They Started to Fix LBB2 Fuel Burn...

[Grav_Moped]

This quoted info from an earlier thread indicates that they realized that the LBB2 flat-amount power plant fuel consumption rule was flawed, and second edition fixed it for small craft but not starships.

I think when LBB:2 77 is talking about building non-starships using the ship construction rules it refers to only 100t+ spaceships rather than small-craft.

As to fuel burn rate I think the 10kg per g is meant to be for small-craft only with 100t+ spacecraft (non-starships) using the burn rate given on page 6 - 288 burns (a burn is a 10 minute turn's worth) with its maneuver drive or 48 hours of continuous thrust at the m-drive g rating.

That's the key. Even starships/non-starships had a fixed kg-per-burn (not kg per-G*tons) consumption rate in the first edition. And it's an explicit link since the Jump Drive didn't need the power plant for operation.

That's where the 10 tons per Pn (rather than percent of hull tonnage per Pn) power plant fuel requirement came from: Starships and small craft both worked that way in the first edition, though power plants from the LBB2 Drive Table had a higher flat kg/burn fuel consumption rate (about 35kg/G-turn).

Second edition changed small craft fuel use rates to a "per maximum G*Tons" formula (by mostly building them under High Guard small craft rules). The starship/nonstarship fix was to make the 10Td/Pn allocation last for 4 weeks instead of 2 days while implying -- but not detailing how much -- that the 10Td/Pn also contributed to the Jump Drive energy requirements.

In other words, they kept the constant-amount fuel requirement the same even though they'd removed the reason for it to be a constant amount rather than proportional to ship tonnage.

 

[Spinward Flow]

Fuel burn (tonnage) per maneuver G per combat turn = rocket engine fuel burn

Doesn't make a lot of sense for reactionless drives ...

 

[Grav_Moped]

Fuel burn (tonnage) per maneuver G per combat turn = rocket engine fuel burn

Doesn't make a lot of sense for reactionless drives ...

The original vision for LBB2 (and LBB5 '77) was that maneuver drives were fusion rockets. LBB5 even let you use them as weapons!

Just to clarify what I was talking about: The quantity of fuel burned was based ONLY on the acceleration, not tonnage. A 10Td fighter doing a 1G-turn burn used exactly the same amount of fuel as a 95Td shuttle doing a 1G-turn burn!

 

[robject]

Fuel burn (tonnage) per maneuver G per combat turn = rocket engine fuel burn

Doesn't make a lot of sense for reactionless drives ...

It's only different from HG in scale, I think.

 

[Spinward Flow]

Point still stands.
I've always considered maneuver drives to be "electrically driven" reactionless engines. Pour energy points into them from the power plant and you'll get thrust out of them for as long as the power plant has fuel to fusion "burn" for energy points. No fuss, no muss.

As for "how" the maneuver drives are reactionless thrust producers, they basically "warp" gravity fields so as to induce a gravity differential across the hull in the desired direction of motion that generates propulsive force ... blah blah blah ... you know the drill, ask the engineer how it works (I just design the things).

 

[Condottiere]

It seems to be manipulation of gravitational field(s) and properties.

I doubt it will ever be settled science.

 

[RandyB]

It seems to be manipulation of gravitational field(s) and properties.

I doubt it will ever be settled science.

And it will never meet the standards of hard SF.

 

[willtron3030]

And it will never meet the standards of hard SF.

I used to warn people that I ran a "science fantasy" game, although not quite "Star Wars" science fantasy. Hard SF - Mohs scale hard SF - is just too easy to fall into a rabbit hole of minutiae.

At one point, I nearly finished a document entitled the "Handwavium Manifesto", which detailed the blatantly unscientific conceits IMTU that underlay reactionless thrust, FTL, psionics (and as lower TL societies called it, "magic"), and strangely the hardest one for me, inertial dampers.

There was one topic where I was pretty resolute: on most ships, up and down were parallel to the thrust of the maneuver drive. It took too much mental effort to justify having up/down be perpendicular to the direction of travel, unless it was a spinning wheel/cylinder hull. Shuttles/cutters/pinnaces that traveled like aircraft had no 'down' gravity until they were in a gravity well.

 

[Grav_Moped]

I used to warn people that I ran a "science fantasy" game, although not quite "Star Wars" science fantasy. Hard SF - Mohs scale hard SF - is just too easy to fall into a rabbit hole of minutiae.

At one point, I nearly finished a document entitled the "Handwavium Manifesto", which detailed the blatantly unscientific conceits IMTU that underlay reactionless thrust, FTL, psionics (and as lower TL societies called it, "magic"), and strangely the hardest one for me, inertial dampers.

There was one topic where I was pretty resolute: on most ships, up and down were parallel to the thrust of the maneuver drive. It took too much mental effort to justify having up/down be perpendicular to the direction of travel, unless it was a spinning wheel/cylinder hull. Shuttles/cutters/pinnaces that traveled like aircraft had no 'down' gravity until they were in a gravity well.

I'm another big fan of tailsitter-configured ships, and am disappointed that there are relatively few such designs out there.

 

[Spinward Flow]

I'm another big fan of tailsitter-configured ships, and am disappointed that there are relatively few such designs out there.

C'mon ... SpaceX only started building them recently ... :rofl:

 

[Condottiere]

A monument to Man's Monument, or a man's.

 

[aramis]

C'mon ... SpaceX only started building them recently ... :rofl:

Grumman & NASA opted for them in 1967... in the lunar lander.

 

[Spinward Flow]

Grumman & NASA opted for them in 1967... in the lunar lander.

When TL=7 space tech was cutting edge during the TL=6 era.

And to be fair, those tail sitters weren't exactly reusable ...

 

[infojunky]

Honestly I have odd fix, if the fusion rocket model, in that power plant fuel is maneuver fuel. The fuel for maneuver water, such that 10 tons of water has volume of one dTon. That load of water give 48 hours of burn.

Refueling the power plant then become a function of Annual Maintenance.

 

[kilemall]

My reasoning is that the fuel is actually used primarily as heat exhaust and also for reaction accel as the M-drive uses gravitics to make the ship 'weigh less' against the normal space time fabric requiring in less reaction mass needed.


If there is no accel but the power plant is powered up, the exhaust still needs to be expelled.


Wave those hands HARDER!

 

[Grav_Moped]

Just to clarify what I was talking about: The quantity of fuel burned was based ONLY on the acceleration, not tonnage. A 10Td fighter doing a 1G-turn burn used exactly the same amount of fuel as a 95Td shuttle doing a 1G-turn burn!

And to further clarify (or at least extend it explicitly into starship/non-starship tonnages), a 200Td Free Trader doing a 1 G-turn burn used exactly the same amount of fuel as a 600Td Subsidized Liner doing a 1 G-turn burn. That's why the LBB2 power plant fuel allocation was proportional to the power plant rating (in '77 this meant proportional to the maneuver drive rating only, since their jump drives were self-powered) instead of the rating AND tonnage.

 

[Spinward Flow]

Yet more proof (as if we needed it) that LBB2 fuel allocation was borken.

 

[Grav_Moped]

Yet more proof (as if we needed it) that LBB2 fuel allocation was borken.

Oh, it was borked.

The problem is they couldn't fix it properly without rewriting all of the game materials they'd been publishing for a few years. So they patched it by declaring "it's enough fuel for a month, instead of just for two weeks of typical use" instead of revising the formula.

 

[Grav_Moped]

Oh, it was borked.

The problem is they couldn't fix it properly without rewriting all of the game materials they'd been publishing for a few years. So they patched it by declaring "it's enough fuel for a month, instead of just for two weeks of typical use" instead of revising the formula.

Beltstrike's fuel rules were probably a better patch. Consumption rates were plausible, but since it didn't waive the mandated minimum the problem still existed.

 

[infojunky]

Beltstrike's fuel rules were probably a better patch. Consumption rates were plausible, but since it didn't waive the mandated minimum the problem still existed.

Sure go point that out. It’s note a bad idea. Really it’s not, heck the table is in a 100 ton increment already.