Oh Lordy (Doug)

Discussion in 'Sailboats' started by bobothehobo, Nov 14, 2006.

  1. Doug Lord

    Doug Lord Guest

    Guts, Courage and Foresight (and a model now and again)

    Ct, many people in the design and development world have used models to prove their new technology would work and then gone on to prove it full size. Among them are Bill Burns of CBTF, Yves Parlier "Mediatis Region Aquitaine(planing cat), Greg Ketterman- (numerous foilers), Dr. Sam Bradfield at least one foiler that I know about tested as an rc model and, I'm sure many others.
    Foilers test really well at small scale for a lot of factors that bear on the performance of the finished boat including altitude control systems, foil placement/CG, tacking abilty and more.
    --------------
    I wish Jon and the Monofoil guys the best of luck and admire the guts, courage and foresight it takes to make a project like that work.
    The guys that first foiled the Moth bi-foil monofoiler did something that at least one "expert" in the field said wouldn't work.
    Jon: good luck and never,ever give up!
     
  2. CT 249
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    CT 249 Senior Member

    Doug, scale models can be very helpful. However, I was just saying that the fact that a model works does not mean that a full-size boat works. Look at Bernard Smith's work; even the webpages for his book readily admit that ideas that worked in his models did not work in the full-size craft.

    Frank Bethwaite went to Smith and watched his videos and spent 20 years and 19 full-size boats trying to get his concepts to work. He didn't succeed. He found that the Smith concept needed too much sail to lift off onto the foils and notes that "Bernard's tiny balsa models had been so light (the cube/square law in reverse) that he had not been faced with this problem".

    So all I'm saying is that success in model form does not PROVE success in full size form will follow. Hell, Farr, Bowler, Jackson, Murray and many other designers have found out you can't scale a 12 foot dinghy up to 14 feet or 18 feet long. Spencer found you can't use a 26 footer as an infallible test for a 62 footer. A scaled up butterfly could neither respirate or fly. Scaling effects matter, we all know that. You can't even scale up a fast speed board to make a fast big windsurfer.

    That's not saying that models aren't great tools for design, I'm just pointing out that the evidence is that they are nothing like infallible.
     
  3. Thin water
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    Thin water Senior Member

    Check out the scale model movie on their site, It really moves out. Boats have looked very similar for hundreds of years, even hydroplanes have not gained a lot of speed in thirty years. It may be time for a change. This looks like it is good for nothing but it's intended purpose, setting the world record. If it doesn't break (Looks likely) and the wing can be kept from touching the water (could prove fatal) they just might pull it off on a good day. If the foil exits the water I think it will pile up in a heap after cartwheeling. To be a success with this design they can't just break the record, they must smash it by a good margin. I wish them good luck.

    JIM
     
  4. DGreenwood
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    DGreenwood Senior Member

    If they were making claims of a 5% increase in sailing speeds I would have a lot more respect.
    I have a question---If this thing will work on water(the wing I mean), wouldn't it work better on ice? What do record breaking ice boats look like?
    C'mon this isn't the 30s! You just don't show up with a design out of Popular Mechanics and increase established records of the sort they are after by 100%.
    Long distance sailing records see big leaps sometimes because of weather system luck or because a small increase in speed will allow better facilitaion of weather patterns.
    The sailing speed record over a short course has inched up over the years 1 knot here and there. Now we are going to see it increase by 45 or 50 knts.
    Wow these guys are impressive.
     
  5. Guillermo
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    Guillermo Ingeniero Naval

    yes, absolutely.

    Why don't we open a poll here and vote about if it's going to break into pieces or not? We should even risk some money on the bet! ;)
     
  6. PI Design
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    PI Design Senior Member

    I totally agree CT, models have their place but are not the be-all and end-all. Its funny you should propose a kite, beceause this design evolved from the kite and hapa combo that has been around for a while. I presume they switched to a solid set up to get lower drag, but, of course, structural strength is now a far greater problem. I wouldn't say thay that it is an aeroplane any more than a kite surfer or foiling Moth is. Having said that, I can't see it having any great effect on traditional yacht and dinghy sailing - it really is a stand alone project.
     
  7. Jon Howes
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    Jon Howes Insomniac- sleep? Wassat?

    A quick post as I am running late for a meeting:

    Purpose of models;

    The models are validation tools for an analytical model. The analytical model is used to design the next iteration. The full scale boat is not a scaled up model.

    Scaling laws;

    Bread and butter to an aero engineer. See above.

    Me (the "nerd engineer");

    Sailing since I was five, now I'm 47, work it out. Experience: The inevitable Oppy followed by British Moths. Various other dinghy and offshore experience, current boat, 5 tonnes of 1936 rotting rainforest with a collossal sailplan. Aero engineer since 1980 or thereabouts, until I left to start my own business I spent 5 years in transonic wind tunnel testing, a couple of years working on robot helicopters and weapons concepts, then 16 years with the UK Civil Aviation Authority. I was the head of the EASA Structures certification team for the Airbus A380. Concord involvment was limited to working out why the tank failed under internal pressure after being hit externally in the wake of the Gonesse crash. Been flying hang gliders since 1984, Pilots licence since 1995. Flown sailplanes as well.

    Monofoil development and the "How dare these people think that they can turn up and go faster than my favourite speedsailor" argument;

    Under development since 1995. Six variants of models of different sizes, purposes etc. (video of three of them on the website). Public presentation in 1998 at the Speedweek AYRS meeting. One overseas gentleman whacked in a patent application on a startlingly similar configuration one month after the meeting, his application even included some of the mistakes that I was making at the time, fortunately, these errors, if propagated to actual testing mean that his boat, as patented, will never work... Could these be related? The hearing will tell.

    Answer to the "Have these people ever been that fast before";

    Fastest aircraft flown to date, about 200kts, fastest boat, 70mph (powerboat, what a pointless activity...)

    As for the "how dare they" crowd, how do they think progress is made? By doing nothing? By being a technological wimp?

    100 knot claims;

    We haven't, we have designed for loads arising at 100 knots. Would we have been more sensible to design for loads at 50 knots and enjoyed the sound of crunching carbon at 60? The boat appears to have the capability to go to the design speed in a manageable wind strength so why stress it for anything less? Would the sensitive souls who get all jittery at people having a go feel better if we aimed for 51 knots? If so pour yourself a nice mug of cocoa, go to bed early and stop looking at scary web sites;)

    Loads;

    At the design point the wing is pulling 2.5 tonnes, the foil about 2 tonnes. By the way, the wing weighs in at 100 kg give or take a coat of paint.

    Assymetric, Stopping to tack;

    No, in theory it could fly through a tack but I am not inclined to try. Same performance on both tacks.

    Stability;

    Fully stable in six degrees of freedom. Models are free sailing with no radio intervention. If it totally leaves the water re-entry is stable and controlled and desiged to be so.

    Rough water behaviour;

    One model has run in .4 m waves, this model was only 1.2m long. Full scale is designed and stressed for a peak to trough wave height of 1.25m at full design speed, more can be handled if speed is reduced. Full speed is therefore sheltered water only, as loads reduce with speed squared a reduction to 70kts would give an additional safety margin of approximately 2.

    Given the title of this thread, I notice that Doug Lord often seems to upset people, largely by being different. At least he has a go, sure, some of his designs and concepts will not behave as well as he would like, that is the cost of trying something new. If rocks are thrown at hard work the sailing world at large should be very grateful that the innovators have the determination to keep going otherwise we can all forget (for example) living in houses and get back up those trees!

    More later after I have enjoyed the brickbats flying out of the collective armchairs.

    Regards,

    Jon.
     
    Last edited: Nov 15, 2006
  8. Doug Lord

    Doug Lord Guest

    speed increases in the real world

    ----------------------------
    In the real world of the Moth class foiler speeds have increased from 23 knots last year to 33.4 knots this year, an increase of 45.2% . So large percentage increases are most definitely possible.
     
  9. CT 249
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    CT 249 Senior Member

    Thanks for the reply, Jon.

    Maybe there's a simple reason for people asking about the level of experience of the group. There are no bios on your site. Googling a couple of your top team members brings little information about issues which some people may think may have some relevance, such as the level of experience in high-speed sailing.

    I'm not in any way saying that there is any lack in the team's ability and experience in these areas; I am merely pointing out the available information doesn't give any reason to assume it is there. Yes, we could take it as read, but perhaps being so credulous is as bad as being so cynical.

    I hadn't realised the direct link between your boat and Smith's work. Was he less aware of the scaling laws? Where they less developed a few years ago and was that responsible for the failure of his (and Frank Bethwaite's) full-scale boats to live up to the performance of his models? I know FDB lacks your formal qualifications but he does have significant experience in sailboat design and many years of full-scale work with boats inspired by Smith. May I ask where you think he went wrong in his attempt to apply these ideas?

    Re "100 knot claims". With respect, to many readers website headings such as "Breaking 100 Knots" does seem a lot like making 100 knots claims, which are supported by headings suggesting 50 knots is a "cruise".
     
  10. Jon Howes
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    Jon Howes Insomniac- sleep? Wassat?

    Hi CT,

    There was no direct link between this work and the Bernard Smith boats. I only "discovered" Bernard Smith after I had been sailing models of this concept form a couple of years. The origins were in consideration of kite boats and what limits their performance, these issues being mainly drag, stability and control (not much left!). The Bernard Smith work still failed to track down some fundamental aspects of stability, briefly: Position of aerodynamic centre about three axes, multiple points of lateral resistance (what happens when one of them lets go?), zero heeling moment without any attempt to develop any heeling stiffness (equilibrium without stability).

    Replacing the string with a rigid streamline foil does much to facilitate the oft-discussed kite+hapa with pilot on the string concept but does not stabilise anything and stability is only a very distant cousin of equilibrium. Most of the work was to ensure that both static and dynamic stability was present during acceleration, at speed when surface running, at speed flying, flying with the foil entering and leaving the water.

    Most designs that I reviewed in the early stages had been the result of the expenditure of much effort simply chasing equilibrium of forces, this is a largely pointless excercise as equilibrium will arrive naturally if stability about all three axes is is provided, for example, I have not found a single example of a high speed sailing craft that has the aerodynamic centre (neutral point) longitudinally behind the CG, not doing this leads to a flip over if the boat ever leaves the water, leaving the water is a certainty at some point if high speeds are contemplated.

    Control may be defined as intentional perturbations to the stable state. This is what ultimately allowed the test models to fly without human input.

    Jon.
     
  11. DGreenwood
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    DGreenwood Senior Member

    Doug:
    You can always pull up some examples of an underdeveloped class that made a recent big leap. The moth is a poor example. That class had not seen the kind of engineering effort that world speed records had seen. It was guys mostly building them in their garages. And keep in mind he is going up against the ORMAS and some pretty smart guys that have been working at foils and the speed record for a very long time.

    "100 knot claims:

    We haven't, we have designed for laods arising at 100 knots. Would we have been more sensible to design for loads at 50 knots and enjoyed the sound of crunching carbon at 60?"


    Pardon Me? Here is the claim from page one of your web site:

    Breaking 100 Knots
    Monofoil has been designed to reach an outright top speed in excess of 100 knots. While this may seem wildly ambitious in conventional sailing terms, it is a relatively modest speed in an aeronautical environment.


    You go on to say that 50 to 70 knots is a "cruising speed" for this boat. And top speed are only dependant on the nerve and durability of the pilot.
    Granted you do not outright claim in that statement to be abe to reach 100 knots but everyone would assume you mean to say that.
    Your audience is very small. Some of them very experienced and some of them have heard big claims before.
    I am aware that you probably need to raise money and dazzling the sponsors is what it is about. On the other hand don't you think that a responsible sponsor is going to investigate the feasability of your claims?

    Just curious...have you ever sailed in excess of 30 knots?

    Have you spent any time talking to (for example) the C-class cat guys or how about any of the folks that work on foil borne tris and cats? What is their response to hitting the modest speed of say 70 knots?

    And I am still curious about the ice sailing thing?

    Another question is:
    Doesn't the recent ORMA carnage i.e. the Route du Rhum, make you wonder how these fellas could be so stupid as to not be sailing on foils with solid wings. Jeez with average speeds under 30 knts they are barely moving.

    All you need is a moderate weather condition and you can show them how it is done around Fastnet Rock!
     
  12. Jon Howes
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    Jon Howes Insomniac- sleep? Wassat?

    "don't you think that a responsible sponsor is going to investigate the feasability of your claims?"

    I sincerely hope so and I will demonstrate the full basis for them to any serious potential sponsor but not here.

    "Just curious...have you ever sailed in excess of 30 knots?"

    No, and I have never flown in excess of Mach 2 although I have designed devices that have gone on to do precisely this. Your point is?

    "Have you spent any time talking to (for example) the C-class cat guys or how about any of the folks that work on foil borne tris and cats? What is their response to hitting the modest speed of say 70 knots?"

    Of course I have, swapped emails with Greg Ketterman (he liked it), know the sailrocket crowd, got bored at Speedweek. What have these people got to say about CFD design of foils and three axis stability? Very little. Your point again?

    "And I am still curious about the ice sailing thing?"

    Monofoil is not, and never could be, an ice boat for some fairly obvious reasons, not least that the foil spends some time creating downforce even when the average force vector has an upwards component. Without this ability to create downforce ice could never generate sufficient sideforce to react the rig at design speed.

    "Another question is:
    Doesn't the recent ORMA carnage i.e. the Route du Rhum, make you wonder how these fellas could be so stupid as to not be sailing on foils with solid wings. Jeez with average speeds under 30 knts they are barely moving.

    All you need is a moderate weather condition and you can show them how it is done around Fastnet Rock!"

    Grow up or get back in your cave. This is why I would rather solve engineering problems than waste time on forums.

    Jon.
     
  13. water addict
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    water addict Naval Architect

    Jon,
    In what true wind speed do you get boat speeds of say 30, 40, 50, 60 knots?
     
  14. RHough
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    RHough Retro Dude

    That's an interesting comment from someone that thinks they deserve respect.
     

  15. DGreenwood
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    DGreenwood Senior Member


    This is why I would rather solve engineering problems than waste time on forums.


    I don't know about that--- you seem to be pretty skilled at muddying the water and dodging simple questions. And I am sorry to be wasting your time.

    We will see who is in the cave when you put this thing on the water. And if I am wrong I will personally get on one of those planes that you have partially designed and come to congratulate you.

    You are the one making extravagant claims. You are the one that has to explain them.
    Getting testy over some difficult questions by experienced sailors and boat builders does tell me something about your where your ego is.

    By the way I can see your point with testing on ice. I hadn't thought of the lack of side resistance.
     
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