Re: starship-design: Vapor Trail Fuel

["bugzapper" <bugzappr@bellsouth.net>]

> > vehicle out of a gun"?
> No just management!
> I still like rail launched!

Me too.

> Why a ramjet -- airships are slow -- ramjets are fast.

Ah, here we go. Airships have only one drag component, which is proportional
to frontal area. But airplanes have a disguised drag component, for
aerodynamic lift can be viewed as redirected drag. It requires energy from
the engine be used to produce airspeed, and hence lift. This is proportional
to wing area, or more exactly to total lifting area, in the case of lifting
body shapes. Aerostatic lift does not have this slowdown.

Why are airships slow? Because they're big in front. This is strictly a
scaling factor. A much bigger airship, volumetrically and in terms of mass,
will have a proportionally smaller effect from this drag. But a much bigger
airplane will require a larger wing area; the demand on engine power from
aerodynamic lift will not decrease. So there must be a crossover point, in
terms of mass, which will make the airship faster than the airplane of equal
weight, for the same engine power. This is strictly aerodynamics. When you
go from big to bigger, this engineering limitation shows itself.

In fact, you do not have to go to extreme size to see the advantage of
airships over airplanes. I consider the slowness of airships to be entirely
a psychological factor. The fact is, all airships are underpowered relative
to airplanes. This psychological factor has engineering roots, because
airships must  be large but lightweight  structures, so they have always
been considered too fragile for high powered engines. We have developed
certain engineering advances, notably geodesic structures and superstrength
materials, which enable us to build large lightweight structures of high
strength. That makes the innate fragility of airships an obsolete
conception, since now we can build airships strong enough to take powerful
engines like airplanes use. Wait till I build them, I'll show you.

There is one theoretical transportation system which can outperform the
airship in terms of energy efficiency: the evacuated maglev train tunnel.
Until that be built, the airship will remain the most energy efficient
transportation system ever devised by man. The only reason it isn't fast, is
because we haven't made it fast.

> Busy designing a 12/24 bit CPU.

I used to do stuff like that. Gave it up when the microprocessors got faster
than anything I could build.

> Ben Franchuk --- Pre-historic Cpu's --
> www.jetnet.ab.ca/users/bfranchuk/index.html

Johnny T.