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Paragon Badger
2008-06-19, 01:08 PM
I have gotten an idea lately.. I wanted to run a D20 Modern campaign that took place about 75% in the skies. Yet, much to my dismay.. there were so little rules in place for such things.

When it is all done, I hope to have rules to simulate the truly tactical aspect of air-to-air combat. And it won't all be skill checks, either. :smallwink:

Once this is finished, I may just post a recruitment thread. :smalltongue:

D20 Modern w/ Airplanes

New Skill Uses:

The Pilot skill has been divided into three now to resemble the added focus to aerial combat. A character may only take 10 when they are free of distractions (such as combat, fatigue, or other conditions)

Pilot(Generic) [Dex; Trained Only]
Used primarily for standard procedural actions or other things not covered by the specific pilot skills.


Take-Off
You must spend 4 full-round actions to preform a normal take-off from a stationary speed. Even if you fail this check, there is no risk of crashing. As you attempt faster take-offs, the deadliness of a crash is higher.

DC to take off with 4 full-round actions: 10
DC to take off with 3 full-round actions: 20
DC to take off with 2 full-round action: 40
DC to take off with 1 full-round action: 60

Taking off from a Carrier increases the DC by 1.5 times.


Land
You must be in the slow speed category and on your next turn, spend a full-round action within 10 squares of a landing strip to begin landing.

DC on Strip: 10
Makeshift Runway: 15
Carrier: 20
Short makeshift Runway: 25

[quote]Recover from Stall
As a full-round action, you may recover from a stall and go back into Slow Speed. There is a 75% chance each round that you'll end up nose-down in a stall, so even if you recover- it may be impossible to pull up in time.

DC to recover: 20+2 for each round you were previously stalling.

Synergy: For every 5 ranks you have in Pilot(Generic), you gain a +1 bonus to Pilot(Evasion) and Pilot(Maneuver)

Pilot(Evasion)
Used primarily for avoiding missiles, debris, or hazards in your path.


DCs:
Missile: (See Weapon description)
Flock of birds: 15
Aircraft debris: 20
Radio Tower: 25
Office Building: 30
Skyscraper: 35
Megalith Tunnels: 40 :smallamused:
SOLG Debris: 60 :smallfurious:

Pilot(Maneuver) [Int]
Used to preform aerial maneuvers that will put you in an advantageous position.


DCs:

Barrel Roll: 5
Immelmann: 10
Flat Scissors: 15
Rolling Scissors: 20
Controlled Stall: 40

Aerial Combat

It usually takes about one minute to enter an airplane and prepare it for take-off in an emergency.

In flight, a square usually represents 100 feet.

TWO DIMENSIONAL COMBAT

When two planes are at roughly the same altitude, combat is resolved as usual with D20 Modern's vehicle rules.

THREE DIMENSIONAL COMBAT

Slightly more complex. Exactly like 2D combat, except facing is three dimensional. Altitude is important because it slows or speeds up your plane.

Maneuverability; Each plane has a different maneuverability. Some are slow and can make fast turns- whilst some are fast and require alot of space to turn.


Sample Plane
Minimum Speed: 5
Maximum Speed: 50
Turn Cost: -1
Yaw Cost: -5
Ascend Cost: -4
Ascend Slowdown: 2
Descend Cost: -2
Descend Speedup: 2
Level-Out: 2

Hover? No

Minimum Speed:
If a flying vehicle fails to maintain its minimum speed, it must land at the end of its movement. If it is too high above the ground to land, it immediatly falls straight down descending 200 feet (-2 Height) in the first round of falling. If the fall doesn't bring the vehicle to the ground, its pilot must spend her next turn recovering from the stall (See Pilot skill for details) With each unsuccessful recovery, the vehicle's falling speed doubles.

Maximum Speed:
The maximum number of squares a vehicle can move through in one turn.

Turn Cost:
The number of squares a vehicle must go forward in order to turn 45.

Yaw Cost:
The number of squares a vehicle must go forward in order to move one square to the side without changing direction.

Ascend Cost:
The number of squares a vehicle must go forward in order to ascend 45 and gain 1 Height.

Ascend Slowdown:
If a Vehicle ascends consecutively the number of times shown, Its speed category automatically decreases by one step. Subtract the pilot's total squares moved from their new speed's allowance. If the pilot has enough to continue moving, she may. If the pilot does not; they may end their turn. If the pilot has negative squares remaining, they begin falling. (As described above)

Descend Cost:
The number of squares a vehicle must go forward in order to descend 45 and lose 1 Height.

Descend Speedup:
If a Vehicle descends consecutively the number of times shown, Its speed category automatically increases by one step. Subtract the pilot's total squares moved from their new speed's allowance. The pilot may continue moving with their new speed if desired.

Level-Out:
The number of squares a vehicle must go forward after descending and then immediatly ascend. Descending after a climb requires no minimum forward distance. Additionally, this is the number of squares required to move forward if a pilot does not want to slowdown or speedup from ascending or descending.

Hover:
Whether or not the Vehicle can hover in place. Hovering Vehicles may move in any direction (including up and down) by spending an additional square at the start of the direction change. They may spend a square to turn or tilt 45. A Vehicle with a minimum speed (like a Harrier) can only hover at that speed -1, and must spend 2 squares to start/stop hovering.


Speed Categories:
Stationary
Slow
Moderate
Fast
All-Out

Stationary
A vehicle cannot move or maneuver in this speed, and it is either on the ground or falling. Both circumstances requires a Pilot check to move into the Slow category.
Defense Bonus: +0
Pilot Penalty: -0
Bomb Range: 0
Bomb Accuracy: -0

Slow (Minimum Speed to 10)
Defense Bonus: +2
Pilot Penalty: -2
Bomb Range: x1
Bomb Accuracy: -0

Moderate (Speed 11-20)
Defense Bonus: +4
Pilot Penalty: -4
Bomb Range: x2
Bomb Accuracy: -2

Fast (Speed 21-40)
Defense Bonus: +6
Pilot Penalty: -8
Bomb Range: x3
Bomb Accuracy: -4

All-out (Speed 41-80)
Defense Bonus: +8
Pilot Penalty: -16
Bomb Range: x4
Bomb Accuracy: -8

If you are going the same speed category and facing the same direction (or opposite direction) as your opponent, their defense bonus is negated. If you are going the same speed category and are at a 45 angle, their defense bonus is halved.

If you are going at a different speed than your opponent, their defense bonus is doubled for each different category. Attacks with Missiles ignore the differences in speed, however.


Weapons & Equipment:
Guns
Missiles
Bombs
Chaff

Guns have limited range but are instantaneous and fairly accurate. You may add your dexterity bonus to attack and damage with them. Most Guns can only be fired at enemies who are directly infront of the plane's front, and the target must either be at the same height as you or at the same vertical angle.

Missiles have great range and can only be avoided with a Pilot check vs. your attack roll. The Missile becomes less accurate the more it has to vary its route, and may take more than one turn to hit its target. You may add your intelligence bonus to attack with them. Missiles can only be fired at enemies who are within the vehicle's front firing arc and are within 1 height difference.

Bombs can be dropped at a surface location specified in the weapon's description (Usually a number of squares directly ahead of your vehicle, depending on speed category) and cannot have any obstructions between you and your target. You may add your wisdom bonus to attack with them, and twice your wisdom bonus to damage.

Chaff can be thrown as an immediate action whenever a character detects a lock-on or missile. It usually subtracts 1d6 from the missile's attack roll.

Guyr Adamantine
2008-06-19, 01:56 PM
I think you're overcomplicating it; D20 Future got the rules you want. Just adapt the vehicle speeds and weapons and you're on. (The rules were for space combat:smallwink:)

Paragon Badger
2008-06-20, 02:16 AM
I think you're overcomplicating it; D20 Future got the rules you want. Just adapt the vehicle speeds and weapons and you're on. (The rules were for space combat:smallwink:)

Eh, it completely ignores height, though.. And in air-to-air combat, that can become pretty important- for gaining speed or slowing down. Also, some planes cannot climb as fast as others- so a player who knows their enemies' capabilities (via Intelligence check, maybe?) will be able to make use of that.

Anyways, I'll try to simplify my own weird version. :smalltongue: