So at this point the pipelauncher is 800' of pipe & spacer plus at bottom end the 200' of single large pipe; all this gives total length of 1000' and mass of 965 tons. Without a rocket payload the structure itself should be able to withstand a 1 gee over an accelerate distance of around 870'*-
of course, there isn't much value in having the pipelauncher accelerate without the rocket payload.
*[the top of lowest 100' section would be about 30' from surface when acceleration is stopped- hmm, actually this won't work, because will be a transitional time as pressure is lowered. A quick fix would be to chop the bottom section in half (making it 50' instead of 100'). So correcting that to be total length of 950' with accelerate length of 820'.]
Because there a number factors to consider, namely how fast can a rocket be accelerated and remain structurally intact [current rockets are designed to blast off at rest and some (or most) are not designed to be transported with their propellent loaded {thereby being lighter and not requiring the additional structural strenght needed to withstand gee forces of moving them around}. And another factor is the gross mass of the rocket that pipelauncher might launch which could range from a suborbital type rocket up something the size of Proton (or larger). Another consideration is that a rocket could be designed for use with an *existing pipelauncher* and therefore the question might be what's the max gees a pipelauncher can deliver with a certain payload size- higher gees requires shorter acceleration distance needed to attain a certain speed [as mentioned in first post, a pipelauncher will be limited to subsonic speeds- this is a practical limitation rather than some theoretic limitation, in other words it gets *really complicated* even approaching the speed of sound with a pipelauncher. Rather than see a pipelauncher as a speed demon, it should instead be seen as an improved launchpad].
Ok, so around 1000' tall is about the limit for this particular pipelauncher- if you wanted a taller pipelauncher you would probably need to increase it's diameter [thereby increasing the displacement ratio]. To adjust this pipelauncher, I can simply remove the 100' sections of pipelauncher- thereby reduces it's weight (by 107.5 tons) and of course, this also shortens it's acceleration length. Btw, removing these sections is meant to be "only on paper", but it could be possible to design a pipelauncher which could actually remove or replace sections- though this added complexity would need to be justified.
So, starting from the max pressure of 60 psi and assuming 33' equals 14.7 psi of depth- 15 times 4 is 60, so 4 times 33 is 132'. Each 1' displaces 603.5 cu' which equal to 37,417 lbs. Times 132 by 37,417 lbs gives 4,939,044 lbs [2469.5 tons] of force. So since the pipelauncher weighs *around* 965 tons to get 1 gee for pipelauncher by itself requires 1930 tons of force- or 60 psi would give 1.56 gees. For 1 gee acceleration the max payload would be 269.75 tons. For .75 gees 446 ton payload. For .6 gee 578 ton payload. And for .5 gees 681 tons. Now take off two 100' sctions: 215 tons. Which makes mass of pipelauncher 750 tons. Giving no payload acceleration of 2.3 gees- and giving a 60 ton payload a 2 gee acceleration. And add 215 tons to other payloads above.
So I would guess that if you had rocket which could take the gees, making the pipelauncher 800' would better- and of course cheaper to build.
Well, I haven't run out of time, but I'll post this, just to avoid having a huge wall of words:)