Brucepts wrote:larrycavan wrote:Square root scales are laid out based on the rise. Change the rise and your scale graduations are thrown off.
Might want to go back and look at the math on this? Once you set the length of the water gauge your percent scale is set based on that length, changing the rise merely changes the angle of the percent scale it does not change the percent scale markings across the length of the scale. If you change the length of the scale then it will change those markings.
With all due respect to Ed [because his orifice flow calculation worksheet is priceless]... I disagree with the assessment of laying out a square root scale as you describe.
You lay out a square root scale by rise. Rise determines the length. Make the rise higher, the angled line has to be extended to reach the intersect of the resting plane on the same angle. The scale needs to be done over.
Either the length of the angled line or the angle of that line has to change. Either change invalidates the original scale.
That's the way an engineer showed me how to do it in 1994. I then laid out my scale using Cadkey on my pc. The math, as I understand it is related to the sin of the angle. So, for an inclined angel of 30 degrees you would have [1 / sin 30 = 2] or 1" on the vertical is 2" on the inclined.
Changing the angle to something other than 30 degrees, as you would if you changed the rise, forces the math recalculation as well. If that change was to an angle of 45 degrees then the math would be 1 Inch on the Vertical would be 1 / sin 40 or 1 /.707. Making 1 inch on the vertical equal 1.414 on the inclined.
Anyway, that's my story and I'm sticking to it unless proven wrong...in which case I will stand corrected.