[MR2] MR2] MR2 news from Top Gear

James seawa.anon at gmail.com
Mon Jan 25 02:13:00 EST 2010


 Yeah, Boeing does the same thing; fatigue testing the wings for
certification.

The Airbus tail problem, I believe, was with a composite tail with a
non-ideal attachment design.  With fuel being the major cost of running an
airline these days, weight's a huge issue, and fly-by-wire is much lighter
than redundant control cables running all over the place.  There was even an
event once where, during a depressurization, the floor panels buckled and
jammed the control cables.

There's some architectural differences between Boeing and Airbus though;
Boeing remains steadfast that, ultimately, total control goes to the pilot.
In events where the pilot choses to induce loads on the airplane greater
than what it was designed to see in service (Limit Load, as opposed to
Ultimate load), the controls offer additional resistance but the pilot can
override with additional force.  Airbus chooses not to allow this
override.

As for automobiles though, I'm with you, simple is good; only recently
embracing the concepts of electrically adjustable mirrors (it's irritating
being on the highway and finding out someone's bumped the passenger side
one) and remote door locks (my subie has five doors and it's a PITA to
manually check them all.  Oh, and my old 944 had this really nifty feature -
it was a "turbo defrost" button on the dashboard.  Push that button and an
HUGE amount of air blasted the windshield and defrosted it in seconds.  VERY
cool.

James


> From: "William Brandt" <wbrandt1 at sbcglobal.net>
>
> Wow - lots of interesting discussions going on. First aircraft have
> redundant systems - Boeing is the best with most planes having 3 hydraulic
> systems. Plus they must be tested ad nauseum for the FAA before
> certification.
>
> I remember 20 years ago, working for Cessna in Wichita, going to the
> company cafeteria and going by the test hanger - they had a Citation 3 wing
> (a medium size exec jet) on some jigs with hydraulic presses constantly
> flexing the wing back and forth to simulate 1000s of hours of flight time.
>
> Even then some of this fly-by-wire stuff is a bit too much - Airbus seems
> to have a problem between their software and the rudder giving too much
> angle in certain situations - causing the tail to fall off ;-) Mercedes has
> a cruise control system that automatically slows the car when it detects too
> small a space up front. And the computer will automatically tension seat
> belts when it detects the driver "slamming" on the brakes.
>
> And Lexus has their auto parking system.
>
> I view all this is fine until it goes bad and then big $$$ to diagnose and
> fix. Then it is just more crap going out. Like the little motors inside the
> LS430 vents that move the vents back and forth to move the air. Fine until
> the motors go bad and you have to tear the dash up.
>
> When you have a car that is 100 times as complex electronically do you
> think you will get the same trouble-free longetivity?
>
> Mercedes electronic brakes - well, they did have a brake system that was
> computer controlled - with hydraulics - even changing the pads and pushing
> the pistons back was a special procedure - offered on the latest SL and the
> last E Class - but I have heard that they dropped it. They had a problem
> first with the initial software. Have a friend with an E Class who loves it
> but as to why they have dropped it I cannot say. At least they have no plans
> on offering it in more models. That is what I heard.


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