pitch calculations
04-03-2008, 11:05 AM
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pitch calculations
HI everyone. I need the calculations for the pitch if possible, I know its probably off topic but it's required as part of some research im currently doing. I Know that the speed has to be estimated and the working rpm but I can't find any information anywhere. If anyone has any info it would be helpful. thanks.
04-03-2008, 01:30 PM
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RE: pitch calculations
Try these links,
hope they will help.
http://www.land-and-sea.com/articles...ve_article.htm
http://www.castlemarine.co.uk/pitch.htm (haven't tried this one, I was at work and program downloads are blocked)
http://continuouswave.com/cgi-bin/propcalc.pl
Dan
hope they will help.
http://www.land-and-sea.com/articles...ve_article.htm
http://www.castlemarine.co.uk/pitch.htm (haven't tried this one, I was at work and program downloads are blocked)
http://continuouswave.com/cgi-bin/propcalc.pl
Dan
04-03-2008, 10:21 PM
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RE: pitch calculations
ORIGINAL: guver
Pitch is teeth per inch (48 and 64 and 32)
Pitch is teeth per inch (48 and 64 and 32)
Not when the topic is propellers.
Citing David Merriman,...
ORIGINAL: David Merriman
In a non slip envrionment, the distance a propeller blade will travel (axially to the propeller shaft) in one complete revolution, is called pitch. Pitch is a linear measurment.
Pitch is not an Angular expression. ...
... Ideally, the pitch at each radious point up and down the span of the blade is the same. therefore, the blade has a constant rate of helical twist to it. the degree of twist is a function of the pitch of the propeller....
...Rule of thumb, (for submarine propeller) make the pitch equal to the disc area ( a circle defined by the tip diameter). So if you know the diamter of your propeller, you have your pitch. If you take sixty percent of that area, and divde the number by the nubmer of blades you want, then you know the developed area of each blade...
In a non slip envrionment, the distance a propeller blade will travel (axially to the propeller shaft) in one complete revolution, is called pitch. Pitch is a linear measurment.
Pitch is not an Angular expression. ...
... Ideally, the pitch at each radious point up and down the span of the blade is the same. therefore, the blade has a constant rate of helical twist to it. the degree of twist is a function of the pitch of the propeller....
...Rule of thumb, (for submarine propeller) make the pitch equal to the disc area ( a circle defined by the tip diameter). So if you know the diamter of your propeller, you have your pitch. If you take sixty percent of that area, and divde the number by the nubmer of blades you want, then you know the developed area of each blade...
04-04-2008, 08:58 AM
#5
RE: pitch calculations
Most of our props are done with a ratio. Octura for instance uses the metric system as it's easier. The pitch may be 1.4-1.9 and sometimes more times the diameter so we know that a 1440 prop's pitch is 1.4 times 40mm. Some use a constant pitch but Octura uses a progressive pitch by cupping the blades.
We also use a slippage factor that can be between 15 and 25% depending upon hull design to help us roughly calculate speed at a certain RPM range.
Take a look at the thread pinned to the top of this forum as there is a lot of information to be had there.
We also use a slippage factor that can be between 15 and 25% depending upon hull design to help us roughly calculate speed at a certain RPM range.
Take a look at the thread pinned to the top of this forum as there is a lot of information to be had there.
