#### Stainless Steel Fox

##### Mongoose
In the High Technology section of High Guard, on page 66, we get a description of the FTL Hyperdrive for TL-17 onwards. Warp Drive works the same way mechanically, just travelling in realspace rather than a hyperspace.

The Hyperdrive/Warp rating is in parsecs per hour, and uses power equal to the mass of the hyperdrive in tons.

All very reasonable, but it also states 'While within hyperspace, the ship uses its conventional manoeuvre drive to travel, though the effect of hyperspace is to greatly magnify its effect in relation to realspace.'

That implies that the speed generated by the acceleration from the M-Drive has an effect on the speed in hyper/warp. How does this work in relation to Hyperdrive/Warp speed if they already provide a fixed FTL velocity?

For a specific example, I have a TL-20 starship that has a TL-20 Warp 3 FTL drive, and a TL-17 Thrust 11 M-Drive. Rules as written, I get the same FTL velocity if I were only running it at 1G, for a much lower power output.

My assumption is that, if we pretend for a moment that a hyperdrive brings you into a bubble of hyper space, other people can, even if unlikely, be in that same bubble. However, regardless of how many people are in the bubble, the whole bubble moves at the stated FTL speed. So the bubble will arrive at the same time regardless of what happens in the bubble.

But, since more than one person can be in the bubble, the m drive allows to to maneuver within the bubble, purely so that you can maneuver compared to the other people in the bubble with you.

But due to the slow speed of the m drive, and the huge ftl speed, no matter how far or fast you go in the bubble, that doesn't change the ftl speed - it's just so that you can have a relative position to other people in the bubble.

Then we realize its not a bubble, it's all of hyperspace, but the same concept holds.

So M-Drives are only relevant for relative motion between vessels sharing a volume of hyperspace. Seems more like the system used in Honor Harrington, where instead of a hyperspace bubble, each layer of hyperspace is a volume unto itself which maps onto lower layers but is more compressed. Though I could see ships using manoeuvring thrusters to change relative positions in an extended hyperspace bubble.

So for my example above, once the warp bubble is established, I can shut down the M-drive completely, just as in Jump drive.

I don't have the HG update, so I can only comment on the original MGT explanation of the jump bubble. It seems to make very little sense if the bubble itself (and it's decay rate) takes you through jump space to your destination while also retaining your original speed and heading (not stated in MGTv1, but in CT, though I don't recall any version contradicting or really even mentioning this).

It's always been that M-drive has no effect in J-space since you are outside normal reality. And, if you consider that this is happening, by another set of MGT v2 rules (that being the standard M-drive being useless at the edge of a star-system), your M-drive will be useless between star systems.

This is one of the annoying parts of MGT - they play very fast and loose with their own ruleset. It's one thing to bolt-on new features and functions, but they constantly end up stepping on their own toes and causing these sorts of conflicts. One would hope that the editors would consult their own tech bibles when accepting new writeups.

The key part of the hyperdrive rules is that while within hyperspace a ship moves "a number of parsecs equal to its Thrust per hour, up to a maximum of the hyperdrive's rating". Thrust is a property of the M-drive not the hyperdrive. Your speed is therefore the lower of your M-drive and hyperdrive ratings.

Essentially, if you have a rating 6 M-drive and a rating 4 Hyperdrive you will move at a speed of 4 parsecs per hour (hyperdrive limited). If however, your M-drive is rating 4 and your Hyperdrive is rating 6 you will still only move at 4 parsecs per hour (M-drive limited).

The key part of the hyperdrive rules is that while within hyperspace a ship moves "a number of parsecs equal to its Thrust per hour, up to a maximum of the hyperdrive's rating". Thrust is a property of the M-drive not the hyperdrive. Your speed is therefore the lower of your M-drive and hyperdrive ratings.

Essentially, if you have a rating 6 M-drive and a rating 4 Hyperdrive you will move at a speed of 4 parsecs per hour (hyperdrive limited). If however, your M-drive is rating 4 and your Hyperdrive is rating 6 you will still only move at 4 parsecs per hour (M-drive limited).
Oh, I see. Hyperspace as opposed to jump space. So it's more like Babylon 5 where faster ships moved through jump space at a velocity greater than the slow transports.

Do the hyperspace rules treat it like B5, where you can get lost, or stuck in hyperspace if your jump engines fail and you can't open a portal back to n-space?

I knocked up a rough and ready Warp drive system that can employ the exisiting published ship (and build rules)

Each level of Jump becomes a level of Warp

Maximum warp speed is Warp level parsecs/week

Fuel use is 10% of ship displacement warp number employed times parsecs travelled
So a 200 tonne ship at warp 3 for 2 weeks uses 60% of hull displacement in fuel to travel 6 parsecs so 120 tonnes of fuel.

Warp drives are dangerous to operate within a gravity well – mirroring the 100 diameter limit.

The key part of the hyperdrive rules is that while within hyperspace a ship moves "a number of parsecs equal to its Thrust per hour, up to a maximum of the hyperdrive's rating". Thrust is a property of the M-drive not the hyperdrive. Your speed is therefore the lower of your M-drive and hyperdrive ratings.

Essentially, if you have a rating 6 M-drive and a rating 4 Hyperdrive you will move at a speed of 4 parsecs per hour (hyperdrive limited). If however, your M-drive is rating 4 and your Hyperdrive is rating 6 you will still only move at 4 parsecs per hour (M-drive limited).

Okay, now that makes sense.

On a separate note, the Space Fold Drive power requirements are unclear. It says the power needed is 50% of the ships mass tines the Fold Drive rating, but is that only for the moment of fold, or is it a continuous input during normal space flight, as it says it requires 24 hours to recharge between Folds. If it said something like recycle or reset it would be clearer.

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