18' Osprey Multifoiler from Dr. Sam Bradfield

Discussion in 'Multihulls' started by Doug Lord, Dec 17, 2008.

  1. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Osprey-Dual Independent Wands

    Just noticed that the picture below is a perfect illustration of dual independent wands. "Wands" are surface sensors tied directly to the flap on each foil. The more angled back the wand the more angle down for the flap(resulting in lift up for the foil). In the picture, you can see that the wand on the port side is angled back further than the wand on the starboard side which means that the port foil is developing more lift than the one on the starboard side which is typical of the foil system on starboard tack.

    click on image to see both wands:
     

    Attached Files:

  2. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Some interesting comparative stats:
    ---W/SA=pounds per sq.ft. sa / smaller number =better
    ---SA/ws= sail area in sq.ft. divided by wetted surface in sq.ft./ foilers flying
    ---Osprey to get wing rig......

    =============

    C Class cat

    LOA 25'
    Beam 14'
    SA 300sq.ft
    Boat weight 300lb
    crew(estimate) 2@ 175lb=350lb.
    Sailing weight(estimate) 650lb
    W/SA= 2.16
    SA/ws(estimate)=8.42/1

    =====================
    A Class Cat

    LOA 18'
    Beam 7.9'
    Boat weight 150lb.
    crew(estimate) 175lb.
    Sailing weight(estimate) 325lb
    W/SA= 2.17
    SA/ws(estimate)= 6.96/1

    =====================
    Mirabaud

    LOA 32.8'
    Beam 17.7'
    SA (upwind) 344 sq.ft.
    ---downwind 527.2 sq.ft.
    Boat weight 374lb
    crew(estimate) 3@ 175=525lb.
    Sailing weight (estimate) 899lb.
    W/SA= 2.61
    SA/ws= 18/1 (on foils)

    ===============
    Moth

    LOA 11'(12.75 incl gantry)
    Beam 7.2'
    SA 86 sq.ft.
    Boat weight 66lb.
    crew(estimate) 175lb
    Sailing weight (estimate) 241lb
    W/SA= 2.8
    SA/ws=13.65/1 (on foils)

    ================
    Osprey

    LOA 18'
    Beam 20'(+foil tips)
    SA 350 sq.ft.
    Boat weight 400lb.
    crew(estimate) 175lb(or less!-foils develop virtually unlimited RM)
    Sailing weight (estimate) 575lb
    W/SA= 1.64
    SA/ws= 18/1
     

    Attached Files:

  3. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Osprey

    =====================
    Turns out the boat ,at 400lb. ,is made with glass hulls, carbon beams, mast and main foils!
     
  4. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Bradfield Osprey foiler

    From Steve Clark on the Osprey thread under multihulls on SA:

     
  5. CutOnce

    CutOnce Previous Member

    Wow. Conditions look very light and the boat is fully foiling. It will be great to see the progress of the boat in stronger conditions - and closer to it's performance potential.

    Getting the boat in the water is a major milestone. Getting it foiling and stable is another. Tuning it to optimal performance potential is as much challenge as the build process (but a lot more fun than fairing).

    Keep the updates coming.

    --
    CutOnce
     
  6. troy2000
    Joined: Nov 2009
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    troy2000 Senior Member

    That's strictly a rhetorical question, because I saw nothing 'constructive' about your criticism. I don't know anything about foilers, but I can identify BS when I get downwind of it.

    How can you complain about the nose being high as though it's a serious concern when it was the very first launch, you aren't sure what the wind conditions were, you don't know at what point the pictures were taken (before, during or after trimming the boat for optimal performance), and you don't even know how high the nose is designed to be when the boat's properly trimmed?

    Seems to me you were just being a wet blanket, because for some reason enthusiasm, optimism and good cheer seem to offend you. Maybe you should go find a goth chick to lay your doom and gloom on; it might turn her on. But it doesn't do much for anyone here.... we're all glad to see another boat on the water, and it looks like a successful first outing to me.:)
     
  7. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Bradfield Osprey

    The boat is still in the shop getting the new carbon rudder ,screecher, and a few other tid bits. Will follow up for the next flight.....
     
  8. Doug Lord
    Joined: May 2009
    Posts: 16,679
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

  9. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 351, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Osprey

    Very good longer video of Osprey ,two up: http://vimeo.com/35372827
    Matt McDonald owner of Falcon Marine, the builder of the boat, is sailing in this video.
    Correction: Mike McGarry(sp?) sailing.....
     

  10. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    An article published on the front page of SA claims the Osprey weighs 475lb
    and the sail area in the pictures and video is 240 sq.ft.. Funny, because I was contemplating that my SRT would have 350 sq.ft and it looked like a much bigger rig than what is on Osprey. I measured it off a picture and came up with 240 sq.ft.. I was given the specs by both Tom Haman and the Man himself. Funny.

    Changes the specs a bit-still excellent:
    1) SA/ws is now 12.34/1 slightly worse than a Moth,
    2) W/SA(175lb. crew)= 2.7/1 slightly better than a Moth with a 175lb crew. Worse than a C Class and A Class cat. See post 17.
     
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