How does one determine a space crafts length?

[meyst]

How tall is this spacecraft configuration from top to bottom?

The combination will be put together as shown in space and tumble to create centrifugal forces (artificial gravity) for the crew during transit.

I would like to figure out how much force would be created while keeping rotation down to a reasonable level (to avoid motion sick kerbals) but to do the maths one needs the distance from the center of mass to the taxi vehicle shown at the top and I have no idea how to get it.

If I am getting numbers that show to low a centrifugal force with a RPM of 3 or less I will be adding spent liquid fuel tanks to lengthen the stack. As I may need to change the length, how to determine the length is what I am looking for.

To assist with measuring I put large Ibeam parts to the right of the ship. Anyone know how long 3.5 of these placed end to end are?

[MalfunctionM1Ke]

You have to put it on the launchpad and stack Kerbals next to it.

One Kerbal is 0,75m tall.

Part CFG

PART

{

name = structuralIBeam2

module = Part

author = NovaSilisko

mesh = model.mu

rescaleFactor = 1

node_stack_top = 0, 1.598274, 0, 0,-1, 0, 0

node_stack_bottom = 0,-1.598274, 0, 0, 1, 0, 0

node_attach = 0, -1.598274, 0, 0, -1, 0, 0

TechRequired = composites

entryCost = 6800

cost = 100

category = Structural

subcategory = 0

title = M-Beam 200 I-Beam

manufacturer = Dinkelstein Kerman's Construction Emporium

description = Handcrafted by Dinkelstein himself, the M-Beam 200 works great for making rockets and skyscrapers alike.

attachRules = 1,1,1,1,1

// --- standard part parameters ---

mass = 0.375

dragModelType = default

maximum_drag = 0.2

minimum_drag = 0.2

angularDrag = 1

crashTolerance = 80

breakingForce = 200

breakingTorque = 200

maxTemp = 3200

fuelCrossFeed = False

}

Unfortunately, no Dimensions listed

Edited April 5, 2014 by MalfunctionM1Ke

[cantab]

Put a capsule right at the top, sit it on the launchpad, and read off the altitude, then take away the altitude of the pad.

[meyst]

Put a capsule right at the top, sit it on the launchpad, and read off the altitude, then take away the altitude of the pad.

This works very well, thank you! For anyone that wishes to save time the pad appears to be 72M above sea level. So your ships on pad altitude -72 meters = your ships height/length.

I would change the topic to answered but I do not know how...

Edited April 5, 2014 by meyst

[RocketPilot573]

Put a capsule right at the top, sit it on the launchpad, and read off the altitude, then take away the altitude of the pad.

But wont the altitude be from the pods CoM, not the top?

[Pursuedtank]

But wont the altitude be from the pods CoM, not the top?

Shouldn't matter, if you use the same pod for both, both measurements would be shifted up slightly.

[M4ck]

I've measured some pieces by stacking something like probe core/decoupler/main structure/decoupler/probe core. After launching and decoupling both of them, check how high above the sea level both cores are - the difference is approximately how long your structure is. It should also work with separatrons instead of decouplers+probes, but I haven't checked it.