SYNAPSE ??

Discussion in 'Announcements' started by Peter Gøthche, Jun 18, 2013.

  1. Dave King

    Dave King Well-Known Member

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    Gary

    The biggest problem is you can't even get props! You can't get XOAR 14 or 15 in props since April. I've been flying on the plastic APC props most of the summer. Josh was the one of the people that recommended to hold off so did Riley from QC who has been playing with the I2C converter setup. Here's what he wrote me:

    "I've been running a Cinestar 8 with I2c converter for a couple weeks now and it works pretty well, minus a few unusual flight characteristics that i haven't been able to figure out (yaw drift mainly) but i personally would recommend just waiting until all the new freefly stuff hits the market. I think it will be worth the wait."

    I don't know how much difference the motor selection would be yaw drift if any. The biggest factor is that you can't even get props.
     
  2. Gary Haynes

    Gary Haynes Administrator
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    Dave you can't get Xoars but T-Motor carbons are available and getting good reviews.
     
  3. Dave King

    Dave King Well-Known Member

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    Thanks man. If I upgrade now, what motors would you recommend to me? Since you are the motor man I thought I would ask.
     
  4. Gary Haynes

    Gary Haynes Administrator
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    I'm not the motor man. Josh and others have had great success with the MT3515. Maybe they can chime in or others that have opinions on HL motors.
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Can't help thinking about the idea of having the BL-Ctrls out in the prop wash -- plenty of airflow there...

    Andy.
     
  6. Dave King

    Dave King Well-Known Member

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    For the MK PDB? It's an interesting idea. Not sure if it would have any timing or feedback problems. I guess you could mount the PDB with no BL's where it normally is and then extend 4 wires out to it. Not sure if there would be any issues with boom 1 and the Navigation electronics for interference but then again the wires run through the boom. I guess you could run the wires out the boom. Any ideas where you could mount the BL's on the boom?
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Dave: I confess I've not really thought much further than pondering the inherent contradiction that the BL-Ctrls run hot for lack of airflow, yet, only a few inches away, is this big fat juicy airflow chucking 12 pounds of air downwards per unit time.

    So, here's some off-the-cuff, your-mileage-may-vary, wild-ass-guess-style thinking:

    If I were going to experiment, I'd try just one BL-Ctrl, use two pairs of twisted pair wire (to reduce noise) and some heavy silicon wire for the main drive current, then mount the BL-Ctrl out on the top surface of the boom "somehow" -- either using boom clamps or using cable ties around the cables to hold the BL-Ctrl under the prop. Intuitively, I'd mount the BL-Ctrl so that it was under the prop, maybe an inch inside the prop-blade disc. I would not cut the motor wires initially -- just cable tie them in a loop along the underside of the boom.

    To test, I'd not try and fly -- just use MK Tool to spin up that one motor without a prop on it to see if the concept worked.

    Only then would I try a test hop with just landing gear on the frameset (no gimbal!) The balance of the copter would be off, but not so far that the FC couldn't compensate for it. You could coil some solder around the opposite boom as a dead weight to offset the shift of the wiring and BL-Ctrl out under the prop.

    Those are just my initial thoughts. I'm sure forum members will have additional ideas (ranging from "That's really daft! Don't do it!" to "Here's a better way....")

    Andy.
     
  8. Dave King

    Dave King Well-Known Member

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    Andy

    those are all excellent ideas and we are on the same page of the way of thinking about how to go about this. I really like when you say "wild ass guess". You need to some how incorporate that into the next video. The only thing that would really need to be thought out would be how to mount the BL's. Since they are so small there's really no surface area to mount any bracket to them. I'm thinking it would have to be some sort of sliding groove for the outer edge of the board. Mounting has to be perfect so that it doesn't damage the electronics but yet it has to be open so it gets the air.
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Dave:
    In my experience of corporate America, there are two types of estimates: USWAG and SWAG. Unscientific wild-ass guesses, and Scientific Wild-Ass Guesses. That's where I learned the phrase, anyhoo....

    I think there are two separate mounting issues: 1) the initial experiment -- in which case, you can cable tie the wires to the boom and they will support the BL-Ctrl temporarily, and 2) actual flight use. For 2) I'd probably construct an arrangement using two boom clamps and some kind of mounting plate. It might be possible to use a single central plate, sort of like a signet ring where.

    Andy.
     
  10. Gary Haynes

    Gary Haynes Administrator
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    Gents if airflow was so important, not saying that it isn't with the MK BL's, you would think that all other ESC's would be mounted out on the booms wouldn't you? Let alone most of the ESC's on the market are encased in shrink wrap of some type and only a few like the Castles have any kind of heat sinks. Just sayin...
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    That's an excellent point, Gary. I think it raises the question, "Why do the MK BL's run so hot?" They're the only ones that seem to be an issue. I suspect the answer is that we're working them much harder than on any MK copter and pushing their envelope.

    As you say, I've not seen any other heat issues reported with other ESC's -- with the exception of one of two reports of ESC's spontaneously bursting into flame, but I think that's just simple component failure.

    Andy.
     
  12. Gary Haynes

    Gary Haynes Administrator
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    Do the upgrade. You KNOW YOU WANT TO......
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Dave might need to. I'm not finding it too much of a problem so it presently falls under the heading, "If it ain't Baroque, don't fixate on it." :) (Or something like that.)

    Andy.
     
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  14. Scott Stemm

    Scott Stemm Member

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    but you look at the "SWAG" part and see that when you hover temps go up when you move temps go down so the airflow has to have something to do with it.
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yeah -- you're right Scott. Hovering = hot, moving = cool. You can see that reflected in the GPX files if you look at groundspeed cf. temperature.

    Andy.
     
  16. Scott Stemm

    Scott Stemm Member

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    what about an air deflection system?
     
  17. Gary Haynes

    Gary Haynes Administrator
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    Scott totally agree that airflow makes a difference. But think it is a combination of technology, BL2.0 have been around for awhile, and improvements in other ESC/components. Burying the BL's in the stack in the center certainly doesn't help. My Freefly Motor Control set has the ESC's mounted on the top frame over each boom. So they get more airflow since they are more exposed but they are wrapped in fairly heavy shrink wrap so aren't getting much if any help with heat dissipation since they are wrapped up. Just think that it is a limitation of the BL's and how we are using them, perhaps expecting to much.
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The problem with that is that you're converting downward moving air into sideways moving air -- so you're reducing the lifting power of the copter commensurately.

    Andy.

    EDIT: Afterthought: Hmmm. I wonder whether that's really true -- the prop has already generated the lift by chucking the air downwards -- if you now deflect some of it, would it really reduce the lift? It will induce a lateral force, but will it reduce the lift? Hmmm.

    Andy.
     
  19. Scott Stemm

    Scott Stemm Member

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    I need to look at my copter when I get home tonight but I was thinking of a little scoop at the end of the tube to force air into the tube and out of the ring in the middle creating an airflow over the electronics. I would think that it wouldn´t need to be much just some movement
     
  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    You might need to have the scoop on two or three adjacent motors -- not all of them as they'd oppose each other.

    Andy
     

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