Inside the Radials

An Examination of the Radial Piston Aircraft Engine on CD-ROM

From the Depression into the Cold War years, aircraft propulsion technology was dominated by the radial piston engine. Inline engines derived from automotive technology powered some of the fastest fighters, but the radials delivered the massive power levels it took to propel the "heavy iron" of World War II and the postwar airline industry. Some of them developed 100 horsepower per cylinder and 1 horsepower per cubic inch, and many a radial brought its pilot home with one or more cylinders shot away by enemy fire.

Today, almost anyone interested in machinery can draw a picture of the major parts of a V-8 or opposed engine and explain how it works -- but the complex geometries of the radial engine are no better known than the valve gear of a steam locomotive.

Inside the Radials is an attempt to bring this information to the Nineties reader. The CD-ROM contains a .pdf file that presents ten animations of the major mechanical assemblies of a representative radial, the Pratt & Whitney R-2800, which is often regarded as the most significant engine of the World War II years. The .pdf file also gives general descriptions of the operating principles. Here are single frames from each of the animations, with descriptions.

Crankshaft with one row of pistons
Crankshaft and all pistons
Second order counterbalances
Valve trains
Cam rings
Supercharger drive (front view)
Supercharger drive (rear view)
Propeller reduction gear (outer gear removed)
Propeller reduction gear (complete)
Complete engine

System Requirements

This product is designed to run under Microsoft® Windows 95® or later, and it needs a reasonably powerful machine for best results. The animation files range from 16 to 37 megabytes long, and for smooth animation your machine will have to have enough memory to cache them. If your memory size is smaller than the animation files, they will still run but there will be jerks in the animation as the files are read and reread from the disk.

In order to keep the file sizes within reason, the animations are rendered at 640x480 resolution. All of them run smoothly on a 64 Mb machine.

This product is based on a .pdf file, which means you will need Adobe® Acrobat®. Most recent Windows® machines have it installed; a copy is provided on the installation disk for those that don't.

The animations are .avi files and will run if you have Microsoft® Video For Windows®(on Windows 95 machines), the Windows Media Player, or any other popular animation display program.

The product has no installation routine as such; it's just a .pdf file that calls .avi files, and you can run it from the CD-ROM or copy it into a hard disk directory and run it from there.

Inside the Radials is available on CD-ROM at $25. To purchase it, go to Contact & Ordering.