R-Drives
- Thread starter robbo6761
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The small craft drives table on page 58 has reaction drives at half the cost and half the size of comparable Gravitic M-drives. I haven't found anywhere in the rules that explicitly states the same relationship for starship or capital ship sized reaction drives, but that's what I use.
Page 42: "Reaction Drive: The reaction drive takes the same space as a gravitic drive, and costs less, but this is offset by the large fuel requirementsin addition to fuel used for the jump drive and power plant. To
calculate a ship’s fuel requirements, use the following system: Fuel Required (as a percentage of the ship’s displacement) = ..."
True, pg 42 and 58 contradict each other for displacement.
For cost, pg 42 vaguely states reaction drive "costs less" than a comparable gravitic drive, but provides no amplifying info. Pg 58 sets reaction drive cost at 50% of gravitic drive cost for small craft.
(shrugs) I choose to regard pg 58 as authoritative, YMMV.
For cost, pg 42 vaguely states reaction drive "costs less" than a comparable gravitic drive, but provides no amplifying info. Pg 58 sets reaction drive cost at 50% of gravitic drive cost for small craft.
(shrugs) I choose to regard pg 58 as authoritative, YMMV.
Then how can you apply the small craft drive cost from Pg. 58 to larger ships?
There should be an errata for page 42 that covers the cost of reaction drives for large ships.
[Off-topic rant: ... but the very fact that the MD for a 100 dT small Craft and a 100 dT spaceship are SO DIFFERENT is the REAL flaw that should have been fixed with errata. Rant over, I feel better now.]
Yes. They need to list the cost for larger ships. I noticed that 100Dt flaw. It is a problem that creeps in when you mix tables with formula based design. It was stupid to use both systems as they aren't compatible.
R-drives
It seems like scale efficiencies work in reverse for Traveller r-drives. The smaller ones take up /less/ space for the same thrust than their larger cousins with the breaking point for vessels under 100 tons.
Maybe it's a matter of economics. R-drives aren't practical except for near space or atmo operations which are usually handled by small craft so there was a push to develop smaller more robust en some featurycle engines being more powerful pound for pound than car engines but dispensing with some features larger engines need.
In other words r-drives are same size as m-drives but half cost.
What are your thoughts on using the technology rules on page 53 for r-drives but applying the tonnage modifiers to fuel use instead of the drive mass? The idea being designs become more fuel efficient over time but not necessarily smaller.
It seems like scale efficiencies work in reverse for Traveller r-drives. The smaller ones take up /less/ space for the same thrust than their larger cousins with the breaking point for vessels under 100 tons.
Maybe it's a matter of economics. R-drives aren't practical except for near space or atmo operations which are usually handled by small craft so there was a push to develop smaller more robust en some featurycle engines being more powerful pound for pound than car engines but dispensing with some features larger engines need.
In other words r-drives are same size as m-drives but half cost.
What are your thoughts on using the technology rules on page 53 for r-drives but applying the tonnage modifiers to fuel use instead of the drive mass? The idea being designs become more fuel efficient over time but not necessarily smaller.
The old Hard Times had some really good rules and data on reaction drives. Where the rules broke from reality for the sake of playability, the author said so and explained that was his reason for doing so.
Using Hard Times as a baseline for comparison, reaction drives should be really small IIRC. Feel free to compare for yourself.
Using Hard Times as a baseline for comparison, reaction drives should be really small IIRC. Feel free to compare for yourself.
Really small but guzzling fuel at prodigious rates.
R-rives and Hyperspace
So looking at the rules in MgT for the Hyperspace drive I see that a ship moves a number of parsecs per day equal to its maneuver rating. that's fine but how do you deal with reaction drives in hyperspace? I mean besides just using a J-drive and saying "The heck with it!"
My take is the ship's vector when it opens a portal doesn't seem to matter (otherwise what happens if you accelerate for a couple of months at 1 gee and enter hyperspace zip! Galactic Core!) Also the distance covered in hyper is linear based on the thrust rating and not logarithmic as in real space travel, otherwise a ship with Thrust 4 would travel merely twice as fast as a Thrust 1 ship, not four times and your speed in pc/day would increase with each hex traveled.
So I'm assuming your ship accelerates for a set time when you trigger the portal: say one hour. That's the velocity you enter hyperspace with and must decelerate from (symmetry you know.)
So looking at the rules in MgT for the Hyperspace drive I see that a ship moves a number of parsecs per day equal to its maneuver rating. that's fine but how do you deal with reaction drives in hyperspace? I mean besides just using a J-drive and saying "The heck with it!"
My take is the ship's vector when it opens a portal doesn't seem to matter (otherwise what happens if you accelerate for a couple of months at 1 gee and enter hyperspace zip! Galactic Core!) Also the distance covered in hyper is linear based on the thrust rating and not logarithmic as in real space travel, otherwise a ship with Thrust 4 would travel merely twice as fast as a Thrust 1 ship, not four times and your speed in pc/day would increase with each hex traveled.
So I'm assuming your ship accelerates for a set time when you trigger the portal: say one hour. That's the velocity you enter hyperspace with and must decelerate from (symmetry you know.)
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