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Old November 16 2012, 04:57 AM   #339
Location: Kentucky
Re: Envisioning the world of 2100

Byeman wrote: View Post
gturner wrote: View Post

Along with re-usability, I've been wondering if horiontally oriented vertical launches would create a major cost-savings.
No. It is not feasible and a bad idea. The engines for supporting the front of the vehicle would be useless mass after rotation. The launch vehicles are not designed to loads horizontally. They can't even support themselves horizontally when loaded with propellant.
Then how are they going to load a Falcon 4 or Falcon 5 into the Stratolaunch? As Elon Musk said, the extra structure to let them do that is pretty trivial. It's a fuel tank. Almost all cylindrical fuel tanks that have to take heavy pounding are horizontal. You can certainly thin one so that it can't, and the original Atlas couldn't even support itself vertically without the pressure of the fuel.

Also, booster engines are not the same as upperstage engines and many are not air startable.
And most booster engines are not air-startable because it wasn't a design requirement. That's a pretty easy thing to do. You just add ignitors, as they did to make an air-startable Merlin. Often when they take an upper-stage engine to use as a first-stage booster engine, they remove that capability because it's not needed.

b. Wrong on the Dracos. To lift the whole vehicle requires nearly the same thrust as the main engines. For example, using a Falcon 9, the thrust of all nine engines would need to be directed down.
No, that would create a disaster because the nine engines would be at one end of the rocket, accelerating it at about 3 G's. You want to use half the lift-off thrust on one end, and half up toward the other end. The easiest place to put the engines is the interstage, which is otherwise mostly empty space.

It is one thing to think of a small horizontally launched vehicle. It is completely asinine to think of one the size of the Saturn V.
I bet you used to run around shouting "A 747 is too big to fly!!!"
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