speed

Discussion in 'Midwest Battle Group' started by captin sobor, May 20, 2008.

  1. captin sobor

    captin sobor Member

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    i'm building a fletcher class destroyer. and i coulculated the speed and it turned out that the scale model (1/144) will be going 4.9 fps. that is to dang fast. the regular speed of the real life destroyer is 35 knots (25.1 fps). its eaither me or that is really fast for a small warship.

    can you make eny speed you want for your warship if its small ( like a destroyer)[:D]
     
  2. Evil Joker

    Evil Joker Member

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    100 feet in 21 sec.that small(fast)gun
     
  3. captin sobor

    captin sobor Member

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    it's accualy Big Gun. i do think that is a bit to fast for a Big Gun destroyer. But i don't know i'm new to this stuff. that is a bit weird. the ship goes 35 knots ( 32.1 fps). or at least i think. and i multiplyed 32.1 fps by .144 and it came out as 4.98 fps.
     
  4. Gascan

    Gascan Active Member

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    For boats and airplanes, you can't simply use a linear scale for speed, because the air and water molecules don't scale down very well. Instead, you use Dynamic Similitude Speed, which is based on the square root of the scale. I wrote up more thorough description of DSS and Big Gun speed up in another thread. Anyway, Big Gun has a speed chart that takes the historical speed and gives a model speed, that is something like 63% of the DSS. You can find the chart in the rule book of any big gun club. Check to see if the Midwest Battle Group's rules are online. If they aren't, the WWCC and NTXBG have their rule books online, along with the speed chart.

    Ah, now that I look at your calculation, you multiplied the historical speed by the decimal .144, but the scale is a fraction: 1/144. For DSS, you would multiply by SQRT(1/144) = 1/12. The Big gun chart is about 63% of DSS (off the top of my head). It also happens that 1 knot in big gun is the same as 1/10 kph, so 33 knots is about 3.3 kph. Check the chart to be sure.
     
  5. captin sobor

    captin sobor Member

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    Thanks, i see what i did wrong now.
     
  6. captin sobor

    captin sobor Member

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    now i'm buildin a light cruiser insted of a destroyer ( there to small to build)