While the initial question is well answered, I'd add a thought  the smaller engine
will take 100 times as long to burn through the reaction mass...but since it's producing 1/100 times as much acceleration, naturally the deltaV comes out the same.
Quote:
Originally Posted by hal
Ok, piggy backing on this thread...
Suppose you decide to design a spaceship with the following in mind:
You have a SM 9 ship. A single "reaction Engine" for this ship will produce 3G acceleration.
However, using the Swapping out rule from page 5 of Transhuman Space ships...
Suppose I decide to use one SM 8 rocket engine to produce 1G extra, allowing for a 4G acceleration?
Further suppose that I use the other two modules for Fuel. Those two fuel will be 2/3rds of a fuel tank for a SM 9 ship.
So what happens to the DeltaV increase (page 17 of the First GURPS SPACEBOOKS rules)?
It states that if you have 6 to 8 tanks, multiply your deltaV by 1.2. If you have 9 to 12, multiply by 1.4
Now, if we have 2/3rds of a tank, we have 2/3rds of the deltaV that a normal SM9 tank would have. No question there.
But what happens to the DeltaV multiplier when you're at the "threshold" level between the multiplier values? In other words...
if you have 5 and 2/3rds of a tank, does this get the full 1.2 modifier? If you have 8 and 2/3rds of a tank, do you get the full 1.4 multiplier?
How would you resolve that issue?

So (A) there's no actual reason to involve the smaller rocket in this, it has no bearing on the question.
(B) Assuming I was using the bythebook deltaV rule rather than using the rocket equation to smooth it, I'd use it by the book  5 and 2/3s is not 6 to 8, it is less than 6, so you don't get that multiplier. 8 and 2/3s is slightly more of a problem, but for consistency I'd put it with the lower group rather than the upper group.