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Old November 16 2012, 06:52 PM   #352
sojourner
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Re: Envisioning the world of 2100

gturner wrote: View Post
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.
Last I checked, Stratolaunch doesn't take off vertically from a resting horizontal position, which has been your argument all along. watch those goal posts.

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.
Yet despite all this, you want to build a tank that has to endure max loads in 2 orientations and all of the mass penalties that go along with it. On a vehicle that has to reach orbit with a useful payload and be reusable.
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.
straw man. an aircraft carrier is not a rocket, but, to better fit the analogy, you want them to lift it out of the water with rockets, then while in flight, stand it on end before continuing to move it.
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.
I think Byeman has already answered thisNice post there and not a bad observation regarding the Dracos. I would be fascinated about how your idea of a horizontally oriented, vertical liftoff rocket would be received there.

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),
You mean this RASCAL? the one that was air launched from a bomber? Yeah, not seeing anything about it being launched vertically from a horizontal orientation.
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