Design Challenge: Trapwing-"on-deck" ballast-12'-22'

Discussion in 'Sailboats' started by Doug Lord, Oct 7, 2009.

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

    Doug Lord Flight Ready

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

    Since the model is nearly complete I thought I'd update the above dimensions.
    LOA- changed to 17' 8"
    And thats it-at least for measurements covered above(except for weight-see below). The "look" of the boat
    -as compared to the original Trapwing and recent Trapwing 15 rough sketches-is very different from just aft of midship forward.
    The prototype will be entirely based on the first aeroSKIFF foiler thanks to Tinho Dornellas -and a little horse trading. And that will drastically reduce build time-though the mods are quite extensive forward and above the current deck line. The estimated additional weight is 38lb making the protohull
    168lb.
    The existing foils will be used on the "Turbo" version and a 100sq.ft. Hoot main and an approx. 140 sq.ft. unstayed rig will be experimented with. The variations in ballast as shown above are still valid.
    And a smaller set of hydrofoils already in stock will be used to explore the "foil assist" aspect of the boat thru sailing and resistance towing where the exact resistance of the boat from zero to approx. 15 knots will be measured and plotted with and with out the hydrofoils and with and without the keel ballast. With help from a bunch of interested sailors, my sailmaker and a local laboratory we'll get real good data about this prototype.
    One of the most important characteristics of this concept that I want to confirm in testing is the very, very wide range of crew weight for the Trapwing-100lb from lightest to heaviest which is the widest crew range of any dinghy under 20' that I know of sailed as a singlehander.( crew weight from 120lb to 220lb)
    -----
    Model pictures fairly soon.......
    ---
    The actual Trapwing Prototype hull minus topsides, deck and new bow
    -and its original configuration:
     

    Attached Files:

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

    Trapwing Prototype-model pictures

    Finally! This has been a very interesting project-just after deciding to do this I made a major design change that took a lot of time to work out to my satisfaction. If you look at the Trapwing 15 rough sketches you may see what I mean.
    This is only two of MANY pictures that will be posted here over the next few days. I'm satisfied that I've got it close to right-and that I can start the full size prototype.
    Keep in mind that this model was built on the model of the original aeroSKIFF hull in the manner that the full size version will be built-see previous pictures but more comparisons to come. Doing it this way has saved lots of time and money.....
    ===========
    These pictures show the singlehander with the rail seat option configuration which I personally prefer at this point to the single seat "sit-in" config. You can see some details such as the wing mount, "plug in" seats ect. MUCH more to come.
    I've got some photo quality issues I need to figure out if I can.

    Click on images:
     

    Attached Files:

  3. Chris Ostlind

    Chris Ostlind Previous Member


    Yes, the issues are called camera movement.

    Even if you shoot from a tripod, it has to be steady, your shutter release stroke has to be gradual, like squeezing-off a round from a rifle... or you'll get camera shake and wind-up with the imagery shown.

    A simple blow-up of the frame reveals a principal image with a ghosted version of the same where the camera moved during part of the exposure. From the way it looks, I'd say it's getting blurred during the front fourth of the shutter opening period.
     
  4. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Thanks but I'm not sure I can deal with that on my camera-guess I'll study the manual. I appreciate the input.
     
  5. Paul B

    Paul B Previous Member

    Maybe the design change to have no bottom in the cockpit area will prove to be an issue.

    A linesplan would tell us a lot more than these photos.
     
  6. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    ==================
    The cockpit sole has the same white with dark swirls non-skid material in it that was used on the majority of the deck on the original aeroSKIFF-Hydro-Turf....
    -----
    These two photos don't begin to tell the whole story-all the pictures taken as a whole in a week or so will be far more descriptive than any "lines plan."
     

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  7. Paul B

    Paul B Previous Member

    That is a very funny statement.
     
  8. bistros

    bistros Previous Member

    True. Classic "Ready, Fire, Aim" development.

    --
    Bill
     
  9. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Trapwing Prototype model pictures 2 (side by side)

    This set of pictures shows the wing in position and centered. On the fullsize prototype there is lead(about 80 to 150lb) sliding inside the wing. As the wing is moved the lead simultaneously moves so that at max movement port or starboard righting moment is at its highest. It will move manually and/or electrically as fast as or faster than a crew could on a trapeze. The wing is supported by "trapeze" wires from the mast. The wing also pivots athwartship adjustably to help keep the weight low to windward and the lee side clear of the water. The whole assembly also slides F & A-as does the crew seat on the "sit-in" version.
    The wing is 100% sealed so that even with the weight at max the boat will not turn over-and the wing automatically helps to right the boat in the event of a knockdown at maximum RM-the wing centers and the buoyancy(in combination with the keel ballast on versions so equipped) "pushes" the boat back up.
    The electrical version will operate with just the movement of a small joystick-
    making the movement of the ballast a piece of cake and as responsive as the same system on an RC sailboat. There is no boat under 20' anywhere that offers the potential combination of grace, speed and ease of sailing as does the Trapwing concept.....

    Pictures show the single hander rail seat option.

    Click on images:
     

    Attached Files:

  10. ancient kayaker
    Joined: Aug 2006
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    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    If you shoot a stationary object, camera shake during shutter release can be eliminated by mounting the camera on a tripod and using the camera's delay timer.
     
  11. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Thanks, Terry.
     
  12. Chris Ostlind

    Chris Ostlind Previous Member


    Most of the time, but not eliminated.
     
  13. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Trapwing Prototype model pictures 2 (side by side)

    From Dave Trude-competitive sailor in the 2.4mtr and other classes and SA's webmaster-published with permission:

    "Doug, That looks hot.

    I would remove the two seats for the skipper/crew and have the person sit inside like the 2.4mR does.

    Can you hang the boat from threads and take some shots from different angles with a white or green screen background??

    Doug, the model looks great. What are the dimensions supposed to be??"


    Dimensions in post 76

    About Dave Trude: http://www.webbdawg.com/dawgblog/
     
  14. ancient kayaker
    Joined: Aug 2006
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    ancient kayaker aka Terry Haines

    Doug: the earlier experiments at sliding ballast (Herreshoff?) used the power of the wind to shift the ballast, analagous to the way a conventional fixed keel carrying ballast will swing to windward as the boat heels. Essentially you are trying to do the same thing without having the boat heel, much as I was doing with Bruce Foils and canted sails instead of moving ballast, a few years ago.

    Have you considered using wind power to shift the ballast to avoid the complexity of electrical positioning, batteries and control systems etc? For example, the boom could be fastened to a rotating mast, and a mechanical transmission from the mast would position the ballast. Properly designed, the amount of power available could be arranged to equal or slightly exceed the amount required, since the ballast need not swing out so far in light conditions. This implies some kind of automatic gearing but a simpler arrangement might be devised.
     

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

    Doug Lord Flight Ready

    =============
    Terry, I'm not convinced that a system like that could work on a high performance boat-doesn't seem to me that the response could be fast enough.
    I could be wrong, though, and I'll take a look at it.
    Herreshoff's system didn't really use the power of the wind to shift the ballast-his system used gravity as its prime mover.
    The ballast on the trapwing will be able to be moved manually or electrically. An able-bodied sailor should have no trouble moving the weight since ,as it moves from center, it is supported by "trapeze" wires. Of course, it will depend on the SA and ballast of the particular version of the boat. The proto will be tested with 100, 120, 165 180 and maybe 200sq.ft. of SA and the appropriate ballast. We'll learn a lot more with that testing.
    A main raison d'etre for this concept is to allow disabled sailors to be able to sail very fast very safely. It also allows people who don't want to run side to side to sail fast as well. Electrical systems have been refined to a high degree for uses in this kind of environment and are not complex-see the post a while back about the Martin system.
    Because "ease of sailing" is a central theme of this boat it is likely that most owners would opt for an electrical ballast moving system(Trapeze Power Ballast System)-and a few would want electrical sheeting and steering like the systems used now in the Martin 16, Skud 18 and others.
     
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