finding thrust

Discussion in 'Powerboats' started by scott steffe, Feb 16, 2007.

  1. scott steffe
    Joined: Jan 2007
    Posts: 26
    Likes: 1, Points: 0, Legacy Rep: 13
    Location: port charlotte fl

    scott steffe Junior Member

    how would one figure out the trust power of a v 6 outboard say 300 horse power
    anyone ??
     
  2. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Without prop data it is impossible. Rules of thumb say maximum thrust of 20-30# thrust per shp @ 0 speed and maximum rpm (n) dependent on delivered torque, falling off at some factor (dependant on the prop pitch to diameter and n^2) with the advance coefficient J= Va/nD. Usually, for most P/D ratios, thrust =0 at J ~ P/D.
     
  3. scott steffe
    Joined: Jan 2007
    Posts: 26
    Likes: 1, Points: 0, Legacy Rep: 13
    Location: port charlotte fl

    scott steffe Junior Member

    so lets see if i get this
    so using a prop caculater for speed you are figuring thrust ?
    14x32 cleaver @ 6000 rpm = 145 mph or so giving what thrust ratio per lb
    so what would be the trust power needed to turn that prop @ 2500 rpm
    300/500/ 600lbs or more
     
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