#RPGThursday – Heavy Hover Tank Design for #CepheusEngine RPG

hammersslammers
By Source, Fair use, https://en.wikipedia.org/w/index.php?curid=40927431

I absolutely love David Drake’s Hammer’s Slammers series of military science fiction stories. I was so excited when Mongoose Publishing rolled out a Hammer’s Slammers supplement for Mongoose Traveller First Edition (MgT1E). Unfortunately, Mongoose did a very amateur job, demonstrating they really don’t understand the military and leaving us consumers with a poor product. Mongoose claimed that all the vehicles were created with the Traveller Vehicle Creation System and were supposed to be fully compatible with every other Traveller books. NOT SO!

The Cepheus Engine Vehicle Design System is Cepheus Engine RPG successor to The Vehicle Handbook for MgT1E. I have had the CEVDS for a while now and decided to try to recreate something close to a Slammer’s hover tank.

TL-12 Heavy Plasma Hover Tank

Using a closed 5-ton chassis (3 Hull, 3 Structure), Armor 25, the Heavy Plasma Hover Tank is a main battle tank. It has the Hostile Environmental Protections System. It carries a Fusion power plant, Code K, and a hover propulsion system, Code K, giving it a top speed of 150kph, a cruising speed of 112 kph, and an Agility DM of +1. Three kiloliters of hydrogen support the power plant for 1 week of use. This vehicle is equipped with the Advanced Vehicle Control System, Class II Laser Comms (LOS or 50 km), Basic Military Sensors (-2), and a Model 2 computer. There is a Basic Cockpit for the Driver and a Standard Seat for the Gunner/Tank Commander. The vehicle has one weapon points. A large, heavy turret carries a TL-12 Rapid Fire Plasma Gun. Cargo capacity is 7 spaces. The chassis is armored with Superdense (x5). It also mounts an Explosive Belt. The vehicle costs 690.12 KCr and takes 1,125 hours or 47 days to build.

Category

Component

Spaces

Price (Cr)

Notes

Chassis Base

60

7800

Code 9
Configuration Closed
Armor

-15

7800

Superdense (Armor x5)
Reinforced Hull

11200

Hull +2
Reinforced Structure Structure +2
Power Plant Fusion

-3

4500

Code K
Propulsion Air Cushion

-4.5

112500

Code K
Fuel Hydrogen

-3

120

Fuel Capacity = 1 Week
Controls Advanced

-2

10000

Agility +1
Communications Class II Laser

-0.04

3000

Laser LOS/Very Distant (50 km)
Sensors Basic Military

-12

20000

Comms DM 0, Very Distant (50 km)
Computer Model 2

1000

Options

500

Hardened
Accommodations Basic Cockpit

-2

1000

Driver
Standard Seat

-2

1000

Gunner/Commander
Armaments Turret (Large Heavy)

-3

93000

Rapid Pulse Plasma Cannon – TL-12

-3

90000

ROF 1/6, 12d6 Dmg
Explosive Belt

15000

Cargo

-7.1

TOTALS

0

690120

Total time to create this design was about 30 minutes. This is still a lot more time that a GM wants to take to create a vehicle at the table, but fine for a prep session. The design is not a Slammer’s blower tank – it doesn’t have a powergun nor the armor to match. But it was a good exercise of the CEVDS and an encouraging start to designing vehicles for Cepheus Engine RPG adventuring.

#TechTuesday – Boxer ATV for #TravellerRPG or #CepheusEngine

atv
Courtesy @biomassart

One of the first vehicles in the Classic Traveller RPG is the ATV, or All Terrain Vehicle. As the TravellerRPG Wiki relates:

 

 

All Terrain Vehicle (ATV): Also known as the ATV, the All Terrain Vehicle is a wheeled or tracked vehicle designed to provide high-quality transportation on the terrestrial surfaces of any number of worlds. It can traverse all but the most forbidding (difficult) terrain and is fully amphibious (capable of water operations).

ATV’s commonly have the following features:

  • The ATV masses 10 tons, and can carry a payload of six tons, including the driver and seven passengers.
  • Cruising speed depends on the terrain being traveled: roads can allow up to 100 kph, while cross-country will rarely exceed 60 kph, and broken ground will keep speeds to 20 kph and under. Tracked ATVs are somewhat slower that wheeled versions, but are more reliable in difficult terrain.
  • An ATV may be powered by a battery charged from a ship’s power plant, or it may contain a small fusion pack requiring water or hydrogen for fuel.
  • The vehicle’s pressurized interior allows up to eight passengers living quarters with reasonable comfort for long periods of time.
  • The major drawbacks of ATVs are refuelling requirements (depending on the specific model), slowness in some types of terrain, and the bulk of the vehicle itself
  • While amphibious, most ATV’s have very poor water performance. Unless intended for short trips, a dedicated watercraft is recommended. And in rough seas or under inclement weather conditions, on large bodies of water, an ATV can be a very dangerous vehicle to be in. Some more advanced ATV’s have better water performance, but most have extremely poor water performance.

Already today we have this:

Looks like the ATV is already here! Now to work up stats using the Cepheus Engine Vehicle Design System.

#TheExpanse Ships in #TravellerRPG

Watching “Home” (The Expanse, Season 2, Episode 5) with the Rocinante at high-g burns got me back to thinking about the ships of The Expanse and how they could be portrayed in tabletop RPGs. I previously looked at the Epstein Drive and how it might be translated into game terms for use in Traveller RPG or Cepheus Engine or Orbital 2100.

**WARNING – Minor Spoilers Ahead**

d70490f270d0e4985ecdeb50683f5b83
Courtesy SyFy

Going all the way back to the first book in the series, Leviathan Wakes, the small shuttle Knight gives us some insight into the technology of The Expanse:

It wasn’t long before Alex called down, “Okay, Boss. It’ll be about a four-hour trip flying’ teakettle. Total mass use at about thirty percent, but we’ve got a full tank. Total mission time: eleven hours.”

“Copy that. Thanks, Alex,” Holden said.

Flying teakettle was naval slang for flying on the maneuvering thrusters that used superheated steam for reaction mass. The Knight‘s fusion torch would be dangerous to use this close to the Canterbury and wasteful on such a short trip. Torches were pre-Epstein fusion drives and far less efficient. (Leviathan Wakes, Chapter 3)

From the book we know that the trip covers 50,000km. Working with classic space travel time equations, we can compute the Knight is traveling at about 1.0368 m/s or just over .1G acceleration.

Later in Chapter 5 we see the Knight running flat-out at 2G acceleration. At this speed the same 50,000 km trip should take only 53 minutes, which is a bit shorter than the approximately 70 minutes obliquily stated in the book. At this point it is unclear if the 2G speed is the upper limit of the teakettle or the fusion torch at low power.

The Knight does eventually clearly light it’s torch:

“Roger that, XO. Bleeding-g burn-and-flip laid in. Angled approach course so our torch won’t burn a hole in the Cant. Time to rock and roll?” Alex replied. (Leviathan Wakes, Chapter 5)

expanse20g20force
Courtesy NBC Universal

Here we have to interpolate the fusion torch acceleration based on Holden and his apparent weight. When lighting the torch Holden weighs 500 kilos. Assuming he is an average 75 kg to begin with, this works out to almost 7G. Interestingly, from the novella The Drive we know that 7G is the instrument limit on Solomon Epstein’s ship that he installed his new drive on, indicating that the fusion torch may have an upper limit of 7G.

In summary, we can say the shuttle Knight has maneuvering thrusters (teakettle) that operate efficiently at .1G. The shuttle also has a fusion drive (torch) that can accelerate it at up to 7G.

The Knight‘s torch drive could deliver a lot of thrust, but at the cost of a prodigious rule-burn rate. But if they could save the Cant, it wouldn’t matter. (Leviathan Wakes, Chapter 5)

The missiles that are fired at the Canterbury are also very impressive:

As if in answer, six new objects appeared on his radar, glowing yellow icons appearing and immediately shifting to orange as the system marked their acceleration. On the Canterbury, Becca yelled out, “Fast movers! We have six new high-speed contacts on a collision course!”

“Jesus H. Christ on a pogo stick, did that ship just fire a spread of torpedoes at us?” McDowell said. “They’re trying to slap us down?”

“Yes, sir,” Becca said.

“Time to contact.”

“Just under eight minutes, sir,” she replied. (Leviathan Wakes, Chapter 5)

For these six missiles to cover 200,000km in 8 minutes means their acceleration has to be around 150G!

In Leviathan Wakes, Chapter 51, Holden tries to remember how fast the Roci can go:

He tried to remember the Roci‘s maximum theoretical acceleration. Alex had already flown it at twelve g briefly when they’d left the Donnager. The actual limit was one of those trivial numbers, a way to brag about something your ship would never really do. Fifteen g, was it? Twenty? (Leviathan Wakes, Chapter 51)

cqb_main
Courtesy solotalkmedia.com

In the episode “Home” if I caught the screen correctly it looks like the Roci was accelerating just over 17g. This again is in line with the book; and way faster than the 6g of Classic Traveller or Cepheus Engine and far ahead of the technology in Orbital 2100 where the alternative Nuclear Pulse Fusion Drive tops out at 1.2g! Compared to the Traveller RPG or Cepheus Engine universe, the ships and weapons of The Expanse are way faster and likely far more deadly too.

As late to the game as I am, I look forward to reading more of The Expanse series and seeing what further ship secrets are hidden within.


PS: The math for figuring time and acceleration is actually easy, but to help there is an EXCELLENT site at http://www.transhuman.talktalk.net/iw/TravTime.htm that does the math for you!

 

 

 

#RPGThursday -To the Far Horizon with Atlas

Two of my three favorite Traveller RPG, uhh…”2d6 Classic Sci-Fi RPG”, companies published new items recently that I acquired.

202309-thumb140The first is Far Horizon from Zozer Games. The cover calls it Far Horizon: A TL9 Exploration Ship for the Cepheus Engine whereas the front matter states Far Horizon: A Near Future Mission and Spacecraft for Cepheus Engine. Both titles are correct, although the second one is more accurate. This title is designed to go with the Zozer’s Alternate Traveller Universe (ATU) setting of Orbital: 2100 although everything is included here to play this adventure with just the basic Cepheus Engine rules if needed. pic3217789_mdInside one finds not only background into the mission but also a complete description of the DRV Far Horizon, a nuclear-thermal rocket for exploring deep space. Included also are rules for TL9 Vacc Suits. The adventure itself is a race-against-time investigation into the unknown.

109517-thumb140Parts of Far Horizon have been available previously. The ship itself is a free download at DriveThruRPG. The rules on vacuum suit construction were in a previous product, Vacc Suit, which is no longer available no-thanks to the Mongoose Publishing Community Content Agreement. So it is refreshing to see this packaging bringing back good near-future, hard-ish sci-fi adventure! Adding to the quality, the product is nicely illustrated by Ian Stead and others.

If one has looked at Orbital: 2100 but are not sure about making the jump into this ATU, Far Horizon is a great way to try out the setting.

202134-thumb140The second product I got was Ships of the Clement Sector 17: Atlas-class Freighter from Gypsy Knights Games. This is the second of what I call “expanded” ship books from GKG. The 50-page product includes excellent narratives to set the mood, awesome ship art by Ian Stead (again), and just enough adventure seeds to whet a GM’s appetite. Indeed, this larger format allows for more of each giving both players and GMs more to think about and more potential for adventure. If you are a fan of The Expanse, you may find a similar vibe to that universe and some of the stories and background presented here. Though many might look at an 800 dT freighter as “not sexy enough to be my ship,” the reality is it takes ships like the Atlas to ply the shipping lanes of the Clement Sector and ekk out a living. This book helps your players do just that. Another must-buy from GKG!


All images courtesy DriveThruRPG.

Far Horizon, ©2016 Zozer Games.

Ships of the Clement Sector 17: Atlas-class Freighter, ©2017 Gypsy Knights Games, LLC.