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Speed of design of airplanes.



 
 
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  #1  
Old December 29th 03, 02:01 AM
Charles Gray
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Default Speed of design of airplanes.

Here's a question-- why does it take so much longer to design and
protoytpe a plane today? Between the JSF and F-22 literally decades
have gone by.
Now, granted, the JSF is orders of magnitude more complex then say
an F-4...but on the other hand, CAD/CAM tools exist that give design
and engineering staffs tools that are also orders of magnitude ahead
of what was possessed in the 1960's.
So, to the engineers in teh group, are we seeing a problem that is
basedin the designing of the planes, or the process used to create
that design, in the administrative and bueraucratic ways things are
done?

  #2  
Old December 29th 03, 02:08 AM
Tarver Engineering
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Default


"Charles Gray" wrote in message
...
Here's a question-- why does it take so much longer to design and
protoytpe a plane today? Between the JSF and F-22 literally decades
have gone by.
Now, granted, the JSF is orders of magnitude more complex then say
an F-4...but on the other hand, CAD/CAM tools exist that give design
and engineering staffs tools that are also orders of magnitude ahead
of what was possessed in the 1960's.


Sure.

So, to the engineers in teh group, are we seeing a problem that is
basedin the designing of the planes, or the process used to create
that design, in the administrative and bueraucratic ways things are
done?


The F-35 seems to be progressing as expected, except for those costs
associated with not being able to tab systems from the F-22. Other than the
structural integrity problems with the F-22, most of the problem was in the
means of procurement; where the DoD attempted to select winner technologies.

With the F/A-18E we see a breakthrough in procurement, where COTS and
designing for reliability were the driving factors.


  #3  
Old December 29th 03, 03:13 AM
SteveM8597
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Default

So, to the engineers in teh group, are we seeing a problem that is
basedin the designing of the planes, or the process used to create
that design, in the administrative and bueraucratic ways things are
done?




In a few words, software, systems integration, changing user requirements,
parts obsolesence and Congressionally mandated funding profiles/milestones.
Drives a contractor into a risk averse position and long development cycle.
  #5  
Old December 29th 03, 03:36 AM
Jack G
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Default

As Steve said, "Systems Integration". The airframe is only a part of the
modern aircraft "system". Factor in the added layers of complexity from
working with the competing and often conflicting cultures and philosophies
of multiple customers and the political influence that assures that every
state/country gets some of the action and it is a wonder that anything gets
from the design stage to actual flight!

Jack

"Charles Gray" wrote in message
...
Here's a question-- why does it take so much longer to design and
protoytpe a plane today? Between the JSF and F-22 literally decades
have gone by.
Now, granted, the JSF is orders of magnitude more complex then say
an F-4...but on the other hand, CAD/CAM tools exist that give design
and engineering staffs tools that are also orders of magnitude ahead
of what was possessed in the 1960's.
So, to the engineers in teh group, are we seeing a problem that is
basedin the designing of the planes, or the process used to create
that design, in the administrative and bueraucratic ways things are
done?



  #6  
Old December 29th 03, 06:31 AM
Thomas J. Paladino Jr.
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Default


"Charles Gray" wrote in message
...
On 29 Dec 2003 02:13:31 GMT, (SteveM8597) wrote:

So, to the engineers in teh group, are we seeing a problem that is
basedin the designing of the planes, or the process used to create
that design, in the administrative and bueraucratic ways things are
done?




In a few words, software, systems integration, changing user

requirements,
parts obsolesence and Congressionally mandated funding

profiles/milestones.
Drives a contractor into a risk averse position and long development

cycle.

So lets say we moved to a wartime footing, where the order was "Get
it done, and in our hands ASAP" with most other considerations
secondary-- would we see a dramatic improvemetn, or just a fwe months
shaved off here and there.
Note, I know that this won' t happen--this is more in the sense of
what *could* be done.


I would think that in a situation like that, near-miracles could possibly be
pulled off. Remember that in Gulf War I, the GBU-28 was designed from
scratch, approved, constructed, tested, certified and deployed in just over
a month, because the need was real and immediate for a precision
heavy-penetrator weapon, and none in the inventory were suited for the
specific task. A program like that under normal conditions could take
several years or more.

Now an aircraft is obviously more complex than a bomb, but under similar
pressure, I would imagine that a timeline of under a year or so would be
possible.


  #7  
Old December 29th 03, 11:23 AM
Cub Driver
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Default


As opposed to when?

It was comparatively easy to design an aircraft in say 1937. All you
had to do was bend some metal, rivet on some aluminium, and send a
brave man up to fly it. If he didn't come back, you went on to another
design. If he did, you could improve it according to his notes. This
is not a valid approach with supersonic aircraft.

But your point is valid. The Word Trade Center was collapsed more than
two years ago, and they're still arguing about the design of its
replacement. Does anybody seriously expect to enter that building on
the 5th anniversay of 9/11? By contrast, the Empire State Building
went from first turn of the shovel to first public occupancy in about
one year.
all the best -- Dan Ford
email:

see the Warbird's Forum at
www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com
  #8  
Old December 29th 03, 11:54 AM
Simon Robbins
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Default


"SteveM8597" wrote in message
...
In a few words, software, systems integration, changing user requirements,
parts obsolesence and Congressionally mandated funding

profiles/milestones.
Drives a contractor into a risk averse position and long development

cycle.

I have a theory that the westernised industrial culture went to crap the
moment they started teaching Project Management at university, adding
countless levels of bean-counting and overhead to engineering projects.

Si


  #9  
Old December 29th 03, 02:30 PM
Smartace11
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Default

So lets say we moved to a wartime footing, where the order was "Get
it done, and in our hands ASAP" with most other considerations
secondary-- would we see a dramatic improvemetn, or just a fwe months
shaved off here and there.
Note, I know that this won' t happen--this is more in the sense of
what *could* be done.





All depends upon the complexity of the system and the requirements that are
laid down. Nowdays the thinking is that each new system must make a quantum
leap in technology and last forever so there is a tendancy to cram every bit of
known and unknown technology into the design. Sometimes designs have to wait
on breakthroughs and new inventions, i.e. the early days of the B-2.

If the design is evolutionary not revolutionary, the funding stream is steady,
the politicians don't try to run the program, and the hardware is off the
shelf maybe 4-5 years is reasonable in peacetime.

I am not sure how much time could be cut from the production phase but the
development phase, could be shortened considerably. Lining up the production
facility, building the jigs, tooling, and test sets is already pretty
efficient. Cutting the test cycles could save time, though would have to be
approached prudently.
  #10  
Old December 29th 03, 02:40 PM
Smartace11
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Posts: n/a
Default

I have a theory that the westernised industrial culture went to crap the
moment they started teaching Project Management at university, adding
countless levels of bean-counting and overhead to engineering projects.


To a large degree, the engineers WERE the project managers in the 70s and if
you take the F100 engine as an example things really fell apart as the
durabilty and reliability specs were non-existant. Too much new technology and
mainoy just a performance (thrust) spec. A large part of the F-15/F-6 fleets
were grounded due to the stall stagnation issue. Then GE and Pratt were
competed against one another and miracles happened. Also programs became far
more multi-disciplined and program management morphed into an integration role.

The problem isn't ptogram management, it is dealing with all the people who
want a piece of the action all the way down to the Congressional reps who have
one tiny supplier to the prime in their districts, and the ones who MIGHT get a
new base or a base buildup. Defense programs mean jobs and votes so
Congressional oversight is intense, even in semi-black programs. That lead to
far more reviews and requirements management that slow down development and
production.
 




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