A Frame Masts

Discussion in 'Multihulls' started by Gus7119, Jan 20, 2016.

  1. UpOnStands
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    UpOnStands Senior Member

    yes, read that some time ago.
    Hard numbers are desired.
     
  2. pogo
    Joined: Mar 2010
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    pogo ingenious dilletante

    What about 5 ?
    Perhaps 7 ?
    Hard Numbers :D

    88 and 69 are softer numbers ;)









    do you Really believe to get a Delta , an absolute Delta Pressed in knots ?
    go windtunnel, then extrapolate

    No Concept will Never ever deliver a reliable Vademekum.
    Claiming absolute Numbers is foolish.
    See it from a practical Point of view.
    For hard Numbers a Designer Would Need two Identical boats/ platforms a conventional One, and One with his New Concept-rigg.
    a Lot of trials ,Tests , ........

    i only know about One Designer WHO had the opportunity to Test two Identical boats in full size
    Always together, Always under the Same conditions
    it was Juan Baader , he tested two Identical 40' Semi-deplacement Motoryachten , One was round- bilged, the Other One Single chined.


    pogo




    juan Baader has written the motorboater's Bible, comparable only with the Gougeons Book about wooden boatbuilding .
    the Book is of course out of Print, at the end Prices wer very high , about 200€.
    about 5 years ago some enthusiasts negotiated with the Publisher and Juan's son.
    the Book is available äs a free Download now,
    But,
    Only in German.
    The book is old, but physiks and hydrodynamics haven't changed.
    http://www.oxly.de/motorkreuzer-und-schnelle-sportboote-von-juan-baader/
     
  3. brian eiland
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    brian eiland Senior Member

    I think you will find that the mast DO rotate. look thru some of the photos here:
    https://chriswhitedesigns.smugmug.com/ATLANTIC-CATAMARANS/Atlantic-47/Atlantic-47/i-zmB2jqt
     
  4. pogo
    Joined: Mar 2010
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    pogo ingenious dilletante



    As Chris White made clear on his HP:
    THE MAST IS FIXED




    The foil rotates around the mast --like a tuffluff around it's forestay.
    The only difference is that the rotation of the foil is under control whole sailing---for more or less lift.
    http://walter.bislins.ch/aviatik/?page=Junkers-Doppelfl%FCgel

    Again the excerpt from White's HP; he differs between mast and it's MastFoil ( sometimes " foil" ):




    However the MastFoil has some critical differences. The main difference is that the MastFoil is a small part of the overall sail plan and can rotate 360 degrees around the load bearing mast which allows it to be feathered on any point of sail and in any wind velocity. Left alone, the foil will continuously feather if the control is set in that mode. Without this critical ability to feather on any heading, a rigid airfoil would typically not be suitable for use on a cruising boat. Another important difference is that the foil does not carry any of the mast compression loads. This enables the foil to be lightweight, structurally simple and rotate easily around the mast.

    ......
    .......
    .......

    FAQs:
    ..........
    What is the mast made of?
    The mast can be made of a variety of materials. A carbon fiber composite mast would be lightest but other materials are possible.
    ..........


    What happens with the MastFoil rig offshore in a storm?
    Nothing, if that is what you want! The foil will feather into the wind on any point of sail. When feathered, the drag of the mast and rigging is reduced by about 90% over a conventional mast. In severe weather having the least windage possible will make handling the boat safer and easier.

    Is the mast rotating?
    No. The MastFoil mast is a very simple non-rotating mast. This avoids the numerous problems associated with rotating masts such as unfair halyard exit leads, corrupted masthead instruments and lights, inability to adequately tension the shrouds, etc.

    How is the mast stayed?
    In the A47 each mast has a very robust headstay and two shrouds. There are no spreaders, diamonds, lower shrouds or running backstays.

    If the foil were to break would it compromise the mast itself?
    No. The mast function is separate from the foil. The foil could be removed and the mast would still behave structurally as it did before.

    .......

    ........

    ...........

    The foils can be gybed conventionally which is quick and easy, and they can also be gybed around the front of the mast, which in severe conditions will eliminate a lot of stress - both mental and physical.





    Alles klar jetzt ?

    Hier noch ein schönes Filmchen einer Wende . Man sieht das drehende MastFoil und die Bedienung dessen V-Flaps
    https://chriswhitedesigns.smugmug.com/ATLANTIC-CATAMARANS/Atlantic-47/Atlantic-47/i-RnZMM5k
    The V is pretty hard on the Windward Side while Smooth on the leeward side----it's a Split flap ( v-Shaped, 'cause for both Sides --the boat is Tacking !) !!!!!!
    See Here
    https://m.youtube.com/watch?v=q_eMQvDoDWk



    pogo
     
  5. upchurchmr
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    upchurchmr Senior Member

    Pogo,

    Your joke is appreciated, but not appropriate in this case.

    The claim was that proper trimming of the foil will increase speed.

    I wasn't asking for comparison to a Bermudian rig.
    I was asking for the delta in proper trim.
    Something to check out the benefit.

    Anytime someone says "better" you better be asking how much. Or you just get BS.
    Because better at my work could be weight reduction. One group spent 200 hours of work to get 0.02# decrease - which is better. Another group spent the same 200 hours and got 40# decrease. Which would you prefer and who would ever actually credit 0.02# when that much could be change by the tolerance in actual size of a part (spar, etc).

    Better is subjective and not worth much. No Joke. :p
     
  6. UpOnStands
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    UpOnStands Senior Member

    for Pogo, well if the builder/designer can't record a measurable difference in speed with the flap properly set versus improperly set (takes 5 seconds to switch) what does that tell you? I am assuming that builder/designer would take all steps necessary to maximize his chance of a clear and unambiguous result.
    IF the flap were a $15,000 option, what would convince you to take the option?
     
  7. pogo
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    pogo ingenious dilletante

    Nö,
    The Claim was that proper Trimming of the flap will Increase Speed.

    proper trim of the foil's Split flap enables the foil to be trimmed to a higher angle of attack without stall, Thus More Lift, More Lift for For the combi of soft sail and it's Doppelflügel/foil.
    in Other Woods--the proper trimmed flap generates max. Camber of the whole System or Less Drag.
    Chris White:
    "Why does the foil have an articulating trailing edge flap?
    Because a flap adds lots of power to the foil with very little additional weight and complication. Reaching and running the flap is set at a significant angle (approx 40 degrees) to the main foil which increases the overall camber of the foil and can nearly double its power. Sailing upwind only a small amount of flap angle is used but it helps create additional lift with very little drag"

    pogo
     
  8. pogo
    Joined: Mar 2010
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    pogo ingenious dilletante


    If !

    perhaps you should try to Understand the System, the Prínciple behind the MastFoil , the Junkers Doppelflügel and the Prínciple of a flap at First.
    http://aviation.stackexchange.com/questions/5018/why-and-when-to-use-flaps

    i don't wanna explain anymore, i don't wanna Argue anymore
    The MastFoil is , apart from the complex Wings of the AC-boats and the C-classic riggs, the First Really articulating rigg.
    it is reefable, it's foil Alone can Act äs a stormsail, it's foil enables Manoubers Never thought of before.
    The whole Concept shows smart and practical solutions in Detail. It is userfriendly .
    It's a cruiser's rigg. it's Not slower than a conventional rigg , sometimes faster. It is easier.
    i Don' Understand Why the advantages above should be Pressed into hard Numbers.
    The advantages are enough, they Stand for themselves. it doesn't Need x more knots to Convince anyone who perhaps didn't Understand neither the Prínciple behind , nor the advantages.


    i' m off.

    pogo
     
  9. upchurchmr
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    upchurchmr Senior Member

    Pogo,

    Usually you have some good comments.

    Good thing you are off in this case.

    That's two reasonable questions you have ducked.

    And I agree it should have been flap not foil. Of course you have to control the angle of the foil to get any value also.
     
  10. Gus7119
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    Gus7119 Senior Member

    Strange A Frame contraption

    Ok so heres a question for anyone with an sort of engineering background. I was on a building site earlier today where to my amazement i saw an 11m A fame that was spread at the bottom 4.5 meters with 5 spares inbetween it it was a aluminium build and was being used for a rig lifting bricks. Hard to explain and I didnt have my phone so no pics. But if anyone has seen the the A frame scaffolding you can hire from places like kennards hire and such it was like a larger version of those but the arms met at the very top. Now these guys reckon that they can lift 4 tonnes of bricks with the full weight of the bricks load being suspended by this frame. Yet the frame was so lite that one person could lift it.
    I asked if it had to be leveled off and secured prior to use or if they had a table for spans and weights but like the good Aussies they were they said nope just did it by eye and hadnt broken it even when thet got lazy at the end of the day and over loaded it. I then asked why I hadn't seen it used anywhere before or anything like it. The answer again in typical Aussie response was 'mate do you know how bloody hard it is to shift those Fing things? So I went to a mates place and after a few cases of beer we thought bugger if we weld this thing together it'll be like, easy'.

    Anyway my question is with my head thinking now if their getting four tonnes vertically and off vertical with this frame and its at the centerline of my hulls and I throw a main and jib on it Id have a ready built mast. Now I know without doing snapping tests compression test stress tests on the material itself its a little hard. But give 4 tonnes and more gets exerted on this thing and has done from what I was told for 2 or more years with no weld breaking no bending and no cracking would sails exert more pressure on it then its intented use. It was rectangular tubes Id say aluminium?
    And after seeing this I am off to Kennards to hire one of their fres to use on my 14ft cat. So I dont have to gerry rig anything as I know itll hold the sails fine and you can get them in the perfect spread distance at the base so I'll b able to do the test with a normal rig and A frame on the same boats head to head. Although I dont expect the Aframe ro win in this test I hope its not to far off the mark. I may even try it with two sails up front and a main but mow not having to build the a frame I can sfart on rigging.
    I know to some this will be a rambling mess to other a WTF moment but I hope someone understands it and after trying to make sense of it ccan help.
    Cheers
     
  11. upchurchmr
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    upchurchmr Senior Member

    Gus,

    An A-frame is the typical home built rig for a hoist on a truck. Not particularly heavy tube but it picks up a car or truck for towing or a load to put in a trailer.
    It works well since the load has to naturally fall straight down from the peak, so the lift is in line with the maximum strength. The load is equally divided between both legs.

    A boat will be a little different since the load from the sail is not straight down, but the A-frame is still naturally strong. Within limits, like everything.

    Good luck with the test.
     
  12. brian eiland
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    brian eiland Senior Member

    Pogo, sorry about that misinterpretation by myself. I had forgotten that the rotating portion was an outer sleeve of sorts. From an aerodynamic point of view I interpenetrated it as a rotating mast.

    Does it appear as though he has experimented with several different flap sizes? Is this a larger flap in this photo?
    https://chriswhitedesigns.smugmug.com/ATLANTIC-CATAMARANS/Atlantic-47/Atlantic-47/i-BTDDfL4
     
  13. UpOnStands
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    UpOnStands Senior Member

  14. brian eiland
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    brian eiland Senior Member

    Triming of the Flap

    I have another question.

    Is that V-shaped flap capable of being trimmed to different angles,....or does it flap from one side to the other?? It does not appear to be 'adjustable to me?

    I also wonder how it is attached to the rear of the foil section. I might have a use for such a flap on my aftmast rig's bare mast :idea:
     

  15. brian eiland
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    brian eiland Senior Member

    Pogo, I agree with you. It is supremely innovative in a user friendly manner.
     
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