Rig Measurements

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This topic contains 21 replies, has 8 voices, and was last updated by  df95usa 1 year, 5 months ago.

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  • #303

    df95usa
    Keymaster

    I’m creating this topic to give a clue to the change in topic from the Intro topic.

  • #288

    Hap41
    Moderator

    Hi Everyone…

    I am looking for the dimensions for the Backstay Length and Mask Rake. I have the dimensions for the “A” rig, but need dimensions for the “B”, “C” and “D” rigs. Has anyone seen this information?

    Hap
    DF95 USA #41

  • #294

    DesertDF95
    Participant

    Hap,
    I had asked Chuck if values for alternative rigs were available but he indicated that data was being gathered with a view to publishing something soon.
    Here are my current measurements, not optimized but maybe it will start a dialog? Same start and end points as for A rig in the manual.
    B – 908 mm; 960 mm.
    C – 835 mm; 805 mm.
    Mike

  • #295

    Hap41
    Moderator

    Thanks for the info Mike. All of the rigs seem to fall in line with the measurements that we have seen. Plop the rig in the boat…tune it a bit…take the measurements and everything is pretty close. Design and engineering at its best!

  • #297

    Hap41
    Moderator

    Hold everything! The measurements that I sent a few days age are not correct…especially for the “B” rig. Chuck…do you have any new information on this??

    Hap
    USA #41

  • #300

    DesertDF95
    Participant

    Oops! Correction I inverted two numbers in my B rig measurement it should read:
    B Rig – 980; 960.
    Too much haste!
    Mike

  • #310

    Hap41
    Moderator

    Here is what I have compiled thus far for the base settings (measurements) for the three rigs…

    A Rake 1135mm
    A Backstay 1090mm

    B Rake 980mm
    B Backstay 960mm

    C Rake 835mm
    C Backstay 805mm

    This is a start. Chime in if you have anything to add.

    Hap

    USA #41

  • #311

    DragonSailing NA
    Keymaster

    Guys,

    I apologize for not chiming in sooner here!

    I have some inquries out to the other channels for theior measurements

    Also we have the White Rock Cup coming in a couple weeks with 12 Df95s eneterd already, so we can get some good data from that event as well!

  • #327

    wstobbs
    Participant

    Hi All, a UK Imposter here…

    Thanks for you guidance in the backstay lengths.

    I can get my C rig Backstay to around the length you are suggesting but then my rake is only around 820mm. no way I can get it to the 835 you guys see unless I seriously shorten the backstay. With my config of 905:820 the mast looks reasonably vertical, but I have yet to try the setup on the water.

    My B is nowhere near your measurements. To achieve the 960mm backstay length I would have a seriously forward-leaving mast.

    With your measurements above, is your mast position still on the A-Rig position? So the 2nd grad mark from the back?

    Thanks in advance for your help

  • #328

    wstobbs
    Participant

    Just to confirm, here are my rig measurements.

    All with the mast step on the 2nd grad from the back
    Backstay measurements from top of hook on transom to middle of topping-lift hot on mast crane
    Rake measurements from back of bumper to jib attachment hole on front of crane

    A Backstay 1090mm
    A Rake 1145mm

    B Backstay 940mm
    B Rake 980mm

    C Backstay 805mm
    C Rake 825mm

    You will notice that I cannot get the A Rake set according to the manual.

    All of these settings are not yet tested on the water, so watch this space… UK Dragon Fest next week will see me up against the big boys….

    • #403

      N0cash
      Participant

      Hello guys,
      I’m watching this thread to get the updated rake and backstay measurements. It seems there was either incorrect measurements in the instruction manual or an issue with inconsistent parts. I am able to achieve ~ 1090mm BS; ~1145 Rake. This with the mast seriously bent aft. Seriously to the point of fear for the structural integrity in the long run. Correct me if I’m wrong here, you can crank the rake and/or the backstay well past taut but doesn’t that mean some other part must be deforming to accommodate?
      Any recent insight on the rake measurement issue?
      Thanks in advance
      Dave
      #22

      • This reply was modified 2 years ago by  N0cash.
  • #330

    Hap41
    Moderator

    If I were you, I’d concentrate on the Rake measurements and let the backstay fall in as it may. One suggestion is to really crank down on the backstay…way more than any other R/C boat that I have sailed. You should be able to strum the backstay like a guitar string. Hope that this helps.

    Hap
    USA #41

  • #413

    DesertDF95
    Participant

    Dave,
    You either misread or mis-typed the Forestay measurement. The manual says 1135 mm not 1145! No wonder your mast was seriously bent aft. To get the suggested measurements the jib needs to be down as close to the deck as possible ~10 mm and, as hap says, the rig is very taut.
    Mike

    • #415

      N0cash
      Participant

      DesertDF95,
      Thank you for the advice on the jib. I readjusted the jib hook-down to 8mm from bottom of jib splice to top of the forward deck eye. I was at 12mm before. Not sure what I gained. Check wstobbs’ last post above. His A rig measurements coincide with what I’m able to achieve. Any tighter makes me uncomfortable about wasting $400 on broken parts.
      I’ll follow Hap’s advice about setting the rake measurement at 1135 and letting the backstay, set reasonably tight, fall in where it may.
      I will continue to monitor this thread.
      Dave
      #22

      • This reply was modified 2 years ago by  N0cash.
      • This reply was modified 2 years ago by  N0cash.
      • This reply was modified 2 years ago by  N0cash.
    • #419

      N0cash
      Participant

      Perhaps some of the confusion might be from the instruction manual calling for the backstay to be set at 1090mm FIRST. To set the rake to 1135mm after is difficult. If the rake measurement is more important, as Hap suggests, shouldn’t that be clarified? “One suggestion is to really crank down on the backstay…way more than any other R/C boat that I have sailed” sends mixed signals as these hulls are fairly thin.
      Dave
      #22

  • #725

    kaerle
    Participant

    This is a bit of a lengthy posting. I am interested in comments or suggestions.
    I had serious issues with the recommended back stay and jib stay measurements. It seemed to put entirely too much stress on the rig. It caused a crease in the mainsail from the third luff ring up (ca. halfway up the luff) to the clew. Essentially, it flattened this area. This tension also transferred up through the mast crane down the jib stay with enough tension to pull up on the forward and aft ends of the jib boom to cause the boom to bow up a bit. I was very concerned with that amount of tension on a scary-thin mast crane. I decided to approach it differently. I pretty much ignored the mast rake and aft stay numbers by starting to tension the back stay until the distortion started, then I backed off a tiny bit until the luff looked normal. (The distortion starts as a small “bubble” at the third eyelet up on the luff. The more tension you add, the more the distortion radiates diagonally down to the clew of the mainsail). Looking from the side, this made the mast curve the same as the luff curve. Then I add just enough tension to the jib stay to keep the aft end of the jib from lifting while sailing. This results in a full, nice shaped mainsail and a jib that does not flutter under load. I think the jib swings a bit easier too. In higher winds, if the jib starts fluttering, add a tad more jib stay tension.
    So, this way I don’t need to fuss with a long ruler – it is a quick, easy setup.

  • #862

    df95usa
    Keymaster

    Pulled these measurements off DF95 forum on RCGroups wanted to save them here for reference.

    A RIG. 1139mm – Top of Bow to front hole in the Head Crane.

    Mast ram pushed back to power up the bottom of the sail.

    Main set just off centre with jib 40mm wide of mast.

    25mm gap between jib leech and leech line.

    The lower rigs like a lot more rake than you think.

  • #917

    zork
    Participant

    Must be setting up something wrong ! Set the backstay at the 1090mm and the bend in the
    mast is A LOT ! ! (new boat, setting up for the first time)
    And I mean really bent.
    Can’t be right.
    Thanks
    Zork

  • #918

    zork
    Participant

    Ok…might have figured it out, the gooseneck ends up about an inch above the deck.
    So….the mast stub is either too long, or for some reason won’t slide up all the
    way on the mast ? ?
    Sound reasonable ?
    Suggestions ? Hate to cut the stub if I am missing something here.
    Zork

  • #919

    df95usa
    Keymaster

    I wouldn’t be cutting the stub off. I do not worry about backstay length. Make sure the jib is where you want it. Then tighten the backstay to keep the rig from coming out of the hull. It is only at this point that you need to start working over the backstay. I usually worry about it last but applying pressure and bending the mast is going to change a lot of the sail’s shape. Once I start getting the shape I want then I start keeping track of measurements on the stays.

    But the mast stub needs to be seated completely in the hull and as a manufacted piece it should be the proper length.

  • #920

    zork
    Participant

    As a starting point in the sail setup, what is the distance of the center of the foot of
    the jib and main from the booms ?
    Thx

  • #921

    df95usa
    Keymaster

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