#1 Flame
The energies involved (electromagnetism and kinetic acceleration) cause heat and compression. During acceleration down the rails there is some friction between the sabot (round being fired) and the rails which cause wear and – ah – shaving – of some metal fragments. The high acceleration, heat, and friction ignite the metal into a high energy plasma that causes the flame.
#2 Line of Sight (LOS) Range
LOS at sea level is about 3 miles, which means from a ship it might be in the 5-10 mile range depending on how high the observer is (standing on a deck or someone using a periscope like device on a higher mast). The railgun accelerates the run to something like mack 6+ that provides a range in excess of 100 miles for the round. The Navy has been targeting things well beyond LOS for generations. Voice communications, GPS, weather, drones, and aircraft in the battle environment can be inputted and linked into battle management and targeting systems that provide effective attack ranges well outside of LOS.
#3 Howitzer
Actually using the 16” guns from WWII as a comparison they fired a round that weight approximately 2000 lbs at about 2700 feet per second (about 1850 mph) for a range of about 25 miles (still longer than LOS). The railgun fires a smaller projectile (7-10 pounds) at very high velocity – about 8300 feet per second (about 5460 mph) for 100 mile range.
#4 Cost
When using long range anti-ship/anti-land based missiles the cost is in the missile itself (outside of launch and targeting systems). The cost of Harpoon anti-ship missile is about $1,500,000 each. The cost of the railgun round is about $25,000. I would expect a shipboard railgun would also be able to carry and fire many, many more railgun rounds to fire than it could carry anti-ship/anti-land missiles.
Hope this helps.
WW
USN Ret.
ATC/AW NAC
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