Things you did not know about the Radian

Discussion in 'Radian' started by Tabb Firchau, Sep 26, 2012.

  1. Ramesh Tahlan

    Ramesh Tahlan Member

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    Andy
    here is the link to the first of two videos i took yesterday...
    this one had 4 Cinestar dampers on a Hex. and dampers between cam mount and cam
    http://youtu.be/Zl4MZUty6CQ
    Ramesh
     
  2. Mario de Roos

    Mario de Roos Member

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    Ramesh,

    I have a few pieces of magnetic balansers tried out and NON of them was consistent, the props that I balansed on them came out worse than before the balancing.

    Try this,
    balans a prop and then turn the locking cone from the magnetic balanser on other positions on the prop hub and look at the results.

    Mario
     
  3. Ramesh Tahlan

    Ramesh Tahlan Member

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    Mario
    thanks for that input..
    time to change my prop balancer
    ramesh
     
  4. Ramesh Tahlan

    Ramesh Tahlan Member

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    Andy
    this is the second video of yesterday
    it has been taken with only the CineStar 4 dampers
    http://youtu.be/bHP9m2AkJGM
    i removed the dampers from between the cam and cam mount
    so it does look like the dampers between cam and cam mount were really not required
    But still cant figure out the shaking.
    And at least with the CineStar damper there is no jelloing effect.
    But is it really possible to get a smoother video from the mcopter.
    Ramesh
     
  5. Ramesh Tahlan

    Ramesh Tahlan Member

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    ok guys
    totally forgot..
    my apologies
    my experiment with Futaba S Bus worked perfect to control Wookong M and Radians
    i am using the 8FG S bus
    this is the channel assignment and connections for Single pilot operation
    i put a S bus hub into Rx S bus port
    then took one output to Wooking M S bus port
    and the other line to first radian pin 1
    ch1 to 4 to fly multicopter
    ch 5 - IOC - switch SB
    ch 6 - Fail Safe - switch SF
    ch 7 - WKM Mode - switch SE
    ch 8
    ch 9 - Radian Mode - Switch SG
    ch 10 - Radian Tilt - Dial RD
    ch 11 - Radian Click - switch SD
    NOW. for two pilot operation, for the time being , till i lay my hands on Spectrum DX18
    on my JR 11 radio, this is what i plan to do
    ch 9 - Radian Mode - 3 way sw assigned
    ch 10 - Radian tilt - trim lever
    Ch 11 - Radian click - 3 way switch
    ONCE i get the Spectrum DX18, i have the option to assign control sticks of Aileron and Elevator to any channel
    SO
    on the Futaba i will assign ch 12 to Pan
    AND
    now on DX 18 i will use the same ch of 9 to 12 that r on Futaba on DX 18
    only now i can assign ch 10 Tilt to elevator stick
    and ch 12 which is Pan to aileron stick
    so the Radian channels will match on Futaba and DX 18 and there will be no conflict
    On 27th a friend of mine is getting a DX18, so will have a look at channel hardware reasignment options
    and then order a DX18 for the second pilot,
    How does that sound
    Ramesh
     
  6. Ramesh Tahlan

    Ramesh Tahlan Member

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    Andy
    just one doubt
    all my motors r mounted vertically upwards
    does it help if they r inclined inwards slights
    OR
    if the clockwise motors r inclined one way
    and the anticlock motors r inclined the other way.
    does this help in better stability of Multicopter or only for yaw purpose. cause i really dont need any more yaw power that what i am getting
    Ramesh
     
  7. Mario de Roos

    Mario de Roos Member

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    I can borrow a MK USB programer from a friend, is it possible to use this for programing the Radian's? and how do I do this?

    Mario
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Keep us posted, please, Mario.
    I wish there was a way to do a loopback test with the Radian USB Adapter in circuit so that we could easily eliminate the data path from the Radian software out to the connector that plugs into the Radians --- then we could exonerate that whole data path.

    Andy.
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Ramesh:
    It seems to me that you're doing all the right things to figure out the cause. I wish there was something more that I could suggest -- it's the classic problem of tele-diagnosis -- namely that Brad, Gary, and I can only see, hear, and know a limited amount of data about the problem. The other barrier we face is that you're using a custom set up and so you're operating out of the envelope of our experience, I'm afraid.

    Right now my concerns are that the booms themselves might be flexing and turning the copter into more of a tuning fork than it should be.
    I would be tempted to strap the iPhone to the hub, set Vibrations up for a long sample, and then hover just above ground effect and hope that you can see the "shiver" happen and capture data about it's frequencies. I seem to recall that Vibrations allows you to do a Fourier transform so you can see what frequency components are present. I suspect you're talking about a frequency down around 3-7 Hz -- which, when you know that the motors are spinning orders of magnitudes faster than that has to tell you something about the beat frequency.

    I wish there was more that we (and I mean Brad, Gary and I) could do to help, but...

    Andy.
     
  10. Gary Haynes

    Gary Haynes Administrator
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    Ramesh looking at the videos and your posts about the motors here are my thoughts. If the motors without props are well balanced you should almost have flat lines on all three of the graphing axis. I don't have any motors with the amount of vibration that you are showing in your pics. All of the XY's look pretty good but not the Z axis.

    And I have found that using a single small piece of tape the size you have, i mount it to the motor, test and then move it a tape width counter clockwise, test and repeat all the way around the motor until I find a spot that is near perfect. Then I test moving the tape a 1/2 width either side of that spot. Some of the other approaches, like using a wire tie to me doesn't make sense. To much overall weight. We are talking about single digit grams of weight to get it in balance. If that doesn't do it then the motors are probably inferior since it shouldn't take that much to balance a good motor. My last batch of 9 motors only two needed to be balanced. And a single piece of tape did the trick.

    After all of the balancing of motors and props that leaves the overall frame and gimbal. Checking vibration on the bench will give a totally different result from actual flight since you don't have any flight loading on the copter.

    Looking at your last two videos and assuming that your props and motors were balanced then that leaves the frame/gimbal. Since it isn't a CineStar frame perhaps the frame and arms are flexing leading to overall vibrations that no amount of gimbal vibration dampers or balancing will be able to handle.
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Gary: I share your observations about the Z axis. If I'm understanding the data correctly, that would be vibration parallel to the prop shaft and without the props on that's likely to be a function of the quality of the motors and their bearings, I suspect.

    Andy.
     
  12. Ramesh Tahlan

    Ramesh Tahlan Member

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    Andy and Gary
    thanks a ton for that discussion
    i am beginning to understand what u guys r says.
    As regards the Z axis vibration, i did wonder why it was highest in all the motors, cause it is the vertical axis along the motor shaft ...
    so it could be the quality for sure, and so the bearing becomes suspect
    The reason why i used the square arms, was cause i need it to fold without removing the arms totally, so i can send in into check-in baggage while travelling by air.. other wise i will have to send it a day in advance by cargo,
    with the round tube arms.. there would be too much of dismantelling and then assembling at the other end
    or would need a read big box to carry it safely
    and cargo handling here is bad
    they will even destroy a steel box hahahaha
    so looks like i have fresh problems on my hand to solve
    And i think i will do that balancing thing once more... i was moving the tape 90 deg at a time around the circumference each time.
    i think will do it 45 deg at a time.
    And next flight will be with the iphone strapped onto the machine to see the shiver
    the max acquisition time on the i phone is 52 sec
    so looks like i will have to land every minute and start again
    is there any way to make it 2 to 3 minutes
    And i really appreciate all the help.
    this distance learning is difficult, and even more diff to solve problems...but in its own way it is helping a lot in some way.
    oh,, any idea,, is there a folding Hex or Octa which has round arms
    or i could make the square arms i have that r 15x15 mm to 20x20 or even 25x25
    looks like still loads of experiments lines up ahead

    Ramesh
     
  13. Ramesh Tahlan

    Ramesh Tahlan Member

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    Andy
    i may just have found the problem
    my arms go into the central body only by 40 mm
    and this may be the cause
    they should go in all the way in which would not be about 80mm
    and this would give the central structure more rigidity and more strength.
    and then less flexing
    cause in my hand i can see flexing and it should not be there.
    the image shows how little the arms go into the central body
    so work started on making the arms long enough to right inside all the way.
    Hopefully tomorrow i should have good news... i guess

    Ramesh
     

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  14. Gary Haynes

    Gary Haynes Administrator
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    Ramesh is the hub made of standard fibreglass sheeting? If so I think you will find that there is to much flexibility in fibreglass. That's why you see so many copters where the bodies, arms, etc are made from carbon fibre. Stiffness and weight.
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    As Gary says, Ramesh, the rigidity of the hub/boom assembly is critical -- otherwise you have created a flying tuning fork that will vibrate like crazy at certain resonant frequencies.

    Andy.
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Sorry for the delay in responding to this, but the answer is that the MK USB Adapter will not work correctly with the Radians.

    Thanks
    Andy.
     
  17. Ramesh Tahlan

    Ramesh Tahlan Member

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    Andy and Gary
    u guys hit the nail on the head
    i am now cutting longer arms so that they go in as deep as possible
    and my central body is 3mm fiberglass
    i will do just this one more change in length of arm so that they go in far deeper into the body,
    if this improves things,,, great...
    if not
    will order 3mm carbon sheets

    Ramesh
     
  18. Ramesh Tahlan

    Ramesh Tahlan Member

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    hi
    hahahaha.. .i think Andy was apt in saying i was flying a tuning fork... the more i think about it the more i am convinced that, that was exactly was i saw as was trying to find the correct word and was calling it "shiver " it was like when u get suddenly hit by a cold breeze and sends a shiver down ur body,,, lasts barely a second
    So now ready for a test flight
    Ramesh
     
  19. Joe Azzarelli

    Joe Azzarelli Active Member

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    sorry I did not see your reply earlier..

    Actually I am using two Spektrums for two pilot ops. I describe it here Things you did not know about the Radian
    One of the benefits with having extra channels in the dx18 is the pilot is controlling the radian mode, not the camera man.
     
  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Mario: I exchanged email with JohnC. One thing to try, with the Radian USB adapter connected to your PC (but without necessarily being connected to a Radian sensor), when you click on Connect in the Radian Configuration software, you should see a Yellow LED flash briefly on the Radian USB Adapter. Do you (or did you) see that?

    Andy.
     

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