High Performance MPX Foil/Self-righting Trimaran-The Test Model

Discussion in 'Multihulls' started by Doug Lord, Dec 28, 2010.

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

    Doug Lord Flight Ready

    Fire Arrow Variation and Fire Arrow

    Its so shallow here-do you have any ideas how I could deal with that better than I already am?
    In the first tests(2nd day) with the Fire Arrow model, I had inadvertently made the main foil wands too long and the ama foils didn't have enough area. And the rudder on the boat had too much authority. The result was that the thing would jump clear of the water, pitch up and mush back down as the foils stalled and even though that second test overpowered the rig substantially no capsize -not even close. However, she did do a beautiful 45-50 degree pitch pole*, righted herself and sailed away. The "two stage ama" and crossarm dihedral allows there to still be lots of righting moment up to and a little past 90 degrees.

    * skippers fault
     

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  2. Doug Halsey
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    Doug Halsey Senior Member

    I don't know how you can improve your situation, but perhaps there are some advantages that you haven't thought of.

    When I was a kid in St. Petersburg, there were some knee-deep flats that were great for sailing models. I could be right there with them, instead of on-shore. These were free-sailing models though, so there were no worries about getting an RC controller wet.
     
  3. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Variation and Fire Arrow

    I'm not concerned about the model or models-just the fullsize version.... Pounding the foils or side of the ama into the bottom is worrisome. I guess the best answer for shallow water is to make it as hard as possible to roll past 40-45 degrees?
     
  4. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Variation-full size

    I've done some preliminary design work on the Variation based on the Fire Arrow using Welbourn -type ama hydrofoils instead of uptip ama foils. No decision about going ahead with a crowd funding proposal yet but if I build anything in the next three years it will likely be similar to this. Primary goal is extreme comfort and excellent performance including takeoff in around 5 knots of wind. The boat will have very shallow draft between 2 and 3' off the foils and less when flying. The boat will be able to sail without the lifting foils-though not as fast.

    LOA 14'/4.27m
    --
    Beam 8'/2.44m
    ---beam with ama foils deployed 15'/4.57m
    --
    Weight-
    --- boat ready to fly minus crew--190lb/81.8kg
    --- boat + crew--380lb/172.7kg
    --
    Sail Area-
    --- upwind-150 sq.ft./13.9sq.m
    --- downwind- 270sq.ft./25sq.m
     
    Last edited: Sep 19, 2016
  5. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Variation and Fire Arrow

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

    The idea of using Welbourn foils on a small tri seems to have some great advantages on a small tri-mainly allowing the platform to be only 8' wide yet have the RM of a much greater beam. The more I study this the more convinced I am that it will work very well.


    [​IMG]
     
  6. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Variation and Fire Arrow

    Below are some of the major advantages of the Fire Arrow concept most of which will work the same way on the 14' Fire Arrow Variation:


    [​IMG]

    [​IMG]
     
    Last edited: Sep 30, 2016
  7. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Variation and Fire Arrow-mainfoil options

    So far in the limited model testing I'm convinced that the dual wand* controlled main foil works best because it's 100% automatic and requires no crew attention.
    In the last test of the model, the foil system ,including the wand controlled main foil, worked 100% perfectly in light air foiling.
    * one midship wand on each side of main hull-windward wand clears the water when flying.
    There are other types of main foil that might be worth experimenting with on the Test Model or the 14 footer if it is built:
    1) Surface Piercing T-foil--Advantage-no moving parts; low drag when racing. Disadvantage-no automatic downforce for gust response and/or more power in stronger wind. Increase in drag as outboard tips breach the surface.
    Possible loss of automatic pitch control with no facility for downforce.
    Highly experimental version could have upside down asymmetrical section for automatic downforce when boat pitches down.
    --
    2) Manual mainfoil flap control--Advantage-less drag when racing; full control of mainfoil and flight altitude including downforce. Disadvantage-requires constant attention. This could be done in such a way as to allow wand control or manual control on demand-in other words the control system could be switched between manual and wand control with a retractable wand.

    [​IMG]
     
  8. Doug Lord
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

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

    Doug Lord Flight Ready

    Fire Arrow Foiling System Testing and Development

    Here is a concept model of a 12' X 17' wide concept model using the Fire Arrow system-ama foils not shown:

    [​IMG]
     
  10. Skyak
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    Skyak Senior Member

    Good topic, lousy post.
    -the link is just to another of your posts, and that post has a link that is not to any germane information, just a well known publication we may or may not subscribe to and a page number -without indicating the magazine month or series number.

    A dozen clicks and I can't help feeling I would be better off just searching on google or bing.

    You post a lot, is it too much to ask that you be more direct?
     
  11. David Cooper
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    David Cooper Senior Member

    I can't see crowdfunding working for that unless there are lots of people keen to get their hands on one of your boats, so you're going to need to sell it a lot better. That means lots of video of the model foiling (upwind and down) for long lengths of time, because people will never trust it enough to put their money into it otherwise.

    Another thing you should do is cost it to show that you're serious: produce a list of the expected costs of making or buying each part (materials and time), then look to see if you can make a prototype on the cheap by cheating (e.g. by replacing the amas with kayaks) in order to prove the design works with the minimum amount of stuff - you only need just enough hull to float and to hold the foils firmly in the right places, and low enough drag to take off (even if that means doing so with a much higher wind speed than the 5 knots that you hope the real thing will need - you have plenty of leeway to build a heavy prototype that should still foil). If some of the foils can be borrowed from an existing design of boat, it might be worth changing the size of the prototype to match the size of the available foils.

    I don't know if the demand for your boat will ever be strong enough to get it off the ground unless you go bigger and stick a cabin on it - that would offer speed with stability in a category of boat that offers much more for the money than a sit-on toy with an extreme price tag. Such a design should be much more attractive than the cat equivalents which can flip over too easily and would open up the possibility of using it for long sea crossings at high speed without extreme risk, but I suspect that existing companies will pinch the idea and get there first, which leads me to think that your best bet may be to team up with one of them.
     
  12. Doug Lord
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    Doug Lord Flight Ready

    Pro Boat

    ===================
    I figured that there are a lot of professionals that visit boatdesign.net that would like a heads up on great articles in this issue of ProBoat. Didn't have the time or inclination to post the whole article.
    They spoke of the three main platforms Kicktarter , Indiegogo and Fundable. One of their "case histories" was the Rave V that wasn't able to raise all their money but was able to keep part of it by making a deal with the "investors".
    Subs to ProBoat are free if you are an industry person or related in some way.
     
  13. Doug Lord
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    Doug Lord Flight Ready

    ===========
    Thanks for your thoughts David. I've written a lot about it above but the probability is that the proto(Fire Arrow Variation or Wolf) will be 14' by 8' and use Welbourn foils instead of UptitP foils. That allows the platform to be trailerable w/o folding or plug-ins and the Welbourn ama foils allow for tremendous RM as well as being able to retract them 100 % and still sail very well. One of the keys for me is that the seating on each side will be extremely comfortable providing a lot of back support and, of course, that the boat foils in very light air.
    The story about Maserati above probably precludes much more model testing EXCEPT that I may decide to change the amas and add Welbourn foils for video purposes. However, thats still up in the air.
    My biggest problem with crowd funding is what to give the investors. One idea(if its even legal) is a sort of lottery that would be designed to raise enough capital to build two proto's one of which would go to the winner. There are other ideas as well. The boat or boats would be mostly built by Falcon assuming they have the capacity when I'm ready. Assembly and building the Welbourn foil plugs/quicky molds I would do.
    The rig design will be a combination effort between me,Scot Morgan, Hugh Welbourn(I hope) and Matt( hope) at Falcon-and maybe CST. It will use an endplate main similar to the newest A Cat rigs and similar to one I conceived of 15 years or more ago. And it will be very light so I can step the carbon mast.
    --
    I'm convinced that a proto has to be built that will function and look like a production boat. We know what works so testing will be tweaking for best performance-not to prove that anything "works"-thats been done already by the Fire Arrow Test Model, the Quant 23 and by Maserati!
     
  14. David Cooper
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    David Cooper Senior Member

    When I look at those benches, I can imagine them folding upwards and then inwards together, creating a small rainproof cabin which someone could sleep in (if the beams are moved further apart). For very little extra cost and weight you would be adding a lot of extra value for the customer, broadening the appeal of the boat and making it easier for them to justify buying something that's more than just an ultra-expensive dinghy.
     

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

    Doug Lord Flight Ready

    Fire Arrow Variation and Fire Arrow

    Thanks David-worth thinking about.
     
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