Gravity greater than M-drive potential

[Lapthorn]

How do you deal with it where a world has greater gravity than a ship's M-drive potential?

(Mainly thinking about CT and other rulesets with simpler ship design; I think GURPS and T5 go into some detail on a ship's aerodynamics.)

You might say the ship just can't get off the ground (and will crash if it attempts to land).

Another way to handle it might be that streamlined ships can still take off (and make controlled landings) where Atm is 4 or greater and the pilot makes one or more successful Piloting throws.

 

[Fovean]

I've been using the theory that every M-Drive produces twice its rating in Gs - half for maneuver, half for inertial compensation. Turn off compensation and you get extra Gs to work with but your crew/passengers/cargo now suffer the effects of G-forces....

 

[mike wightman]

Ships that operate in an atmosphere generate lift.

They take off like an aeroplane and accelerate, getting faster and faster and faster.

They gain altitude, and continue getting faster and faster.

The magic maneuver drive continues generating 1g of acceleration until you reach escape velocity.

 

[whulorigan]

How do you deal with it where a world has greater gravity than a ship's M-drive potential?

(Mainly thinking about CT and other rulesets with simpler ship design; I think GURPS and T5 go into some detail on a ship's aerodynamics.)

You might say the ship just can't get off the ground (and will crash if it attempts to land).

Another way to handle it might be that streamlined ships can still take off (and make controlled landings) where Atm is 4 or greater and the pilot makes one or more successful Piloting throws.

MT/DGP postulated that the M-Drive could be "overpowered' by +40% for an certain amount of time with minimal risk as long as there was a qualified engineer monitoring it (and could be ramped-up to +400% for a few minutes with proper engineer-supervision and significant risk).

T5 includes (form prior rulesets) both Lifters (Z-Drives) and G-Drives & M-Drives. Lifters merely negate weight (and are a hull-fitting) and allow a small degree of lateral movement. With the Lifters in use, the G-Drive or M-Drive can then operate at full acceleration-efficiency unhampered by planetary G-Fields.

 

[mike wightman]

Al that is necessary is streamlined hull generated lift, an airframe hull does so with even greater efficiency.

 

[Whipsnade]

How do you deal with it where a world has greater gravity than a ship's M-drive potential?

From the first I assumed "contra-grav" or "anti-grav" capabilities as implied parts of the M-drive.

After all, LBB:2 allowed acceleration up to 6 gees without ever mentioning inertial dampening, internal "gravitic nets", or even gee-tolerating mechanisms like special suits, special couches, or the Forever War's pressure-buoyancy tanks.

It was when MT added much detail to ship design and description that we got all the systems CT had earlier implied; contra-grav, gravitic deck plates, plus radios, masers, radars, different sensors, etc.

If you want to ignore CT's implied capabilities while also not using MT's increased numbers of systems, you use the suggestions already posted; aerodynamics, overpowering M-drives, etc.

If exploring a "gravitics-free" setting sounds interesting, you might be interested in fellow COTI member Omer G. Joel's up coming Hard Space. Here's a link

 

[aramis]

From the first I assumed "contra-grav" or "anti-grav" capabilities as implied parts of the M-drive.

After all, LBB:2 allowed acceleration up to 6 gees without ever mentioning inertial dampening, internal "gravitic nets", or even gee-tolerating mechanisms like special suits, special couches, or the Forever War's pressure-buoyancy tanks.

It was when MT added much detail to ship design and description that we got all the systems CT had earlier implied; contra-grav, gravitic deck plates, plus radios, masers, radars, different sensors, etc.

If you want to ignore CT's implied capabilities while also not using MT's increased numbers of systems, you use the suggestions already posted; aerodynamics, overpowering M-drives, etc.

If exploring a "gravitics-free" setting sounds interesting, you might be interested in fellow COTI member Omer G. Joel's up coming Hard Space. Here's a link

MT did NOT add Contra-Grav - that was TNE.

MT used 400% thrust on axis for up to 10 minutes, and inertial compensation.

 

[Whipsnade]

MT did NOT add Contra-Grav - that was TNE.

Same difference.

CT implied certain technologies while later versions detailed the same down to mass, volume, and power requirements.

 

[Jeff M. Hopper]

I like Repulsors.

If they can deflect incoming missiles, then surely they can loft payloads into orbit or give those pesky merchant vessels with no legs a helping lift, for a small fee of course.

 

[aramis]

Same difference.

CT implied certain technologies while later versions detailed the same down to mass, volume, and power requirements.

Not quite. TNE's CG cuts the ship off from 98% of local gravity. Which is VERY VERY different from MT's 400% thrust.

MT, you can take off, but you don't have time to dawdle - 1G in a 1.5 G, you make the roll, and push at 2.5G net... some risk of failure and drive damage.

It also puts all but the cloud tops of GG's as needing to be hypersonic parabolae, even with the 400% thrust, because the journey is too long to maintain it...

The Inertial Compensation simply prevents those on board from being thrown about; it has no external protection.


TNE, however, 1 G in 1.5G is taking off at 0.97G with no risk. In fact, TNE CG means you can go down to near crush depth of a brown dwarf and still escape with a near-zero speed... because you can do down to the 19G line and still be accelerating, and be in deep enough to scoop while doing so, so fuel time isn't an issue.

TNE's CG is a HUGE and significant difference from MT's pure thrust and internal acceleration compensation. And TNE also has IC, in addition...

Essentially, in TNE, any ship with 1G can leave any non-gas-giant world under normal thrust with at least 0.5G's of acceleration, and can pretty safely skim; at crush depths, they typically will be wanting to rise to the surface if the CG is working.

In MT, anything past 4G is unreachable by civil shipping, and further, much of the depths are dangerous.

 

[Whipsnade]

Not quite. TNE's CG...

The details are irrelevant to the point being made, Wil.

CT strongly implied unseen and unnamed technologies which allowed 1g ships to take off in +1 gee gravity fields.

MT by GDW continued that model leaving the answer up to the referee.

DGP, a third party publisher writing for MT, wrote that M-drives can be "overclocked" up to 400% in SSOM, a product just like the Judge's Guild output, is merely approved for use with Traveller.

TNE then decided to answer the questions by providing specific equipment.

So, my point again is, CT left things about to the referee with some sort of CG being part of the M-drive, while later versions provided specific answers with specific attributes.

 

[atpollard]

I guess that makes me the lone heretic.

If the ship has too little thrust to lift off, then it docks at the highport or stays in orbit and waits for a shuttle.

JUST LIKE A ROCKET WITH A T/W <1!

(This IS rocket science.)

IMTU a ship with a 400% of 1G MD is called a 4G MD. (Duh).

 

[aramis]

The details are irrelevant to the point being made, Wil.

CT strongly implied unseen and unnamed technologies which allowed 1g ships to take off in +1 gee gravity fields.

MT by GDW continued that model leaving the answer up to the referee.

DGP, a third party publisher writing for MT, wrote that M-drives can be "overclocked" up to 400% in SSOM, a product just like the Judge's Guild output, is merely approved for use with Traveller.

TNE then decided to answer the questions by providing specific equipment.

So, my point again is, CT left things about to the referee with some sort of CG being part of the M-drive, while later versions provided specific answers with specific attributes.

Actually, DGP's SSOM was cited as canonical by GDW staffers even while in print. It was clearly considered canonical by GDW, in a way that other licensees weren't, as, essentially, GDW outsourced MT to DGP.

The nature of the handwavium also was already reflected in the times to orbit table in MT IE...

 

[kilemall]

IMTU double the G output of the M-drive at a cost of one day's fuel per 100 seconds (effectively forgoing the efficient ion/Emdrive like normal cruise thrust by dumping fuel in for a chemical/grav compressed mode).

It is also stressful, starting at 300 seconds continuous one starts rolling for cracking the M-drive chamber.

G-liners operate more like slow air/rafts in a stressed G capacity (1:1). They simply won't go to high-G planets (grav driven craft are for civilized space).

 

[kilemall]

I've been using the theory that every M-Drive produces twice its rating in Gs - half for maneuver, half for inertial compensation. Turn off compensation and you get extra Gs to work with but your crew/passengers/cargo now suffer the effects of G-forces....

That's rather clever. At the moment I want a more guaranteed painful experience at higher Gs, but that could be a fun alternative.

 

[Fovean]

Thank you. Clever perhaps, more about simplification. Unfortunately there's little in the RAW dealing with lack of inertial compensation that I can find so I've had to house-rule that :/

Which actually is not a big deal. Acceleration couches/benches, g-drugs and certain EVA/combat suits all take care of most worlds. I've come around to inflicting damage in these situations (if any) at the speed of plot rather than devising over-arching rules. Outside of extreme evasive maneuvers it would generally amount to bruises, nose bleeds and black outs so unless it's the pilot that suffers one of those the team can generally count on getting to the next beat.

Basically I'm doing MDrive - WorldG = Actual MDrive

What makes this simplification interesting to me is the SPEED at which a ship can or can't exit the gravity well - a lot of those hi-g worlds have really fast atmospheric/interface raiders/interceptors that can really mess up a sluggish 1G or 2G ship's day. So yeah, it ain't the maneuvers that'll get you, it's the bad guy running circles around you... Or the disgruntled high passenger suffering an extra 0.4G in addition to the extra several hours to the jump point...

 

[kilemall]

Fovean, Marchand, we went into this in detail in one of my first threads, a good read for several takes on a solution to your OP.

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=34502

 

[Lapthorn]

Fovean, Marchand, we went into this in detail in one of my first threads, a good read for several takes on a solution to your OP.

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=34502

Excellent, thanks. I thought it must have been covered previously but couldn't find a reference.

Many good suggestions already in this thread.

 

[Timerover51]

I guess that makes me the lone heretic.

If the ship has too little thrust to lift off, then it docks at the highport or stays in orbit and waits for a shuttle.

JUST LIKE A ROCKET WITH A T/W <1!

(This IS rocket science.)

IMTU a ship with a 400% of 1G MD is called a 4G MD. (Duh).

Make that two heretics.

Edit Note: I should add that I use mainly Classic with a touch of Mongoose for ship design (mainly to get the variety of the interstellar drives in Mongoose). I assume that the maneuver drive rating in Gees is for a fully loaded ship, with all jump fuel and fully loaded with cargo. Generally, I assume 5 tons mass per Traveller displacement ton of volume for Free Traders and mixed passenger-cargo ships, and 15 tons of mass for dedicated cargo and bulk carrier ships. I have some formulas that I use to convert Traveller hull volume to mass for private and commercial ships, with military ships a different category. As such, once a ship jumps, it has a bit of maneuver drive reserve in terms of Gees. The result is that a ship with a listed capability of 1G, if post-jump and traveling light on cargo may actually be capable of 2 or more Gees.

In My Heretical Traveller Universe, fuel for ship operation is a negligible factor in ship's mass, so more of a cushion.

 

[mike wightman]

Typical Traveller ships do not have rocket drives, they don't throw reaction mass out of the back and don't have to worry about delta-V or orbital mechanics. The magic 1g maneuver drive provides a constant 1g of thrust.

Don't take off like a rocket, take off like an aeroplane - you accelerate along the ground until you achieve sufficient speed to become airborne thanks to lift - your ship is streamlined remember.
You now keep accelerating and climbing, getting faster and faster until your horizontal thrust is matched by air resistance, so you climb to lesson the air resistance, your thrust remains 1g and you keep climbing and getting faster.
When you reach an altitude where their is too little air to provide lift you will be going fast enough to point the nose up and achieve orbit - gravity falls off with distance and even if you only have effectively 0.01g of net acceleration for this 'rocket' stage of the flight you will still achieve orbit. It won't be as fast as just blasting off with a 2g drive, but you will get their.
Taking off from a 1g world with a 1g ship is easily doable.