Author Topic: Logistics - Fuel Consumption  (Read 2182 times)

boilerman

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Logistics - Fuel Consumption
« on: 14 September 2017, 20:04:42 »
This is part of the same essay Moving the Goods is from.  The formulas are based on the fuel consumption formulas for support vehicles from when they were first introduced, long before the TechManual

Fuel

Fuel can be, by mass, the single largest category of consumable an army requires, not only among its combat vehicle regiments, but also among BattleMech regiments, due to the large number of support vehicles modern warfare requires.  Indeed, since the Amaris Civil War the number of fusion powered vehicles, combat and support, with their minimal fuel requirements, measured in milligrams per hundreds of thousands of kilometers, has plummeted, while the number of fuel burning vehicles has increased almost exponentially.  Thus fuel remains among the biggest of concerns for logisticians. 

Fuel, in most military services, is handle much like supply allotments; each unit is allocated so much to operate with.  Each regiment usually has the lift capacity to carry three full days worth of fuel, where that fuel is controlled from however depends on the service.  Most services provide a day’s worth of fuel within the company field train and hold the rest at the regiment level; some, however, prefer to spread it out evenly among the company, battalion and regiment field trains.

Calculating fuel requirements is an art as much as it is a science, logisticians spend consider time adding up fuel requirements for specific conditions, most military services have a volume or two of instructions on how to do it, but as with most military plans few survive contact with the enemy.  In other words demand usually outstrips supply so commanders must be flexible, but they must also know their basic requirements, and that requires a lot on basic information and math.  Essentially a command staff starts by adding up the basic fuel requirements for all of its fuel burning vehicles and equipment.  This information usually comes from a reference table list fuel requirements for various periods of time and distances traveled. 

Most units start calculating their fuel requirements by determining each vehicle’s hourly or per kilometer fuel consumption rate, while it is moving at its cruise speed.  From there they multiply that consumption rate by the hours or kilometers the vehicle is expected to operate during a typical day, which is usually 12 hours out of every 24.  Most units do not actually operate their vehicles’ engines at cruise speed for a full 12 hours a day, but experience has shown that on average a combat vehicle will burn about 12 hours worth of fuel in a day road marching, shifting position regularly, moving cross-country and fighting, when a driver is more concerned about power, rather than fuel economy.  Support vehicles frequently spend more than 12 hours a day on the road to insure that the supplies keep flowing.  Once each vehicle’s fuel consumption rate is known, they are all added up to get a grand total for the unit.  This gives the commander and logisticians a good idea how much fuel they will require for planning purposes.
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Table of Fuel Consumption Rates for known Combat Vehicles

Hover
APC, Hover, 10-ton           0.62kg/km         67.4kg/hr
Blizzard Hover Transport     1.28kg/km        110.2kg/hr
Centipede Scout Car          0.82kg/km         70.5kg/hr
Condor Heavy Hover Tank      2.04kg/km        176.3kg/hr
Gladius Medium Tank          1.63kg/km        141.0kg/hr
Harasser Missile Platform    1.50kg/km        162.0kg/hr
Heavy APC, Hover             0.82kg/km         70.5kg/hr
Maultier Hover APC           0.77kg/km         74.4kg/hr
Maxim Heavy Hover Transport  2.04kg/km        176.3kg/hr
Musketeer Hovertank          1.59kg/km        120.2kg/hr
Pegasus Light Hovertank      1.43kg/km        123.1kg/hr
Plainsman Medium Hovertank   1.79kg/km        173.5kg/hr
Scaracen/Scaracen/Scimitar   1.43kg/km        123.1kg/hr

Tracked
APC, Tracked, 10-ton         0.78kg/km         50.5kg/hr
Behemoth Heavy Tank          1.56kg/km         33.8kg/hr
Bulldog Medium Tank          2.34kg/km        101.1kg/hr
Demolisher Heavy Tank        2.03kg/km         65.6kg/hr
Engineering Vehicle          3.12kg/km        202.2kg/hr
Goblin Medium Tank           1.75kg/km         75.8kg/hr
Heavy APC, Tracked           1.13kg/km         61.1kg/hr
Heavy LRM Carrier            1.25kg/km         26.9kg/hr
J-27 Ordnance Transport      0.57kg/km         30.5kg/hr
LRM Carrier(TRO3058)         0.94kg/km         20.2kg/hr
LRM/SRM Carrier              1.52kg/km         49.1kg/hr
LT-MOB-25 Long Tom Artillery 1.56kg/km         33.7kg/hr
Hi-Scout Drone Carrier       2.34kg/km        101.1kg/hr
Pathtrack (TRKD) Drone     0.18kg/km         15.9kg/hr
Napfind (HOV) Drone        0.47kg/km        127.4kg/hr
Huitzilopochtli Assault Tank 1.33kg/km         28.6kg/hr
           (Clan)
Ontos Heavy Tank             2.42kg/km         78.3kg/hr
Partisan Heavy Tank          2.02kg/km         65.6kg/hr
Pike Support Vehicle         1.52kg/km         49.3kg/hr
Po Heavy Tank                2.34kg/km        101.1kg/hr
Scorpion Light Tank          0.98kg/km         42.2kg/hr
Sturmfuer Heavy Tank         2.16kg/km         70.1kg/hr
Vedette Medium Tank          2.85kg/km        152.7kg/hr
Zhukov Heavy Tank            1.90kg/km         61.6kg/hr
Zorya Light Tank (Clan)      1.37kg/km         59.0kg/hr

Wheeled
APC, Wheeled, 10-ton         0.45kg/km         29.2kg/hr
BattleMech Recovery Vehicle  2.25kg/km        145.8kg/hr
Coolant Truck (Class 135-K)  0.68kg/km         29.2kg/hr
Darter Scout Car             0.78kg/km         58.7kg/hr
Flatbed Truck                0.33kg/km         17.6kg/hr
Heavy APC, Wheeled           0.90kg/km         58.3kg/hr
Heavy 'Mech Recovery Vehicle 1.58kg/km         68.0kg/hr
Hetzer Wheeled Assault Gun   0.90kg/km         38.9kg/hr
Light SRM Carrier            0.90kg/km         38.9kg/hr
Skulker Wheeled Scout Tank   1.20kg/km         90.8kg/hr
Striker Light Tank           1.14kg/km         61.7kg/hr

VTOL
Cavalry Attack Helicopter    0.98kg/km        105.3kg/hr
Ferret Light Scout VTOL      0.44kg/km         69.5kg/hr
Hawk Moth Gunship            0.64kg/km         55.0kg/hr
Karnov UR Transport(TRO3026) 1.41kg/km        167.5kg/hr
Karnov UR Transport(TRO3058) 1.17kg/km        126.4kg/hr
Kestrel VTOL                 1.39kg/km        179.8kg/hr
Marten Scout VTOL            0.98kg/km        136.7kg/hr
Warrior Attack VTOL          0.83kg/km         89.1kg/hr
Yellow Jacket Gunboat        0.45kg/km         29.2kg/hr

Naval
Monitor Naval Vessel         1.02kg/km         33.2kg/hr
Neptune Submarine            1.37kg/km         44.2kg/hr
Sea Skimmer                  2.24kg/km        217.2kg/hr

Note: these fuel consumption rates for canon combat vehicles are based on the Support Vehicle Construction Rules in Combat Equipment.  All ICE powered vehicles from Technical Readouts 3025, 3026, 3058, 3060 & 3067 are included and assumed to have Tech Level 1/D ICE engines for the purposes of these calculations.

Calculating Fuel Consumption

Fuel consumption or efficiency can be calculated for any fuel-burning CBT vehicle using the formulas listed below, all the information that is required is the vehicle’s Cruise MP, Mass and Technology Level.  To determine the vehicle’s fuel efficiency or fuel consumption rate you must first determine its K factor, which is a multiplier to adjust for unit conversions and technology level.  You can select the K factor from the charts below or you can calculate it yourself using the K factor formula.  Once you have the appropriate K factor simply plug the various numbers into the FE or FC formula.  The result comes out in either kilometers per kilogram or kilogram per kilometer units, depending on the formula used. 
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Fuel Efficiency Formula

           1
FE = ______________   Units: Kilometers/kilogram
     (k(4+(C*C))*V

Fuel Consumption Formula

FC = (k(4+(C*C))*V    Units: Kilograms/Kilometer

Where:  K = K factor, see below
        C = Cruise Movement Points
        V = Vehicle Mass (tons)


K Factor Formula

K = 0.001*X*Y*Z

Where: X = Base Engine & Transmission Factor, from the
           Support Vehicle Chassis Table p88 in Combat Equipment

       Y = Engine & Transmission Weight Multiplier, from the
           Power Source Modifier Table p103 in Combat Equipment

       Z = Fuel % of Engine & Transmission Weight per 100km, from the
           Power Source Modifier Table p103 in Combat Equipment


Vehicle K Factors
Small Wheeled (100-4999kg)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.00075  0.0005    0.000375  0.000325  0.00025
  Electric (Battery)      -     0.001875  0.0015    0.00125   0.001
  Electric (Fuel Cell)    -     0.00045   0.000375  0.000338  0.000263

Medium Wheeled (5-80tons)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.00225   0.0015   0.001125  0.000975  0.00075
  Electric (Battery)      -     0.005625  0.0045    0.00375   0.002625
  Electric (Fuel Cell)    -     0.00135   0.001125  0.001013  0.000788

Large Wheeled (80.5-160tons)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.0045   0.003     0.00225   0.00195   0.0015
  Electric (Battery)      -     0.01125   0.009     0.0075    0.006
  Electric (Fuel Cell)    -     0.0027    0.00225   0.002025  0.001575

Small Tracked (100-4999kg)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.0018   0.0012    0.0009    0.00078   0.0006
  Electric (Battery)      -     0.0045    0.0036    0.003     0.0024
  Electric (Fuel Cell)    -     0.00108   0.0009    0.00081   0.00063

Medium Tracked (5-100tons)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.0039   0.0026    0.00195   0.00169   0.0013
  Electric (Battery)      -     0.00975   0.0078    0.0065    0.0052
  Electric (Fuel Cell)    -     0.00234   0.00195   0.001755  0.001365

Large Tracked (100.5-200tons)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.0075   0.005     0.00375   0.00325   0.0025
  Electric (Battery)      -     0.01875   0.015     0.0125    0.01
  Electric (Fuel Cell)    -     0.0045    0.00375   0.003375  0.02625

Small Hover (100-4999kg)*
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.00075  0.0005    0.000375  0.000325  0.00025
  Electric (Battery)      -     0.001875  0.0015    0.00125   0.001
  Electric (Fuel Cell)    -     0.00045   0.000375  0.000338  0.000263

Medium Hover (5-50tons)*
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.0012   0.0008    0.0006    0.00052   0.0004
  Electric (Battery)      -     0.003     0.0024    0.002     0.0016
  Electric (Fuel Cell)    -     0.00072   0.0006    0.00054   0.00042



Large Hover (50.5-100tons)*
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.0024   0.0016    0.0012    0.00104   0.0008
  Electric (Battery)      -     0.006     0.0048    0.004     0.0032
  Electric (Fuel Cell)    -     0.00144   0.0012    0.00108   0.0084

Small VTOL (100-4999tons)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.0006   0.0004    0.0003    0.00026   0.0002
  Electric (Battery)      -     0.0015    0.0012    0.001     0.0008
  Electric (Fuel Cell)    -     0.00036   0.0003    0.00027   0.00021

Medium VTOL (5-30tons)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.00075  0.0005    0.000375  0.000325  0.00025
  Electric (Battery)      -     0.001875  0.0015    0.00125   0.001
  Electric (Fuel Cell)    -     0.00045   0.000375  0.000338  0.000263

Large VTOL (30.5-60tons)
Engine Type/ Tech Level:  B         C         D        E         F
  ICE                  0.0012   0.0008    0.0006    0.00052   0.0004
  Electric (Battery)      -     0.003     0.0024    0.002     0.0016
  Electric (Fuel Cell)    -     0.00072   0.0006    0.00054   0.00042
*Note: hover vehicles must allocate a minimum of 20% of their overall mass to their engine and transmission as per the Support Vehicle Construction Rules.

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Alsadius

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Re: Logistics - Fuel Consumption
« Reply #1 on: 14 September 2017, 20:35:56 »
This is good stuff - I've always felt that logistics is one big weak spot of the BT universe, and this seems like quality material to fill in those gaps. Please post more(though perhaps confine it to a single thread as best you can?).

Thanks.

I am Belch II

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Re: Logistics - Fuel Consumption
« Reply #2 on: 15 September 2017, 08:06:39 »
Nice job.
Some things in the CBT universe are really fuel efficient for their size!!!
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idea weenie

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Re: Logistics - Fuel Consumption
« Reply #3 on: 15 September 2017, 18:42:48 »
It looks like thanks to the equation, that vehicles with a high cruising speed have a high fuel consumption rate.  If you double the cruising speed, they consume ~4 the amount of fuel.

But very nice work, thank you for making this.  Now for the fun if calculating how far a cargo vehicle can go when it is carrying only fuel, and compare several different designs.

Col Toda

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Re: Logistics - Fuel Consumption
« Reply #4 on: 18 September 2017, 17:29:37 »
Fuel is serious . I prefer fusion engine or hydrogen fuel cell engine combat vehicles . So everything uses hydrogen . Landing near a water source to crack hydrogen to resupply the spent fuel . If combat is intense enough your vehicles fuel consumption will be the limiting factor on how long the drop ship load can remain on planet . Otherwise it ammo or food .

idea weenie

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Re: Logistics - Fuel Consumption
« Reply #5 on: 18 September 2017, 20:52:22 »
Fuel is serious . I prefer fusion engine or hydrogen fuel cell engine combat vehicles . So everything uses hydrogen . Landing near a water source to crack hydrogen to resupply the spent fuel . If combat is intense enough your vehicles fuel consumption will be the limiting factor on how long the drop ship load can remain on planet . Otherwise it ammo or food .

One post on this board had the concept of a fusion-powered 'recharging' vessel, and the other vehicles in the unit used electric engines.  The batteries could be swapped out while on the move, so a battery powered vehicle would use up from one battery, detach the used battery, and swap it with a full battery from the fusion-powered recharging vehicle.

A similar idea for a fusion-powered vehicle cracking the water from fuel cells could be used to refuel them during rest stops (connect pressurized hoses, transfer compressed hydrogen in one hose and oxygen in the other, and keep on going).  Limit is going to be the solders' butts.

boilerman

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Re: Logistics - Fuel Consumption
« Reply #6 on: 18 September 2017, 21:02:06 »
I like the battery-powered trucks and Milkcow fusion-powered truck; recharge on the move, stop only long enough to swap out batteries.

I fluff an ICE-powered combat-vehicle-type truck as battery powered and away we go.
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Col Toda

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Re: Logistics - Fuel Consumption
« Reply #7 on: 18 September 2017, 21:17:59 »
Something always limits the time a unit is on station . Units that use a lot of ICE vehicles can be hampered by scorched earth tactics and starved into withdrawal . I do on site salvage and use the most prevalent armor type by ERA so long as I win a battlefield I can supplement the armor stores I came with . My most common limiting factor is ammo reloads . After 3 full reloads unless I can get resupplied I have to withdraw . Food can become a problem on subsistence worlds . Logistics became very serious in any contract that is not an objective raid . Since most contracts I have seen are objective raids logistics is very easy , you have what you bring and what you can take during the raid , it is normally over in less than 2 days planet side , preferably 8 hours . Garrison and Cadre requires far more uninterrupted supply  .

 

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