ICE dropships

[Daryk]

An Orion drive is still bound by real physics, and thus can't compete with BT fusion rockets (which exceed the efficiency of pure matter/anti-matter annihilation).

[VhenRa]

Significantly better then chemical propulsion, maybe even high-end nuclear propulsion methods.

But still nowhere near as good as magic fusion torches.

[cray]

Significantly better then chemical propulsion, maybe even high-end nuclear propulsion methods.

But still nowhere near as good as magic fusion torches.

Yep. Orion drives beat the pants of any real world chemical, nuclear, or electric rocket. They can have exceptional specific impulses combined with very high thrust - usually there's a trade of one for the other. However, BT's fusion torches are better, achieving better efficiency in strategic mode while retaining good thrust levels.

[idea weenie]

Suddenly I wonder about an external-combustion-engine DropShip, and decide a moment later that there isn't a JumpShip in the galaxy that'd let you decelerate for docking (let alone accelerate away) - and that of course doesn't say anything about what an Orion would do to its own landing zone.

That said, what about an all-up warship?  How does the plutonium-powered pogo stick concept fare against BT's magical thrust for the big ships?  Just how much nope is there in the rear-arc of that thing as well, as far as damaging anything in its hex or using the detonating packages as an antimissile system?

Let's get some data for this:
Orion drive overall info and launch site recommendation.  Short version: max efficiency (aka Specific Impulse) for an Orion drive is ~1 million seconds.

Battletech fusion engine, assuming tactical mode (aka less efficient than strategic mode), and the highest fuel consumption for tactical mode, and putting that on the lightest Warship (aka stacking the deck against the BT ship):
Mass: 100,000 tons
Fuel points/ton: 2.5 (so 1 pt of fuel is 400 kg)

Assuming you want 1 G of acceleration, that is burning 800 kg of fuel every minute, to accelerate 100,000 tons of Warship at 1G
Using the Atomic Rocket equations:
Mass flow: 800 kg/minute = 13.33 kg/second
Current mass = 100,000,000 kg
Acceleration = 9.81 m/s^2

Calculations:
Force = Mass * Acceleration = 100,000,000 kg * 9.81 m/s^2 = 981,000,000 kg m/s^2 (aka Newtons)
Specific Impulse = Force / (9.81 m/s^2 * 13.33 kg/sec) = 7,500,000 seconds

So worst case BT fusion engines in tactical mode are still seven times better than the best Orion drive

[AdmiralObvious]

I mean, I've modded an Orion drive, as well as Fusion into a few games. Fusion is significantly safer than an Orion, for one, and it's generally more efficient, and will push you farther on the same amount of mass. The Orion drive can potentially be used as a weapon, but Fusion torches can too, the flame of a Fusion engine is comparable to the Sun itself, and goes REALLY far from whatevers being pushed, and that assumes everything else is just a conventional rocket assembly. Orion's are effectively just nuclear explosions which push the ship, and you're gonna need to build to handle the sudden forces they create. With Fusion, you can throttle it quite a bit.