amc

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About amc

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  1. amc

    Emirates Team New Zealand.

    Are you sure that is not a reflection of the sky tower?
  2. Yeah hopefully it might give you a starting point to zero in on the right answer.
  3. Would it help to work backwards from what we can guess the performance is and derive some rough estimates of the unknown values then try to fine tune them. Might not be describing this well hope you get the idea.
  4. amc

    Emirates Team New Zealand.

    There are lots of references on the interweb and they mostly give me a headache reading them coz I’m not that smart but roughly if the tail (Rudder foil in this case) area multiplied by the distance from the main foil ( i.e. area x distance called volume by convention)is correct for the main foil size, shape etc then an airplane (yacht) can be designed to be stable in pitch. It still requires some adjusting while under way but nothing too drastic. If this were not the case then it would be impossible to fly ordinary airplanes. Interestingly relaxed static stability is good in some cases like fighter aircraft. But in this case fly by wire control systems do the hard graft and the pilot just decides where to point the thing. Computer does the rest. Something like that anyway. Keep up the great work though you are way beyond what I can do.
  5. amc

    Emirates Team New Zealand.

    If they have done their sums correctly and have the right tail volume ratio, there will be a degree of longitudinal static stability. That said there are a lot of moving forces to deal with.
  6. amc

    Emirates Team New Zealand.

    Wouldn’t you like to know the tow line tension compared to other boats
  7. amc

    Boats and foils comparison

    Except that you have a very high thrust line and so something has to stop the pitch down effect of that.
  8. amc

    Emirates Team New Zealand.

    Until they hit the water they could be made from candy floss could they not?
  9. Birdstrike I think judging by some photos doing the rounds.
  10. amc

    Emirates Team New Zealand.

    You know it is just possible that what “one hears” is a warning shot to someone or some people not to take things for granted.
  11. A quick look at sa forums reveals an app called rigedge from smar azure ltd. to do that calculation. But it is not free of course.
  12. Here is what Arvel Gentry says about jibs. Doesn’t really help work out centre of effort though. http://gentrysailing.com/pdf-theory/A-Review-of-Modern-Sail-Theory.pdf I think you are on the right track though.
  13. For what it is worth I think both the main and jib work together as a unit. I am away from my laptop for a few days but when I get home I will have a look at that javafoil app from Martin Hepperle’s site and see if there is any clues there.
  14. amc

    AC36 - The Venue

    I think they are as ac36/12 decision in the first part says: If any part of the course area etc. All parts are accessible so that doesn’t apply. Also ac36/14 specifies parts b and c of ac36/12 still apply and part b happened.
  15. amc

    Emirates Team New Zealand.

    They should be able to shift the whole country with that now.