The perk system is a way for HTC to introduce some interesting but otherwise unbalancing planes on a limited basis but the benefits go deeper than that. Perk planes (and vehicles) would be things like Me 262s, Ta 152s, Tempests, B-29s, Ar 234s, Tiger IIs, etc. These are interesting rides but would be very unbalancing if they were available on an unlimited basis. So there won't be unlimited availability but they'll be available as bonuses or perks every so often.
You can earn a perk by accumulating Perk Points until you have reached the cost of the perk plane that you want. You need to have the required amount of points to fly a given perk plane, but you do not lose those points unless you lose the perk plane, so survival is important when flying perk planes. These points are totally separate from the regular scoring system and are not reset with a new tour.
There are three separate point totals, one for fighters, one for bombers, and one for vehicles. Flying fighters earns fighter perk points and those points can only be used on perk fighters, not perk bombers or vehicles. That's true for all 3 categories. Plane, vehicle and boat multipliers and costs can be viewed in the model selection list on the clipboard in the Hangar. Along with the fighter, bomber and vehicle perk point totals, the perk points earned on your last sortie are also displayed.
Perk Balancing System
To balance arena numbers, both perk points earned and the cost of perk planes are adjusted by the perk point bonus based on your countries numbers. The formulas are as follows:
The formula for the perk point bonus is calculated at the start of a sortie as follows:
If you are in the country with the fewest number of players, you will earn more perk points per sortie and the perk planes will cost less. Conversely, if you are in the country with the most players, you will earn less perk points per sortie and your perk planes will cost more.
Earning Perk Points
Points are awarded for both kills and damaging and destroying enemy targets. This in turn is weighted by the type of plane that you and your opposition are using. Flying the less popular planes will get you more points whether you are in air-to-air or air-to-ground mode. Likewise, the higher quality the planes of your opposition, the more points you get for them. If you shoot down lower quality planes with higher quality ones, you don't get much for doing that but you do get a lot for the exact opposite. This makes shooting down a perk plane double rewarding as you deprive somebody of a perk and get more points for doing it. Also, landing your sortie will apply a 1.25 multiplier to your perk points.
Examples:
With the values listed above, if you are flying the P-51D (ENY value of 18) and you score a kill on a Panzer (ENY value of 15), you would receive (18/15) = 1.20 fighter perk points.
Had the Panzer scored the kill on you in the P-51D, he would receive (15/18) = 0.83 vehicle perk points.
A TBM-3 with an OBJ value of 25 that destroys a bunker with a point value of 20 would receive (25/20) = 1.25 bomber perk points.
Of course, the values used in this example may not be the current values in the game. The perk point multipliers are subject to change at any time without notice.
The controls in the perk system are in how fast points are accumulated and what point cost the perks are set to. Because these points have a real and redeemable value, they're useful to influencing the flow of the game. Aside from making it useful to fly less popular planes, we could do things like awarding points to the side that wins the war or dropping perk prices when your side is greatly outnumbered.
