MPX-11 Very Small High Power Trimaran

Discussion in 'Multihulls' started by Doug Lord, Jul 13, 2010.

  1. Munter
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    Munter Amateur

    Maybe Gary reviewed what you were capable of delivering and decided more simplification was required? You really have a knack for taking genuine advice badly and making an *** of yourself in reply Doug.
     
  2. twosheds
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    twosheds New Member

    I have been "lurking" on these forums for a while now, and have been following this thread. I don't know what it is about the sailing community in general, and this forum in particular, that seems to be so vehemently opposed to new ideas, whether it be multihulls in the America's Cup, hydrofoils, or Doug's trimaran here.

    Yes, everyone is entitled to their opinion, but personal attacks against a member here just because his design is not traditional seems uncalled for. Sure, maybe the design won't work, but what's it to you? Why do you seem to want Doug to give up? If the Wright brothers gave up when people criticized their design, where would we be today?

    Any way, Doug, best of luck on your project, I hope you prove the naysayer's wrong. Nothing ventured, nothing gained!

    Thats my rant for the day...
     
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  3. Doug Lord
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    Doug Lord Flight Ready

    ==================
    TS, thanks for the vote of confidence/fairness! It's amazing but thats just the way it is.
     
  4. twosheds
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    twosheds New Member

    Ya, It is hard to believe sometimes. I was reading a past thread here on Jon Howes Monofoil project, and the attacks and criticism that he had to put up with was mindboggling. I think many people tend to be afraid of what they don't (or won't) understand.
     
  5. Cheesy
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    Cheesy Senior Member

    Gary is onto something, is it possible to find a broken/damaged Weta, that way you could try different armas, different foils, rigs etc and have a good base line to compare your concepts to (one or two changes at a time max), this sort of method makes it a lot simpler to figure out any unintended quirks that may pop up, and potentialy fix them. Building the boat as is may or may not work, if it doesnt it may not be easy to figure out what is wrong.
     
  6. Doug Lord
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    Doug Lord Flight Ready

    ====================
    The Weta is too heavy to be of any practical use-I think-and its so new it would be hard to find one at reasonable cost. This is so simple that building it should be very easy-especially just a mockup where the cosmetic surface finish work is left to the tooling(but that tends to go against the grain). My friend at Calema has a good size powerboat that we could hook up an ama mock up to to test the lift and be sure the area and theory of the ama shape is sound. It would be almost as simple to just build the whole thing and modify one ama at a time if it should need modification. Since the ama design works directly with the foils it would be difficult to learn anything really meaningful with just part of the system functioning.
    Should I decide to go forward with the prototype I can't do anything until the Trapwing proto is sailing.
     
  7. Gary Baigent
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    Gary Baigent Senior Member

    Twosheds, my so-called attack on Doug's brilliant innovations and experiments (thought I was being reasonably polite) is an attempt to introduce a simple reality. I'm all for breakthroughs in yacht design (have attempted a few on my own) but I'm also capable of seeing nonsense too. And likening Doug's stuff with Jon Howe's quite brilliant ideas and build is an insult to Howe. His is real original thinking and I'm for that. But numbers of us here have been inundated with flashy stuff from Doug, miles of print and repetition and fractional changes .... and that's the end of it; nothing gets built, nothing goes sailing - then he switches to some other flashy project ... on reams of paper or small red models photographed from many angles. If you believe Doug is an unrecognized genius, well, check his history, there is plenty here, then if you disagree after this evidence hits you, well, little do you know, that the little that you know ... is very little.
     
  8. Doug Lord
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    Doug Lord Flight Ready

    ============
    Gary, you're assessment of my work is downright disgusting. You simply can't discuss details calmly ,one on one-you were incapable of making any useful comments about the details presented in the Trapwing thread and are similarly incapable here. Your only comment of any note was that the devils tail ama just didn't look right. Well, ok. That's the limit of your ability to discuss the details and that's just too damn bad.
    Calling my work nonsense is absolutely pitiful. Both the Trapwing and this boat are on-going projects that have been conceived of and designed publically on this forum-they may work well or not-we'll see. I've designed and built dozens of boats over 50 years(see some of them in my gallery)-mostly experimental- some production.
    Some have succeeded more than others. I'm not afraid of making a mistake and have made plenty-but I have also done some significant work as well.
    And with the Trapwing and MPX-12 projects I have backed up my ideas with verifiable numbers and comparative ratio's that actually do mean something even though you-apparently- can't deal with them. With your own roto-tri you have provided almost no design detail-very, very little. No comparative ratio's very little in the way of any detail.
    You amaze me with your inability to discuss new designs in a professional and detailed manner......
    ===
    You obviously also have trouble reading: you have misstated numerous things about this design and the trapwing and have done it in an aggressive and rude manner.You accused TS of comparing my work to Jon Howe-what a crock-he did no such thing!!
     
  9. Munter
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    Munter Amateur

    Two sheds.
    There are certainly pockets of resistance to change within the sailing community but I don't think that is the main reason for criticism of Dougs designs. I can't speak for others but my comments are attempts to correct basic errors and mis-representations with what Doug puts forward. I'm certainly not against new technology and I don't believe that my posts show such an attitude. I do believe, however, that designs should be challenged, particularly if grand claims are made as to their success without these being backed up with proven, practical evidence. Doug's designs are full of holes and when I raise these I do it as clearly as I am able. These are not anti-technolody issues, they are simple ones like errors in claimed boat mass, the resistance of leeway, the structural integrity of the vessel (now cutely addressed by Doug with the application of a sticker!). By all means lets design and build hydrofoil unicycles but lets not dream something up, ignore the problems, claim victory and live in ignorance of reality.

    In case you haven't lurked long enough to know, Dougs standard approach is to latch on to one or two new-to-Doug design ideas, combine them in a design proposal and then claim new levels of performance, comfort and achievement that have been overlooked by the lazy design establishment. When queries are raised he dismisses them with a magic wand. Unfortunately, in focusing on a single area he overlooks many issues and chooses premature self congratulation instead. Are you aware that this whole design was hashed out in another thread and when Doug could no longer ignore the reality of the problems with his design he deleted all his text and started this thread as a substitute?
    Doug's grandios claims never get tested because the designs don't make it past the red model stage. In the mean time there is the endlessly repeated text, selected project justification and multicoloured text. There is a distinct lack of reality about his design proposals. Normally such a designer would get the reality check once a design was built and launched but this doesn't happen with Doug's foiling designs. Take the aerofoiler for example. This boat was built, apparently sailed then scrapped (the parts are back in the garage aren't they Doug?) and then the claims that it actually foiled began. No proof, an intentionally dis-assembled boat and an obvious reluctance to try it again. Why? Perhaps because that does of reality was easier to ignore than to really address the fundamental problems within the design. I object to this approach to project development.

    So what should one do? Let exagerated claims go unchallenged or attempt to moderate them with injections of reality?

    Bring on the new technology but lets not pretend that daydreams are the same as real, functioning boats.

     
  10. Doug Lord
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    Doug Lord Flight Ready

    Version 4 and updates-start 9/20/10

    MPX-12--FLASH TRItm featuring the "Devils Tail(tm)" ama*


    --- Version 4 specifications revised and updated from 9/20/10 on.
    1. Version 1-top of page 1-estimated production specs.
    2. Version 2-top of page 2-one-off specifications reflecting higher weight of the one-off boat while maintaining ratios close to version 1. Refinement of some parameters as the design has progressed.
    3. Version 3-top of page 3-continued refinement.

    ---As stated previously IF this thing is built it will be done as a one off which means it will be heavier that the production(molded) estimate in post #1.
    A small conceptual model is being built now-pictures will be posted in this thread(see first pictures page 3-crossarm angle to be changed). Work on the model has been instrumental in helping to refine the one-off design.
    And,this is a hot little boat as you'll see in a while........
    These are the revised specs:

    Note #1: the MPX-12 uses planing hulls because at this size displacement hulls carrying this kind of weight can't be "skinny" enough to take advantage of the low resistance characteristics of a high L/B hull-particularly with the main hull. It may be possible to use a skinny (L/B 14/1 or higher) ama hull coupled with a hydrofoil.
    --
    Note#2: The MPX-12 uses two lifting hydrofoils-one on the rudder and one on the main foil. These foils are critical to the function of the boat. The system they comprise will be called the Flight Control System(FCS) and its derivation and application is detailed in subsequent posts. See post # 29, page 2 for more info.

    -- LOA-12' 7" - changed 9/15/10
    -- LWL-12' 7" - changed 9/15/10
    -- Main hull beam-5.29'- changed 9/15/10
    -- Main hull beam at the waterline 3' (correction 8/7/10)
    -- L/B-mainhull at waterline-4.19/1(planing hull/planing threshold: 5.3knots-1.5 SLR / 7knots-2 SLR ) (change 9/15/10)
    -- Overall beam- 16.5'(15' cl ama to cl ama) updated and corrected 8/19/10--NOTE: approx the same overall Beam/overall Length as Hydroptere.(not including gantry on MPX-12)
    -- LOA- ama-10
    -- Ama LWL-6'
    -- Ama beam- 1.5'(max and max at waterline)
    -- Ama L/B- 4/1(planing hull/planing threshold-4.89 knots(aspect ratio of planing surface varies between 2/1 and 1/1)
    -- Ama Buoyancy - 3.25 cu.ft/ 208lb / 53% of sailing weight / RM just due to buoyancy= 1560ft.lb.(HM in 10 knot breeze=960 ft.lb)
    -- Sail Area- 163 sq.ft /23.5' mast length. Slightly taller than a scaled down A Class Cat. updated 8/19/10
    -- Main foil planform area-1.6 sq.ft.updated 8/19/10
    -- Daggerboard immersed planform area(boat @ 10 degrees)- 1.195 sq.ft.
    -- Rudder immersed planform area(boat @ 10 degrees) - .8 sq.ft.
    -- Rudder foil planform area-1.3 sq.ft.
    -- Draft(max) -3.5'
    -- Draft @ 10 degrees -2.39'
    -- Weight-155lb all up,ready to fly minus crew updated 8/13/10(Compare with the Baigent designed "Flash Harry 19.7' by 19.7' with 190+ sq.ft on a wingmast at 150lb!)
    -- Total sailing weight(displacement)- 395lb- updated and corrected 8/19/10
    -- Max crew weight-240lb updated 8/7/10 ( note this gives a little wiggle room for hull weight)
    -- Minimum crew weight(at max power)-120lb (boat can sail in same windstrength with minimum or maximum crew weight(!)
    -- Max Mainfoil loading - 157.5 lb/sq.ft. in .3lb wind pressure @ takeoff @ 80% total load. NOTE: this is LESS mainfoil loading than a Moth with Veal(very light) updated and corrected 8/19/10---Loading DECREASES as speed increases.
    -- Wand- altitude control system used in combination with the lifting hydrofoils on the daggerboard and rudder. Can be used to control sailing heel angle and compensate for different crew weights. Allows the boat to fly the main hull much earlier than it otherwise would.
    -- Max Pressure/w/o reefing 1.8 lb/sq.ft( 1.8 for F18 and 18 tri) The boat should be reefed(or the sail twisted off) in these conditions to prevent potential structural damage. After testing a warning label similar to the one installed in the Rave cockpit would probably refer to max speed or max apparent wind.
    -- Designed Sailing Angle- 10 degrees from 5 knot wind. Maintained by wand surface sensor in conjunction with main hydrofoil and rudder hydrofoil.
    System allows hydrofoil to lift up or pull down automatically-regardless of wind(up to 1.8lb. per sq.ft) or crew weight(120-240lb.)
    -- SA/WS:
    a. not flying main hull-5/1
    b. flying main hull-13.8/1(moth on foils=13.65/1) updated 8/4/10
    -- SA/D= 47.47/1( updated 8/13/10 )
    -- W/SA= 2.42 (240lb crew-better than Moth w/Veal or Payne!) (Weight/ Sail Area="sail loading"-quick and dirty comparative ratio for low resistance boats-particularly foilers. 26' Mirabaud and 11' Moth about the same)-updated 8/13/10
    -- SCP/total weight*= 72.9% updated 8/13/10 -see note below
    -- MAX RM-3322 ft.lb.+(37lb. foil downforce X 7.5)=3600 ft.lb. updated and corrected 8/19/10
    -- MAX HM(before reefing/depowering)-3600ft.lb updated 8/13/10
    Notes:
    ---The crew will sit on a very comfortable sliding seat with a backrest.
    ---The seat will slide a maximum of 2' .
    ---The boat will have a simple robust folding system-nothing to take apart-ready to go in 5 min.
    --- See Wand above: this boat uses just two lifting hydrofoils which are critical to its operation.
    ---Ideas under consideration:
    a. jib pivot point traveler( see bottom of page 2)
    b. small "ballestron"/rotating whole rig with "ribbon square top jib"( see bottom of page 2)

    These are all targets albeit very realistic targets and the potential is just flat wild.



    ===========
    Change, 8/4/10: Definitely will add 2' gantry to boat. Will be adjustable in overhang and facillitate rudder hydrofoil angle of incidence change.

    Change, 8/13/10: Beam to increase to 15' CL ama to cl ama, 16.5' overall all. Allows nominal 9" clearance of main hull at a 10 degree angle of heel with amas at a 10 degree cant(bottom outboard with boat vertical). RM does NOT change.

    Change, 8/13/10: Boat to use gybing/canting daggerboard +mainfoil. Eliminates leeward component of hydrofoil at designed sailing angle of 10 degrees. Gybing board(F18 Capricorn and several dinghies) improves windward performance. As noted above the boat uses a sliding seat that moves a maximum of 2' and can be used to move the canting/gybing board from tack to tack(8/19/10)

    Change , 9/15/10: Seven inches added to overall length. Main hull beam slightly increased.

    Change , 9/19/10: Angle of cross arms changed for model and prototype. Angle of ama increased 3.6 degrees on model only(probably).This will change set angle of heel of boat as set by the wand if it is maintained for prototype.


    ----------------------------------

    More Power, Much more Comfortable, Much easier to sail than ANY similarly powered up boat!

    --More Power: more sail area than almost any current 12' trimaran. Much more beam and power to carry sail than any 12' trimaran-in fact more than any 12' sailboat period. The only 12' design I know of capable of automatically adding righting moment as it is needed and which maintains maximum righting moment regardless of crew weight in the range of 120 to 240 pounds. Usable power: the only 12' trimaran design that matches the numbers for the Moth in Power to Weight(W/SA) and Sail Area to Wetted Surface ratios.

    --Much more comfortable: sumptous seating with 3" cushions w/backrests-nothing like it in any current boat with this much power at this length. Seats slide easily up to 2' athwartship.

    --Much easier to sail: the design of the boat limits required crew movement to 2'-no running across a tramp-just a small cockpit. No hiking or trapezing required. Much less physically demanding than any other small boat with this much sail area. Sheet leads from forward-not aft like on some cats. Amas fold for easy and quick transport. Easy to reduce sail area(or increase sail area).Daggerboard(and ama foils,if used) retract for beach launching. Weta type dolly(SC version)-the best I've seen for a small tri. Gantry(extension that holds rudder) retracts to shorten overall length.
    Difficult to capsize of pitchpole but will have a simple righting system in that event. Buoyancy at masthead will prevent turning turtle.
    updated 9/24/10



    More later.....

    *Devils Tail was from a comment by Gary Baigent in post # 40
    -------------------
    --*SCP(sail carrying power)= the RM in ft.lbs divided by the distance in feet between the CE and CLR.
    SCP/total weight-To get Bethwaites ratio SCP is then divided by the total weight in pounds. SCP/Total Weight- A ratio of 30% or better permits upwind planing.
    IMPORTANT NOTE: this ratio was mis-written and has been corrected as of 10/1/10. The word "into" was somehow substituted for the word "by" in the formula-my humble apologies!



    Previous Revision of this page complete 10pm, 8/19/10 .

    +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    ===========================================================================================
    +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    Important Stats-see below

    This is an update of post 19,p2 reflecting the changes to the specifications:


    The changes to the boat to facillitate a one off(and on which the model is based) shown in the post above reflect a very high SA/ws and a low W/SA.
    A) The Sail Area/wetted surface ratio:
    --
    Wetted Surface, main hull flying-------------
    --
    Main foil-(1.6 sq.ft. planform area)--------------3.2 sq.ft.
    Rudder foil-(1.3 sq.ft planform area)------------ 2.6 sq.ft.
    Vertical Fin/dggrbd(2' immersion)----------------2.39 sq.ft.
    Rudder----------------------------------------1.6 sq.ft.
    planing surface(ama)--------------------------2 sq.ft.
    ____________
    TOTAL WETTED SURFACE---------------------11.79sq.ft.
    MXP-11(12) SA=163sq.ft.

    SA/ws= 163/11.59= 13.83/1


    ---------------------------------------
    Comparison to Moth:
    --------------
    Main foil (planform area 1.1 sq.ft.)-------------2.2 sq.ft.
    Rudder foil( planform area .88 sq.ft.)-----------1.76 sq.ft.
    Vertical Fin/dggrbd(18" immersion)-------------1.17 sq.ft.
    Rudder---------------------------------------1.17sq.ft.
    _________
    TOTAL WETTED SURFACE-------------------- 6.3 sq.ft.
    Moth SA= 86 sq.ft.

    SA/ws-86/6.3= 13.65/1

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

    B) Main foil loading(assuming that the main foil supports 80% of the weight/load). On the MPX-12 the foil lifts both up and down.

    ---Because of the nature of the foil system on this boat the highest foil loading occurs in the lightest air(.3lb. per sq.ft. wind pressure) at takeoff. In this case the main foil loading is 252lb. of vertical lift( 157.5 lbs. per sq.ft. main foil area).
    The next highest loading is with the minimum weight crew in maximum conditions(1.8lb. per sq.ft. SA pressure) where the the load is 187 lb. down force ( 116.8 lb. per sq.ft. main foil area).
    Summary:
    Heavy Crew-Max vertical lift: 252lb(157.5 lbs per sq.ft.)
    Lite Crew-Max downforce: 187lb( 116.8 lbs per sq.ft.)
    ----------------

    ---Comparison to a Moth(vertical lift only-main foil @ 80% only) :
    Lite crew(154lb)=160 lb/per sq.ft.
    Heavy crew(180lb)=178.9 lb. per sq.ft.
    ===========================
    C) W/SA=weight in pounds divided by sail area in sq.ft.( sail loading-smaller=better )

    --MPX-12=all revised:
    a. Heavy=395/163= 2.42
    b. Lite= 275/160= 1.69

    ---------
    --Moth=
    a. Heavy= 246/86= 2.86
    b. Lite= 220/86 = 2.56

    ==========================================================
    ==========================================================
    Interesting A Class & C Class Cat comparisons with Moth and MPX-12--ALL WITH 175 lb* crew:
    *(2 X 175lb. for C Class)

    1) W/SA(weight in pounds divided by sail area in sq.ft.) smaller better :
    a. Moth(66+175=241lb) 241/86= 2.8
    b. A Class Cat( 150+175= 325) 325/150= 2.16
    c. MPX-12( 155+175= 330) 330/163= 2.02
    d. C Class Cat(approx.)-680/300= 2.27


    2) SA/WS(sail area in sq.ft. divided by wetted surface in sq.ft.)
    Note: A Class calculated with one board, one rudder and flying one hull. In addition 10% of its wetted surface is deducted to account for lift from the new curved boards.

    A) FLYING:
    a. Moth(from above) SA/ws= 13.65/1
    b. A Class Cat(wetted surface=21.53 sq.ft) SA/ws= 6.96/1(corrected)
    c. MPX-12(from above) SA/ws= 13.83/1
    d. C Class Cat (wetted surface incl 1 board,1 rudder=35.63sq.ft./approx.) SA/ws= 8.42/1

    B) NOT FLYING :
    a. Moth- SA/ws= 3.51/1
    b. A Class- SA/ws= 5.56/1
    c. MPX-12- SA/ws= 6.17/1
    d. C Class Cat(approx.)- SA/ws= 7.5/1


    ====================================
    page updated and corrected 8/19/10 Updated 9/28/10

    click on image then again on resulting image:
     

    Attached Files:

    Last edited: Oct 1, 2010
  11. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    There has been one sided "discussion" about simplification and making a nice sweet little trimaran with no foils and a nice catamaran like trampoline. About
    the extraordinary "complication" involved with any description I make of the MPX-11(12).
    I feel I need to remind certain individuals who have made an uninformed crusade of this thread of the title of the thread-you know those words that appear in blue above:
    MPX-11 VERY SMALL HIGH POWER TRIMARAN
    ----
    In the thread that first discussed the concept of a small high power tri it was pointed out that almost no trimaran under twenty feet is designed to fly the main hull. In fact most designs of small trimarans are under powered compared to monohulls the same length!! For instance, the Weta is a great little trimaran 14' long with 120 sq.ft of sail upwind. And it looks real good and has TWO trampolines. But the International 14 has 190 sq.ft. of upwind sail area! Kurt Hughes nice little 12 ' trimaran is dwarfed by the sail area of the 12' Cherub or 12' Skiff!
    Why so many seem willing to let the most powerful configuration in sailing be out designed in the performance arena by monohulls is baffling to me.
    It seemed to me then, as it does now, that no small trimaran designer has taken advantage of the real performance potential of small trimarans-most have left performance to monohulls or beachcats. Wait, there is one guy and he is a Cherub designer who drew some amas for his Banshee design. But from the looks of it it wasn't designed to fly the main hull. But cool nonetheless!
    -----
    Now, it seems that in the case of at least three contributors to this thread so far reading is not their first occupation, priority or interest and yet it is thru reading that one gets information. That explains,at least partially, why so much of the criticism posted here is so baseless and uninformed.
    Take the concept of simplification-no lets not-lets remember the Title of the thread and the goal described in the first post to conduct a design exercise to determine the feasibility of a Very Small High Power Trimaran.
    In the previous thread that gave birth to the MPX-11(12) concept and in the early posts of this thread it was pointed out why new state of the art technology MUST be used if the Very Small High Power Trimaran was also going to be High Performance. If you increase the beam so that you have the righting moment to carry a large rig on a small trimaran several problems arise:
    1) with the wide beam the initial righting moment is so large that the boat won't fly the main hull until its blowing over 15 knots.
    2) with the main hull stuck in the water drag is very great and the potential of
    High Performance is limited by not being able to use the ability to fly the main hull in light to moderate air-where most people sail.
    3) with the boat not able to use all the power of the big rig because of the drag of conventional hulls the potential for pitchpole is much greater. Not only that but at a length of 12' or so it is very difficult to take advantage of the skinny narrow(High L/B) hulls that are so associated with multihulls.
    ========
    My solution to these serious design issues has been and is the subject of this thread. The thread is not the design of your mama's sweet little conventional scaled down fourty footer-it is a balls out Very Small High Power, High Performance trimaran the likes of which you and I have never seen at this size. It is a trimaran that uses state of the art technology to solve prickly design issues. It is a design exercise to prove the viability of integrating these modern developments into a boat with the VERIFIABLE NUMBERS that show that there is a good chance of the concept working well. There is no design that has been presented on this forum for a small sailboat with a tenth as much detail as I have presented here.
    Those that continue to criticize without reading the detail that has been presented do no good for themselves or this thread. I welcome intelligent, well founded, INFORMED criticism-the rest is not worth my time or anyone else's. You don't have to like modern technology or the looks of this boat and that is your right and it is your right to say so. But to make uninformed criticisms of something you can't admit you don't understand is just a waste.
    ========
    At any rate, this thread is about Power, Speed, technology and developing ways that it can be handled easily and automatically while providing a "fun factor" not found in any other current small trimaran design. Of course, that's assuming the experimental part of this continued development works-which appears very promising due to the approach where science and comparative ratios are used extensively to validate the design every step of the way from Version 1 to Version 4 now.
    Not to mention the genuine, intelligent positive comment and criticism I've received from a few very experienced sailors who know small boat performance design inside and out-for that I am grateful!
    Now to get the rig(s) ready for the model........
     
  12. Doug Lord
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    Doug Lord Flight Ready

    Devils Tail(tm) Ama

    This is a tentative, working name like Flash Tri.
    I took one model ama to a friend who is a long time champion windsurfer, sailor and windsurfer designer, Olympic windsurfing coach, and sailing instructor. He also sails a 30' trimaran and is a damn nice guy.
    He thought the design was very good and he thought it should work well. His only suggestion was that I might want to reduce the angle of incidence of the planing surface slightly. I explained that it is completely adjustable.
    He particularly liked the transition from "wave-piercing" hull to planing hull and my conversation with him was very encouraging.
    -----
    Features of the ama design:
    --- the key to understanding this concept is that hydrofoils on the main hull are used to "assist" the ama by controlling pitch and roll. It is another, though fairly unique, application of "foil assist" on a multihull. This dictates the shape of the ama with the forward part of the lower half of the ama designed similarly to a "wave-piercing" hull that then morphs into a planing surface. The upper,rear, half of the ama is designed specifically to provide additional static buoyancy in a thin low drag configuration while structurally placing the planing surface in the best position.

    --- relatively high aspect ratio planing surface

    --- 53% of sailing weight total buoyancy up to crossarms. Not close to a cruising tri value but more than enough here for initial stability when you consider the beam of 16.5' on a 12' main hull.

    ---center of lift ahead of the center of lift of the hydrofoils and nominal CG. The distance ahead is to help relieve any pitch down tendency from the rig though this is primarily controlled by the foils themselves.

    ---low drag wave piercing forward sections.

    ---adjustable running angle:
    a. by mechanically changing angle of incidence of bottom
    b. by adjusting rudder foil flap and/or main foil angle of incidence

    --- unlike "normal" planing hulls this hull does not start at zero speed with a full load-the load is gradually applied until the hull is planing with a full load at around 15 knots of boat speed.

    --- position of center of lift vis a vis main foils and designed running angle of the planing surface seriously reduce the chance of pitchpole working together with the foils. Running angle(trim angle of the planing surface), once adjusted, is automatically maintained by the hydrofoils.

    --- Most importantly: unlike a "normal" trimaran that flies the main hull, instead of the ama controlling the attitude of the main hull the exact opposite is true with the MPX-12. The main hull, thru the two hydrofoils, controls the attitude of the ama in pitch and the angle of heel of the ama planing surface is automatically maintained at zero degrees by the altitude control system(wand) of the main foil. This should dramatically reduce the incidence of pitchpole because the ama is going thru waves and chop at a set pitch attitude( a preset trim angle of the planing surface) that is not affected by waves encountered by the ama.The ama shape is designed to penetrate waves, as necessary, with little fuss and NO change in pitch attitude. Again, the fully submerged foils on the main hull control the ama pitch attitude and angle of heel(roll).

    --- In extreme conditions small ama hydrofoils may be used to assist the ama in coping with conditions if the foils prove to work well in testing-and if they are worth the extra complication. See post # 34 and #13.


    approximate planing surface at two different speeds shown in right photo:
    (click on image)
     

    Attached Files:

  13. Eralnd44
    Joined: Oct 2006
    Posts: 68
    Likes: 2, Points: 0, Legacy Rep: -38
    Location: Eurohut

    Eralnd44 Wanderer


    I spend time looking back on here as to way mr. paul b. say to me. very soon to now i see a big project on trapingwing and never see anymore now. is mr. paul now correct mr. doug that you have big energy on project and never get to built that one.

    why you make so big a comments on trappinngwing and then to forget on more to end of work. is flashingtri also to know this dead place. is flashing tri big talk dream and not to care with work on build to sail.

    i have no understands of this way. my job owner say to us make new project and we make project all the way on work model then to test. experment is fun but with paper it can not be as real model. i think is much needed to have the know on thsi boat. this must be another way with heavy talk i now see here.

    i think now you have madness as we ask a question on this boat. not a good way at us if you like to learn. maybe mr. munter and mr. gary are sad on the story here. i am this way. i think time is since here to talk on new place.
     
  14. Eralnd44
    Joined: Oct 2006
    Posts: 68
    Likes: 2, Points: 0, Legacy Rep: -38
    Location: Eurohut

    Eralnd44 Wanderer

    mr. doug you build many boats as you say so. what good boat you make since last three year and is here for us to look for truth. i see dangering sail little model flashingtri on stick to glue. i not see truth boat now.

    where we see trappingwing at work with full man to sail. where is to test foil boat out from hobie parts. is it to work somewhere today. where is to find big aeroo skiff out of long time since victory sail. you say to look at picture gallery to see famous boats since your life work. when look to this picture place it is all from the old time with no boat since many year along.

    is sad to say mr. doug how i see this story. good time on your boat work looking now over. is only to say big thing now from you and then nothing from truth.
     

  15. Eralnd44
    Joined: Oct 2006
    Posts: 68
    Likes: 2, Points: 0, Legacy Rep: -38
    Location: Eurohut

    Eralnd44 Wanderer

    mr. gary and mr. munter. you have strong points to make to thread. i do proposal. can you join to me to make drawing on new small trimaran and desire to have better than is here.

    i have many ideas and have desire on making easier also better boat since comparing to flashingtri as we see now. write to me as privately message and email to make trio on project. we put boat here as drawings and such to show small tri as fun and strong.

    please if you can write to me soon.
     
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