Main engine technology: Theory
paulm's picture
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Wednesday, October 25, 2017 - 19:01
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We 're gearing up to start prototyping the vessel's main engines, so I thought it would be useful to review the current state of the technical theory handed over by the research team. This is the way they're recommending we approach the prototype design: http://crew.isdc.network/liais/propulsion/mie-impulse-engines-263

The magnetic impulse coils are all based on alien room-temperature superconducting technology so that's an obvious place for the real-world build to depart from theory. What are the group's thoughts on the rest of the recommended design?

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Alfisti's picture

Submitted by Alfisti on October 26, 2017 - 22:30

At the moment the vessel design utilises a single cowling to mount and protect multiple thruster pairs. This also contains the mechanicals for thrust reversal and vectoring. This has the advantage of ease of maintainence, as well as allowing the thruster pairs to be swapped out rather than maintained in situ, minimising yard time. It also means the pairs can be reconfigured easilly should we find a more optimal setup.

That being said, my current gut feel is that we would want to be implementing a minimum of two to four thruster pairs, ideally four. While the drives have been maintained as close in line with the vessel's centre of mass as possible, in the event of a failure or battle damage the fact remains that, given the anticipated output of each unit, we are unlikely to be able to install sufficient RCS and gyro capacity to counter the differential thrust generated. By the use of four pairs, the opposing pair would be able to be shut down, whilst still maintaining 50% total output/acceleration. More drives would of course mean more redundancy, but also create additional complexity and potential for failure, as well as possibly reducing the per-drive output efficiency.

Thoughts?

paulm's picture

Submitted by paulm on October 31, 2017 - 12:25

...so I'd recommend two pairs (a total of four MIE units). The design models we're looking at are pretty compact, so this should fit the spaceframe design requirement.

MIE units need to be paired because of the strong magentic fields they generate which would require heavy sielding to prevent interference with vessel systems and increase the vessel's detection profile. Deploying MIEs in a "balanced pair" with each unit having opposite magnetic polarity means their fields cancel each other out once outside the exhaust nozzle.

The ship should be able to maneuver on one pair alone, including the ability to reach FTL velocities (but at reduced elevels of performmance). If the pairs are mounted crosswise (eg one pair port-dorsal/starboard-ventral and vice versa) this should minimise differential thrust effects to the point where engine gimballing could compensate.