>The strong points of airships are (IMHO):
>- No new technologies required, can be implemented *today*
>- Require little or no ground infrastructure, ideal for
developing
> country's and 'neck-of-the-woods-operations'.
>- Can handle any size/wheight cargo, as opposed to underground
> tunnelsystems. A complete factory or offshore rigg would pose
no
> problem for a large airship.
The last time I saw an economic model for airships, the numbers
indicated that conventional aircraft, at the time, did the job at
less cost. That analysis, though, dated from about fifteen years
ago. Since that time, the cost of infrastructure, capital
investment in airframes, fuel costs (and efficiencies), flying
crew, etc. costs have no doubt changed quite a good deal. In
addition, that fifteen year old model may have contained many
errors and omissions.
You may have already published a "business model" breakdown; if
so, perhaps you could dig through your messages and privately
forward it to me.
Factors related to airship transport that would have to appear in
a useful comparative business model would include such factors as
service range and anticipated service duty-cycle. Some factors
not particularly relevant for conventional aircraft (which, for
the most part, fly "above the weather" and thus have
weather-dependencies limited to conditions at airport locations)
include blocked service because of predicted intermediate weather
conditions, and limited service range because of the unreliability
of medium term weather forecasts.
Other factors that might have relevance (and might get overlooked)
relate to the barriers that airships faced (and could not
overcome) in the '30's. One worth considering relates to the
availability (both quantity and political control) of helium.
Another factor that needs to get addressed relates to the
structural survivability of airships in the face of strong
wind-shear conditions. (Has anyone performed a finite element
analysis?) I would guess that increased survivability would
increase service availability, but reduce payload per unit capital
investment. A relatively complex model might prove necessary to
determine an optimum balance between those factors plus the cost
of air and ground crew.
How do the fuel-efficiency numbers (joules per kg-m of payload)
work out? Alternatively, for low mass cargo, how does the
efficiency work out when measured as joules/m^4? (How many joules
to move a cubic meter one meter?) Lower speeds would presumably
result in lower turbulence losses, however I would guess that an
airship (or collection of airships) capable of moving the payload
of a 767 would have a much greater frontal area than that of the
767. I have no idea of how the numbers turn out.
Ground-crew and ground real-estate requirements also need some
consideration. What does it take to land a sufficient number of
airships to represent a payload equivalent to, say, a 767, and how
long would those airships stay on the ground compared to that
hypothetical 767? In the event of a complete grounding of the
fleet, how much storage area would be necessary for the
payload-year equivalent of the current conventional aircraft
fleet?
While, for the most part, airships would probably occupy flight
levels well below those of commercial aircraft, it would seem
desirable to estimate the population of airships necessary for
more than symbolic service (an estimate of, say, 30% of current
aircraft payload moved per year would probably give a rough
first-guess at the size of an effective airship fleet), the
flight-paths for a hypothetical business system, the impact on
general aviation, and the political risks involved.
Finally (of the things I can think of for a realistic business
model), it would probably be possible to make at least a rough
estimate of the investment necessary to design and produce
(including factory capital equipment) such airships. I would
guess that a twenty-year return on investment comparable to, say,
Boeing, would probably represent a reasonable starting point for
estimating the selling price of a 767-payload-year and a
767-payload-lifetime equivalent airship.
-R
Richard Plourde .. rplourde@andesign.mv.com
"The word is not the thing, the map is not the territory"
http://www.crl.com/~isgs/isgshome.html
http://www.general-semantics.org/