Lesson 2 1 J. Byrne 2015

String & Pins String & Pins Take half the Major axis and strike an arc on the X line to give you a Focal Point. F1 Repeat for the other side. F2 The plural of these are called Foci Points. Half Major F1F2 2 J. Byrne 2015

Draw an Ellipse given F1 & F2 and Minor Axis Draw an Ellipse given F1 & F2 and Minor Axis The distance between the Foci points is 160mm The length of the Minor axis is 72mm 3 J. Byrne 2015 Half the Major from F1

Draw an Ellipse given F1 & F2 and Minor Axis Draw an Ellipse given F1 & F2 and Minor Axis Once you have your major axis you now have both axis lengths and can draw in the Ellipse. Put a point on your ellipse. Draw a line from both F1 & F2 to this point on the ellipse. Bisect the angle and extend the line. This is the Normal. 4 J. Byrne 2015

The Normal bisects the angle made by joining the two foci points. The Tangent is at 90º to the normal. To find Normal bisect the angle between F1 and F2. To find the Tangent bisect the angle between F1 and extension of F2. 5 J. Byrne 2015

Below is a drawing representing a wine glass The curve ABC is part of an ellipse with a major axis 130mm & F is the focal point. The curve JKL is based on a parabola with K as the vertex 6 J. Byrne 2015

This drawing is the elevation of a lamp. The curve ABCD is based on an ellipse with a major axis 150mm & minor axis of 80mm. E & F are the foci points. The line AT is a tangent to the ellipse at A The curve GAH is based on a parabola with A as the vertex Draw the design showing all construction lines. 7 J. Byrne 2015

Draw this design full size and dimension correctly. All construction lines and POC’s must be shown. Please note the following: The curve AED is part of an ellipse with F & F1 its focal points. The curve ABC is a parabola with the vertex at B. The line CD is a tangent to the ellipse. The 5 windows are identical and equally spaced. 8 J. Byrne 2015 Template for a wooden toy aeroplane.