James Turner wrote:
> Well ... basically, but some of the landing modes get pretty involved.
> For example, you need to calculate the roll angle to counter-act the
> crosswind, and then prior to touch-down you need to convert roll into
> crab to avoid an engine scrape. Even DC-10 autopilots (which are
> presumably an analog electronic nightmare, not digital) do this, IIRC.

I'd guess that they were digital computers.  The DC-10 entered service
in the mid 70's.  By this time, computers were well-entrenched as
control mechanisms for all sorts of application.  An autopilot doesn't
require a whole lot of CPU power; I could imagine doing it well with a
PDP-8 equivalent (12 bit word size, 4k memory, ~1 MHz, cost: something
like $10k and 200 lbs).  Certainly, this could be installed on a big
aircraft without much hardship.

For lightplanes, obviously, digital electronics had to wait for the
availability of cheap microprocessors in the 80's.

Even the smaller military jets had computers.  The late model A-4's,
for example, had a distinct hump on the fuselage aft of the cockpit.
This was added to house "extra avionics" in the late 60's -- almost
certainly controlled by digital (albeit discrete transistor logic)
computers.

Andy

-- 
Andrew J. Ross                NextBus Information Systems
Senior Software Engineer      Emeryville, CA
[EMAIL PROTECTED]              http://www.nextbus.com
"Men go crazy in conflagrations.  They only get better one by one."
 - Sting (misquoted)


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