safe.
    Just take care of loading them with 1C charging rate.
    i have 8 10A batteries wich results in 1 hour flighttime - the same i had with my cinestar and 12 5s 10A batteries. perfect!

    btt: with black isolators and 12-35 panasonic i have GREAT results. i flew with 25mm (50mm FF) and have superstable clips!!
    ALTA and MoVi work now together as a dream team!
    Good work, freefly!
     
  17. Steve Maller

    Steve Maller UAV Grief Counselor

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    First of all, it's important to understand the relationship between current and voltage. Your 6S batteries contain 6 "cells" that, when fully-charged, will output 4.2V. Depending on the battery you're using, you also want the battery to output anywhere from 30 amps to 60 amps. That's where it gets tricky. The "mAh" rating on a battery indicates how many amps it can output for one hour. But the 'C' rating is a multiplier for that figure, so a 10C 10000mAh battery can theoretically output 100A (10x10). But in order to do that, the voltage generally sags well below 4.2V. What's the "critical" point for voltage? That depends on who you talk do, but most people don't like to run their LiPo batteries below 3.4-3.5V. I've run mine down to 3.2V and seen no adverse issues.

    Now the "percentage" figure you're seeing is something of a misnomer. The best indication of LiPo consumption in my experience is when you recharge your battery. If you have a reasonably intelligent charger, you can see the number of mAh that is put back into the battery. It's good to watch the relationship between the voltage you see in the air under load and the amount of "juice" that's put back in when you recharge it. If your battery is getting close to 3.3V per cell under stress but the charger's only replacing 50% of the rated mAh of your battery, you have a substandard battery. I use Tattu batteries, and they are very robust in my experience. I've run some of them down to the point where I put back over 90% of their rated capacity, even though their voltage stayed comfortably above my critical threshold.

    So there...I'm glad I got that off my chest. Now what was the question again? :rolleyes:
     
  18. Aj White

    Aj White Member

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    Awesome, thanks Steve. Yeah I am flying all Freefly LiPos and I tend to land when I'm down around 22.2v displayed on telemetry. However I notice after landing in about 30 seconds telemetry is back up to 22.8-23v. I notice this is worse in cold weather.

    I think I can afford to get a little more flight time out of them... what number do you tend to land at?
     
  19. Steve Maller

    Steve Maller UAV Grief Counselor

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    It's expected that the voltage will sag a bit (or a lot) under stress, and that the voltage will recover a bit (as much as 1-2V total) after landing under no load.

    I generally fly down to 22V if I'm not too far away, and make sure I'm on the ground before they hit 21V. But under some situations I'll fly them a little lower. 20.5V is not uncommon. But that's the absolute limit. Any farther than that and I'd be very nervous.

    But all this assumes high-quality, healthy batteries.
     
  20. Rolf Ableiter

    Rolf Ableiter Active Member

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    i still have vertical vibrations :( thought they are gone but still i have them.
    I used the GH4 with tokina 11-16 and speedbooster on a M10. Nothing more.
    my ALTA settings are default and i use the black isolators (i also had the vibrations with teal and red isolators...).
    what should i change? the M10 worked great with the cinestar 8 and blue isolators.
    the only parameter i found usefull to try is "vertical stiffness"?

    the gimbal and camera are well balanced and i tuned it while hanging under the ALTA.

    someone out there flying an ALTA with GH4? (with M10 would be great)
    can anyone tell for what payload (Kg) the default setting are good for?

    thank you!
     

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