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

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

  1. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiling System Testing and Development

    Probably the most significant feature of the Fire Arrow is that it uses two completely independent altitude control systems for the first time on any trimaran:
    1) UptiP ama foils(also a first for any size trimaran*) that control the height of the ama above the water,
    *used on this boat way before they were used on any other tri.
    2) Wand controlled mainfoil on the daggerboard-controls main hull height above the water which, in turn, sets the angle of heel for the whole boat.The mainfoil also allows the main hull to fly in very light air.(5mph)
    But its the interrelationship between the main and rudder T-foil with the ama foil that makes the system so significant. The rudder T-foil is a trailing foil and "follows" the main foil. Altitude and angle of heel for the whole boat are set by adjusting the wand length. The boat is extremely stable in pitch because of the bi-foil arrangement on the main hull-the daggerboard foil and rudder foil always work together to control pitch. But they also control the ride angle and pitch of the ama foil which can't pitch on its own-in other words the ama foil can't all of a sudden "go negative" and cause a pitch pole.
    In an early test before the ama foils were the right size and the wands were set incorrectly the boat did a wannabe pitch pole caused by being overpowered and attempting a gybe in those conditions when off the foils. She recovered very quickly and sailed on.
    So while the system is unique and has many advantages common sense sailing is still important as I learned(again) in that incident.
    ---------
    The Fire Arrow advantages would work very well on almost any size small tri and possibly work well on much larger tri's as well. Hopefully, I'll be able to get the help I need to build a 19.5' version of the Test Model which would be a very cool trimaran and would illustrate well why this system is such an advance in small trimaran design.
    In the meantime, I'm planning on get more video with the reefed rig and shorter mainfoil and rudder foil.

    From 7/24/14-the first day the foil system worked perfectly:

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

    Light Air Foiling!

    Just saw some of the OMAN ACWS(America's Cup World Series)-thanks to Corley- and it's such a drag that the boats need so much wind(around 10knots min, I think) to foil! I'd think if they were going to go to light air venues they'd have a way to add lots of SA or different main foils or even a way to increase the area of the uptip portion of the foils so the boats would foil in the lightest breeze. After all thats the raison d'etre of those boats! They're foilers they should foil!!
    The builder of the full size Quant 23 foiling keelboat scow has set a low end wind range for foiling at 5 knots! Which makes sense since people that buy a foiler want it to foil most of the time they sail it.
    Way back in 1999-2000 when I designed and built the first production RC sailing foiler-the F3- it was targeted to foil in a 5mph(not knots-4.35 knots!) breeze-which it did*. And my latest foiler Test Model-the Fire Arrow foiled in a 5mph breeze the first time it ever foiled.
    The point is for a foiler to use the same wind range-or as close as possible-to the wind range of a seahugger.
    The D2** will foil in a 5mph wind-that has been a design target since day 1 of that project and it is a target that will be met........
    *She also did over 18mph(29kph) in a 22mph(35kph) breeze reefed to the max.
    ** D2-(Dominion 2-HW) design and build log: http://www.rcgroups.com/forums/showthread.php?t=2434531
     

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    Last edited: Mar 2, 2016
  3. Doug Lord
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    Doug Lord Flight Ready

    Fuel Cell for Miniature Power Supply

    ------------------
    I found the above awhile back --now there is a new type-completely different and may be even better: http://www.gizmag.com/drone-fuelcell-batteries-postech/42222/

    This is exciting stuff for the future of drones and rc Test Models like the Fire Arrow!
     
  4. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiling System Testing and Development

    This is a variation on the original Fire Arrow system. The only difference is that the ama foils are based on Hugh Welbourns Quant 23 foils. These foils can allow the platform to be narrower if the center of lift of the foils coincides with the center of lift of the original UptitP ama foils. The may be able to operate in shallower water than UptiP foils as well:

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

    Fire Arrow Foiling System Testing and Development

    I've already built a set of Welbourn foils for the Dominion model and I still have the quickie molds so I'm considering building a set for the Fire Arrow. They would have to be able to take twice the load of the D2.
    Problem is finding a way to install a different trunk in the Fire Arrow amas and/or building new amas-which I don't want to do at all.

    D2(Welbourn type) main foils:
    click--
     

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  6. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiling System Testing and Development

    I mocked up the Fire Arrow ama with the Q23 foils(from the Dominion 2-HW project) and it appears all I have to do is install a trunk just behind the current UptiP foils. It will be easy to set up and test but I'll probably have to make up a new set of foils because they will carry twice the load on the Fire Arrow as is required on the D2......
    --------------
    UPDATE-3/19/16-I'm probably going to do this but instead of adding trunks just for the Q23 foils the trunks will use a removable wedge to allow the UptiP foils to be moved back about 3". For the sake of testing foil placement it is a worthwhile experiment allowing both types of foil to be tested in the further aft position.
    --------------
    The D2 foils will be higher up than shown because when they're foiling they won't generate any lateral resistance:


    [​IMG]
     
    Last edited: Mar 19, 2016
  7. Doug Lord
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    Doug Lord Flight Ready

    F3-Worlds First Production RC Sailing Foiler*

    * designed by me in 1999-2000
    Here is another shot of the boat sailing in very light air(Dec 2015)-under 5mph-in San Diego a short while ago. Should have some video of the boat on foils in New Jersey in a couple of months or so:

    [​IMG]
     
    Last edited: Mar 22, 2016
  8. Doug Lord
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    Doug Lord Flight Ready

    ===========================================
    In the post above, I neglected to mention a major advantage of the wand controlled foil on the main hull: that is the ability of the wand to cause the foil to create downforce which can add significantly to the righting moment of the boat. It is an automatic response to the boat heeling even a slight amount-the wand will cause the flap to go up as much as is necessary to restore the main hull to its designed flight altitude. That can add a large amount of righting moment to the boat.
    It's been well proven on the Trifoiler ,Rave, and Osprey that the drag caused by doing this is not as much a disadvantage as the extra RM is an advantage.
    These boats have dual independent altitude control systems and their foils can produce all the righting moment required by the boat.
     
  9. Munter
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    Munter Amateur

    Luckily you had mentioned it 17 times in the thread anyway so there probably wasn't too much risk of it being missed.

    https://www.google.com.au/?gws_rd=ssl#q=search:boatdesign+%22create+downforce%22+MPX&filter=0
     
  10. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiling System Testing and Development

    Based on other discussions I've had it's not so much that it's been mentioned before, it's that there is a great lack of understanding of how downforce works and a group of very uninformed people who don't believe it works at all! Facts don't reach these people so I'll have to work harder to help them to understand.
    The concept of using a main hull foil that generates downforce on a trimaran has never been tried on another tri in the history of mankind as best I can tell.
    That's part of the reason some find it hard to understand because "everybody knows there's nothing new under the sun". Well, they don't really "know" they just think they do! Kinda funny really.
    -------
    17 times in this whole thread, huh? I must be slipping. Given that there are 151 pages with about 15 posts per page(10 on this page so far) which is 2260 posts of which only 17 deal with downforce?!
    No wonder there is so little understanding--that is only about 8 tenths of one percent of the posts!
    -------

    [​IMG]
     
  11. David Cooper
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    David Cooper Senior Member

    Well, they believe you now, the ones whose minds are sufficiently open, but it isn't for lack of you telling them. The problem is that you tell them too often and they don't want to believe you because they find you so irritating. Don't spend too much time laughing (a few days should be adequate) - you need to get that model back on the water and prove that it's worth someone putting in the money to build a full-size prototype.
     
  12. Gary Baigent
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    Gary Baigent Senior Member

    Doug, you are full of yourself with your nauseously insufferable (to bonkers) repetitve self advertising. Instead of going boo hoo or alternatively 'I am superior to thou,' build a fargo trucking full size boat that can carry your large and weighty posterior ... and then the "ill informed, completely ignorant" or words to that effect critics might believe you.
    And all this complete and utter BS about main hull foil producing down force ... why bother, how useless is that on a flying hydrofoil? - "never been tried before in the history of mankind," FFS!
    Does it mean that your toy flies so high and with such rapidity that it requires a pull down force to retain its correct equilibrium? Not from what I've noticed in your endless video repeats, your toy is so slow it only hops its arse out of the water momentarily on very rare occasions. A hold down force is perhaps the last thing you would want?
     
  13. David Cooper
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    David Cooper Senior Member

    Doug has just been proved right about the foils on the S9 - they're symmetrical (or very nearly, if not exactly so) and have a flap capable of producing downforce like on the Rave and Osprey. The S9's designer has confirmed that it produces downforce, and it improves the stability of the boat during gusts by holding the windward hull down. I doubted him and was doubting him more and more over time due to the weight of opposition to him from foiling experts, but no: he was the one who had been right all along. The same principle applies to the Fire Arrow and it may well be a fully viable design. The fact that Doug is irritating and insufferable (and has a phobia about putting his model in the water off the end of the jetty) does not negate the rightness of some of his most contested claims. We still don't know if he's right about the foils on the Whisper, but a photo of them's bound to appear at some point. It may be that its higher speed performance depends on aesymmetric foils which may have more difficulty producing downforce, but I'm basing that on comments from people who have just been proved wrong about the S9, so it wouldn't surprise me now if Doug is right about that one too.
     
  14. Doug Lord
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    Doug Lord Flight Ready

    Fire Arrow Foiling System Testing and Development

    ====================
    Thanks for your awe-inspiring comments ,Gary! I'm surprised you don't understand how mainfoil downforce works-and why:
    1) the main foil has a flap that is connected to a wand(surface sensor).
    2) as the boat starts to move the wand is pushed way back and that lowers the back end of the flap creating enough lift in very light air to fly the main hull before it would fly due solely to wind pressure in the rig. This is a major advantage because the boat is oversquare and would not fly the main hull "normally" until a minimum of 15 knots of breeze. But with the foil, the main hull will fly in a 5mph wind which will reduce drag and help the whole boat to fly. The very first time the whole system worked perfectly the boat did exactly that(July 24, 2014).
    3) As the boat speeds up the main hull rapidly achieves its designed flight altitude which occurs at an angle of heel of 10 degrees. This is the point where the flap has gone from max down, to start with, to neutral. The foil is set at +2.5 degrees angle of incidence so it lifts well when the flap reaches neutral.
    4) If the boat is hit by a gust and the heeling force increases it will only heel a fraction of a degree before the wand causes the flap to rise. When the flap rises it ,initially, reduces lift on the foil as a response to the gust and that could bring the boat back down to its designed flight altitude.
    5) However, if the wind continues to increase the wand will cause the flap to go up higher and this will cause the foil to start pulling down rather than lifting. This downforce, due to higher wind pressure, will continue and/or increase until the boat returns to its design flight altitude or the rig is reefed.
    Downforce as a result of the foil pulling down increases the righting moment of the boat, increasing it's power to carry sail and its overall speed.
    Another advantage of using downforce is that it also produces a small component of lift to weather-similar to the weather component of lift on a Moth with Veal Heal.(See the illustration below)
    ---------------
    In the limited testing so far the last time the boat sailed it worked perfectly and was very stable and did close to twice windspeed in a 5 mph wind.
    ===============
    The concept of using downforce has been well proven on the Hobie Trifoiler, Rave, Skat and to some extent on new foilers like the S9 and Whisper foiler cats.
    ============
    Gary, your obnoxious comment calling this boat a "toy" is so very ridiculous-this thing is a test model carefully built to be an exact scale test model of a 19.5' hydrofoil trimaran.
    A hydrofoil trimaran using a foil system that features two different types of altitude control for the first time on any trimaran anywhere at any time.
    Further, it is the first trimaran of any size to use UptiP ama foils-which were used successfully on this boat over a year before a single UptiP foil was trialed on Gitana.

    [​IMG]

    [​IMG]
     

  15. OzFred
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    OzFred Senior Member

    Do you have a reference for that? All I've seen is a statement that an attempt was made to sail with the windward foil raised and it didn't work (Sailing Anarchy Multihull forum, "14' Stunt S9 Foiling Cat" post 73).

    There are pictures of the foils here, they aren't very clear but the foils seem to be asymmetric when the flap down profile is compared to flap up. But the photos aren't all that clear, so not conclusive really. Attached is a picture of a Mach 2 foil in profile, can you tell if it's symmetric or not?

    Doug takes a small fact and extrapolates to hyperbole. He points to early T foilers that could generate down force then deduces that a multihull must produce down force in order to achieve stable foiling, despite the existence of successful foilers (even record–setting ocean–crossing foilers) that do not generate down force such as Hydroptre, AC 72, Quant 23 and A Class catamaran (yet). If they can do it, then a T foil system with wands doesn't need to do it either (which doesn't mean they can't, only that they don't have to and that stable foiling is not evidence that down force is being generated).

    That's the logic he used to state that the S9 must produce downforce, others were simply saying there was no evidence of that and Doug had no evidence either. He just kept repeating that other boats can and therefore the S9 must. The argument continued only to try and convince Doug that down force isn't necessary for the S9 to foil steadily in the face of his denial.

    His logic also says that the the boat can maintain constant height while the foils produce lift when to leeward and down force when to windward without changing the ride height or making some other adjustment. He has no design for such a system, simply claiming "it's automatic".

    He also thought Moths generate down force, it took some time to convince him otherwise.

    The Rave guys who wanted to optimise forces from the foils used manual control of each flap (see Replacing Rave Wands with Manual Controls, PDF, 142kB), that's possible on the Rave because the crew sits snuggly in the boat and steers with their feet, freeing one hand for foil adjustment. It's entirely impractical for a single handed trapeze or hiking foiler (even one with only one flap to control). A former dual Moth World Champion and extremely accomplished sailor (soon to be Olympic sailor) tried manual control and decided the wand was better, but Doug wouldn't accept that.

    So whether the S9 generates down force or not doesn't really prove much of anything. Doug's logic for coming to his conclusion remains flawed.
     

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