Re: [ERPS] This is one way to do it - Wonder it is works?

[Ian Woollard]

Randall Clague wrote:

On Thu, 11 Sep 2003 18:06:15 +0100, Ian Woollard
<[EMAIL PROTECTED]> wrote:
 

I'm not saying they're theoretically as good as a turbojet; but quite a 
bit of the cost of a launch vehicle is in the purchase of the said 
launch vehicle and jets cost a whole lot more. Fuel is the cheap bit. 
I'd bet dollars to donuts that it's more cost effective in this case.
   

I'll take that bet.

It's unclear that either of us will collect.

 There are no commercially produced ramjet
engines.
Hey, perhaps that's something to do with no zero-speed thrust? That, 
plus they're not more efficient than turbojets at any speed below mach 
1. Where they win is the low development cost. In obscure cases, that's 
a win. My claim is that this is one case where they are very probably a 
win; since development costs are about half of the launch costs.

But people have built ramjets before for launching stuff; IRC NACA 
achieved 150,000 ft and with a tiny R&D program- that's not bad at all; 
and that's an acceleration mission where ramjets do not especially shine.

 There are dozens of commercially produced turbojet/turbofan
engines.  I'm positive a turbine-based RTLS launch vehicle system
could be produced for less money than a ram-based system of equal
performance.
 

If there's a cost effective, existing turbojet/fan of just the right 
size, ok, then that's probably the way to go. If there isn't I'm  
reasonably sure the ramjet is better.

I'd also bet, though a smaller amount, that you couldn't make a case
that either one is competitive with the equivalent existing ELV.
 

Depends on the launch rate; largely.

-R
 

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