The new features of Chains Of War: Aircraft Damage

April 27, 2017 · Posted in Command 

The “Release Candidate” (ie. public beta) phase of the v1.12 update (the companion to the upcoming “Chains Of War” DLC pack) continues steadily on the MatrixGames forum. The feedback on the new  additions like the new 2x time compression step and much improved 4K/UHD support has been overwhelmingly positive, and the new sonar masking feature has also been well received. Chains of War, however, will introduce a number of major new features with significant effects on scenario design and gameplay. We already had a look at communications disruption. Today we are looking at another significant enhancement, aircraft damage.




Getting back home – in one or more pieces

– The other problem is that the A-10 is vulnerable to hits because its speed is limited […]. We had a lot of A-10s take a lot of ground fire hits. Quite frankly, we pulled the A-10s back from going up around the Republican Guard and kept them on Iraq’s [less formidable] front-line units. That’s fine if you have a force that allows you to do that. In this case, we had F-16s to go after the Republican Guard.

– At what point did you do that?

– I think I had fourteen airplanes sitting on the ramp having battle damage repaired, and I lost two A- 10s in one day [February 15], and I said, “I’ve had enough of this…”

(Interview of Chuck Horner to Air Force Magazine, June 1991)

Comprehensive aircraft damage modeling, while well-modelled on most combat flight simulators, is something of a rare appearance on grand-tactical, operational or strategic-level simulations and wargames, for a number of reasons. Command, following the paradigm of numerous other similar titles before it, started with the simple binary “100% healthy until shot down” model for aircraft. It has always, however, been our intention to do something more comprehensive. With v1.12 we are taking a significant step forward in this regard.

When the “Aircraft Damage” feature is enabled on a scenario (it is “off” by default in order to avoid disrupting existing scenarios), aircraft are evaluated for specific damage when hit by a weapon. Each aircraft now has a damage-point value representing its fundamental structural tolerance (similar to ships, subs and land units & facilities) plus three distinct armor levels – for cockpit, fuselage and engines. When a weapon impacts the aircraft, the damage is applied to the overall structure and in addition the chance of penetration is evaluated against each armor level. Each penetration probability is obviously dependent on the armor level and the nature and severity of the weapon warhead (e.g. penetrating rounds have a better chance than impact-explosive ones), but geometry factors are also taken into account; for example a cockpit hit is far more probable if the weapon impacts in the frontal quarter, engine hits are most common in rear-quarter impacts, while the fuselage is most vulnerable to side hits.

This Fulcrum driver is having a rather bad day

Similar to other platform types, when immediate damage is sustained, secondary fires can also erupt. The aircraft crew will attempt to suppress those every 5 seconds. The fire burns through the aircraft fuselage quite rapidly, causing structural damage, and if it evolves to conflagration can even cause a fuel explosion, destroying the aircraft (few things are as infuriating as blowing up from uncontrollable fire just as you are on final approach to land…). Critical hits from penetration are also possible; if the cockpit is compromised the aircraft is immediately out of control and destroyed, whereas a critical hit to an engine will damage or destroy it (for single-engine aircraft this has rather unpleasant consequences). Aircraft with at least one operational engine can still limp back home but all their kinematic properties are negatively affected. A plane with more than 80% structural damage will disintegrate in mid-air.

Because the existing armor levels were geared mostly towards surface & land targets (the smallest amount of armor being 40mm RHA equivalent), we also had to add several lesser armor levels in order to properly differentiate the differences in armor commonly found on aircraft. The revised armor levels are:

  • None (Human flesh, unarmored aircraft etc.)
  • Armor – Handgun (Human body armor or equivalent – can stop a handgun/pistol round)
  • Armor – Rifle (human body armor or equivalent – can stop a rifle or LMG round (5.56 / 7.62mm etc.))
  • Armor – HMG (can stop a heavy machine gun or heavy sniper rifle round (12.7 / 14.5mm etc.))
  • RHA – 20mm (20mm RHA – can stop a 20mm AP round)
  • RHA – 25mm (25mm RHA – can stop a 25mm AP round)
  • RHA – 30mm (30mm RHA – can stop a 30mm AP round)
  • RHA – 35mm (35mm RHA – can stop a 35mm AP round)
  • Light (41-90mm RHA – as before)
  • Medium (91-140mm RHA – as before)
  • Heavy (141-200mm RHA – as before)
  • Special (201+ mm RHA – as before)

The topmost armor levels will naturally have to be revised in the future as we [ REDACTED ].

Aircraft are also assigned “damage tolerance” levels before they abort/RTB. For fighter and attack aircraft this is set to 30%, for CAS aircraft 50%, and for all other aircraft to 10%. Once this threshold is exceeded, the aircraft breaks off and attempts to RTB. The player can of course issue an RTB order before this level is exceeded. Damaged aircraft will jettison their heavy stores when RTBing due to damage (regardless of the “Jettison stores under attack” doctrine setting).

Down for repairs

Damaged aircraft that manage to return to their base are not “magically” restored; they need an extensive amount of time to be repaired. The so-called “Estimated Time To Commission” (ETIC) value is calculated based on the extend and types of damage and may range from a few additional hours to entire days or even weeks. Obviously, depending on the duration of the scenario, this may mean that an aircraft is effectively out of the fight (On the Professional Edition, the method for calculating the ETIC is far more extensible and can use private customer data). The estimate for the repair time is communicated to the player through the message log, for example: “Aircraft-X (class Y) has damage that requires an estimated time-Z to restore. The repair time will be added to the aircraft’s ready-time.”

Developing and testing the improved damage model for aircraft has been a lot of fun for the dev & beta teams. There are cases where the differences in combat resolution are not significant; for example heavy AAMs or SAMs will take down a small aircraft, no ifs and buts. On the other hand, with light-caliber AAA or missiles with small warheads (Stinger, AIM-9 etc.) and particularly against large or well-armored aircraft the effect is quite dramatic. We were never comfortable with the fact that a single Stinger or machine-gun burst could bring down a B-52 with a lucky hit; this is now rectified.

Another factor (and a significant “last straw” in making us not delay this feature any longer) is the gradual service introduction of high-energy lasers. By their nature, these are currently not powerful enough to take down an aircraft (or in fact even large drones) with a single burst; concentrated or consistent fire is necessary (oddly, this is reminiscent of gunfire-vs-aircraft in WW2). The improved AC damage model is ideal for modeling this peculiarity which will probably last for at least the near future.

May your battle damage repairs never keep you down for long!


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