Re: End of airliner evolution?

From:         wangermn@barder.Princeton.EDU (Pablo Wangermann)
Organization: Laboratory for Control and Automation Princeton University
Date:         11 Oct 96 19:44:50 
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In article <airliners.1996.1989@ohare.Chicago.COM>,
IMacduff <> wrote:
>I would like to hear others views on where advances in aeronautics will
>take us and how far away is the end.  I find it curious that the basic
>design of airliners hasn't changed that much ( nothing revolutionary
>anyway) since the 707.  How efficient can you make jet engines?  Do higher
>speeds (supersonic) come free or will they always require compromise (ie
>fuel efficiency, safety, approach speeds)?  Are there any revolutionary
>aerodynamic designs still untried in the wind tunnels or computer
>I believe that fifty years from now we will be flying airliners very
>similar to todays, with only minor enhancements.  They will still be
>almost entirely subsonic and have very similar overall performance.  I am
>criticized for this by day-dreamers who believe Mr. Ingenuity always has
>another trick up his sleeve, and hypersonic travel will be commonplace in
>the future.  However, airliners of today are a mature technology, with
>most major advances to take place on the flightdeck and not in the actual
>airframe.  Even technology on the flightdeck will mature and stabalize
>soon.  After all, once you can pinpoint your position in real time
>anywhere in the world to within a few feet and carry a topographic map of
>the entire world on CD ROM (not far away), where do you go from there?

A few random thoughts on this subject, sticking entirely to subsonic
flight (I'll let others discuss supersonic/hypersonic flight).

1)  Until you move to a flying-wing design, the tube with wings design
is about as efficient as it can get.  Small benefits may be made with
canards (see biz-jets like the Avanti), particularly for weight, but may
be offset by system complexity and certification issues.

2) Current airports couldn't handle a flying wing design, except at
remote stands.  As the designers of VHCTs are finding, the current
airport design is very limiting as to what you can do  (Wing span
limits, undercarriage loading, etc)

3)  ALs could get serious benefits not so much from improved
aerodynamics but from lower turnaround times.  10-15 minutes to de-plane
a 757 and 30+ to board it is ridiculous.  With just one jet-pier to one
narrow door to one or two narrow isles, this will always be a problem.
In Europe's small to medium airports, where it's still far more common
to walk or bus across the tarmac and load and aircraft through front and
rear doors loading time is much shorter.  (Personally, I much prefer to
smell the jet fuel and hear the screaming APUs, than antisceptic,
constricting jetways).  There have been concepts (see Jane's Airport
Review - one of the 95 issues) for using all the doors on boths sides of
an aircraft to deplane, service, then board, to tackle precisely this
problem.  However, it will take a coalition of major airlines and a
major airport construction project (T5 at Heathrow?) to get an
airport that allows this and aircraft that can make full use of this.

4)  V/Stol is at the moment a very unfashionable area of civil air
transport.  None of the forecasts for V/STOL from the 60s and 70s have
come true.  Quietly, some airlines (and aircraft) are making a success
of this niche  (London City, Berne, the Avro RJ, etc).  For every step
forward for this segment, however, there seems to be a step back.
Chicago Meigs field's closure is an example.  Many downtown airports are
reserved for business only (Cleveland riverside, I think).  I believe
that this area will continue to quietly expand for 2 reasons

i) The main choke point in today's air transport system is runway
capacity.  Airlines will increasingly look for under-utilized airports,
which usually means shorter runways.  Also, congested hub airports, may
not have room to add extra full-length runways, but could add short
strips.  While the success of "Stub" runways has so far been hindered by
the lack of suitable ATC equipment to handle the different approaches,
the advent of GPS-based ATC procedures and systems could (finally)
improve the feasibility of this.

ii) Many passengers (myself included) are sick of having to fight choked
access roads to distant mega-airports, to distant parking lots, to long
check-in lines, etc.  This can easily take longer than the flight
itself.  As the large airports clog-up, city-center and under-used
suburban airports (e.g., Trenton, NJ, Providence, RI) will be able to
attract more air services.  The success of the CRJ, and the arrival of
the EMB-145 will help in attracting prop-averse (!!) passenegers.

Oh - thought of #3

iii) The V-22 may yet be a basis for a vehicle that will be able to use
downtown heliports and make a profit for operators AND provide
significant passenger service.  This may still be more than a decade
away, but don't count it out.

So, that's what I see in my crystal ball for aircraft and air transport.

John Wangermann

John P. Wangermann              
Dept of Mech and Aero Eng.                (609) 258 5340
E Quad, Olden St,                     Fax (609) 258-6109
Princeton NJ 08544, USA