Expanded list of Autocannons for CE

[atpollard]

I feel like expanding the list of options for Autocannons in CE. First, let's talk about what an Autocannon is ...

An autocannon is a REALLY BIG Machine gun, specifically:

• Large (not hand held)
• fully automatic
• rapid-fire
• 20–60 mm projectile (typical range)

Some history for anyone interested:
The first recoil operated Machine gun was the .45 caliber Maxim Gun in military service by 1886. By the 1890's a 37mm version of the Maxim Gun was available as the "QF 1 pounder" (commonly called the "Pom-pom" after the sound it made). The Pom-pom was the first Autocannon, predated 1900, fired exploding shells and served as both an infantry and anti-aircraft gun. With a 300 round per minute cyclic RoF, the weapon was capable of up to 30 rounds per 6 second combat turn. All of which is just my long winded way of saying that there should be a TL 5 Autocannon and while we are at it, why not fill in some TL 7, TL 9 and TL 11 Autocannons. By TL 12, the Gauss Cannon replaces the Autocannon.



Statistics common to all Standard (40mm) Autocannon:

• 24 VDS spaces (2 dTons)
• range = distant
• stabilized weapon
• Law Level 3

Standard Autocannon statistics by TL:

• 40mm Autocannon-TL 5: Cr 150,000; RoF = 1/3; 5D6 damage; 0.75m (0.5 sq.) damage radius.
• 40mm Autocannon-TL 6: Cr 200,000; RoF = 1/4; 6D6 damage; 1.5m (1 sq.) damage radius.
• 40mm Autocannon-TL 7: Cr 250,000; RoF = 1/5; 7D6 damage; 2.25m (1.5 sq.) damage radius.
• 40mm Autocannon-TL 8: Cr 300,000; RoF = 1/6; 8D6 damage; 3m (2 sq.) damage radius.
• 40mm Autocannon-TL 9: Cr 325,000; RoF = 1/6; 8D6 damage; 3.75m (2.5 sq.) damage radius.
• 40mm Autocannon-TL 10: Cr 350,000; RoF = 1/6; 9D6 damage; 4.5m (3 sq.) damage radius.
• 40mm Autocannon-TL 11: Cr 400,000; RoF = 1/7; 10D6 damage; 5.25m (3.5 sq.) damage radius.

Since the CE VDS includes guidelines on Heavy and Light versions of weapons, why not add them ...

Light Turret Weapon (TL3): Any vehicular armament that can be mounted in a turret can be purchased in a
lighter version. Multiply the weapon’s price by 0.75, increase the weapon’s range by one range band, and
decrease the weapon’s damage by 1D6. This cannot be stacked with Heavy Turret Weapon.

Statistics common to all Light (20mm) Autocannon:

• 24 VDS spaces (2 dTons)
• range = very distant
• stabilized weapon
• Law Level 3

Light Autocannon statistics by TL:

• 20mm Autocannon-TL 5: Cr 112,500; RoF = 1/3; 4D6 damage; 0.75m (0.5 sq.) damage radius.
• 20mm Autocannon-TL 6: Cr 150,000; RoF = 1/4; 5D6 damage; 1.5m (1 sq.) damage radius.
• 20mm Autocannon-TL 7: Cr 187,500; RoF = 1/5; 6D6 damage; 2.25m (1.5 sq.) damage radius.
• 20mm Autocannon-TL 8: Cr 225,000; RoF = 1/6; 7D6 damage; 3m (2 sq.) damage radius.
• 20mm Autocannon-TL 9: Cr 243,750; RoF = 1/6; 7D6 damage; 3.75m (2.5 sq.) damage radius.
• 20mm Autocannon-TL 10: Cr 262,500; RoF = 1/6; 8D6 damage; 4.5m (3 sq.) damage radius.
• 20mm Autocannon-TL 11: Cr 300,000; RoF = 1/7; 9D6 damage; 5.25m (3.5 sq.) damage radius.

Heavy Turret Weapon (TL3): Any vehicular armament that can be mounted in a turret can be purchased in a
heavier version. Multiply the weapon’s price by 1.5, multiply the weapon’s ROF by 0.5, and increase the
weapon’s damage by 1D6. This cannot be stacked with Light Turret Weapon.

Statistics common to all Heavy (60mm) Autocannon:

• 24 VDS spaces (2 dTons)
• range = distant
• stabilized weapon
• Law Level 3

Heavy Autocannon statistics by TL:

• 60mm Autocannon-TL 5: Cr 225,000; RoF = 1/1.5; 6D6 damage; 0.75m (0.5 sq.) damage radius.
• 60mm Autocannon-TL 6: Cr 300,000; RoF = 1/2; 7D6 damage; 1.5m (1 sq.) damage radius.
• 60mm Autocannon-TL 7: Cr 375,000; RoF = 1/2.5; 8D6 damage; 2.25m (1.5 sq.) damage radius.
• 60mm Autocannon-TL 8: Cr 450,000; RoF = 1/3; 9D6 damage; 3m (2 sq.) damage radius.
• 60mm Autocannon-TL 9: Cr 487,500; RoF = 1/3; 9D6 damage; 3.75m (2.5 sq.) damage radius.
• 60mm Autocannon-TL 10: Cr 525,000; RoF = 1/3; 10D6 damage; 4.5m (3 sq.) damage radius.
• 60mm Autocannon-TL 11: Cr 600,000; RoF = 1/3.5; 11D6 damage; 5.25m (3.5 sq.) damage radius.

I hope you enjoy this and find it useful ... I always like having more options.

 

[Timerover51]

Now some Real World costs.

The armament for the two battleships, HMS Lord Nelson (completed in October of 1908) and HMS Agamemnon (completed in June of 1908) cost £110,000 each. (£ is the symbol for the English Pound currency). The completion dates put both ships at Tech Level 5. The data on cost and armament from R. A. Burt's British Battleships 1889-1904

The armament was as follows:
Four 12 inch 45 caliber Mark X guns, firing a 850 pound projectile.
Ten 9.2 inch 46 caliber guns, firing a 380 pound projectile
Twenty-four 12 pounder guns, firing a circa 12 pound projectile
Two 3 pounder guns, mainly for saluting, firing a circa 3 pound projectile

Now, at the time, both the pound and U.S. dollar were valued in gold, with the Dollar being worth approximately $4.87 per British Pound. That would make the cost of the entire armament of each of the two ships at $537,500. The U.S. Dollar was valued at $20.67 per ounce of gold.

You have the 40mm Tech Level 5 autocannon, firing an approximately 2 pound projectile, at 150,000 Credits. I am not sure how the Credit is valued in terms of U.S. Dollars in the Cepheus Engine. If it is valued in terms of 1977 U.S. Dollars, then the inflation rate from 1 January 1913, when inflation data began to be collected, to 1 January 1977 is 5.97, meaning that $1 U.S. in 1913 was worth $5.97 in 1977 Dollars. In Adventure 2: Research Station Gamma, it is stated that gold was worth 200 Credit per ounce. In terms of 1913 U.S. Dollars, that would make about 10 Credits to the Dollar. Now, there are two ways of looking at this based on these data points.

If you increase the costs of the battleship armament and the autocannon by 6, the approximate inflation factor, the cost of the ship armament in U.S. Dollars goes up to $3,225,000, while the cost of the autocannon goes up to $900,000. The battleships therefore could be armed with four 40mm autocannon for $3,600,000 U.S.

If you use the 10 Credits to the Dollar factor, then the cost in terms of Dollars for the battleships would increase to $5,375,000 or 5,375,000 Credits, with the autocannon staying at 150,000 Credits. Now the Agamemnon-class ships carried a total of 40 guns. Replacing these with the 40mm autocannon on a one-to-one basis would cost 6,000,000 Credits, but I fear that the ship would be a bit underarmed for its size, considering weight and range differential of the 12 inch gun, to say nothing of its damage capacity compared to an approximately 2 pound projectile.

As for the damage radius, this would be pretty much strictly fragmentation effects. You increase the damage radius per round from 0.75 to 5.25, a factor of 7. Increasing the damage radius while maintaining the same likelihood of hitting a man-sized target means increasing the number of fragments by a factor of 49, as surface area increased by the square of the radius. That means that the fragments of the highest level projectile are 1/49th the weight of the lowest level of projectile. Before someone claims that the fragments of the highest tech level of projectile will be traveling so much faster, in atmosphere, the fragments will have 1/49th the mass but 1/7th of the surface area. They are going to slow down a lot faster. The real issue is that the damage radius for the Tech Level 5 projectile is too low, not that the radius for the Tech Level 12 projectile is too high. And by the way, the effective fragmentation radius for the projectile fired by the 40mm grenade launcher during the Vietnam War was 5 meters. That would be Tech Level 6 per the Vehicle Design Guide.

 

[Timerover51]

I would hate to think what an eight-barrel mount with remote power control connected to a Mark 51 director would cost. The Mark 51 was a simple one-man ballistics computer mounted away from the gun for better visibility that would compute the firing solution for the connected mounts or mounts based on range and tracking rate change. It performed quite well for its time, which was during World War 2. Also, for anti-aircraft fire, the gun did use 275 round magazines that were fed by 25 round metallic link belts. The director was about the sire of a 2-foot square box with a set of binoculars.

The British 2 pdr/40mm gun was rated, in an eight-barrel mount, as equivalent to a single quad 40mm Bofors mount when it came to shooting at torpedo planes, but was as good as an eight-barrel Bofors mount when it came to shooting at kamikazes. who would be coming pretty much straight at the mount. The British gun was a straightforward improvement of the original Maxim 40mm Pom-Pom. The Bofors was a different gun entirely, developed by Bofors of Sweden, with a much longer barrel.

The Japanese made some use of the British gun, not on ships however, where they desperately needed something like that verses the 25mm Hotchkiss-derivative that they actually used. The Bofors was widely used by the Allies, being built in the U.S. and supplied via Lend-Lease, and some use was also made of it by the Germans.

Anyone who wants to play around with designing heavier guns should really take a look at Campbell's Naval Weapons of World War Two or a copy of Jane's Weapon Systems. Norm Friedman's U.S. Naval Weapons Systems covers both guns and fire control systems, and also has a very good chapter on sonar. If you are thinking of earlier guns, a lot of World War One guns were still in use in World War 2, and are covered by Campbell. Otherwise, take a look at some of the Brassey's Naval Annuals from the late 1880s or early 1900s, where Space; 1889 gets a lot of data.

If you are designing wooden warships, then I would highly recommend Archibald's The Wooden Fighting Ship in the Royal Navy AD 867 to 1860, which does have information on manning and costs. As for information on how wooden fighting ships actually fought, it would be hard to beat Coggins' Ships and Seamen of the American Revolution. For warships in general, then there is Archibald's The Fighting Ship in the Royal Navy AD 867 to 1984. Then there is always Jane's Fighting Ships and Conway's All The World's Fighting Ship series. For those desiring more detail, I would highly recommend Norm Friedman's series on U.S. warship design and development. Those are all historical ships covering up to Tech Level 8, and you can extrapolate a bit into the future with them.