Flight Mechanic

Aircraft Mechanic School Study Supplement for Future Aviation Maintenance Technicians




You are here: Home / Basic Aviation Maintenance / Aviation Mathematics / Computing Area of Two-dimensional Solids – Circles and Ellipses
Regretfully, Flight-Mechanic will be turning out the lights after fifteen years. Google, in its infinite wisdom, has chosen to remove Flight-Mechanic from its search results (the claim is that the content on this site is spam). We appealed their decision to shut us down, to no avail.

Unfortunately, since Google has a monopoly over internet search, this means that traffic levels on the site will drop to a level that makes maintaining it uneconomic. As time progresses, we will no longer be able to maintain the server space and will remove the site from the internet. Thanks to all who have supported us over the years.

To fight back against the monopolistic practices of companies like Google, we recommend using a competing search engine such as Brave (you get the added benefit of not being spied on by Big Tech) and advocating for anti-trust legislation from your representatives.

Computing Area of Two-dimensional Solids – Circles and Ellipses

Filed Under: Aviation Mathematics

Circle

A circle is a closed, curved, plane figure. [Figure 1‑20] Every point on the circle is an equal distance from the center of the circle. The diameter is the distance across the circle (through the center). The radius is the distance from the center to the edge of the circle. The diameter is always twice the length of the radius. The circumference, or distance around, a circle is equal to the diameter times π.

Figure 1-20. Circle.
Figure 1-20. Circle.

Circumference = C = d π

The formula for the area of a circle is:

Area = π × radius2 = π × r2

Example: The bore, or “inside diameter,” of a certain aircraft engine cylinder is 5 inches. Find the area of the cross section of the cylinder.

First, substitute the known values in the formula:

A = π × r^2.

The diameter is 5 inches, so the radius is 2.5 inches. (diameter = radius × 2)

A = 3.1416 × (2.5 inches)^2 = 3.1416 × 6.25 square inches = 19.635 square inches

Ellipse

An ellipse is a closed, curved, plane figure and is commonly called an oval. [Figure 1-21] In a radial engine, the articulating rods connect to the hub by pins, which travel in the pattern of an ellipse (i.e., an elliptical or obital path).

Figure 1-21. Ellipse.
Figure 1-21. Ellipse.

 

Flight Mechanic Recommends

Rod Machado's Private Pilot Handbook -Flight Literacy recommends Rod Machado's products because he takes what is normally dry and tedious and transforms it with his characteristic humor, helping to keep you engaged and to retain the information longer. (see all of Rod Machado's Products).
   
-->