Rules Clarification: Maneuver Drive + Reaction Drive

[FoolishWanderer]

I'm building out a relatively low TL (10) ship for MTU. In doing that, I was wondering what the intent was around putting both a M-Drive and a Reaction Drive in the same ship - say for the purpose of using the fuel-efficient 3 Thrust M-drive for regular patrolling but then kick into another 3 Thrust Reaction in combat. Can it be done (the rules don't seem to say it cannot). If you do, do you add them or would I need say a 3T M-drive and then a 6T Reaction drive. F=ma would imply that they could combine and add (each gives a force at the same time that add giving you higher acceleration), but then that seems you could put two 3T M-drives in a ship and get around the TL limits on 6 Thrust, etc.

I know of course I can just make whatever work for MTU, but I find it useful to at least know the intent of the good folks at Mongoose before I start making stuff up

 

[Arkathan]

The back-up reaction drive (High BOOST Thruster) is intended to add to the thrust of the main drive.
Edit: breakaway hulls show that there is an intent for backup M-Drives to add to main thrust as well.

 

[Condottiere]

A high-burn thruster is an auxiliary chemical rocket designed to give a temporary speed boost to a ship. This is done by adding a reaction drive whose Thrust is cumulative with that of the ship’s regular drive system. A reaction drive used as a high-burn thruster should require far less fuel than a ship that uses reaction drives as its main source of thrust because typical applications are designed to provide thrust for a limited amount of time. For example, high-burn thrusters might be used to reach jump point faster, run a blockade or elude pursuers.

 

[Arkathan]

A reaction drive used as a high-burn thruster should require far less fuel than a ship that uses reaction drives as its main source of thrust because typical applications are designed to provide thrust for a limited amount of time. For example, high-burn thrusters might be used to reach jump point faster, run a blockade or elude pursuers.

Clarification: the fuel is reduced because it is used less often, not because the HBT is more efficient.

Not that you needed the explanation, but for GP, that statement without the tables could be construed to imply fuel efficiency.

 

[FoolishWanderer]

yes, I saw the HBT - but does that then exclude a typical reaction drive being added? I read it as "yes you can add one with less fuel for shorter burn".

 

[Condottiere]

It's a victim of copy pasting.

Though, to be fair, customization could skew fuel (in)efficiency.

 

[FoolishWanderer]

Thanks... so seems like "yes you can add them" but I might want to throw in inefficiency.
BTW, do Reaction drives include acceleration compensation for crew? Clearly HBT does not but what if you're using just a "regular" reaction drive? Seems like the high-G ones would be useless if it didn't but its a totally different tech base.

 

[Arkathan]

No. That is a function of the Grav drives. Reaction drives are boots-on-the-aft-wall rockets.

 

[FoolishWanderer]

That's interesting and makes a ton of sense (would have been my first instinct)... what then is the role/purpose of a 16T Reaction drive besides making paste of the crew? (p.16 High Guard). It seems a g-suite + g-tolerance drugs gives you +4G max.

 

[Sigtrygg]

It gives robot crewed ships the edge...

 

[FoolishWanderer]

Ah! Very cool. Okay - thanks for all the help!

 

[Condottiere]

Thanks... so seems like "yes you can add them" but I might want to throw in inefficiency.
BTW, do Reaction drives include acceleration compensation for crew? Clearly HBT does not but what if you're using just a "regular" reaction drive? Seems like the high-G ones would be useless if it didn't but its a totally different tech base.

Depends on the interpretation of the printed text.

At best, I'd say it was a very gray zone.

And, there are likely consequences.

 

[rinku]

The G-LOC section in High Guard and associated equipment gives you some ability for the crew to handle extra boosts. No, nothing is provided be the reaction drive itself, but basic acceleration couches are standard crew station fittings.

M-Drives take care of all their own thrust (turning on the internal gravity is optional - a 6G M-Drive can have the crew floating around even at full thrust). So generally an extra 1G reaction thrust is tolerable long term, 2G is good for short periods, and longer if everyone is securely strapped into couches. Above that it's more a tactical thing - dogfighting turns are 6 second, for example, so short bursts of high G's are more practical there, especially for a seasoned pilot that's cocooned in an acceleration cradle.

Reaction drives should also be able to be used for agility thrust; the rules are a bit vague there, but clearly if the pilot is using them to jank the ship around in short bursts it may not be as punishing as a full turn at +2G would be.

 

[AnotherDilbert]

That's interesting and makes a ton of sense (would have been my first instinct)... what then is the role/purpose of a 16T Reaction drive besides making paste of the crew? (p.16 High Guard). It seems a g-suite + g-tolerance drugs gives you +4G max.

With enough augmentation and support a pilot can be made to survive a 16 G reaction drive:
https://forum.mongoosepublishing.com/threads/return-of-the-fighter.124691/post-975407

 

[rinku]

Maybe not for hours upon hours, though. Bursts during a dogfight or brief sustained thrusts for a turn or two is probably the limit, unless the augmentation involves a robot brain too...