cox radial engine project

[RotarySMP]

Radials only need the odd number of cylinders if they are four strokes.

[dynosor]

Originally Posted by eject_21 Here's my stupid question... Why do radial engines need to have an odd number of cylinders? Could you have a twelve cylinder radial engine? (Four cycle implied)

Conventional single row radial engines share one crank pin by means of what is called a master connecting rod. As such, odd numbers of cylinders result in a smoother running engine: An even number of cylinders would imply that pairs of opposing pistons would move together such that when one piston is at tope dead center, its mate is at bottom dead center. The vibration characteristics of such an engine would be similar to an engine with half as meany, but twice as heavy pistons.

http://upload.wikimedia.org/wikipedi...gine_large.gif

As for even numbers, 10, 14 and 18 cylinder radial engines exist, but use two rows of 5, 7 or 9 cylinders.

[eject_21]

I believe the Anzani engines were made up of multiple rows. (two rows of three cylinders each, and two rows of five cylinders each.)
The Radcam engine is a two-cycle.
I guess you could have a twelve cylinder, Four rows of three? Sounds like more trouble than it's worth.

Edit:
Sorry,I didn't see page three before I posted the above.