How is M-Drive Thrust applied?

[AnotherDilbert]

Engineering-wise, the explanations provided in SOM and the passage in HG. Safe operations is the number 1 priority for carrying passengers and for merchants.

The issue here, as I see it, is that they are just unwilling to answer the question simply and logically. Anti-gravity is a MASSIVE boon for designers and for safe operations. If you have a personal grav belt, you are gonna have anti-grav in these ships. Also, the designs/illustrations imply that these ships have the ability to negate gravity and land/take off using it.

Engineering-wise, by CT (and T5), anti-gravity and M-drives just produces [magical] thrust. By MT, they are basically the same thing, M-drives are just a bit more advanced, with less limitations.

A ship with M-drives and an anti-grav drive handles the same as a ship with a bigger M-drive, but the bigger M-drive can always be used, not only in landing operations.


The thrust vectoring and overdrive system in MT SSOM is silly, but it's canon, whatever I think about it...
Apparently the drives can be overdriven safely for short periods of time:

 

[AnotherDilbert]

The Starship Operator's Manual for MGT2 has yet to come out, but there's still its MegaTraveller equivalent! Any of this might be superceded, though.

The latter, though there are a couple of earlier sources I don't quite recall implying the former.

How about:

MT RM, p56:
The fourth significant development came from the search for a starship maneuver drive that did not lose efficiency when away from a strong gravity well. Artificial gravity and damper technology led to yet another sub-atomic force-based technology. This new, artificially generated force pushes against a vessel's "thrust plates" themselves, which make true reactionless thrusters a reality for starship-sized vessels.

I don't think CT says anything detailed about this.

Not sure how inertial compensation works in this context, maybe it's tied into the artificial gravity systems?

The artificial gravity system IS the inertial compensation system. If you can produce a 1 G force field "downwards", you can equally well produce a 1 G force field "forwards" (= inertial compensation).

LBB5'80, p17:
Tech level requirements for maneuver drives are imposed to cover the grav plates integral to most ship decks, and which allow high-G maneuvers while interior G-fields remain normal.

"Grav plates" makes sure that interior gravity is "normal" (≈ 1 G "downwards" = artificial gravity), regardless of acceleration (= inertial compensation).

 

[Vormaerin]

Someone is quite fond of this burst use model. The same sort of excuse is used for why Power Plants can run the whole ship for weeks on a relatively small amount of fuel, but then ALSO process a comparatively vast amount of fuel in minutes to fire the jump drives.

I liked it better when the Jump Drives processed the jump fuel way back in the day.

 

[Annatar Giftbringer]

Engineering-wise, by CT (and T5), anti-gravity and M-drives just produces [magical] thrust. By MT, they are basically the same thing, M-drives are just a bit more advanced, with less limitations.

A ship with M-drives and an anti-grav drive handles the same as a ship with a bigger M-drive, but the bigger M-drive can always be used, not only in landing operations.


The thrust vectoring and overdrive system in MT SSOM is silly, but it's canon, whatever I think about it...
Apparently the drives can be overdriven safely for short periods of time:
View attachment 1069

The description from pushing the drive limits makes it sound like it’s potentially dangerous to overload them enough for a 1G ship to hover, takeoff or land.

If that’s how it works, it would be dangerous and foolish to construct ships intended for planetary use with 1G M-drives…

While Solomani Front was vague with details, I figured it would be active for way less than 5 minutes, since that’s almost a full spaceship game turn, and the rulebook mentions raising thrust with +1 for the duration of a turn, at a cost.

The Solomani Front description in combination with 25% lateral thrust, must surely mean that 400% overdrive can only be kept for way less than 5-6 minutes if 100% overdrive for 6 minutes can only be done once before a visit to the workshop is needed..?

Apologies if I don’t make any sense, tired and away from the books

 

[Condottiere]

Maximum Speed
Initiative Cost: 4
Type: Combat
Requirements: None
All available power is allocated to the engines. The ship may only fire half its turrets and bays this round, rounding down, but may increase its Thrust by 1.


Mongoose First High Guard page eighty two.

 

[AnotherDilbert]

The Solomani Front description in combination with 25% lateral thrust, must surely mean that 400% overdrive can only be kept for way less than 5-6 minutes if 100% overdrive for 6 minutes can only be done once before a visit to the workshop is needed..?

You only need 400% for a very short time, only enough to take-off and point the nose up. After that you can fly as a tail-sitter with full thrust as the drive is pointed down.

SSOM sayeth:





The Solomani Front stuff looks like the same as described in Core 2017:

MgT2 Core (2017), p160 [Space Combat Actions]:
Overload Drive (Engineer)
By overloading the manoeuvre drive, the engineer can lend the ship extra speed and manoeuvrability. A successful Difficult (10+) Engineer (m-drive) check (1 round, INT) will increase the ship’s Thrust by one during the next round. If the check fails with an Effect of –6 or less, the manoeuvre drive suffers a critical hit with Severity 1, as detailed on page 160. This check suffers a cumulative DM-2 each time it is attempted after the first.

So, you can do it for a round or two, but if you persist the drive will fail.

 

[Annatar Giftbringer]

Ah, yes. That’s it. Difficult check for +1 thrust for one round, and I just checked Solomani Front rather than going off memory. Overthrust landing or takeoff is a difficult task as well, for a short but unspecified time.

Combining High Guard update vectoring with Solomani Front overthrust means that Overthrust must be able to provide up to 400% thrust, for a typical Free Trader to be able to takeoff.

The overload drive action from High Guard is +1 for six minutes. Solomani Front must be able to provide +4 for “a few moments”. Combined with its more lenient side effects/failure table, I’d say it’s a minute at a time, tops. Probably more like 30 seconds or so.

It looks like a problem to me however, if almost every commercial craft needs a 10+ skill check for each takeoff and landing on a planet. Sounds very dangerous, given the amount of traffic there is?

Most results of a failed overthrust landing are quite lenient, but still.

The alternative is to simply handwavingly allow them to “grav float”. Guess it comes down to what type of setting and feel each group desires.

 

[Condottiere]

I interpreted that as six seconds, a dogfight round.

Since you're basically struggling with the leash.

The way I saw it, is that I'm basically back in secondary, doing hop, skip and jump: complex procedure to get in position, and then airborne for a brief period of time before crashing down.

 

[phavoc]

Stupid Canon remains stupid. SSOM is a great book, their drive explanation is just stupid. That's no excuse for not calling it what it is.

It's unlikely since you have other grav vehicles and even belts that don't have those limitations.

GURPS traveller specifically calls out grav lifters in ships, which also makes it Canon.

In the never-ending debate for traveller, it seems best to adapt and tweak concepts that fit together the best. Which has always been the sad part of things because it is a problem that is easily solved (as evidenced by the high production qualities of the SJG version).

 

[Annatar Giftbringer]

Stupid Canon remains stupid. SSOM is a great book, their drive explanation is just stupid. That's no excuse for not calling it what it is.

It's unlikely since you have other grav vehicles and even belts that don't have those limitations.

GURPS traveller specifically calls out grav lifters in ships, which also makes it Canon.

In the never-ending debate for traveller, it seems best to adapt and tweak concepts that fit together the best. Which has always been the sad part of things because it is a problem that is easily solved (as evidenced by the high production qualities of the SJG version).

That’s how I’ve always simply assumed it works.

Since grav manipulation is a thing, and grav vehicles presumably float without much trouble, and belts, and thingies in general, then surely ships as well.

I suppose vectored thrust and overthrust can still be around, along with float/lift functions.

 

[Vormaerin]

If you can float cities, I expect you can float a ship.

 

[Annatar Giftbringer]

One would think so, yeah.
I’m partial to the idea that the grav compensators onboard can cancel external gravity as well, “creating a local bubble of 0G” that allows a ship to “float”. Internally the gravity gets adjusted by grav plates in the floors.

The grav compensator can cancel gravity up to the drive’s rating, so a Free Trader can hover/float in a 1G environment, and ascend/descend at 0.25G by vectoring it’s M-drive.

Short duration overthrust (from Solomani Front) will still be a thing, and useful in gravity wells exceeding the M-drive’s rating.

Something like that.

 

[Vormaerin]

It's not clear to me what the advantage is to having the reactionless magic drives only "thrust" in one direction. What game play opportunities does this provide or in game jank does it stop?

 

[Annatar Giftbringer]

Before High Guard Update, I hadn’t heard about it (only read/play Mongoose) and thought ships could simply push in any direction.

Limiting it could make sense, from an “explain how the underlying tech works”-perspective I suppose, if that’s the way it’s decided that it works?

It does mean ships need to actually turn around after half the realspace journey in order to decelerate in time, rather than just reversing thrust.

Design choice?

 

[Vormaerin]

Sure, you can just decide it works like that. But if I'm deciding how space fantasy tech works, I'd prefer to make decisions that make for the best gameplay. Not actually flying backward half the trip doesn't really change anything about gameplay. The travel time is still full accel to half way, then full decel the rest of the way.

Whereas this partial thrust concept means the players' venerable Type A no longer can safely land on worlds above size like 4? Previously, getting stuck on a planet mattered only on size 9+ worlds (if then).

What cool game play experience am I getting by implementing this more restrictive design choice? Feels more like adding jank than anything.

 

[Condottiere]

There's more than one way to skin a cat.

 

[Vormaerin]

The other "new" innovation about maneuver drives is the 1000d limit. What cool game play derives from suddenly being 1/10 normal speed in the outer reaches of the solar system?

I just don't get it. *shrugs*

 

[Annatar Giftbringer]

I don’t disagree. As mentioned above, imho if a 1G ship has trouble within a 1G gravity well, nobody in the it right mind would ever design ships intended for use within gravity wells/on planets with 1G drives!

If 4G M-drives are the minimum for safe and secure handling on regular, typical planets, then every ship intended to even come near planets should have a 4G drive!

Gameplay-wise, it seems to add nothing, just make everyday life in-universe more difficult for everyone.

 

[Condottiere]

1. Well, the equation, as presented in the current set of rule books, obviously doesn't add up.

2. Which begs the question, can rockets overthrust?

 

[Annatar Giftbringer]

1. Well, the equation, as presented in the current set of rule books, obviously doesn't add up.

2. Which begs the question, can rockets overthrust?

And how much, for how long, at what cost, can they overthrust? Why add a limitation to the game that seems to require every single 1G ship to be rebuilt into a more safe and reliable 4G drives?

If every planetary takeoff and landing is to be a difficult/10+ check, accidents will happen.