Fred J. McCall wrote:
:I wasnt pretending this was military grade weapon (the GPS component rules
:that out straight away) but if someone told you this 10 years ago you would
:write it off completely.

Really? I find that quite odd, since I remember George talking about
how to build a rocket much more cheaply than we are STILL building
them and didn't "write it off completely". I'm pretty sure that was
more than 10 years ago.

I started saying that more than 10 years ago now, yeah.

There are now several other companies flying stuff in
the price / performance / complexity range I was talking
about, though I have not yet gotten full development
funding for my project and didn't receive one of the
DARPA FALCON project awards, though several of the
others did.

I do find the price tag pretty ludicrous,
given that you can't buy a car for that kind of money.

A lot of that is markup and costs associated with stuff
that has nothing inherently to do with the structure or
systems (interiors are not cheap).

Car engines and drivetrains also cost a lot more than
pulsejets do, cruise missile wings don't have to be
structurally all that complicated, etc.

People build homebuilt aircraft that are far larger
and more complicated (other than guidance electronics)
than our notional cruise missile for a thousand or two
thousand hours work invested, using tools and technology
that can be obtained in the bush in Rwanda if need be.
If we assume the cruise missile is half that effort,
that's five hundred to a thousand hours of effort.
In a lot of countries, people get paid a couple of
bucks an hour for reasonable tech-oriented labor.
If you wanted to do this with a prop (or, ducted fan)
there are two cycle aviation engines off the shelf
in quantity one at $2k and down for low power,
$4-5k and up some for about a hundred horsepower.
The ducted fan / afterburner job used in the
second generation, never used Kamizaze plane
used a hundred horsepower engine and a wooden
fan unit.

The only cost center which runs the risk of running
severely outside the budget is the computer and guidance
hardware. The INS will be several thousand in quantity
even if it's fiber optic gyros and MEMS accellerometers,
if you're aiming for 10 meter inertial accuracy over
those 200ish kilometers. The camera system engineering
will not be trivial, though the camera itself may end up
being very cheap (or cameras... CMOS cameras for $20 or
less retail today means that some solutions may just be
"buy more cameras"). The computer itself is trivial
and off the shelf, even hardened for flight. The software
is a sticky point but not as hard as some have made it out
to be, other than the image-matching software. I believe
that the image-matching problem is overstated here based
on previous investigations I have done, but I am not a
competent expert on that corner of the problem.


-george william herbert