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Old November 16 2012, 12:40 PM   #346
Location: Kentucky
Re: Envisioning the world of 2100

sojourner wrote: View Post
gturner wrote: View Post
None of the reasons the X planes didn't achieve orbit have anything to do with the the orientation of the fuel container.
but it has everything to do with the size of the fuel container. Not enough fuel, no orbit. Try to build a tank big enough and strong enough to ly on it's side fully loaded AND deal with the stress of a vertical liftoff and you have 2 outcomes. a vehicle that splits in half or a vehicle that doesn't have the mass fraction to achieve orbit. Because>>>>
Because, apparently, you don't understand basic engineering, even at a child's level. I could discuss loading of a fluid column, tensile stress on a uniformly loaded simply supported cylinder, the varying section modulus of a vertical tank optimized for a given G load and fuel height, and some other things, but you can't even grasp that the horizontally carried liquid fueled rockets for the Stratolaunch are designed to achieve orbit, and survive far more than 1G of horizontal loading for the aircraft to be certified for flight. Try to wrap your tiny little brain around this: Horizontal launch orbital vehicles are being built. You claim it's impossible. Call the Air Force, the NRO, and Burt Rutan and demand they stop building a vehicle whose possible existence you've disproved.

When you start looking at very large rockets, one of the only ways to avoid severe hydrostatic pressure problems is to spread it out horizontally, to avoid tank bottom pressures that would crush a nuclear submarine, and which must be contained by massive increases to the wall thickness, dropping the mass ratio.

Even if you only support a horizontal rocket from the ends, the key factors in determining the maximum tensile stress is the wall thickness and tank fineness, and the wall thickness was already heavily determined by the tank height and pressurization. For most existing rockets, you're probably looking at a 10 to 15 ksi stress increase, consentrated along the bottom, if you don't try to distribute the forces along with load.

not while on it's sideon it's side?not while on it's side
It's actually easier on its side. If you asked the navy to lift an aircraft carrier out of the water using rockets, the last thing they would do is stand it on its end. Basic engineering and common sense tells you thise things.

seriously? I'd like to see you terminate the thrust of a solid before it runs out.
Earth to Sojourner. We've been terminating the thrust of solids on command since before I was born. It's critical for precisely targeted ballistic missiles. It's also trivially simple.

Hmmm, I was gonna comment on your "came up with an idea that improved a conjectural LEM design", but you seem to have retracted it. Oh wait, here it is:
So yes, compared to you, I am certainly a genius, which is probably why the re-configurations of a lunar lander I did yesterday got picked up on some blogs as shaving weight, mass, and complexity, boosting redundancy, reducing weight, decreasing the complexity, lowering the center of mass, adding partial re-usability, all in a few simple changes on how they should exit, leading to a cascade of benefits.
POST PROOF OR RETRACT. Oh, that's right, you already did. nevermind.

Not my blog, and a throwaway comment, but still nice. I decided it wasn't worth mentioning here, as the people here can't even figure out how use a rocket, much less optimize one, much less running through mass ratios and structures.

When I blogged heavily, for a while I got a couple of dozen multi-hour visits a day that traced back to the Air Force, who were reading my posts explaining the math of missile engagements at extremely long ranges. There were some fundamental things they hadn't seen explained before, with equations.

You need to learn to think outside your tiny little box to see what's possible with rockets, otherwise the life's work of Walter Dornberger (who developed the RASCAL, a horizontally launched liquid fueled rocket), Wily Ley, and the Navy Resarch folks will have been wasted, having shown that all sorts of things that were once thought impossible were trivially easy with a rocket engine and some thinking.

Now, not only is anything they didn't think to do claimed to be impossible, half the stuff they did is claimed to be impossible. They would weep at the breathtaking ignorance, and think their efforts wasted.
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