Idea for battens that *decrease* camber in higher wind speeds

<< First  < Prev   1   2   Next >  Last >> 
  • 17 Jan 2020 05:41
    Reply # 8597796 on 8587768
    Deleted user

    I don't mean to sound caustic or anything, but as someone who has had 12 years of junk rig sailing including two ocean crossings, I don't know why we would need to even bother with this given how easy it is to reef a junk sail, thereby de-powering the rig. Having come back for the time being at least to a conventional bermudan rig with all sorts of controls to power up, or power down the rig I think nothing could be simpler than the junk rig as it is developed right now, and certainly with a camber panel sail the battens need to be as stiff as possible. The same also goes for the flat sail. Keep the battens stiff otherwise the battens will form a great big air brake at the leech of the sail, and I don't think it would be possible to easily stop this from happening if the battens were able to be shaped.

    Last modified: 17 Jan 2020 05:48 | Deleted user
  • 16 Jan 2020 07:53
    Reply # 8588540 on 8587768

    Richy,

    I think you're overlooking the fact that battens always try to bend in the direction that's easiest for them. Rectangular section battens rotate through 90˚ if you hold them down with a downhaul near the mast, and bend upwards. That may apply here, with a sheet that's not at the aft end, I'm not sure. There's only one way to find out...

    I've long been a fan of trying out new ideas in a small dinghy rig, before spending megabucks on a big rig. You're well placed to do the experiment.

  • 16 Jan 2020 05:56
    Reply # 8587785 on 8587768
    Deleted user

    You'd have to run two lines to each batten - one on either side of the sail. But I don't necessarily see that as a huge obstacle.

  • 16 Jan 2020 05:56
    Reply # 8587782 on 8587768
    Deleted user

    If this works, you could even taper the battens along their length, to get just the right amount of flex at any point along their length, and theoretically get the sail panels to adjust their camber profile depending on wind speed...

  • 16 Jan 2020 05:54
    Message # 8587768
    Deleted user

    Hey all,

    a thought just occurred to me:

    Imagine using battens on a junk rig that are flexible horizontally but not vertically - think e.g. wooden battens that are three times as high as they are thick.

    Then imagine attaching the sheet lines that go to each batten not at the end of each batten, but in a point somewhere near the middle of its length.

    Then if the battens are flexible enough, with higher wind speeds the batten would bend away from the wind, since its middle is held by its sheet line.

    If you use sail panels between the battens that have camber, and if you get the flexibility of the batten just right, wouldn't that reduce the camber in the middle section of each sail panel with increasing wind load?

    I hope I am explaining my thought well enough.

    Obviously to get this right would probably require a bit of a marathon of iterations between calculations and trials.

    But right now as I understand it camber tends to either increase with wind speed if you have flexible battens; or stays relatively unchanged if you have very rigid battens.

    If my idea works, you could get a design that actually decreases camber with higher wind speeds, automatically, without any hinges or manual adjustments of any kind.

    I'm absolutely not in the position to test this, but just in case there is any merit to this idea, and in case someone would want to try this, I thought I'd share it here.

    Of course, either I'm overlooking something here, and / or someone is going to tell me now that this has already been tried in some way. There's rarely anything new under the sun.

    But still, just in case I thought it's worth sharing.

    If you do try it, please do let us know how it goes! I would really like to know.

    Richy


<< First  < Prev   1   2   Next >  Last >> 
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software