Ever heard of a cannononball .. ovoid?

[fearn]

re heating cherry red: the thing about these balls is that they're thick. If it's hot on the outside, it almost certainly won't be that hot on the inside.

If it was hot enough to deform, it would droop, not turn egg-shaped. You can run this experiment yourself with a candle, a ball of wax, and something to roll the ball of wax over the flame.

You can also try rolling an egg down a rail, with the long ends on the rails. The egg is going to "want" to spin the long axis, so it's going to twist as it rolls to roll on the short axis. In doing this, it will probably get stuck. So having an oval design isn't going to keep a cannonball on the rails. Round would be simpler.

The thickness of the cannonball will affect how it ignites. For example, if it skips across the water (another place where a spinning round shape works well--see the dam busters), only the part that touches the water will cool, and the heat from the inside will move to the outside. You could get the interesting situation of a cannonball with a cool outer skin hitting a piece of wood, then getting hot enough on the surface to ignite the wood (and this assumes the wood was dry).

Best,

F