Doug Lord

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  1. Doug Lord

    14' Stunt S9 Foiling Cat

    From The Foiling Week-designed by Michele Petrucci
  2. Doug Lord

    F101 Foiling Tri--2017

    From the newsletter: For 2016, the focus was on F101’s design, building the prototype and getting out on the water. We then moved into test phase to prove the concept of the platform, both in the UK and in Spain. We have now successfully carried out extensive test sailing sessions and the F101 has come through this phase surpassing all our expectations. It really does do everything that we envisaged and more. One of our test team even managed a full capsize, to date this has proved very difficult to do - indeed this was the first capsize in anger away from the safe confines of the marina in an early experiment. He successfully righted the boat with ease, using the pre-planned method of flooding one outrigger, sinking this to get the boat to 90 degrees and then righting conventionally. The outrigger then self-drains and off you go - we are however not convinced by his claims that this was intentional for testing purposes! The next phase is moving into full production. The prototype had a number of components that were custom made, or borrowed from other boats and so we are now finalizing the F101’s specific, purpose designed components. These are well underway and the two pre-production boats are planned to be ready in time for the RYA Suzuki Dinghy Show.
  3. Doug Lord

    Radio Control Multihulls

    These are some boats I designed- and produced for a while-they aren't being produced now but were ahead of their time in 2001. Lets see whats going on now in RC Multihulls-like the guy that built an RC Tri with curved main foils and put T-foils on the rudder to fly it-there must be others..... Note: for an indication of the size of the Flyer 3 look at the picture of the two boats on the dock and notice the man standing in the upper left corner of the picture. pixs from
  4. Doug Lord


    Macif---- I think its going to be real interesting to see the mods that are made to Macif now. One thing I think will be done is to add a controllable lifting foil to the daggerboard since Gabart talked about that early on. It would add roll and pitch stability to the boat and possibly provide an automatic response to gusts by developing downforce. Gabart thinks such a foil may have helped him to sleep...... In François Gabart 10 nov. message : ""You have to find the balance to be able to stay in support on the central hull, but it's not so easy when you go fast. I cannot stay on the central hull all the time and I'm still not comfortable sleeping like that. It's starting to come, it will take training again. But my sleep is damaged, despite fatigue. I still managed to take a few naps." "Is it not in this case that a foil on central daggerboard, when adjusted to provide a small downforce, which can add passive safety when the singlehander is sleeping ? In case of gust of wind with a move to more heel, the inflow incidence on this foil increase instantly and can provide an extra RM which adds to the one due to the weight. And moreover in steady state condition, this foil RM component is in squared speed boat, can increase in parallel with heeling moment in squared apparent wind speed. I am right ?"
  5. Doug Lord


    Dario Valenza along with many others (including me) has been doing much research on foils-particularly for the A Class. This is a segment published Wednesday December 10, 2014: Active foils with mechanical sensors tend to be at a disadvantage in light winds and marginal foiling conditions because there is a drag penalty associated with the control system. In non-foiling conditions the sensors can be disconnected and retracted. But then no lift is available so any puffs would see the passive boat move ahead in foil-assisted mode. Arguably the active setup is also heavier depending on where the sensors are located and how they connect to the foils. So on a small cat the passive foil would have the competitive edge in very light winds. The exact crossover remains a subject of investigation and will be found to depend on variables such as displacement/length ratio, sail area/wetted area ratio and the exact design of the foils... Once foiling the active system requires less deliberate correction by the skipper. This favours the less advanced sailor but probably makes little difference to the nuanced expert who is constantly making adjustments by muscle memory. The crucial difference is this: An active foil can be smaller for a given takeoff speed because lift coefficient can be maximized when needed and dialed out when not required. You can have an aggressively cambered foil on takeoff and a flat low-drag one at high speeds. This is not impossible with passive foils. For example, the section used in the upper portion can have more camber than the one used near the tips. But the compromise is more critical. It is more difficult to have early takeoff and low drag at high speeds.
  6. Doug Lord

    Maserati on Foils

    Maserati in spectacular video: from
  7. Doug Lord

    Crossbow fl 2017

    Crossbow fl 2017--This thing has such great potential that it needs to be mentioned every now and then: Summary of Features and Specifications: ------------------------------- Features: 1) Self-bailing cockpit 2) Boat rightable from 90+ degree knockdown by crew w/o crew movement using the wing regardless of the position of the sliding ballast. a. ballast wing is sealed and has buoyancy much greater than that required to float the ballast sliding inside. b. ballast+ wing can be moved manually or electrically faster than a crew on a trapeze could move. 3) Rig utilizes modified rotating, A Class wing mast, sealed with masthead buoyancy to prevent turtling, 4) Ballast wing pivots: a. to allow trailering b. to move ballast aft when required with wing extension. c. also pivots athwartship to keep weight low to windward and to keep lee side of wing clear of water. 5) Ballast is adjustable in 10lb increments, 6) Boat can be sailed off a beach, 7) Boat features an asymetrical spinnaker, an underdeck spinnaker chute and retractable bow pole, 8) Seating arrangement: (NEW) . a. The skipper will sit relatively low in the boat on a seat that will manually or electrically rotate 180 degrees. This will allow the skipper to steer with his or her aft hand and handle the single sheet and Trapeze Power Ballast System with their forward hand. For Class racing weight equal to the difference between 250lb. and the skippers weight will be carried in a ballast compartment under the seat. 250lb is the maximum crew weight for racing. 9) Large, buoyant "spray rails" act to help provide a dry ride and knockdown recovery, 10) Self-tending jib with variation of Swift solo single sheet system. 11) Boat uses removable, "plug-in" DSS foils for greatly increased power to carry sail with speed. 12) The new changes effectively "turbo" the boat even allowing for windward planing. 13) Boat has an extremely wide crew weight range: approx 100lb to 250lb for normal sailing. All ratios are based on 250lb crew and would drastically improve with lighter crew weight. For class racing, it would be my desire to see a class adopt the maximum crew weight as standard with lighter crew carrying weight under the seat-or perhaps two "weight classes"-whatever it takes to encourage the widest participation. ------------- Specifications: (changes are to be expected) Hull length-15.6' Beam- 4.75' ---at waterline-3.75' Sail Area-(boat will use a carbon A Class wing mast from Matt McDonald/ Falcon Marine LLC, laid up specifically for this boat). --upwind- 161 sq.ft. -- downwind- 290 sq.ft. Weight-sailing weight w/o crew- 223lb which includes: --hull, rig, foils-124lb --Trapeze Power Ballast System: ---wing-21lb. @ 12'-16' length overall, pivots for transport, and moving weight aft. --- max ballast 78lb(8 pieces of lead-removable-.25" X 8" X 12"-about 9.72lb each) Max Crew weight: 250lb-boat is designed as a singlehander. All up sailing weight including crew-473lb DSS Foils: each 1.63 sq.ft.( 6" X 39") 6.5/1 aspect ratio, Welbourn section. Electrical System for moving ballast: Engineered by Rick Willoughby, who did the original "ballast mover" spread sheet. ------- Ratios- see Eric Sponbergs Design Ratio's PDF below ------------- DLR=55.6 --- SA/D= --upwind-42.48 --downwind- 76.78 --- SA/ws- --3.7/1 --3.48/1 including DSS foil --- SCP/Total weight= .3 and .34 if upwind RM from DSS foil is counted. =========== Attached Files:
  8. Tell me, gbs: what version do you use when you talk to people about the foil: up-tip, UptiP or uptip?! One things for sure : you don't use any version when you write about it........
  9. Facts on Monitor-Hanno Smits-about 1995: Monitor videos:
  10. Doug Lord


    What you ,apparently don't get, is that foil design depends to a large extent on the operational RE for the foils and on the way they are intended to be used. So foils for the Moth and for the Fire Arrow Model are bound to be different. Further, the Fire Arrow foils are designed for very low speed takeoff as a priority not top end speed and are very experimental. For instance, the iFLAP allows the UptiP ama foil to work almost like a wand controlled foil(with no moving parts) with high lift at low speed and low drag at high speed. The small endplates being tried on the partial span flap of the Fire Arrow main foil are experimental and based on an endplate installation on an airplane. They may not work beneficially at all because the characteristic of a partial span flap is that the change in lift can extend past the end of the flap and the endplate may prohibit that causing more drag ,not less. Then again because this partial span flap is longer than the adjacent foil chord that may not happen. Experimental!
  11. Doug Lord


    As I said the SLR is "somewhat relevant" when designing for low takeoff speed but the relevance depends on the L/B ratio of the hull or hulls contacting the water before takeoff and the size of the boat. Moths are 10-11/1 L/B ratio, many other multihulls are 15-20/1. The L/B ratio of the main hull of Fire Arrow is 6.6/1. The test model and full size version(19.5') are designed to take off in a 5 mph(model) or 5 knot(full size) breeze. Boat speed at take off for the model is about 4-5 mph-the SLR for the model is 3.5mph using Velinga's formula. The SLR for the fullsize version is 6.62mph which is about what her projected takeoff speed would be in a 5 knot wind(5.75mph). The SLR for the 15.5' WOLF is 5.59mph with an L/B ratio of 6.65/1 which corresponds to her estimated takeoff speed in a 5 knot wind. The SLR is never more than somewhat relevant, even less so on models but an interesting reference for fullsize hulls with less than an about 8/1 L/B ratio for earliest takeoff target. The relatively wide planing hull on Fire Arrow/WOLF keeps the main hull rocker small for clearance when flying and provides reserve buoyancy forward and planing area forward for incidental contact with the water at speed. Note difference in rocker between Rave and Fire Arrow: Rave pix from Hydrosail website/Dr.Bradfield-- Fire Arrow pix DL and Dan Burke---
  12. Note that Monitor was able to tack and gybe on foils..........
  13. Doug Lord


    What an uninformed idiot you are............
  14. Wrong to the point of being utter nonsense! UptiP foils have been used for ama foils on two of the state of the art maxi trimarans designed from scratch to use a version of the foil configuration pioneered on the Fire Arrow test model. You can't get more high performance than Gitana and Banque Populaire! They use UptiP foils because they can be designed to have automatic altitude control. Guillaume Verdier specifically referenced the TNZ foils from 34 in explaining his choice of ama foil. A llittle over half way through he mentions TNZ's discovery of an auto stable foil--click on the sound icon: Gitana UptiP ama foil pictures by Fred Monsennec--
  15. Doug Lord


    SLR is somewhat relevant when you are designing for a specific takeoff speed-particularly low speed ,light air takeoff. Show me a picture of a later development by the Decavitator team instead of just running your poorly informed mouth!!!!!
  16. Thats just not true-its used by the inventors of the foil. And by anybody that has the common decency to give them credit for the invention of the foil and the name they chose! Part 1, paragraph 4
  17. Doug Lord

    Whisper Foiling Catamaran Sailors

    Great, Martin-thanks! Did you go after the Weta?
  18. Doug Lord

    Sailors Powerboat

    My Dads motorsailer.He started out with a Larchmont "O" boat and then decided to take the family on a cruise. So he found a good deal on this Hand designed motorsailer and had it completely refurbished at Higgins in New Orleans and we took off for Miami, the Isle of Pines, Havana, Nova Scotia and ,finally Brazil......
  19. Doug Lord


    why I waste my time with a complete ass like you beats the hell out of me... I don't -generally- use Froude #'s in design work. I use the old "speed-length ratio"(1.34 X square root of the wl length) or as modified in Vellingas book- 1.5 instead of 1.34 for monohulls. Of course, if for any reason I needed a Froude number I would just multiply the SLR X .30........
  20. Doug Lord


    And I was thinking good riddance! Don't let the door hit you in the ass......
  21. Doug Lord


    Latest development of decavitator foils(record setting) : Decavitator rudder foil showing offset.pdf
  22. Doug Lord


    Well, you weren't gone long!! For water: speed in mph X Chord in ft.X 121,000 or for quick reference, table p35 vellinga's book
  23. Doug Lord


    Actually, my foils are based on the work Mark Drela did with Decavitator, foil below. At it's fastest Fire Arrow would be operating at Reynolds numbers very close to Decavitator. The shape of foils is greatly affected by the speed they are intended to work at so foils on a scale model of Super Foiler or of an AC 50 would look a lot different on the model. Since Fire Arrow is a scale model of a 19.5 ft. foiler , the model foils and the fullsize foils would be somewhat different particularly in thickness/chord ratio. Planform would be very similar. As to "footprint" your comment was more nonsense: whether the rudder and board are aft or forward on the foil, as long as both are the same the footprint wouldn't change!- Decavitator foil from Dr. Mark Drela on 10/27/13 : It is currently in storage at MIT. On 27 October 1991, Mark Drela set the human powered world-record speed with Decavitator of 18.5 knots (21.3 mph; 34.3 km/h) over a 100-meter race course on the Charles River in Boston, Massachusetts. Fire Arrow has done 2 times wind speed in initial testing- about 10mph in a 5mph wind the very first time she foiled. My 56" LOA by 72" F3 did 18mph max reefed in a 22mph wind about 18 years ago and over 2.4 times windspeed in a 5 mph breeze. She had extremely thin foils......
  24. Doug Lord


    Fire Arrow Main and Rudder foils: since the last , most successful test of the boat in July 2014 a lot of study went into the foils including the main and rudder foils. Both the daggerboard and rudder were shortened 6" (1.7' to scale) to reduce wetted surface. The daggerboard was tricky since the foil had to be opened up and the flap pushrod disconnected, then the daggerboard was cut and lengthened. Finally the pushrod was lengthened, the board closed up, sealed and cosmetisized. Then the mainfoil flap was lengthened and small experimental endplates were added to the flap. Note the short and long partial span mainfoil flaps.