Calculating Star Ratings For Fighter Ace Aircraft

From The Air Combat Wiki

Contents 1 Quick Link 2 Durability 3 Speed 4 Maneuverability 5 Firepower 6 Climb Rate 7 Ground Attack 8 Quick Link

Quick Link

• Fighter Ace Flight Museum: WWII US / GB / SU / GE / JP / Jets and Post WWII // Planes Inventory (text list)
• Fighter Ace Plane Physics: Speeds / Accelerations / Climb Speeds / Star Ratings
• Fighter Ace Weapons: Guns / Rockets / Bombs / Torpedoes

Durability

The durability value is calculated by taking the "hit points" for the plane's wings or fuselage (whichever is greater), dividing it by 100, and rounding to the nearest value.

Speed

The speed rating is based on the top speed of the plane in mph. This uses the plane's best speed at any altitude and the following table:

# Stars	Top Speed (mph)
1	0 to 124
2	125 to 174
3	175 to 224
4	225 to 274
5	275 to 324
6	325 to 374
7	375 to 424
8	425 to 474
9	475 to 524
10	525 and faster

Maneuverability

The maneuver value is based entirely on the wing-loading of the aircraft, using the following table:

# Stars	Wing Loading (lbs / sq ft)
10	0 to 19.99
9	20 to 24.99
8	25 to 29.99
7	30 to 34.99
6	35 to 39.99
5	40 to 44.99
4	45 to 49.99
3	50 to 54.99
2	55 to 59.99
1	60 and higher

Firepower

The Firepower rating is calculated based on information contained in Tony Williams' "On Guns" discourse. The critical information is the hitting power and range information crossed with the rate of fire. Measurements are based on 10 seconds of sustained fire, which allows ammo load to be a factor.

First, Tony Williams' "Score" table of relative firepower for each gun type:

Score	Guns
1	All .30 caliber/7.x mm machine guns
3	13mm MG 131 and IJN Type 2, 12.7mm Breda and Scotti, IJA Ho-103
4	.50 Browning, 12.7mm Beresin, 13mm IJN Type 3
6	15mm MG 151
8	20mm MG-FF, ShVAK, IJA Ho-5, IJN Type 99-1 and 99-2
12	20mm Hispano/AN-M2, MG 151/20 (M-Geschoss), IJA Ho-1 and Ho-3
24	23mm VYa, NR-23
30	30mm Japanese (any)
50	30m MK 108 and MK 103
75	37mm Ho-203, Ho-204
100	37mm M4/M10, 40mm Vickers S, N-37
130	37mm BK 3.7, NS-37
200	50mm BK 5, 57mm Molins

Next, we create a table that shows the number of rounds fired in 10 seconds of sustained fire. For guns that give a range of ROF, I used a median value.

Gun	ROF	rnds/ 10 sec	Grp
.30/.303 Browning	1000-1350	196	1
7.62mm ShKAS	1800	300	1
7.7mm Vickers (JP)	450-750	100	1
7.9mm MG17	1000-1100	175	1
7.9mm MG81	1200-1500	225	1
.50 Browning M2	600-800	117	3
.50 Browning M3	1200	200	3
12.7mm UB	900-1050	163	3
12.7mm Ho-3	900	150	3
13mm MG131	900	150	1
13mm Type 2	900	150	3
13mm Type 3	800	133	4
15mm MG151	700	117	3
20mm AN/M2	600-700	108	3
20mm Hispano II	600	100	3
20mm Hispano V	750	125	3
20mm ShVAK	800	133	2
20mm B-20	800	133	2
20mm MG/FF & MG/FF-M	520-540	88	1
20mm MG151/20	700	117	2
20mm Type 99-1	500	83	1
20mm Type 99-2	490	82	2
20mm Ho-1/Ho-3	400	67	2
20mm Ho-5	700-850	129	3
23mm VYa	500-700	100	4
23mm NR-23	850-950	150	4
30mm Mk-108	600-650	104	1
30mm Mk-103	360-420	65	4
30mm Type 2	400	67	3
30mm Type 5	450	75	3
30mm Ho-155	450-600	88	3
37mm M4	140-150	24	2
37mm N-37	250-350	50	4
37mm Bk-3,7	400	66	4
37mm H-204	300-400	58	3
40mm Vickers S	100	17	4
57mm Molins	60	10	4

The next table we need is another Tony Williams table. This one is based on his "effective range" calculations from "On Guns". The values we are concerned with are the effective range (in meters) for hitting a fighter sized target depending on the gun "grouping" and the location of the guns, either being in the wings or nose:

Group	Wing %	Nose %
1	50	65
2	65	85
3	75	100
4	85	110

We now combine the information based on what guns are each plane, where they are located, and the amount of ammunition carried. The "range" factor above is converted to a percentage multiplier for use in the calculation. For example, Group 3 wing guns would multiply the score by 75% (group 3 wing = 750 = 75%). This is all combined in the following formula:

Firepower = score * rnds per 10 sec * # of guns * group %

Note that when the number of rounds per gun carried by the plane is less than the "rnds per 10 sec" value, the number of rounds actually in the gun are used. For example, the MG/FF has a "rnd per 10" of 88, but most MG/FF installations used a 60 rnd drum magazine. In those cases, the 60 value would be used instead of the 88 value.

Following are some examples of planes and the calculations:

Hurricane Ia/Spitfire Ia = 8x .303 in wings = 1 * 196 * 8 * 0.5 = 784

US Standard = 6x .50 in wings = 4 * 117 * 6 * 0.75 = 2106

Bf-109E = 2x 7.9mm in nose = 1 * 175 * 2 * 0.65 = 480 AND 2x MGFF in wings = 8 * 60 * 2 * 0.5 = 227.5 TOTAL = 707.5

The final step is to cross the firepower result for each plane with the following table to determine how many stars to give on the description:

# Stars	Firepower
1	0 to 500
2	501 to 1000
3	1001 to 1500
4	1501 to 2000
5	2001 to 2500
6	2501 to 3000
7	3001 to 4000
8	4001 to 6000
9	6001 to 8000
10	8001 and above

Climb Rate

The climb rate display is based on a simple table using the plane's measured climb rate, in feet per minute:

# Stars	Climb Rate (fpm)
1	0 to 999
2	1000 to 1499
3	1500 to 1999
4	2000 to 2499
5	2500 to 2999
6	3000 to 3499
7	3500 to 3999
8	4000 to 4499
9	4500 to 4999
10	5000 and greater

Ground Attack

The ground attack values from 3.0 are not very good and are being changed here to the following method. The method considers the total weight of bombs and rockets carried by the plane, the number and size of cannon, and the number of paratroops carried.

The first step is to calculate the total weight of bombs and rockets carried by the planes. Since torpedo loads are usually smaller than the maximum bomb/rocket load, they are ignored. The weight of bombs, in pounds, is then crossed with the following table to get the base number of stars to give the plane:

# Stars	Ordnance Weight (lbs)
1	0 to 999
2	1000 to 1999
3	2000 to 2999
4	3000 to 3999
5	4000 to 4999
6	5000 to 5999
7	6000 to 6999
8	7000 to 7999
9	8000 to 8999
10	9000 or more

The next consideration is the number and type of cannon used. Each cannon will add a fraction of a bonus star to the star total, using the following table:

Cannon Type	Stars/Gun
20mm Oerlikon	0.25
20mm (all others)	0.50
23mm	0.75
30mm	1
37mm/40mm	2
57mm	3

Next, each paratrooper carried is worth 0.33 star bonus.

Finally, add the total number of star bonuses and add them to the star value based on ordnance weight, then round to the nearest whole value, to get the final total to be displayed.

Quick Link

• Fighter Ace Flight Museum: WWII US / GB / SU / GE / JP / Jets and Post WWII // Planes Inventory (text list)
• Fighter Ace Plane Physics: Speeds / Accelerations / Climb Speeds / Star Ratings
• Fighter Ace Weapons: Guns / Rockets / Bombs / Torpedoes