[Spaceships] simply fuel math...

hal · 10-03-2017, 08:47 PM

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 Delta-V increase (page 17 of the First GURPS SPACEBOOKS rules)?

It states that if you have 6 to 8 tanks, multiply your delta-V 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 delta-V that a normal SM9 tank would have. No question there.

But what happens to the Delta-V 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?

10-03-2017, 08:47 PM	#6
hal Join Date: Aug 2004	Re: [Spaceships] simply fuel math... 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 Delta-V increase (page 17 of the First GURPS SPACEBOOKS rules)? It states that if you have 6 to 8 tanks, multiply your delta-V 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 delta-V that a normal SM9 tank would have. No question there. But what happens to the Delta-V 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?