Re: Multiple Engines???

[EMAIL PROTECTED] (Greg) wrote in message news:<[EMAIL PROTECTED]>...
> [EMAIL PROTECTED] (David Shannon) wrote in message 
> > 2STO typically uses 1/3 the propellant for a given payload, although vehicle empty 
> > weights are higher.<
> 
> I don't have a problem with 2STO for a RLV. But how do you get the
> first stage back? If you have good mass ratio between the 1st and 2nd
> stage, its likley to be going fast at the seperation point making it
> quite hard to do.

I suspect the TSTO can glide back. Even at mach 8 separations, is the
first stage all that far down range, more than 100-200 miles? It'll
have a lot of energy from altitude and speed that can be spent turning
around and gliding back.

However, despite my ill-edumucated suspicions, I do note many early US
shuttle concepts seemed to favor lots of jet engines. The "winged
Saturn", the Saturn V flyback first stage, had 10 jet engines.

Mike Miller, Materials Engineer