TEXT: 4c. Mass Combat
  Revolution ver 1.0 – 15-Oct-2016. The following text is designated as Open Game Content.
  These Mass Combat rules are a direct derivative of the core Conflict rules. All rules from Chapter 3 which are not 
  negated or overridden in this section remain in effect.
  Specific genre supplements, or rules that you craft on your own for your campaign might complement or replace this 
  sub-system. These rules are recommended for battles that involve only or mainly land units. We recommend you run 
  ship-to-ship or spaceship-to-spaceship battles with the rules for vehicle combat found in the previous section.
  Battle scale
  First of all, determine the scale at which the engagement will operate. Assess the size of all armies involved in number 
  of warriors, and divide all numbers by ten time and again until they are reduced to a reasonable scale, that is one of 
  them is lower than ten, or all of them are in the 10-50 range. The total number by which you have divided (10, 100, 
  1000, etc) is the Scale of the engagement. This many people will constitute one Resolution Point when computing the 
  Resolution Point Pools of the armies.
  Example: In the Battle of Thermopylae, about 10.000 Spartans fought some 200.000 Persians. By dividing everything 
  by 1000, we have a reasonable number for Spartans (10) but an unmanageable number of Persians (200). Thus we 
  divide by 10.000 and must now stop as we have a 1 for Spartans, while the Persians are now 20. The scale of this battle
  is thus 10.000 men for one Resolution Point. 
  Resolution Point determination
  Mass battles are one typical example of a Conflict where the starting Resolution Point pool is not based on individual 
  Characteristics. Each army will have Resolution Points corresponding to its relative strength, computed according to the
  procedure provided in this section.
  Base RP totals
  In order to determine the Starting RP, calculate the total number of troops for each side, as you did to find the total 
  scale. However, only infantry counts as one person per actual soldier. Mounted troops, artillery and vehicles count for 
  more than one per single soldier. Before adding them to the total number, apply the following modifiers:
  •
  Each soldier on a mount or fighting vehicle counts double: a rider counts for two, an elephant with a mahout 
  and four archers counts as ten, a war chariot with two people counts as four, the US M4 Sherman tank with a 
  crew of five counts as ten.
  •
  Passengers on a transport vehicle do not count double, although the crew does if the vehicle also has 
  independent offensive capabilities: a truck counts as the number it transports plus one for the driver, a Russian 
  BMP-1 APC with a crew of 3 and 8 passengers counts as 14, as its weaponry makes its crew count double.
  •
  Each soldier operating or supporting a gun counts double: an AT gun with a crew of four counts as 8.
  •
  Each person operating or supporting an aircraft or fighter spacecraft, including the personnel at the craft base 
  who do not take part in active combat, counts as two: a Sopwith Camel with a lone ace pilot and barely one 
  supporting engineer at the airfield counts as 4, a hi-tech fighter aircraft with two pilots, and the ten on board its
  carrier counts as 24.
   Add the adjusted number to the number of infantry soldiers. Then divide the total number by the Scale Factor and 
  round up to find the Base RP total for each side.
  Technology and morale
  Improvements due to technology and morale apply to the base RP total, not to each individual. This means that even if 
  most vehicles on one side are technologically inferior, the presence of some advanced models will boost the RP Pool as 
  if all vehicles were high-tech.
  
  You should apply a Technology improvement for each type of arm present on the battlefield (infantry, cavalry, AFV, 
  artillery, anti-aircraft, aviation, battle-mecha, etc.). This improvement ranges from 0 to 5 and is largely dependent on the
  context.
  Troop training, like technology, provide an improvement from 0 (levy) to 5 (ultra-elite). Similarly to technology, even a 
  small number of elite troops will raise the effectiveness of a whole army. You may subsume the morale of troops in the 
  training improvement, or handle it as Consequences. 
  Fortifications
  Only one side may benefit from a fortification bonus. Fortifications provide a variable bonus between 1 and 10 RP, 
  applied to the base RP total, too. Again, the context will determine whether one kind of fortification is worth a 
  meaningless 1 or an almost-impenetrable 10. Stone walls were very effective in ancient and medieval times, but became
  barely a nuisance once gunpowder was invented.
  Fighting the battle
  Once each side has determined its Resolution Point Pool size, list the applicable Consequences that might influence the 
  battle (fatigue and surprise act like in Basic Combat) and determine the Command or Strategy skill of the respective 
  commanders. Particularly relevant troop types such as artillery, heavy vehicles, aviation, counter-troops (anti-air, anti-
  cavalry pole weapons, etc.) can be noted down and used as Consequences during the battle.
  The battle takes place like any Conflict, with each side Rolling for Effect at most once per Round. Use Consequences 
  (see above) rather than Support Bonuses to alter specific rolls, in order to avoid giving an excessive advantage to the 
  side where the player characters are. 
  The specific Trait used to roll is normally the commander-in-chief's Communication [Command] or Knowledge 
  [Strategy]. However, in a round in which a specific unit is committed to attack or a specific technique or equipment is 
  employed, it may be more appropriate to use another officer or pilot's specific skill. 
  For example, if the commander of the PC army orders another PC to perform an air strike against the enemy lines 
  rather than committing land troops, the pilot PC will Roll for Effect with his or her Operate [AGM Missiles] Skill, 
  perhaps hindered by a Negative Consequence if the enemy has a “SAM Missile Battery”. In the absence of specific 
  rules for your setting, the Narrator will have to improvise a little bit.
  Player character intervention
  Mass battles are a perfect framework into which you can fit some interesting action for the player characters. A personal
  or vehicular challenge featuring the PCs may substitute a Roll for Effect at any moment in which it is narratively 
  appropriate.
  Use the Secondary Conflict rules to represent individual or group confrontations involving the player characters and 
  how they influence the outcome of the battle. Sometimes, a good result by the PCs may even put an end to the battle if 
  their side was already having the upper hand. However, do not exaggerate the result of their actions, either. If not all the 
  opponents were vanquished, limit the effect of a PC victory to1d6 RP “damage” rather than 2d6.
  Outcome
  The outcome of a battle follows normal rules for effects and consequences. The generic Conflict rules already include 
  examples about the Consequences of a victorious battle. A Quick Exit may or may not be appropriate to a battle, 
  depending on the context. In the case of a fortified position, you need to bring the opposition to zero to capture it. A 
  partial victory is essentially a withdrawal to retry again on the following day, and might be more convenient for the 
  loser than for the winner.
  Consequences apply to participating PCs when they were somehow involved in the battle. If they commanded the army 
  or a specific unit, or performed a key attack represented with a secondary Conflict, then they may receive the relevant 
  Positive or Negative Consequences.
  
SOURCE: textdata/thevault/Revolution d100 SRD/RD100-SRD-04c - Mass Combat.pdf