Classic Traveller: The Lost Rules

[BlackBat242]

Further, an airframe can take off with less than 1G thrust. (Boeing's 737-600 generates 22,700lb-thrust, with a maximum take-off weight of 145,500lbs max TO weight. ref)

With 1G, one can push a clean airframe to rather high altitudes...

Nitpick... that is the thrust of EACH of the B-737-600's 2 engines... 45,400 lb.s.t. total.

Still less than 1/3 of the total airframe weight, though.

http://www.deagel.com/Turbofan-Engines/CFM56-7_a001738006.aspx
"The CFM56-7 is the latest member of successful CFM56 family of engines. It has a dual annular combustor for low emissions capability and reduced fuel burn through advanced thermodynamic cycle. Its thrust ranges between 18,500 and 27,300 pounds."

 

[chshrkt]

How many canon traveller ships have an airfoil incorporated in their design again? As far as I know it is only the Subsidized Merchant that has an obvious one...

 

[mike wightman]

Sorry to continue this - but the rules supp4 quotes are evident that the Striker design system is either broken or ship maneuver drives work differently to grav vehicles.

Which, by the way, probably means broken since in evrey write up for the air/raft I can find it states that it can make orbit given enough time.

 

[mike wightman]

Oh, and 1st edition High Guard states that CT maneuver drives are fusion rockets - which can be used as weapons in an emergency.

A 1g continous burn fusion rocket is not going to have a problem taking off from a planet - not straight up mind you it has to fly like a plane and get faster and faster and faster.

Andy Slack was just plain wrong, Striker offers design rules for grav vehicles which contradict earlier canon, ship engines are different - there finished.

 

[beowulf2044]

Traveller Book Weapon Damage

The Traveller Book weapons matrix has at least three errors present; the aforementioned Body Pistol and Cutlass damage errors and the range modifier for the Dagger is listed as +2 at short range, instead of -1 that it should be. This looks to be a carry over from the range matrix of the Club listed above Dagger.

 

[DonM]

Interesting that the 1981 LBB actually has the dagger modifier correct in this case. And the damage for the Body Pistol and Cutlass are correct in the listings of weapons in the skill sections, but wrong in the range matrix table.

Remember that errata for TTB and STT isn't what I'm looking for here -- however, knowing about it means I won't think that those are fixes to errata in the 1981 LBBs.

 

[Supplement Four]

1977 Sensors. Note to go check those.

I don't have the 1977 LBB edition, but I know about this from looking at the Judges Guild Traveller GM Screen.

I suggest looking at any other early GM Screens you may have access to. A quick glance could highlight something we are missing.

Escape Velocity/Fuel Skimming: 1981 LBB drop confirmed as errata closure; these items were dropped on purpose;

That's what I had thought. It seemed to be there in early Traveller stuff, then stopped just after Striker was published (except for LKW's recent 20 ton Launch supplement).

Can you shed any light on this just for curiosity's sake? Did they drop it for simplicity? Did they drop it for physics reasons?

I'd be interested to know why this was dropped.

I actually use it in my game. It makes the game more "fun". Star systems become interesting and certain problems for the players pop up.

So...can you clue us in on why Marc & Co. dropped it?

 

[Supplement Four]

Sorry to continue this - but the rules supp4 quotes are evident that the Striker design system is either broken or ship maneuver drives work differently to grav vehicles.

Check out the section in Striker called Integrating With Traveller.

Grav drives and M-Drives are two different types of drive (which is why Loren's 20 Ton Launch isn't rated as a 2G M-Drive).

For example, in the Traveller Book, under the air/raft, it states: interplanetary travel in an air/raft is not possible.

The TB also states: Air/raft skill is a synonym for grav vehicle skill, therefore grav vehicles cannot make interplanetary journeys.

Grav drives are used for orbit-to-surface travel only.

Maneuver drives are used for orbit-to-deep space operations.

Which, by the way, probably means broken since in evrey write up for the air/raft I can find it states that it can make orbit given enough time.

No, the Striker rule isn't broken. The air/raft in CT isn't given a G rating. What you get is a cruise speed of 100 kph and a max speed of 120 kph.

If you turn to the Grav Vehicle Speed table on page 5 of the Striker Design Sequences booklet, it's easy to determine, at a glance, that the air/raft is rated at somewhat less than 1.1 G's. (You'll have to interpolate a bit on the chart as the smallest unit is .1 G's, and the air/raft is slower than that. The air/raft will be rated at something like 1.07 G's or so.)

This craft is rated more than 1G, so it can make escape velocity from a Size 8 world. It will just take the vehicle forever to do it...which is in line with the description of the air/raft.





When in doubt, it's easy to figure this stuff by looking at the Standard Worlds chart on page 79 of the Traveller Book. There, it lays out for you, the surface gravity of each world size and shows how gravity decreases the higher you get from the world's surface.

For example, technically, an air/raft cannot lift from the surface of a Size 9 or Size A world (each having surface gravity of 1.125 G and 1.25 G respectively).

These are high G worlds with many strange effects. A crafty GM, noticing this, would have heavy duty air/rafts in use on his planet (sporting grav drives pushing 1.26 Gs!).

High tech worlds may have bean stalks, these surface-to-orbit constructions to allow people to live in lower G enviornments (and this would be the domain of the standard grav vehicles).

So much info can be derived by just looking at the Standard Worlds chart. At a glance, you can tell exactly how tall your bean stalks will need to be: A Size A world will have bean stalks at 8,900 km tall, where the gravity is rated at a standard 1 G. This will be the domain of the standard air/rafts, zipping around from stalk to stalk.



Fuel Skimming

Note that the Standard Worlds chart can also be used to show how deep a vessel can fly into the surface of a gas giant with either hiding from vargr corsairs or fuel skimming.

If your gas giant is Saturn, your 1G Free Trader can zoom quite deep into the gaseous folds of the planet, to about 72,100 km from the gas giant's "surface", where gravity will be about .75 Gs.

 

[beowulf2044]

Striker Personal Armor Values

Forgive my rant in this space, please. But when the subject of early errors come up, I'm always drawn to the difference between AHL and Striker when it comes to personal armor values. AZL appeared first, and Striker was a continuation of that system.

So when the Striker armor values drop one pont of protection for Cloth and Flak Jackets (and thereby Combat Enviroment Suits) and leaves all other armor values unchanged, it makes me think that someone made an error somewhere. An error that has been carried forward through Mega Traveller and every other incarnation since.

Yes, it's one lousy point. But why does this vary and all other armor remains unchanged? It's unfortunately the little buggy things like these that drive me to distraction.

Thanks. Rant over.

 

[aramis]

S4:

Again, you're conflating orbital and escape velocities.

An air raft can be spiraled up to escape velocity once in orbit. It takes less than 0.1G to transition from orbital velocity to escape velocity.

Getting to orbit does not require escape velocity; it requires, in point of fact, stopping short of escape velocity!

Anything with more thrust than local effective gravity and extended thrust capability can simply make a direct thrust exit, and escape velocity is meaningless in such cases, as by balancing thrust over local experienced gravity.

On the other hand, if delta-V is limited (essentially limited duration of thrust), then escape velocity and orbital velocity is a vital consideration: can you get to speed before you run out of fuel.

 

[Gruffty]

Right, I think I understand now.

There is the Jump route table from the '77 edition of LBB3 that is missing from the '81 edition.

 

[Supplement Four]

Again, you're conflating orbital and escape velocities.

Wil,

I'm not confusing anything. The strength of gravity weakens the farther one gets from the surface of a planet.

And, I'll I've been reporting is an early rule in Traveller that was dropped between 1st and 2nd editions.

 

[CosmicGamer]

Escape velocity is sometimes misunderstood to be the speed a powered vehicle must reach to leave orbit and escape a gravitational object.

A powered vehicle can depart at any speed.

Escape velocity usually refers to the speed required for a vehicle or object to escape from the surface or a specific orbit (usualy LEO) of a gravitational object without any more kinetic energy input. The instant propulsion stops, the vehicle can only escape if its speed is greater than or equal to the local escape velocity at that position. At sufficiently high altitude this speed can approach 0.

Orbital velocity is the speed at which one object orbits another. This will usually not be a perfectly circular orbit and the speed will vary at different points of the orbit. The average or mean speed is often used. This speed may or may not be maintained with the use of additional kinetic energy input. An object could orbit the earth at an elevation of 10 miles, 10 thousand miles, or any distance.

GPS satellites typically orbit around 20,000km from earth.
The moon is approximately 375,000 km from earth.

Escape velocity is away from an object. Orbital velocity is around an object.

LEO - Low earth orbit is from the surface of the earth to 2000km or 1240 miles. Objects in LEO encounter atmospheric drag. Although the Earth's pull due to gravity in LEO is not much less than on the surface of the Earth, people and objects in orbit can experience weightlessness because of the speed of orbiting without thrust.

The International Space Station is in LEO.

 

[mike wightman]

Exactly - CT maneuver drives are 1g constant thrust minimum, they can achieve .99c given enough time.

Lifting from a planet is no problem if you understand how acceleration works.

 

[Supplement Four]

Exactly - CT maneuver drives are 1g constant thrust minimum, they can achieve .99c given enough time.

And fuel.

I've wondered before if you took a CT M-Drive, mounted it with enough fuel, and sent it sprawling out into the void.

What would eventually happen?

What happens when it reaches 0.9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999c?

It would be a neat way to test Einstein's Theory.

And, would it ever reach the speed of light?

 

[ShapeShifter]

And, would it ever reach the speed of light?

Only if Picard said "Make it so, Helmsman!" :rofl:

 

[DonM]

Sigh...

Come on, folks... focus.

S4: that stuff was dropped because GDW received letters from a bunch of people telling them that they didn't understand science. Some were friendly, others read like postings on CoTI about T5. Maybe Loren likes the rule. I've found that between Frank, Marc and Loren there are very DIFFERENT perspectives on the game. John Harshman probably had similar views, but I've never discussed Traveller with him face to face.

And there are moments like the Coronel issue where you discover that Marc has been waiting since 1977 to implement a specific change he wanted but was told NO by the others.

And there are some things I wish had been brought back to the core rules from Mayday 1983, Snapshot and AHL. For example, Mayday 1978 has the same Shifting Fire rule that we see in LBB 1977 and 1981, and TTB and STT. However, Mayday 1983 has a totally different rule, and I think it's much simpler and plays better, but it never made it into the core.

And the polearm rule from 1977 (the Pike footnote) is turned into a full rule by Snapshot, but not brought back to the core.

And then there's the Hydrographics change. In 1977 LBB, the world generation checklist and the Hydrographics rule show Hyd as 2D-7+Size.

In the 1981 LBBs, in TTB, and in STT, the checklist has 2D-7+Size but the Hydrographics rule shows Hyd as 2D-7+Atmosphere. (Note that while MT ignored this change, whereas T4 implemented it as the default rule.)

Marc provided some insight here, in that the Hydrographics formula was the subject of much debate within GDW, but he thought that Size won; however, it appeared in T4 (Note that T5 is back to Size).

 

[mike wightman]

Interesting insight there Don.

I promise to behave

 

[far-trader]

OK, I've been pondering if this fits the program or not and still can't decide. I kind of think not but here it is anyway...

The TL for starship weapons varies between Book 3 and Book 5. It's not exactly a lost rule, but it's overlooked because the TL is not part of the design sequence in Book 2. The TLs are in the TL chart in Book 3. For comparison:

Book 3        Weapon        Book 5

 TL 5       Sandcaster       TL 7

 TL 6        Missiles        TL 7

 TL 7       Pulse Laser      TL 7

 TL 9       Beam Laser       TL 7

I dislike the internal inconsistency, and actually prefer the Book 3 choices (for what that's worth ). It makes for more interesting design considerations, especially if you change the TL bonus breaks in Book 5 to match as well.

Anyway, your call if that's at all useful to you and Marc.

 

[atpollard]

Boeing's 737-600 generates 22,700lb-thrust, with a maximum take-off weight of 145,500lbs max TO weight.

... and how many 737-600s reach orbit?

[Sorry, I couldn't resist.]