Ever heard of a cannononball .. ovoid?

fearn · 30th August 2010, 05:47 PM

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

kronckew · 10th September 2010, 10:31 AM

just found this manual: (pdf format)

Gibbon Artillery Manual 2nd ed. 1863

rather extensive tome covering gunpowder and how to make it, artillery history,theory, construction in bronze and cast iron for coastal defence, naval and field artillery, alloys used, casting methods, bore turning, fittings, fixtures, tools, methods of employment, loading, firing, cleaning, spiking, unspiking, testing, etc. etc. also includes use with hot shot, heating shot in furnaces, how use of hot shot varied in differnt countries (french used wet hay wadding) use of sabots, rifling, elongated shot, shells, and even mentions electrical measurements of velocity (odd for 1863) as well as the development of gun cotton in 1846 which proved too strong for the guns and small arms of the time so was abandoned in spite of it's smokelessness...

fernando · 10th September 2010, 01:29 PM

Grrrreat stuff, Wayne.
Thanks for sharing.
I have just kept it in my files.

30th August 2010, 05:47 PM	#1
fearn Member Join Date: Dec 2004 Posts: 1,247	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

10th September 2010, 10:31 AM	#2
kronckew Member Join Date: Mar 2006 Location: Room 101, Glos. UK Posts: 4,249	just found this manual: (pdf format) Gibbon Artillery Manual 2nd ed. 1863 rather extensive tome covering gunpowder and how to make it, artillery history,theory, construction in bronze and cast iron for coastal defence, naval and field artillery, alloys used, casting methods, bore turning, fittings, fixtures, tools, methods of employment, loading, firing, cleaning, spiking, unspiking, testing, etc. etc. also includes use with hot shot, heating shot in furnaces, how use of hot shot varied in differnt countries (french used wet hay wadding) use of sabots, rifling, elongated shot, shells, and even mentions electrical measurements of velocity (odd for 1863) as well as the development of gun cotton in 1846 which proved too strong for the guns and small arms of the time so was abandoned in spite of it's smokelessness...

10th September 2010, 01:29 PM	#3
fernando (deceased) Join Date: Dec 2004 Location: Portugal Posts: 9,694	Grrrreat stuff, Wayne. Thanks for sharing. I have just kept it in my files.