Yes, to make a 90 you will need 3 feet.
Not sure if anyone posted the following information on this forum but while determining what length of Logstor I needed, mathematics struck me in the brain again.
A 3 feet minimum bending radius does not mean the bent length of pipe is 3 feet long! (this is probably why some guys come up short on the length of their purchased Logstor.... just a guess).
Mathematics:
Circumference of a CircleIf one acknowledges that a 90 degree bend is basically 1/4 of the circumference of a circle, the actual length of Logstor piping that is needed strictly for the bend can easily be calculated.
Circumference of a Circle = 2 * pi * (
radius of the circle)
For a circle with a radius of 3 feet,
Circumference = 2 * pi * 3 ft. which equals 18.86 feet circumference length
A circle consists of 360 degrees but we only need to make a 90 degrees bend.
90 / 360 = .25 or 25% of the circumference of the circle with r=3.
25% of 18.86 = .25 * 18.86 feet =
4.71 feetIn short, for each 90 degree bend of Logstor piping with a minimum bending radius of 3 feet, one needs to purchase 4.71 feet of length.