My first approximation is that no support and just a guess is not
much investment on your part in your idea, so its not worth much.
Ed Kelleher
At 10:18 AM 11/11/2016, Ed LeBouthillier wrote:
I was thinking about the effects on cost of scaling up a rocket design and I came to a rough conclusion:
The invested cost in the testing of rockets goes up by the cube of the scale.
Now, I know that's not a hard and fast rule (and maybe it's not a n^3, maybe it's n^2.5). I also don't have any real support for the figure, but it's a guess at approximating it.
Also, notice that I say "invested cost" because if you already have a test stand and infrastructure for what you're doing, then you don't have to pay anything, but if you have to develop that stand from the ground up, I don't find it hard to believe that the cost of the testing apparatus might not be related to the weight of the engine/vehicle. So, by the time you get to developing something like the Apollo Saturn, it takes 10% of the GDP for many years to get all of the testing equipment and the testing of the important propulsion components.
What do you think? Does this make sense? Do you have contradictory thoughts? Is the scaling factor less?
Thanks,
Ed L
