|View single post by Helmut|
|Posted: Sat Jan 25th, 2020 09:53 am||
What else than 21.95", to be exact, would you have expected?
You can calculate that Radius within 2 minutes,
when you just look at the geometrical dependencies.
Look at the drawing given in the link:
x/L = L/2R = sin(D/2)
So x=L*sin(D/2) =2R*sin²(D/2) or R= x/(2*sin²(D/2))
Take your values:
3/4" = 19mm, D=15°, sin(D/2) = 0.13, sin²(D/2)=0.017
Insert in formula for R: R = 19/(2*0.017) = 558.8mm = 22"
To calculate y, just remember that x/y = tan(D/2) and so y= x/tan(D/2)
In our case, y= 0.75/0,132 = 5.7
As easy as pie.