Power according to Ayre

Discussion in 'Props' started by Mikthestik, Apr 16, 2016.

  1. Mikthestik
    Joined: Mar 2016
    Posts: 55
    Likes: 1, Points: 0, Legacy Rep: 24
    Location: devon

    Mikthestik Junior Member

    This formula comes from Ayres book dated 1910 and seems to be very accurate. The problem with it was I could not be sure how to get MSA. That is no longer a problem. The results from this formula multiplied by 1.36 to give HP in average conditions. The calculation for Bismarck was wrong by about 170 SHP.
    What I noticed is at about SL =1.34 Power required is about 4hp/Ton which is an accepted rule of thumb.
    I feel it is a better formula than the admiralty formula on the same poge.
     

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  2. FAST FRED
    Joined: Oct 2002
    Posts: 4,519
    Likes: 109, Points: 63, Legacy Rep: 1009
    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "SL =1.34 Power required is about 4hp/Ton"

    A FINE NUMBER FOR THE MILITARY WITH FREE FUEL.

    Most folks who pay their own fuel bull will cut the bill in half or more ,by choosing SL .9 to 1.15 as a cruise target.
     
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