Some input please?
Fg = mg = W (weight of an object is usually taken to be the force on the object due to gravity) in Newtons. http://en.wikipedia.org/wiki/Weight
W = mg.
A shell has a mass (m) of 0.3kg and gravity (g) is 9.8 m/s2. W = 0.3 x 9.8 = 2.94 N
(1) Mortars can be constructed from heavy cardboard, plastic (HDPE=High Density PolyEthylene), GRP (Glass Reinforced Plastic) or metal sunk into the ground or mounted in racks. The shell must fit snugly inside the mortar to allow proper thrust.
Shells measure from two inches to three feet in diameter and can weigh up to 700 pounds. http://www.paramount...m/launching.asp
If shell, "must fit snugly inside the mortar to allow proper thrust
" this is 2.94 N + frictional force between the shell and mortar surface + X newtons of force to accelerate the shell to a Y muzzle velocity.So lifting force is, (Weight of shell 2.94 N) + (Friction N) + (Acceleration N) = Y muzzle velocity.
(2) The last thing to do now is to make sure the shell will drop freely into the mortar from which it is to be fired.
If the shell is too snug, you can roll the leader side of the shell on a flat surface to reduce its thickness. http://www.skylighte...Ball-Shells.asp
If shell, "drop freely into the mortar
" this is 2.94 N + X newtons of force to accelerate the shell to a Y muzzle velocity. Frictional force between the shell and mortar surface is negligible.So lifting force is, (Weight of shell 2.94 N) + (Acceleration N) = Y muzzle velocity.
This also has effect on the ballistic chronograph accuracy, to measure Y muzzle velocity, of the shell exiting the mortar muzzle. No issue with "fit snugly inside the mortar", but the "dropped freely into the mortar" will cause the lifting charge expanding gasses + solids dust (smoke) to escape before the shell at the mortar muzzle. Usually, Infra Red (IR) LED's are used, but I was going to used a laser diode to compensate.So my question is, "dropped freely into the mortar" or "fit snugly inside the mortar" ???