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11 Whiner

About oatsandbeans

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  1. Ok so if you were building a AC boat for the next cup what foil design would you use? Answers of “just copy ETNZ foils” are not allowed as sure as hell they won’t be using them next time round!
  2. I agree 100% Mozzy your videos are great, really interesting technically, but also very well presented and you even manage to get a bit of humour (oh and the odd dodgy jumper), keep it up 98% of us think you are terrific!
  3. Thanks that’s really good-anybody know if the data behind these graphics can be exported into a day file?
  4. Is it possible to get the data from the boats in a file format (eg.csv). I would like to do some work on the vmg data. Any links would be great
  5. Sorry I missed the bit about how to define the baseline. First I would try a single continuous line as this is simple and it would define the start of the tack as when the vmg moves above this in the luff. The end of the tack would be when the vmg returned to this value.
  6. The area above the line is distance gained to windward in the first phase of the tack which is a gain. (The head up) . This quickly goes negative as the boat goes through the wind bears off and the speed drops.
  7. The best way to analyse the efficiency of the tacking would be to draw a straight horizontal line across the graph and measure the positive area above the line (distance gained to windward ) and subtract that from the area below the line ( distance lost to windward). This will tell you how good the tacking is rather than just looking at the minimum speed in the tack.
  8. Don’t knock the second derivative-its really good at showing you what’s really going on under all the noise!
  9. I definitely agree on the jumper- a disappointment , but I had a thought on the main/ jib thing . To get a good “high” mode upwind keeping the main leach on the CL is important to maximise the upwash and really point. If you have the wrong jib (too big) on you can’t keep the main in and so no “high “ mode.
  10. Looking at the TNZ latest foils it reminds me of “The area rule “ that all you aero buffs will know relates to cross sectional area consistency to minimise drag is this relevant ( yes I know it has been a bit slow on this topic so come on give it a go!)
  11. Well that’s good-and he used a Fourier Transform -well [email protected]@er me I never even thought about that full marks!
  12. No there isn’t- carbon mast sections can take surprisingly high deflections with no effect on them. When they go they go without any warning with a Big Bang . ( metal is not like this that is why a metal wind turbine blade wouldn’t last but a composite one can take millions of cycles at high strains)
  13. When the sail is fully sheeted the force generated by the wind is a summation of many small vectors from across the same. If you ease the sail the vectors at the front get smaller-thus the sum of the remaining vectors moves aft as the vectors generally are perpendicular to the sail with the vectors in the aft pointing more aft.
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