Bp series propeller chart

Discussion in 'Props' started by Laranjo123, Oct 21, 2011.

  1. Laranjo123

    Laranjo123 Previous Member

    Hello gudday sirs. Where can i find a bp series propeller chart?. Cause mine is very blured?
     
  2. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

  3. Laranjo123

    Laranjo123 Previous Member

    Sir sorry to ask such question but how do i read this graphs....? i have bp=69.15
     
  4. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    I don't understand why you would want to use a Bp-Delta chart instead of calculating Kt Kq directly for any wheel. If you have Bp based upon installed power and desired speed, then you will have to check several of the charts to get the best fit blade number and size. By calculating directly you can get a more optimum prop. You already have all the data you need (i.e. torque, rpm and speed) to start optimization.

    Anyway, here is a source of Bp-Delta charts for some wheels. With the Kt, Kq data above you could develop your own charts.

    http://hem.bredband.net/lagaren/props.htm

    So was your question on how to use a Bp-Delta chart or how to convert Kt,Kq and J data to Bp-Delta?
     
  5. Laranjo123

    Laranjo123 Previous Member

    I want to know the delta, pitch ratio and the efficiency using the bp. I don't know how to use the BP chart it's my first time to use this...
     
  6. Adler
    Joined: Jan 2010
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    Location: PIRAEUS - GREECE

    Adler Senior Member

    Advice

    Dear,

    You can find the method to D.Gerr "Propeller Handbook" Chapter 6 p.66-82.
    There is an extended and popular breakdown of Bp-δ method.
     
  7. jehardiman
    Joined: Aug 2004
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    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    Enter your chart with your Bp accross the bottom. Go up your Bp line until you reach the maximum eta (efficency), it is usually marked as a line that curves down left-to-right through the eta curves (think of the eta curves like a topographical map, you want to be on the highest point you can). Use this point to read off your delta (the curves that sweep down from right-to-left) and your pitch ratio (left axis).

    I will tell you right now that your Bp is too high for good efficency. Are you using the wake reduced Va? And if so, you should consider increasing the reduction in your gearset. Increasing reduction will make the prop larger and increase the pitch ratio.
     
  8. Laranjo123

    Laranjo123 Previous Member

    Yes i did use of that wake..What will happen if i still continue?...
     
  9. Laranjo123

    Laranjo123 Previous Member


    Sir what chart which is which? What B do i have to use?...Btw how many blades are involve in this chart?.....
     
  10. Laranjo123

    Laranjo123 Previous Member

    [​IMG]

    Sir i would like to know which is the ( efficiency , delta, MWR, BTF )
    The yellow = pitch ratio
    the cyan = my BP somewhere there
    the violet = bp ranges
    red =?
    blue ? ( is it the eta? )
    red =?
    green =?
     
  11. Laranjo123

    Laranjo123 Previous Member


    Mr.Adler i don't have that book do you own one? Do you mind could you share it to me?...Please
     
  12. Laranjo123

    Laranjo123 Previous Member

    Any help people just tell me what B chart do i need and what particular name does those color stands for.?..
     
  13. Anttey
    Joined: Nov 2011
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    Location: Maldives

    Anttey Junior Member

    Now quite the similar topic here. I am at the diameter determining stage. The series is Wageningen.But first I'm suppose to determine the blade number so that I could proceed to Bp-delta chart. I'm asked to determine it from the simmilar type of yachts I'm working on..

    Would anyone suggest me the number of blades for a twin screw motor yacht?
    L=26.17
    B=6.96
    T= 1.22
    Cb= 0.46
    for 30knots iv around 3000HP per screw.
     
  14. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    Start with the lowest number of blades commercially available, find the optimum prop and then perform the cavitation check. If cavitation is predicted, increase the number of blades. Repeat the process until the cavitation check returns an acceptable value.
    Cheers
     

  15. Anttey
    Joined: Nov 2011
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    Location: Maldives

    Anttey Junior Member

    Thank you.
    Cheers
     
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