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Old 01-08-2009, 11:26 AM   #1
PPoS
 
Join Date: Sep 2007
Location: Sweden (but mostly this forum)
Default Dogfighting Rules (Suggestions are welcome!)

I've been pretty disappointed at GURPS's lack of a fast and action-paced system for handling Dogfighting, so I decided to make my own.

The Dogfight is split into 4 steps; Spotting, Initiative, Maneuvering and Shooting.

1. Spotting
The Dogfight cannot start before one or both combatants actually spot each other. Each of the combatants rolls against their Perception (or Electronic Operations for Radar or similar system) modified by any bonuses or penalties. The winner of the roll gets Initiative and may start his Maneuvering. If both sides succeed with their rolls; go to the next step.

Modifiers for Spotting Roll
  • Cockpit Visibility
    +/- depending on Aircraft
  • Ground Based Radar
    Gives a bonus of +3 (Any other suggestions on this?)
  • Weather
    Use standard modifiers from Basic Set
  • Camouflage
    Use standard modifiers from Basic Set
  • Wingman
    (Not sure about this one. Either roll a second roll for the Wingman or use any modifier that seems to make sense.)

2. Initiative
Once both combatants have spotted each other they must roll for Initiative. This works according to the rules of Partial Surprise in Basic Set (however, ignore the rules for "mentally stunned"!). Each combatant rolls 1d, anyone with Combat Reflexes gets +2, highest IQ gives +1 and having the Tactics (Air-to-Air) skill at atleast IQ-2 gets +1. The winner is the one with the highest roll.

3. Maneuvering
Once Initiative order is set, one or both combatants may start maneuvering. This is simply to get into position to fire on the other. The base starting range of a Maneuvering contest is 500 yards and the attacker (one with first Initiative) may decrease this range before attacking.

First off, both combatants must roll against their Tactics (Air-to-Air) skill (ignore this if only one of the combatants have Initiative, see Step 1). If the roll succeed the combatant gets half the degree of success in bonus on his next roll (rounded down), this works the same for both combatants. When the Tactics roll is done both combatants roll against their Pilot skill with any modifiers (again; ignore this if only one have the Initiative). Determine the degree of success for both combatants, the attacker (the one who acts first) subtracts the other combatant's degree of success from his own. Once this has been worked out, look at the table below to see how close/far away from the target the attacker is. Thus, if the target made a good roll he might actually get further away from you.

Degree of Success | Range Increase/Decrease
0 = 50
1-2 = 100
3 = 150
4 = 200
5-6 = 300
7-9+ = 500


If the range to the target is reduced to 0; treat this as 20 yards in range (this is because most fighters have a SM of +5 which offsets the penalties for range). If range would exceed 500 yards go back to Step 2.
If the attacker thinks he is within good range he may start attacking (next Step) or he can wait and end the turn. If only one has the Initiative; go back to Step 1 and see if the other combatant spots the attacking aircraft this time. If the turn ends; do Step 3 all over again.

Modifiers for Pilot Roll
  • Aircraft's Handling Rating
    +/- depending on Aircraft
  • Aircraft Speed
    +1/-1 for each 2 aAccel faster/slower than target

4. Shooting
Shooting is handled just as it is in Basic Set. Use rules for range/speed as normal. An optional rule (which I use) is that the shooter does not need to take a turn to Aim (but add the Acc of the weapon anyway). Most pilots actually just fired a burst (or "squirt") against the target; this can be handled by using half of the weapons RoF. The target may dodge as usual, using his vehicular dodge of course. Once hits or misses has been worked out, go back to Step 3. Do this until the Initiative changes or one of the aircrafts has been blown out of the sky! Tally-ho!
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Old 01-08-2009, 11:27 AM   #2
PPoS
 
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Default Re: Dogfighting Rules (Suggestions are welcome!)

Here is an example fight between a F4F Wildcat and a A6M2 Zero.

TURN 1

Spotting
The Wildcat pilot rolls against his Perception (11) and gets a 10, success! The Zero pilot also rolls against his Perception (11) and gets a 14, failure.

Maneuvering
The Wildcat decides to close the distance to the Zero before attacking. He rolls against his Tactics skill (13) and rolls a 12, success (degree of success is 1). Next is the Pilot roll (15) modified by -1 for aAccel (14), the Wildcat rolls a 11, success with a degree of 3. This means that the Wildcat closes in from 500 yards to 350 yards (500-150=350). The Zero pilot rolls against his Perception again and succeeds. The Wildcat decides to close in even further before attacking, the turn ends.

TURN 2

Initiative
Since the Zero spotted the attacking Wildcat in the previous turn both must roll against Initiative. The Wildcat pilot rolls a 5 and gets a bonus of +1 for Combat Reflexes for a total of 6. The Zero pilot rolls a 1 and gets a bonus of +1 for Combat Reflexes totalling 2, the Wildcat goes first.

Maneuvering
Both pilots now roll against their Tactics skill (13). The Wildcat rolls a 6 and succeeds by 5; the Zero rolls a 9 and succeeds by 4. This means that the bonuses for the pilots are +2 for the Wildcat and +2 for the Zero.

Next, the pilots both roll against their Pilot skill (15). The Wildcat pilot gets the following modifiers: +2 for Tactics roll and -1 for aAccel totalling +1 giving a effective skill level of 16. The Zero pilot gets +2 for Tactics roll and +1 for aAccel totalling +3 for a effective skill level of 18.
The Wildcat rolls a 10 succeeding by 6, the Zero rolls a 16; succeeding by 2.
Now the Wildcat subtracts the Zero's degree of success from his own giving him a degree of success equal to 4 (6-2=4). This means that the Wildcat closes in from 350 yards to 150 yards.

The Wildcat decides to fire at the Zero and rolls against his Gunner skill (13), modified by +5 for SM, -14 for Speed (166 y/sec) and Range (150 yards), +5 Acc, +4 RoF (6x4=20) (effective skill level of 13), and rolls a 9. Success by 4 means that 5 bullets hit the Zero, if it cannot dodge them. The Zero has a Dodge rating of 10 (15/2 +3) and rolls a 10 meaning that it evades one hit.
The Wildcat rolls for damage getting 96 as resulting damage*. The Zero has a HP of 50 and gets a major “wound”, it has to roll against its HT which is (7fx, -3 for incendiary attack), and the Zero rolls 12 failing. The Zero doesn’t explode but it catches on fire and will take an additional 1d-1 fire damage each turn after this one. The Zero is no longer usable by the pilot and he decides to bail-out.

*6dx2 pi+, rolls 27x2=54, 54x0.5 for Unliving Target and -3 for DR=24, 24x4 for additional hits =96.

Here are the two example Aircrafts:

F4F Wildcat

HP: 70
HT: 12f
Hnd/SR: 0/4
SM: +5
DR: 4
Speed/aAccel: 319 mph/7

A6M2 Zero
HP: 50
HT: 7fx
Hnd/SR: +1/1
SM: +5
DR: 3
Speed/aAccel: 333 mph/9

Last edited by PPoS; 01-08-2009 at 02:21 PM.
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Old 01-08-2009, 12:18 PM   #3
PPoS
 
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Default Re: Dogfighting Rules (Suggestions are welcome!)

I'am also going to add rules for making Stunts and a System Damage chart for airplanes (fuel lines, weapons, radio etc.)

Here are some clarifications on the stats of the aircrafts shown above.
  • HP: Used the rules for calculating HP of objects in Basic Set: Campaigns
  • HT: Used the numbers in 3ED WW2 books and added F or X where needed.
  • Hnd/SR: Actually I just assigned some that looked good enough using the Basic Set, but I can't really figure out how they've reasoned. So I recommend using this formula (posted by someone on this forum): ((3rd edition maneuver rating/Top Speed in mph) * 200) - 5 (I would say that -4 instead of -5 will give more realistic results), that means that the F4F Wildcat would actually have -2 in Hnd and the Zero would have 0. I use Techniques to eliminate these penalties (one for each aircraft) which also simulates a pilot experienced with his aircraft.
  • SM: Used Basic Set to decide this
  • DR: Used numbers from 3ED WW2 books
  • Speed/aAccel: Used numbers from 3ED WW2 books

Last edited by PPoS; 01-08-2009 at 01:31 PM.
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Old 01-08-2009, 01:51 PM   #4
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Default Re: Dogfighting Rules (Suggestions are welcome!)

Quote:
Originally Posted by PPoS
I've been pretty disappointed at GURPS's lack of a fast and action-paced system for handling Dogfighting, so I decided to make my own.
Have you looked at the dogfighting rules in VE2?
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Old 01-08-2009, 01:55 PM   #5
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Default Re: Dogfighting Rules (Suggestions are welcome!)

I have. Didn't like it, maybe it isn't so bad but it's just not my cup of tea. Great site BTW, have alot of WW2 vehicles that are missing in the books.

Last edited by PPoS; 01-08-2009 at 02:00 PM.
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Old 01-08-2009, 04:27 PM   #6
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Default Re: Dogfighting Rules (Suggestions are welcome!)

Quote:
Originally Posted by PPoS
I have. Didn't like it, maybe it isn't so bad but it's just not my cup of tea.
I've never used it, but then I haven't needed to. The only air-to-air battle that has taken place in a campaign since I got VE2 involved passengers in two civilian planes firing rifles at each other.

Quote:
Great site BTW, have alot of WW2 vehicles that are missing in the books.
One of these days I'll get around to the B-24, probably the most important vehicle that hasn't appeared in a book yet. Otherwise, most of the designs I'm considering tend to be rare or obscure (and, sorry, I don't like to do large ships).
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Old 01-08-2009, 08:56 PM   #7
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Default Re: Dogfighting Rules (Suggestions are welcome!)

One other thing to consider is that most wing-mounted guns on WWII aircraft were set to converge at 200 yards. . .making this the "sweet-spot" when engaging enemy aircraft. Farther away, you were probably only hitting with the guns from one wing. Closer, and you risked being struck by pieces from the aircraft you just destroyed.

Quote:
Originally Posted by copeab
One of these days I'll get around to the B-24
Excellent! I'm salivating already. . .
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Old 01-09-2009, 05:00 AM   #8
PPoS
 
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Default Re: Dogfighting Rules (Suggestions are welcome!)

Quote:
Originally Posted by Phaelen Bleux
One other thing to consider is that most wing-mounted guns on WWII aircraft were set to converge at 200 yards. . .making this the "sweet-spot" when engaging enemy aircraft. Farther away, you were probably only hitting with the guns from one wing. Closer, and you risked being struck by pieces from the aircraft you just destroyed.
Yes that is correct, between 150-200 yards. Firing (and hitting) at about 250 yards could be done against an enemy that was not flying evasively (i.e. unaware of the impending attack). GURPS models this pretty fine with penalties for Range and if using my system, you will have to maneuvre well to get closer to the target. I guess that when a plane explodes you would treat it like any other explosion with fragmentation damage, if you are close enough; your plane would be hit. However there are examples of WW2 dogfights where the pilots have been very close to their exploding enemy, flying straight through the debris field, and didn't get a scratch.
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Old 01-09-2009, 05:08 AM   #9
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Default Re: Dogfighting Rules (Suggestions are welcome!)

Another thing .. The calculation that I used to compute Handling for the aircrafts seems to give strange numbers.
If you use the calculation, ((3rd edition maneuver rating/Top Speed in mph) * 200) - 5, for say the Zero, you would get a resulting Hnd of 0.
If you do the same thing for a SBD Dauntless you would get a Handling of +3, and a +4 for a B-17. I don't think this adds up, sure the SBD had pretty good handling IIRC; but a +4 for the B-17?

This is using the stats for the SBD Dauntless on copeab's homepage and the stats for the B-17 from WW2: Dogfaces.

Anyone have any other suggestions on this?
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Old 01-09-2009, 07:35 AM   #10
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Default Re: Dogfighting Rules (Suggestions are welcome!)

Quote:
Originally Posted by PPoS
Another thing .. The calculation that I used to compute Handling for the aircrafts seems to give strange numbers.
If you use the calculation, ((3rd edition maneuver rating/Top Speed in mph) * 200) - 5, for say the Zero, you would get a resulting Hnd of 0.
If you do the same thing for a SBD Dauntless you would get a Handling of +3, and a +4 for a B-17. I don't think this adds up, sure the SBD had pretty good handling IIRC; but a +4 for the B-17?
You could use wing loading (loaded weight divided by wing area, the lower the better) to determine how agile a plane is, although this could lead to some strange situations too (frex, the PBY had a lower wing loading than the Zero).

I wouldn't figure top speed into handling. While speed is important in being able to disengage from a foe, acceleration is more of a factor in actual dogfighting.
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Last edited by copeab; 01-09-2009 at 10:33 AM.
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