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

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

  1. P Flados
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    P Flados Senior Member

    Congratulations on getting the video proof.

    It was obvious to anyone up on what it takes to foil (assuming a willingness to be honest) that the boat had foiling ability. Needing some "tuning" / "tweaking" for initial foiling was always a likely thing.

    "High performance" on the other hand is subject both needing a benchmark to compare to and is subject to qualifiers like "optimized for light air" etc. I am sure the boat can provide "high performance" in some conditions but it is still likely to require more than a few adjustments (as to be expected for a prototype) to get close to what you want.

    Now that you have video of low speed foiling, I would suggest that you should consider sailing at every medium to light air opportunity you get even if you have to skip the video.

    I agree that we are all eager to see what it will do closer to the upper end.

    However, more value will come from the "prototype" if you eventually get around to doing some comparisons with things like "ama + rudder foils only".

    I know you are only mildly influenced by suggestions. However, at some level you probably really want to get on with the "real development" in addition to just providing "I told you so" proof of function to the ugly crowd of critics.

    Again, the video was great to see.
     
  2. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiler/ MPX Foil System Testing and Development Testing and Development

    Thanks, Paul. If she'll do that in a 5mph breeze I can't wait to see what she'll do in 10 or so with a reefed rig. But thats at least a month away-unless I get lucky.
     
  3. oldsailor7
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    oldsailor7 Senior Member

    Congrats Doug. I knew you could do it. :D
    All it needs now is fair weather and some fine tuning. :cool:
     
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  4. daiquiri
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    daiquiri Engineering and Design

    I did not follow the thread with big attention lately, Doug. Too many posts, as I already told you (and you already replied me). But I have read some info about it today, and it does sound like a good and original idea - although somewhat penalizing in terms of drag at displacement and pre-foiling speeds.

    Since so much time has passed since the beginning of your project, you have to pardon me if I have lost few pieces of your rationale in the meanwhile... For example, now that I saw the boat in action, I am wondering why do the amas have such an odd shape and why is the main hull shaped like a surfboard? Talking about these:
    MPX.jpg

    The only reason I can think of is that the scope of the project has changed so much during these years that this trimaran has become a mere test bed for the foil system. Is that right? Perhaps I just need an indication to the post in which you had already explained these things.

    Cheers
     
  5. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiler/ MPX Foil System Testing and Development

    The ama foils work almost exactly like a wand controlled t-foil: as the UptiP portion emerges from the water the high lift drag is reduced-just as it is when the wand controlled foil reaches flight altitude which neutralizes the flap-both have high drag at pre-take off speeds-which are very, very low on this boat and would be on the full size version as well.
    The main hull was originally based on my 16' foiler hull-that's why its not a real skinny hull. I added about 8% to the hull because at her final weight the transom was partially submerged which I felt would adversely affect low speed sailing. Her L/B is 8/1. The final shape turns out to be excellent-I'm not sure I would go with a skinnier hull for the full size version which would be a sport foiler with the emphasis on low windspeed foiling. For a strictly race version the design would probably include a skinny main hull.
    I disagreed with your and Richard Woods assessments of this thread-it is very detailed because it documents the progress in my thinking as well as the progress in design and development of the boat. You wouldn't have asked the question you did about the ama if you had read it-just sayin.
    ---------------
    The ama + curved piece are designed for two different functions: the ama to float, plane and support the ama foil, the curved piece to support the ama without touching the water except in the event of a knockdown where its buoyancy and the dihedral of the cross arms prevent a capsize-I haven't tested this yet but theoretically she could take a 90 degree knock down and still come back up. We have already seen that she can take a 45 degree pitchpole and come back up.
    The emphasis on the project changed from self-righting to the MPX Foil System after I discovered UptiP foils. When I first understood how significant the TNZ UptiP foils were I decided they would be the best ama foil for a trimaran because of their intrinsic altitude control. The i-flap is an improvement on the original TNZ concept.

    PS- one of these days I'll take the time to do an index-it's easier to explain it to you again than it is for me to go through everything to find the explanation-but I assure you it is there somewhere!

    PS#2- check out the mainhull on Mirabaud the 30' monofoiler that now uses amas for training:
    click-
     

    Attached Files:

  6. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiler / MPX Foil System Testing and Development

    ---------------
    Thanks Paddy! And thank you for your encouragement all the way through.....
     
  7. daiquiri
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    daiquiri Engineering and Design

    That's exactly the point, Doug... ;)
     
  8. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiler / MPX Foil System Testing and Development

    Here is the long version of the video. If unbridled enthusiasm bugs you turn down the volume.
    Note the stills below that show the lee ama flying with the main hull still sea hugging-and as soon as the main hull takes off the ama altitude remains close to the same. Flat remarkable altitude control!
    https://www.youtube.com/watch?v=4YBOEolFqiE&feature=youtu.be
     
  9. Madrc570
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    Madrc570 Junior Member

    Congratulations!

    Congratulations Doug!!!

    (Sorry I'm a bit late to the party :p)

    The boat looks far more stable now than in the last clip and a lot faster too. I think the increased area on the rudder foil, combined with the I flap made the big difference, I also love the I flap concept!

    Keep up the great work and sail as much as possible, even if it isn't videoed.

    You have proved now to a large audience that this brand new foil system works and that is a huge achievement. Its also incredibly inspiring for me and others building foilers!

    Thanks for making my day, and my weekend for that matter!

    Regards
    Curtis
     
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  10. Jim Caldwell
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    Jim Caldwell Senior Member

    Looking Good!!!!
     
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  11. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiler / MPX Foil System Testing and Development

    Thanks Curtis and Jim!
     
  12. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiler / MPX Foil System Testing and Development

    This is a sort of summary of the theory and practice of the new i-flap equipped UptiP ama foils:
    What I did was glued on a piece of balsa at a 15 degree angle to serve as a sacrificial mold then carbonated it with 5.7oz woven material. The extra area was from the radius between the daggerboard portion and the angled up lifting portion to the tip. The tip is twisted the exact opposite way it would be if the foil had washout-in other words the angle of incidence of the foil increases from the radius to the tip. The idea will be to trim away as much of the high lift area as possible and still have high lift at take-off and have as much of the high lift area as possible disappear when the tip breaches the surface. So when its right there will be high lift at take off which goes away the faster the boat goes. Which is exactly what happens with the wand controlled main foil but the ama foils require no moving parts. The testing will allow us to get the right combination of high lift/ low wetted surface lift throughout the speed range. I know we can trim it some already because the photo below shows the tip poking thru in this 5 mph breeze. Both ama foils exhibited the characteristic proven by TNZ: the single UptiP foil can control altitude as both did here so well. If a choice has to be made between top end speed and low wind speed take off the low wind speed take off will win every time. If the full size version is ever produced it would also takeoff in a 5 mph breeze because I consider that critical for marketing a foiler in the US where the sailing winds are under 10 knots in many places much of the time. So in order to coerce someone to buy a thing like this they have to know that they will be foiling most of the time.......

    Pictures,L to R, 1) This photo shows the ama foil tip emerging from the water at relatively high speed (for the wind: est 10mph boat speed), 2) This shows the approximate waterline of the foil at high speed,3) This is the waterline as the ama first flys- you can see this in the long video and in pictures where the ama is flying but the main hull isn't(see pix 5),4) You can see the twist in the foil from the radius to the tip induced by the addition of the i-flap*,5) main hull still seahugging ,ama flying,6) picture of the area of the foil I anticipate that will be removed while still retaining high lift takeoff,7) i-flap sketch:
    *i-flap=intrinsic flap
    click on pictures for best view--
     
  13. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiler/ MPX Foil System Testing and Development

    This is an illustration that should go with the previous post-it shows why I call the modification to the original ama foil an "i-flap" and why it is not just another foil section. It's a picture of the port ama foil bottom side:
    click-
     

    Attached Files:

  14. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiler / MPX Foil System Testing and Development

    I cropped these two pictures to illustrate how well the intrinsic ama altitude control system works. The lee ama usually flys before the main hull, picture "A", but in picture "B", with the main hull flying, you can see that the lee ama is about the same altitude even though the load/speed has changed:

    click--
     

  15. troy2000
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    troy2000 Senior Member

    Most impressive, Doug.

    I hope you appreciate the sacrifice I made by clicking on your videos, though.... it cut into the metered bandwidth on my cellular internet, thereby reducing the amount of **** I could've watched this month without incurring extra charges. :p

    add: As I've mentioned before, this sort of sailing is completely outside my experience and understanding; I tend to hang out in sailing technology and methods that were well-established a hundred years ago (the general idea being that if it worked and was cost-effective back then for professionals, it'll work for amateurs now). But I still enjoy the window you provide into a totally different type of sailing.
     
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