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Trammel method is a construction of an ellipse using a strip of paper, thin cardboard or sheet celluloid.

Construction of Ellipse using Trammel Method

Trammel method is a construction of an ellipse using a strip of paper, thin cardboard or sheet celluloid.

An ellipsograph uses the trammel method to create ellipses.

Construction of Ellipse using Ellipsograph

An ellipsograph uses the trammel method to create ellipses.

An ellipse can be constructed by pinning three pins and tying an inelastic in tightly around the pins.

Construction of Ellipse using Pin and String

An ellipse can be constructed by pinning three pins and tying an inelastic in tightly around the pins.

Create diameters with major, minor axes, or a pair of conjugate diameters. Construct a parallelogram, then divide into equal parts creating intersections for the curve.

Construction of Ellipse using Parallelogram

Create diameters with major, minor axes, or a pair of conjugate diameters. Construct a parallelogram,…

"Join A and D. Lay off DF equal to AC-DC. Bisect AF by a perpendicular crossing AC at G and intersecting DE produced at H. Make CG' equal to CG and CH' equal to CH. Then G, G', H, and H' will be centers for four arcs approximating the ellipse. The half of this ellipse when used in masonry construction is known as the three-centered arch." —French, 1911

Approximate Ellipse with Four Centers

"Join A and D. Lay off DF equal to AC-DC. Bisect AF by a perpendicular crossing AC at G and intersecting…

"This (five centered arc) method is based on the principle that the radius of curvature at the end of the minor axis is the third proportional to the semi-minor and semi-major axes, and similarly at the end of the major axis is the third proportional to the semi-major and semi-minor axes. The intermediate radius found is the mean proportional between these two radii." —French, 1911

Approximate Ellipse with Five Centered Arc

"This (five centered arc) method is based on the principle that the radius of curvature at the end of…

"When the minor axis is at least two-thirds the major, the following method ma be used: Make CF and CG equal to AB-DE. Make CH and CI equal to 3/4 CF F, G, H, I will be centers for arcs E, D, B, and A." —French 1911

Approximate Ellipse using Lines

"When the minor axis is at least two-thirds the major, the following method ma be used: Make CF and…

"Any noncircular curve may be approximated by tangent circle arcs, selecting a center by trial, drawing as much of an arc as will practically coincide with the curve, then changing the center and radius for the next portion, remembering always that if arcs are to be tangent, their centers must lie on the common normal at the point of tangency." —French 1911

Curve Inked with Circle Arcs

"Any noncircular curve may be approximated by tangent circle arcs, selecting a center by trial, drawing…

Aerodynamic of the ellipse where the area at point DD is small. The small area creates less resistance for the plane while in flight.

Ellipse Aerodynamic

Aerodynamic of the ellipse where the area at point DD is small. The small area creates less resistance…

The illustration of constructing a circle or ellipse using isometric drawing. The inscribed circle is transferred to the top part of the cube by creating diagonal lines through the center and series of squares.

Isometric Drawing of Circle using Square

The illustration of constructing a circle or ellipse using isometric drawing. The inscribed circle is…

A diagram showing the motions a young frog makes while swimming. In this stage of life, the frog makes ellipses in order to move through the water.

Ellipses of Swimming Frog

A diagram showing the motions a young frog makes while swimming. In this stage of life, the frog makes…

Sections of a cone. a, parabola; b, ellipse; c, hyperbola.

Cone

Sections of a cone. a, parabola; b, ellipse; c, hyperbola.