Redesigned this as part of the CPR sequence for doing the M1 Abrams series
of MBT
Some thoughts that have occurred to me over the years (and this time in
particular):
Ammo is pretty far off and should probably be more detailed. Rather simple
assumption, regardless of type. The table should adjust for materials and
intent, as well as just TL. For example, 120mm ammunition if I'm reading
right is 30kg regardless if it's APFSDS, AFSDSDU, HEAT (HEAP, etc). Real
Life� ... or even Wikipedia. much less my FM-17-12 (aka 3-20) tells us the
M829 sabot variants ranged from 18.6 to 22.3kg depending on the propellant
and density of the DU penetrator as well as details like metal vs carbon
fiber sabots, etc.
Loading times and crew requirements don't seem to fit my experience or
understanding of our own MBT. I don't consider the Abrams to have
mechanical assist, for example, and default timing is one 5-second combat
round per MJ. In the standard crewman skills test, the deadline is 7
seconds for the 120mm and my manual says 5 seconds for the 105mm. In the
Fleet, a loader is gonna kicked if he can't do it in 4-5 seconds which is
about the minimum for the hydraulic door to open enough to grab the round.
The crew requirements might work for indirect fire as it is, though and
would also either be a human loader or an autoloader. Almost ironic that
NATO used human loaders and Warsaw Pact nations used mechanical
autoloaders given their doctrines on man vs machine.
The time/power discrepancy actually seems to be somewhat proportional to
the MJ difference, which has a natural correlation to the size and thus
weight of the round at the MJ calculated (8.85MJ for the M256 vs 6.90MJ for
the M68/L7 105mm). Realistically, the proper time to load should be a
function of the size of the round and the strength of the loader and
experience and familiarity with the task. In a skill system like TNE,
basic Task Failure would be accomplished in the speed of the MJ while basic
success would just beat it by exactly 2 seconds each. Outstanding success
would double that by shaving 4 seconds giving realistic times. Critical
failure would mean damaging the round, possible causing misfire or perhaps
striking the combustible case and releasing propellant in the turret! Ref
discretion. There, that nit is picked with my House Rule.
The Abrams uses safety features that actually slow down the loading, though
increases crew safety. Lap-loading (holding a round in the lap while
waiting for command), etc could be much faster and while I hear it was SOP
in the old days with the M60 but that was before blow-off panels, etc.
Soviet autoloaders are SLOW (they max elevate to eject the round) but one
5-second round per MJ still sounds excessive. 2 seconds per MJ rounded up
to the nearest whole combat round is more reasonable for autoloaders. Most
Soviet/former-Soviet designed tanks are going to take 2-3 rounds or so
which is between 150-200% the time a NATO meatbag loader not messing it up
is going to take . Not sure what the thought process was for this design
sequence. I imagine it's indirect fire but maybe Dave can elaborate.
anyhoo:
*M256 Cannon / Rheinmetall 120mm L/44*
TL8
528cm Long (120/44 caliber)
Laser Rangefinder (LRF)
Optical Rangefinder (GAS)
TL8 Digital Ballistic Computer
Direct Mount
No options
8.85 MJ muzzle energy
Crew: 2
Range: KE 494m / HE 370m
Reloading: 9 rounds* [1-2 rounds per Skill/Task roll]
Volume: 2.0204 m3
Mass: 2.0204 tonnes
Price: 0.048 MCr
*Ammunition*
APFSDSDU (M829)
TL8
12cm
Damage: 26
Burst: nil
Penetration: Short: 145, Med: 135, Long:125, Extreme: 105
Price: 900 Cr
HEAP (HEAT M830)
TL8
12cm
Damage: 16
Burst: 29
Penetration: 113C
Price:450 Cr
of MBT
Some thoughts that have occurred to me over the years (and this time in
particular):
Ammo is pretty far off and should probably be more detailed. Rather simple
assumption, regardless of type. The table should adjust for materials and
intent, as well as just TL. For example, 120mm ammunition if I'm reading
right is 30kg regardless if it's APFSDS, AFSDSDU, HEAT (HEAP, etc). Real
Life� ... or even Wikipedia. much less my FM-17-12 (aka 3-20) tells us the
M829 sabot variants ranged from 18.6 to 22.3kg depending on the propellant
and density of the DU penetrator as well as details like metal vs carbon
fiber sabots, etc.
Loading times and crew requirements don't seem to fit my experience or
understanding of our own MBT. I don't consider the Abrams to have
mechanical assist, for example, and default timing is one 5-second combat
round per MJ. In the standard crewman skills test, the deadline is 7
seconds for the 120mm and my manual says 5 seconds for the 105mm. In the
Fleet, a loader is gonna kicked if he can't do it in 4-5 seconds which is
about the minimum for the hydraulic door to open enough to grab the round.
The crew requirements might work for indirect fire as it is, though and
would also either be a human loader or an autoloader. Almost ironic that
NATO used human loaders and Warsaw Pact nations used mechanical
autoloaders given their doctrines on man vs machine.
The time/power discrepancy actually seems to be somewhat proportional to
the MJ difference, which has a natural correlation to the size and thus
weight of the round at the MJ calculated (8.85MJ for the M256 vs 6.90MJ for
the M68/L7 105mm). Realistically, the proper time to load should be a
function of the size of the round and the strength of the loader and
experience and familiarity with the task. In a skill system like TNE,
basic Task Failure would be accomplished in the speed of the MJ while basic
success would just beat it by exactly 2 seconds each. Outstanding success
would double that by shaving 4 seconds giving realistic times. Critical
failure would mean damaging the round, possible causing misfire or perhaps
striking the combustible case and releasing propellant in the turret! Ref
discretion. There, that nit is picked with my House Rule.
The Abrams uses safety features that actually slow down the loading, though
increases crew safety. Lap-loading (holding a round in the lap while
waiting for command), etc could be much faster and while I hear it was SOP
in the old days with the M60 but that was before blow-off panels, etc.
Soviet autoloaders are SLOW (they max elevate to eject the round) but one
5-second round per MJ still sounds excessive. 2 seconds per MJ rounded up
to the nearest whole combat round is more reasonable for autoloaders. Most
Soviet/former-Soviet designed tanks are going to take 2-3 rounds or so
which is between 150-200% the time a NATO meatbag loader not messing it up
is going to take . Not sure what the thought process was for this design
sequence. I imagine it's indirect fire but maybe Dave can elaborate.
anyhoo:
*M256 Cannon / Rheinmetall 120mm L/44*
TL8
528cm Long (120/44 caliber)
Laser Rangefinder (LRF)
Optical Rangefinder (GAS)
TL8 Digital Ballistic Computer
Direct Mount
No options
8.85 MJ muzzle energy
Crew: 2
Range: KE 494m / HE 370m
Reloading: 9 rounds* [1-2 rounds per Skill/Task roll]
Volume: 2.0204 m3
Mass: 2.0204 tonnes
Price: 0.048 MCr
*Ammunition*
APFSDSDU (M829)
TL8
12cm
Damage: 26
Burst: nil
Penetration: Short: 145, Med: 135, Long:125, Extreme: 105
Price: 900 Cr
HEAP (HEAT M830)
TL8
12cm
Damage: 16
Burst: 29
Penetration: 113C
Price:450 Cr