Structural Coefficient

[SanderBuruma]

I've been trying to find some in-depth articles, books, literature etc that describe structural mass fraction, or the structural coefficient. I understand what it is (ie, the % of the dry mass that isn't payload) but not exactly and in detail its relationship with vehicle size and payload size in particular.

As it is, as a vehicle (lets say a hypothetical SSTO) gets larger it needs more and more structural mass to counter the challenges of acceleration, oscillations, air friction, engine heat and so on so the craft doesn't experience structural failure.

Presumeably also, there is a theoretical certain maximum of payload that can be launched in one go given present day technology and the exact type of vehicle used.

My basic question is how does payload/structure decrease as payload to LEO increases mathematically and is there some literature out there that addresses this relationship specifically?

 

[RisingFury]

If you're looking for an equation, you will not find it.

There are so many variables:
- Materials used.
- Construction techniques used.
- Propellant and engines used / propulsion system used.
- Quality of guidance and flight trajectory.
- Required tolerances and limits.


You have to figure it out based on whatever launch vehicle you're analyzing, but in general, the larger the vehicle, the more efficient it is when it comes to putting payload into orbit.

Think of it this way: There is a certain minimum size where a rocket can only just barely put itself into orbit with no payload. You have to make it larger in order to put itself and a payload into orbit. You have to make it even larger to put a bigger payload and itself into orbit and so on.

 

[RGClark]

I've been trying to find some in-depth articles, books, literature etc that describe structural mass fraction, or the structural coefficient. I understand what it is (ie, the % of the dry mass that isn't payload) but not exactly and in detail its relationship with vehicle size and payload size in particular.
As it is, as a vehicle (lets say a hypothetical SSTO) gets larger it needs more and more structural mass to counter the challenges of acceleration, oscillations, air friction, engine heat and so on so the craft doesn't experience structural failure.
Presumeably also, there is a theoretical certain maximum of payload that can be launched in one go given present day technology and the exact type of vehicle used.
My basic question is how does payload/structure decrease as payload to LEO increases mathematically and is there some literature out there that addresses this relationship specifically?

Do a google search on: mass estimation relations launch vehicle.

For the specific case of a SSTO, add SSTO to the search terms.

Bob Clark