A Consolidated Errata list

[BMonnery]

Another major change (one I proposed over 10 years ago ISTR) is for MHD Turbines to burn petrol instead of hydrogen. Due to the fuel: oxidiser ratios (H2/O2 is only 1/9th fuel) we get a much increase in the stored energy per ton. In fact a fourfold increase. Oh, and I also started installing a lot of solar cells. Insystem they're the most mass efficient power system

Yet another was in the active sensors rules. Simply inverse square law tells you a spherical active scanner needs several hundred MW of output to make a detection (FWIW: modern military naval radars typically need the best part of a MW to detect a missile 100km away). I simply stopped them being spherical, and made them directional, you could use the active to "interrogate" a hex with black globes.

One upshot was ships started carrying multiple active arrays IMC.

Also, I decided that the rear endcap with "glowy bits" (that look like star wars engines) are actually the heat exchanger/ radiator. What I never then got round to doing is altering the sensor rules so that ships are less visible to passive detection from the front....

 

[BMonnery]

One interesting note. While copying the NAM over to word for editing, I noticed that for years prettymuch everyone (me included) failed to included engineering crew on the bridge...

 

[shaunhilburn]

Another major change (one I proposed over 10 years ago ISTR) is for MHD Turbines to burn petrol instead of hydrogen. Due to the fuel: oxidiser ratios (H2/O2 is only 1/9th fuel) we get a much increase in the stored energy per ton. In fact a fourfold increase.

The term "turbine" confuses players, I prefer the term "generator" as that's exactly what it is. They're only called turbines in sci-fi sources derived from 2300AD.

To generate power with a conducting plasma stream requires sustained temperatures several thousands Kelvin, far beyond the melting point of any modern materials and any in the foreseeable future.

The current technique is to dope the armature gas with an alkali metal like potassium or cesium, the gas becomes *much* more conductive and the MHD channel temperature drops to a manageable 2,500 K.
This causes corrosion problems in the electrodes.

See http://en.wikipedia.org/wiki/MHD_generator

 

[BMonnery]

The term "turbine" confuses players, I prefer the term "generator" as that's exactly what it is. They're only called turbines in sci-fi sources derived from 2300AD.

To generate power with a conducting plasma stream requires sustained temperatures several thousands Kelvin, far beyond the melting point of any modern materials and any in the foreseeable future.

The current technique is to dope the armature gas with an alkali metal like potassium or cesium, the gas becomes *much* more conductive and the MHD channel temperature drops to a manageable 2,500 K.
This causes corrosion problems in the electrodes.

See http://en.wikipedia.org/wiki/MHD_generator

True, it seems to imply a high tech Gas Turbine. I've always assumed that MHD generators are the extraction method for getting energy out of the fusion/ fission plant, but fail to see how a hydrogen burner would really work.

I can remember guestimating the components of a fusion reactor, and not quite half the mass being the MHD extraction system, and much of the rest being a liquid radiation shield, the actual reactor being a fairly small device.

GDW assume a 60% efficiency for MHDs (and 75% for fuel cells), which in itself is pretty amazing.

However, replacing H2/O2 with Dodecane/O2 (diesel) and we go from 100 tons/ MW/ week to about 25 tons/ MW/ week (ca 20 tons/ MW/ week with fuel cells). The question of doping with heavy metals becomes very similar to doping with Lead.

I just think people wouldn't accept a diesel starship....

 

[shaunhilburn]

GDW assume a 60% efficiency for MHDs (and 75% for fuel cells), which in itself is pretty amazing.

Consider:

MHDs consume 100 tons per megawatt-week

Divide by 168 hours = 0.595 tons per megawatt-hour, or ...
1/0.595 = 1.68 megawatt-hours per ton.

Am I correct so far? I hope so, this is leading somewhere...

I just think people wouldn't accept a diesel starship....

The whole premise of Star Cruiser was modelled after submarines.

Diesel subs -> diesel starships. Players accept fuel-cell starships, and fuel cell subs are a reality now.

So why not diesel starships?
Hell, even diesel *piston* powerplants, with globs of engine sludge and lube oil floating in zero-g

 

[BMonnery]

Consider:

MHDs consume 100 tons per megawatt-week

Divide by 168 hours = 0.595 tons per megawatt-hour, or ...
1/0.595 = 1.68 megawatt-hours per ton.

Am I correct so far? I hope so, this is leading somewhere...






The whole premise of Star Cruiser was modelled after submarines.

Diesel subs -> diesel starships. Players accept fuel-cell starships, and fuel cell subs are a reality now.

So why not diesel starships?
Hell, even diesel *piston* powerplants, with globs of engine sludge and lube oil floating in zero-g

Hydrogen is the most energy dense fuel (see http://en.wikipedia.org/wiki/Heat_of_combustion ) but requires 8kg of O2 per kg of fuel or roughly 15.77Mj/kg of fuel and oxidiser

Diesel is less energy dense at ca 45Mj/ kg, but only requires about 3.5kg of O2 per kg of fuel or 12.92Mj/kg of fuel and oxidiser

So H2 is slightly more energetic, despite my memory, but whether it's more usable....

 

[shaunhilburn]

Hydrogen is the most energy dense fuel (see http://en.wikipedia.org/wiki/Heat_of_combustion )

According to that page, the HHV energy content of H2 is 141.8 MJ/kg = 39.38 kWH/kg = 39.38 MWH per ton.

MHD gens consume 100 tons per megawatt-week.

Say a 1 megawatt MHD plant runs for one week (168 hours) and consumes 100 tons of fuel, 1/9 of this is H2 = 11.11 tons.

168 megawatt-hours output / 11.11 tons H2 consumption = 15.12 tons per megawatt-hour.

15.12 / 39.38 = ~38% HHV conversion efficiency.

 

[BMonnery]

According to that page, the HHV energy content of H2 is 141.8 MJ/kg = 39.38 kWH/kg = 39.38 MWH per ton.

MHD gens consume 100 tons per megawatt-week.

Say a 1 megawatt MHD plant runs for one week (168 hours) and consumes 100 tons of fuel, 1/9 of this is H2 = 11.11 tons.

168 megawatt-hours output / 11.11 tons H2 consumption = 15.12 tons per megawatt-hour.

15.12 / 39.38 = ~38% HHV conversion efficiency.

To make the calculation simpler, lets use the 600kg per MW-Hr statistic (yes 168*.6 is not quite 100). In theory there's 9.453 GJ in 600kg = 2.63 MW thermal. Yes, 38% efficient is correct.

Bugger.

 

[shaunhilburn]

3. Should Submunitions get the benefit from a targeting computer?

Yes. Per NAM pg 14, submunitions have no active or passive sensors, ergo they need telemetry from the mother ship.

NAM pg 7 states, "... each computer installed can lend its aid to any number of weapons firing from a ship." I take this to include submunition dispensers.

 

[shaunhilburn]

Yes, 38% efficient is correct.

Bugger.

A 1 MW plant with 38% conversion efficiency produces 1.63 MW of waste heat, the total output is 2.63 MW.

Should we change the radiator rule to reflect the total output vs rated output?

 

[BMonnery]

A 1 MW plant with 38% conversion efficiency produces 1.63 MW of waste heat, the total output is 2.63 MW.

Should we change the radiator rule to reflect the total output vs rated output?

Other GDW products rate MHD generators as 60% efficient, I wonder about increasing efficiency.

Yes, the radiators need to be calibrated against MWt rather than MWe, there is a major question about fusion reactors efficiency though.....

 

[kmsoice]

The turrets are actually too small. A 6m focal array just doesn't really cut it given the physics involved (yes, it's a 6m mirror!). If it does, then I'm happy to build a 12m FA and shoot out to 2 hexes......

The scale is broken, the easiest fix is to alter the time dimension to roughly 17 mins (I round to 20), which, oddly enough, is the Classic Traveller space combat turn length. I believe they optimised based on traveller rules, then changed later.

The scale provoked one of the largest arguments in 2300 web history BTW....

One of the major changes I'd make (aside from general fixes) is a system for designing turret weapons, in the process heavying them up. FWIW, it looks like the focal array may in fact be a 6m diameter disk of lead (!)

One interesting note. While copying the NAM over to word for editing, I noticed that for years prettymuch everyone (me included) failed to included engineering crew on the bridge...

It is pretty obvious that someone has been around for a long time and has been privy to a lot of work and discussion that was before my time and cannot now be found on the net (hint, hint). I think someone needs reread my post to this thread on May 2, 2008 @12:35 (Hint. Hint.) . I think someone needs to write it all down and update their website which has not been changed since Oct 23, 2005! (HINT! HINT!)

 

[BMonnery]

It is pretty obvious that someone has been around for a long time and has been privy to a lot of work and discussion that was before my time and cannot now be found on the net (hint, hint). I think someone needs reread my post to this thread on May 2, 2008 @12:35 (Hint. Hint.) . I think someone needs to write it all down and update their website which has not been changed since Oct 23, 2005! (HINT! HINT!)

I joined the old 2300AD mailing list (which I am now banned from) quite late, about 1997 or 8. These days I mostly hang around at etranger (groups.yahoo.com/group/etranger ), although that's less busy than it used to be.

Some of the early discussions (mostly in 1996, when Wade Racine, Kevin Clark and a few other were active) are fascinating, but I don't think they're online anymore. Certainly, a decade on I thing the 20 year old me was a jerk ;-)

Archive.org has some of the archive: http://web.archive.org/web/19981203040054/http://2300.iinet.net.au/ actually looks like it got the pages but not the zips!

I have NAM as a word file now. I may start modification, starting with power plants, once we're happy with the result.

 

[E.D.Quibell]

Any chance you could put the Errata into a PDF?

Best regards,

Ewan

 

[kmsoice]

Any chance you could put the Errata into a PDF?

Done. Included the latest updates as well and changed the url slightly. You can find the files at
http://www.geocities.com/kelvinsoice...ted_Errata.htm
or a pdf version at
http://www.geocities.com/kelvinsoice...ted_Errata.pdf

Again, please let me know of any additions, corrections or changes you think are needed! Do not forget to include your reasoning why you made the choices you did.

 

[shaunhilburn]

I am trying to keep the cannon (but corrected) elements separate from the technically-non-cannon-but-I-think-are-really-necessary-rules elements with the ‘Alternate Rules’ section at the bottom.

Fuel Station:

A fuel station producing 1 kg/hour only consumes 110 kilowatts to separate and liquefy the hydrogen. During that hour it would vent 8 kg of oxygen, not 40.

The output needs to be doubled to 2 kg/hour, or the power consumption needs to be half (0.1 MW).

Interestingly, the 20 kg empty tank holds 20 kg of (presumably liquid) hydrogen, this tank would be about 90 US gallons (the liquid plus 20% ullage space at the top.)

A 1 kg hydrogen tank is a cylinder 4.5 US gallons, roughly the size of those jugs on an office water cooler.

 

[shaunhilburn]

...some are just poorly written and could be exploited by a rules lawyer like me, and others are much more severe.

Interplanetary travel time: This is a controversial topic, the subject of a few "May Madness" flamefests on the old 2300 list.

The listed value of 0.645 AU/day doesn't square with the speeds in basic space combat or Star Cruiser. The 0.645 rate is slower by nearly 18×.

Assuming that the Star Cruiser movement rates represent flank speed (http://en.wikipedia.org/wiki/Flank_speed), a vessel should be able to sustain full speed about 30% slower indefinitely, this is still far faster that 0.645 AU/day. It doesn't seem reasonable to cruise at a stately rate 18× slower that the redline maximum.

Movment rates derived from Star Cruiser imply a rate of WE 1 = 0.48 AU/hr = 20,000 km/sec. Canon purists object for some reason I can't recall.

There *is* a canonical basis for the faster rate, however. Challenge No. 37, "Three Blind Mice", pg 49, has a table showing various warship speeds that give support to the 0.48 AU/hr rate. They're not exact but close enough.

 

[BMonnery]

Worse than that, there were 3 rates mentioned, and another implied from SC (which includes TBM, which used SC movement rates, not warp eff).

0.645 is correct (and was errata'd), but something wierd happened. If you assume the length of a SC turn is equal to Traveller space combat, then everything works fine, errors are within rounding conventions. However, the is a mention of a turn length being 1 minute in the boxed set.

What I think happened is that GDW started with the Traveller turn length, but typo'd in the length of a ground combat turn.

Personally, I liked to divide distances in AU by .645 (this is probably the source of 6.45, someone wrote the mathematically correct .645, without the zero in front, and a less math savvy editor though they meant 6.45) and call the distance "virtual light years".

 

[shaunhilburn]

What I think happened is that GDW started with the Traveller turn length, but typo'd in the length of a ground combat turn.

The ground combat turn is 30 seconds with *two* allowed actions per turn.

One area fire burst and one mag change in 30 seconds? Thats just nuts. T2K uses a 30-second turn with 6 actions.

A trained rifleman should be capable of 16 - 24 aimed shots per minute (ROF 2) with a semiauto or bolt-action rifle. The upper limits of aimed fire in the "mad minute" are 30-36 rounds (ROF 3).

All this makes sense in the context of a 5-second action, six per turn. So yes, Mr. Chadwick botched the ground combat turn length.

 

[shaunhilburn]

All this makes sense in the context of a 5-second action, six per turn. So yes, Mr. Chadwick botched the ground combat turn length.

I haven't properly caffinated yet

I meant to say the allowed actions per turn is wrong. We need six per turn, or a ten-second turn.