Where can this be helpful to the hvac industry? If you need
to cut into a duct to add a round pipe at a particular angle,
you can quickly draw an elliptical shape to use as a pattern.
Takes the guess work out of it.
An ellipse is a closed curve which has two axes, namely, a
major axis, or longest diameter, and a minor axis,
or shortest diameter. It also has two points on the major
axis called the foci, which lie equidistant from it's center.
How to determine the length of
the major and minor axis?
Our illustration shows a 5 inch cylinder or tube that has been
cut across at 60 deg.. To develop the ellipse, you must find
the length of the major axis as well as the length of the minor
axis.
Draw a a plan view and a top view of the cylinder. Our cut
line is 60 deg. That surface becomes an elliptical shape.
An ellipse is a closed curve which has two axes,
namely, a major axis, or longest diameter, and a minor
axis, or shortest diameter.
Find the true length of the major axis looking
perpendicular to the plane.
shows the difference in length. Elevation view Vs the front view.
Take notice the 60 deg. plane is only approx. 8 5/8 compared to
the true length of nearly 10".
in fig 2 you can see how the major axis is developed by projecting
lines perpendicular to the plane. The top view shows the true
length of the minor axis (Remember,
looking perpendicular to its plane).
