4.0.2. Wind Effects on Aircraft Movement. When an aircraft of any type takes off, it enters a fluid medium, which moves as the aircraft moves through it. In most cases, the movement can be compensated for without worrying about it in the game, but if aircraft speeds are slow, or the wind speed is high, it can significantly affect a plane's range, or even Xs ability to move in a particular direction.
If the wind speed is one-quarter or more of an aircraft's speed, the aircraft player must compensate for the wind in his movement orders. This may result in advantages as well as disadvantages.
Example 1: A plane flying north at 100 knots encounters a 30-knot headwind. Effectively, its ground speed is 70 knots. It should either be moved at this speed and its position is important, or its endurance should be calculated based on its ground speed rather than its air speed.
Example 2: The plane commander cannot fulfil his mission in time if he has only a 70-knot ground speed. He must increase his air speed to 130 knots (his maximum speed), which he is able to do, but means that he is using a higher throttle setting, and his endurance will be lowered as a result.
Example 3: An airship with a maximum speed of 70 knots is escorting a convoy. The wind is from the northeast at 20 knots. If the airship places itself over the center of the convoy, it can move to the northeast at 50 knots. By stationing itself on the northeast side of the convoy, it shortens travel time to a threat on that side, and it can move to the southeast, with the wind, at 90 knots.
4.9.1 Airship Flight Control.
4.9.1.1. Airship Payloads. An airship can carry:
Water ballast can be replenished if the ship can remain stationary at neutral trim at VLow altitude over a body of water. Airships often carried special equipment that allowed them to drop a suction hose or even lower buckets to take on ballast.
Each airship will have its payload expressed in points, each point representing ten percent of its useful lift. The Annex B listing for each airship shows how many points it may use for fuel, ballast, and ordnance. Any number of payload points can be used to carry water ballast. Payload points can be modified by an airship's speed or other actions, and are used to determine its maximum altitude.
4.9.1.2 Airship Lift Control. Airships depend almost entirely on their gas for lift. The amount of gas contained in its cells determines how much the ship can carry, after the weight of structure, the engines, the crew, etc. is subtracted. This amount is called the "useful lift."
Each airship has ten Lift Points, each representing ten percent of its usable lift. This can be used to carry payload points, as described above.
If the ship has more payload points than Ldt Points, the ship is "heavy," and will descend until it reaches the ground or the trim is corrected. If it has fewer Payload Points than Lift Points, it is "light" and will rise and will continue to do so until it reaches its operational ceiling, or until the trim is corrected. If the ship is properly trimmed, it has neutral lift and will hover, motionless in still air.
Even if the air is still, the airship isn't. As it moves through the air an airship's envelope generates lift, called "dynamic" lift because it is caused by the ship's movement, and to distinguish it from "static" lift, created by the gas.
Dynamic lift can be used to take off with a heavy load of fuel and bombs by using a rolling takeoff. It can be used to "hold down" a ship that is trimmed "light." It can also be used, to some extent, to compensate for the loss of gas due to battle damage.
An airship moving 25% to 75% of its maximum speed generates one dynamic Lift Point. At full power (100% of maximum speed) it generates two dynamic Lift Points. This lift can be ignored, or applied to trim a ship up or down.
Example: An airship has dropped part of its load, reducing its payload from 10 to 9 points. If it has all ten Lift Points, it is now light and will start to rise. If the ship can maintain a speed of at least 25% or more, it can cancel out the rise with dynamic lift, remaining at lower altitudes.
4.9.1.3 Airship Altitude Changes. Neutrally trimmed airships may change altitude as they choose up through their maximum ceiling. Their climb and dive rates are shown on the Aircraft Altitude Change table.
Airships whkh are heavy must descend at least one level (500 meters) and their maximum dive rate on the Aircraft Altitude Change table is tripled. They cannot climb. Airships which are light have their climb rate tripled, and must climb one level per turm. Airships can use dynamic lift points to offset a heavy or a light trim.
4.9.1.4 Airship Maximum Altitudes. Airships neutrally trimmed may operate at any altitude level within the Low altitude band. If they wish to rise into the Medium altitude band, they must be light by at least two Lift Points. In other words, operating in the Medium altitude band penalizes an airship two Lift Points.
4.9.1.5 Airship Speeds and Course Changes. Airships can change course up to 45° in a 30-second Air Combat Phase. They may change speeds up to 25% of their maximum speed each 30-second Air Combat Phase.
4.9.1.6 Airship Endurance: An airship's fuel capacity will be listed in terms of the number of payioad points it can carry. The Annex B listing will also tell how much range each point of fuel provides.
Players tracking an airship's endurance over a long period of time will want to note each time the airship uses up a point of fuel. The fuel is replaced by water, because of the airship's water recovery system. In other words, the fuel has become ballast that can be dumped or retained, as the player wishes.
4.9.2 Airship Ground Handling. Before launch, an airship must be brought out of its hangar. Similarly, after recovery (landing) it must be hangared as quickly as possible. Airships are handled on the ground either by gangs of men (manually) or with power-assisted machinery. In its most sophistiated form, handing lines are passed to powered trolleys that run on rails leading into the hangar. Manual handling works well enough for smaller ships, but can run into problems in high winds. Powered handing equipment can work in higher winds, but they also have their iimits.
Example: A ground crew is walking out a nonrigid airship in a 15-knot wind. The chance of the airship being damaged is (15-10)*2% or 10%. If the wind speed is 10 knots or less, there is no chance for an accident.
When landed, airships must either be hangared or moored to a mast. Even if they have been trimmed "heavy," they are still subject to even light winds, and as was proved several times, are demolished by high winds or storms.
Airships could be moored at masts in all but the most violent storms. Early masts were "high," designed to allow the ship to fly while moored, but it took a great deal of effort to keep them at neutral trim through a day's temperature and wind changes.
In 1929, the US Navy introduced the low or "stub" mast. The airship moored to the end normally, but the mast was sized so that the ship's lower fin almost touched the ground. The end of the fin was secured to a wheeled car that ran on a circular track around the mast. With both ends of the airship secured, the trim did not have to be watched so closely and the crew could rest. Mooring to either a high or a stub mast takes the same amount of time.
4.9.3 Airship Launch. An airship is launched by ordering it in the plotting phase (The plotted order is "Up Ship!"). In the next Air Movement Phase the airship can begin to acceierate and climb, from a starting speed of zero and a starting altitude of zero.
4.9.4 Airship Recovery (Landing). Lighter-than-air craft had to be "landed" by flying them low and slow enough so that ground handlers could grasp the handling lines. Airships would
fly into the wind, matching its speed so that it was stationary with respect to the ground, but the natural turbulence of the wind often created difficulties for the ground handlers.
Example: An airship approaching in a 24-knot wind will need D6 * (24/10) Tactical Turns. If the player rolls a 3 on D6, then it will need 3*2.4 or 7.2 (rounded to 7) Tactical Turns to be recovered.
4.9.5 Launching Planes from an Airship. When ready for launch, the plane is extended into the airstream on the trapeze and released. This is ordered in the Plotting Phase and in the next Air Movement Phase the launched plane is flying at the same course and speed as the airship, slightly (50m) below. The handling gear can bring one plane into the launch position each Tactical Turn (i.e., five Air Movement Phases to bring out, one Phase to launch)
4.9.6 Recovering Planes by an Airship. Both the plane and the airship must be fitted with special trapeze equipment, but no other modifications are needed. Pilots described the procedure
as extremely easy, almost trivial.
In any Air Movement Phase the fixed-wing plane must match altitude, course, and speed with the airship, and in the next 30-second Air Movement Phase it is latched on the trapeze.
One aircraft can be recovered each Tactical Turn (i.e., one Air Movement Phase to recover and five Phases to stow the plane).
6.xxx AA Fire Against Airships. If an LTA craft flies within range of antiaircraft guns, a can be attacked, but there are a few special rules:
Airships have a +20 modifier to a ship's M strength on the Antiaircraft Combat Table.
The firing player rolls normally to see if his Area or Light M guns hit, but unlike firing at fixed-wing aircraft, all hits are applied against the airship, each one being treated as a Critical Hit (see 7.xxx). If there are both airships and fixed-wing planes in range,
the player must declare what his guns are firing at. He cannot divide his fire, although he can fire his Area M at one type of air target and his Light M at another. If there is more than one airship in range, the players must designate which one they are firing at.
Once the number of Criticals is found for each airship under attack, roll to see whether the Critical hit affects the gondola (1 on a D10) or the envelope (2-10 on D10). These numbers are then taken to the Airship Critical Hit Table.
6.xxx Air-to~Air Attacks Against Airships. All airships, regardless of size, have a maneuver rating of 0.5 both full and lightly loaded. This value is used to see if a plane can get into firing position against an airship.
Once in position, the attacking player must declare whether he is aiming for the envelope (90% chance to hit) or the gondola (standard ATA fommula to gain position). If the player rolls and hits, use the Air Attack Critical Hit table (7.xxx) to see how much damage is inflicted.
7.XXX Airship Damage. Because they are not dependent on airfoils to remain airborne, and because of their size, a successful hit on an airship does not automatically mean it is
shot down, even if it has hydrogen in the cells. Like warships, airships are subject to critical hits.
The number of Critiical hits depends on the weapon attacking. M guns inflict Criticals equal to the number of hits rolled on the table (see 6.xxx for details). Air-to-air attacks must be resolved on the Air Attack Critical Hit Table:
The player uses the Gun Attack strength of the attacking aircraft, cross-indexing a D10 roll to see how many Critical hits are inflicted on the airship.
Once the attacking player knows how many critical hits have been inflicted on the gondola or the envelope, Roll for each critical hit on the Airship Critical Hit Table. This tells exactly what has been hit, and the descriptions below provide their effects:
Starred (*) items start a fire, in addition to the listed critical. If the envelope is filled with helium, ignore the fire.
7.xxx Airship Critical Hit Effects.
Control: Roll D6. On a 1-2 the airship loses elevator control, on a 3-4 it loses rudder control, on a 5 it loses valving control, on a 6 it loses ballast control, Airships
without elevator control cannot control their height. Each Tactical Turn the ship must roll to see if it randomly climbs or dives an amount equal to half the maximum rate, or remains level. Airships without rudder control can steer using the engines by halving their speed (to 50% of
maximum). Airships without valving control cannot release gas to descend. (The airship commander can always order any number of cells to be "ripped," which involved the crew ripping out special panels to vent all the gas in a cell at once.) Airships without ballast control cannot release ballast to lighten ship, although they can always jettison fuel, ordnance, or mission equipment.
Communications: The airship's radio or associated equipment is destroyed. It can still communicate by blinker or message streamer.
Engine: One of the airship's engines is destroyed. Reduce its maximum speed at all altitudes proportionately. If the airship has no rudder control and no other engines
on the same side as the damaged one, it will circle in that direction. If a has rudder control, but no other engines on that side, it must throttle back to half remaining speed on that side
to maintain control.
Fire: A fire in a hydrogen-filled envelope means the ship is lost immediately. Helium envelopes will not burn.
If the fire is in the gondola, roll D10 in the plotting phase of each Tactical Turn. If the airship uses hydrogen there is a 30% chance the fire spreads to the envelope and the ship is lost (8,9, or 10 on the die). There is a 50% chance it is extingukhed (1-5 on the die). If it is not extinguished, Roll once on the Airship Critical Hit Table in the following Resolution Phase for one additional Critical HR.
Fuel: One-quarter of the airship's maximum fuel is lost. If the airship has used up one-quarter or more of its fuel, see which tanks have been hit by rolling dice. If all fuel is lost, the airship drifts with the wind, losing all elevator and rudder control. It can still valve gas and drop ballast.
Gas Cell: One of the airship's gas cells has been ruptured. Annex B1 Airship Characteristics will tell how many cells each airship has. Roll randomly to see which cell has been hit, since one cell might sustain several simultaneous hits.
The effect of the loss depends on how many cells have been lost:
Players may compensate for the loss of one cell by dumping all ballast, all payload and throttling to maximum speed to generate lift over the envelope.
Airships, by Robert Jackson, Doubleday, 1973.
BT
At right, the USS Shenandoah (ZRS-1) moored to the the USS Patoka (AO-9).
At right, a F9C lands on the trapeze.
Air Attack Critical Hit Table
Die
RollGun Attack Value .1 .2 .4 .6 .8 1.0 2.0 3.0
4.0 5.0+ 1 0 0 0 0 0 0 0 0 1 1 2 0 0 0 0 0 0 1 1 1 1 3 0 0 0 0 1 1 1 1 1 1 4 0 0 1 1 1 1 1 1 1 1 5 0 1 1 1 1 1 1 1 1 2 6 1 1 1 1 1 1 1 1 2 3 7 1 1 1 1 1 1 1 2 3 3 8 1 1 1 1 1 1 2 3 3 3 9 1 1 1 1 1 2 3 3 3 4 0 1 1 1 1 2 2 3 3 4 5
AIRSHIP CRITICAL HIT TABLE
Die Roll Gondola Envelope 1 Engine Gas Cell* 2 Engine Gas Cell* 3 Engine Gas Cell* 4 Fuel Gas Cell* 5 Fuel Gas Cell* 6 Control Gas Cell* 7 Control Gas Cel* 8 Comm. Gas Cell 9 Sensors Gas Cell 10 Weapons Gas Cell
24% or less: No effect
25 - 49%: The airship may not climb.
50%+ The airship must descend at maximum rate of descent.
75%+ The airship is in an uncontrollable dive at three times the maximum rate of descent.
Bibliography
The Airships Akron and Macon, by Richard K. Smith, Naval Institute Press, 1965.
American Airship Bases and Facilities, by Jarnes R. Shock, Atlantis Productions, 1993.
The British Airship at War, by Patrick Abbott, Terrence Dalton Ltd., 1989.
German Airships: Parseval-Schutte-Lanz-Zeppelin, by Heinz J. Nowarra,
Schiffer Military History, 1990.
Rigid Airship Manual, US Government Printing Office, 1927.
Sky Ships, by William F. Althoff, Pacifica Press, 1990.
United States Navy K-Type Airships Pilot's Manual, Goodyear Aircraft Corporation.
Up Ship! by Douglas H. Robinson and Charles L. Keller, Naval Institute Press, 1982.
USS Shenandoah, by C.L. Keller, World War I Aero Publishers.
Warship International 4179, RD. Layman letter.
The Zeppelin in Combat, by Douglas H. Robinson, Schiffer Military History, 1994.
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