ALTA after market props

Discussion in 'ALTA' started by Justin Marx, Oct 20, 2015.

  1. Justin Marx

    Justin Marx Active Member

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    Has anyone found an alternative to the propellers from Freefly ? I have jobs coming up, and no back ups. Such an inexpensive thing can bring a shoot to its knees. How are all of you managing to show up on a shoot without any back up props? I fly with a back up cinestar, so that's no help. Thanks for the help!!
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    I do not have a solution. I manage to grab a few backups when they were in stock. Used one already. :rolleyes:
    But the issue with "backups" is that there's no way you'd want to mix aftermarket props like T-motor or even the KDE collapsibles (which look pretty close to the Freefly props) with the real ALTA props. So you'd have to replace all the ALTA's props with your "backups", but then you'd be on your own as to whether you'd be able to rely on the SYNAPSE's settings. It's a slippery slope...I wouldn't do it myself.
     
  3. Justin Marx

    Justin Marx Active Member

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    They were in stock at some point?? I must have missed the email from Freefly telling me they were in stock?
    Hopefully they come in before I leave out of the country on a job this weekend.. Would be such a shame if anything were to happen after I've pushed all of the Alta features to the director and I'm grounded because of a prop..
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Justin: As I recall there was an initial stock that then was sold -- so you didn't miss an email -- they were in stock until they weren't (so to speak!) :)

    Andy.
     
  5. Chris Jordan

    Chris Jordan Member

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    I snagged a few pairs too when I picked up the Alta.

    As for going ALL KDE, They are actually very different than the T-motor foldables by Freefly. Patrick sent me a set for a our Heavy Lift we are building, and the curvature is different. They are 18.5" x 6.3 pitch. Not sure how the Synapse would like them.
     

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  6. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Chris do KDE adapters fit the Alta motors ?
     
  7. Chris Jordan

    Chris Jordan Member

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    They are totally different, and I haven't tried. I Don't plan on it!
     
  8. Ozkan Erden

    Ozkan Erden Distributor

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    I wouldn't be afraid to try the KDE props. Just make sure you use a tork wrench to tight the props. They shouldn't be loose or too tight. Make sure all the props are at the same tightness.
     
  9. Howard Dapp

    Howard Dapp Active Member

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    I'm curious to know what are FreeFly's folding prop torque specs. I've seen some Alta videos where the blades seem to easily fold during motor start/stop. KDE folding props need re-torquing of the blade holder screws to keep them within spec during a day of flying. Overtime the lock nut nylon insert becomes a little less effective making re-torquing more frequent...very time consuming.
     
  10. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Howard looking at the nut that holds the prop it looks as both have a lock nut, the KDE has a metal box around the nut perhaps to prevent the nut from loosening

    Chris I know you are not planing to try them but out of curiosity is the hole pattern different

    prop.jpg
    picture by Chris Jordan
     
  11. Chris Jordan

    Chris Jordan Member

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    No the hubs are very different. FF being 10.4 mm between holes (roughly) and KDE being 8.3mm. The thickness of the blade where it sits between the hub is KDE 4.6mm and FF 3.6mm.
     
  12. Chris Jordan

    Chris Jordan Member

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    Yes mine have come loose after only 3 flights. That being said, this is normal. Been flying folding props for around 3 years, and I always check tightness every few flights. torque specs (IMO) aren't critical, just that they have a general amount of the same "foldability". For me, it's that they won't fall down on their own if held sideways, but with a light tap of the finger could move, but not flop.
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I've often wondered why the folding props need to be torqued down?

    My perhaps over-simplified mental model is that the moment the motor starts up, the centrifugal force caused by the rotation will (and should) more or less immediately fling the blades outwards and hold them there. Even if the flight controller varies the RPM to stabilize the copter, the centrifugal forces would (I think) still keep the blades firmly extended.

    Is the need to torque the hinges just to avoid the blades departing from the prop hub? Or is it part of the mechanism necessary for folding props to actually work?

    Andy
     
  14. Howard Dapp

    Howard Dapp Active Member

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    Chris, are you flying a flat or coax config? Which motors?
     
  15. Chris Jordan

    Chris Jordan Member

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    Andy in my experience and my own logic the answer would be yes, so that there's no horizontal play in the blade pitch from a hub being too loose. But I've also noticed vibrations when the blades don't have enough tension on them from the hub. And of course if they're too tight they also have issues.

    Howard we have a coax and I'm building a Hexa at the moment to carry up to 45 AUW. Coax' are popular but I'm not a fan really, only from my own experiences and after some intense training (as well as flight school) I'm not seeing the benefits. But that's just me. We don't ever fly the coax anymore. We did a lot last year, but with an issue upon every flight. And many different flight controllers. Some guys have a great success with coax systems, but that's a conversation for another thread :)
     
  16. Howard Dapp

    Howard Dapp Active Member

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    We've been flying the kde folding props for about a month now on a coax setup. We stopped using them when, on occasion (once every 5 or so flights) We would experience tracking issues. My theory is the turbulent down wash from the upper props would interfere with the tracking of the lower props causing them to, you guessed it, track poorly and cause the rig to become unstable as if it lost power to a motor for a split second. This was when using the kde 4014-380kv motors on a coax rig weighing 28-30 lbs. Switched back to the t-motor cf props and all is fine. Our purpose of going the folding prop route was to save setup time by keeping the props installed. It seems the time saved is lost because i'm having to re-torque the props during flights. For us the constant monitoring of the props made them unattractive for use on shoots. I'm going to use them on a flat hexa soon just for testing.

    For anyone interested in using the kde 18.5 x 6.3 props on an alta here are some specs. (Prop bolt is 3mm)


    image.png
     
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  17. Chris Jordan

    Chris Jordan Member

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    Were you using 18's on top and bottom?
     
  18. Howard Dapp

    Howard Dapp Active Member

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    Yep, 18 top and bottom with mk mixer 64 top 71 bottom.
     
  19. Chris Jordan

    Chris Jordan Member

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    Top blades always need to be smaller, or pitched differently than bottom size. Otherwise you lose authority. Surprised the T-motor blades aren't giving you issues. Cheers.
     
  20. Gary Haynes

    Gary Haynes Administrator
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    Follow the outline for prop maintenance in the Alta manual for adjusting the prop screws.
     

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