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Re: Vacuum Instrument bashing!

Subject: Re: Vacuum Instrument bashing!
From: Robert L. Nuckolls III <nuckolls@aeroelectric.com>
Date: Tue, 11 Jul 2000 10:32:30

>If your alternator goes out, your battery dies or your buss fries,  a
>few suck type instruments would look mighty good up there in a murky sky.

   The 'dark panel' syndrome has been topic of many a hair-raising,
   wing-and-a-prayer hangar tale for decades. Virtually all of these
   experiences happend in a government approved, certified aircraft
   where the technology and design philosophy are carved into
   1960's era regulatory stone.

>With all electric, you could lose  all instrments at once unless you have a
>lot of back up electrical systems in place.

   There is no reason for a modern aircraft to suffer an electrical
   emergency of any kind. Wires are no longer cotton-covered-rubber
   or nylon-over-PVC insulation. Reasonably maintained batteries are
   dependable sources of power when and if the alternator craps. A second
   alternator capable of extended endurance engine powered flight
   costs less than a vacuum system and weighs 1/2 to 1/3 the pounds.
   Certified alternators repeately demonstrate 50-200 hrs limits before
   something breaks . . . modern alternators that ran the lifetime of
   the automobile they came out of are ready to go another thousand
   hours or so in your airplane. Simple departures from system architectures
   revered for decades provide operational alternatives to every
   simple failure of any component.

   Physics and facts don't support the rhetoric. Busses don't "fry",
   any battery that enjoys a modicum of preventative maintenance doesn't
   die in flight, and alternators (particulary two of them) are going
   to be there in one form or another when you need them. MOST importantly,
   YOUR airplane is going to be fabricated and maintined under aviation's
   finest traditions of craftsmanship and attention to detail.

   On an assembly line, the kid bucking rivets has been working there two
   weeks. If something doesn't quite line up, he'll stick an awl
   into the hole and MAKE them line up. If something gets bent or broke,
   3 supervisors and 5 inspectors will stand around for an hour and
   deduce the MINIMUM effort and expense that will allow the factory
   to LEGALLY put the airplane out the door. Is that how your
   airplane goes together?

>So you install double alternators, double batteries, seperate busses and so
>on. Also, if I am not off the bubble, electric instruments cost a lot more.

   True. But you save on vacuum system weight and installation time.
   The rat's nest of plumbing and hoses behind panel go away. Weight of
   system goes down. In 1965 while working at Cessna single engine
   engineering I was told that it was worth $100/pound to the end user
   to reduce the weight of an airplane. Each pound left OUT didn't have
   to be fabricated, installed, maintained nor was fuel burned carrying
   that extra pound of stuff around in the sky for the lifetime of the
   airplane. What is a pound of excess weight worth to you 35 years
   later? What's it worth to have reliability in a single engine airplane
   that rivals or exceeds that of a LearJet? What's it worth NOT to
   fabricate, install and maintain several pounds of plumbing?

>Vac. pumps have been around  for  ever and  to suddenly say they are no good
>makes little sense. With Vac. pumps as with most other things, you get what
>you pay for. Even one supposedly good  for only  three hundred hours would
>run most pilots three years.

   It runs deeper than getting what you pay for . . . you can pay
   a lot of money for trash. If you endorse the "been around forever"
   philosophy then how about keeping dual VOR and an ADF in the
   panel? I know some folks that would make you a really good deal
   on a DME. 

   I work daily within the morass of regulated aviation. A substantial
   portion of my time is expended trying to figure out how to fix
   a problem without opening the Pandora's box of recertification.
   The system works against truly effective solutions to problems.
   The very reguations offered up in the quest for aviation utopia
   are in fact making airplanes less friendly to the people who
   own, maintain and fly them. You don't know how refreshing it is to come
   home and work the folks who are building the finest airplanes to have
   ever flown.

   You may find comfort in a familiarity with "the devil
   you know". However a little study of aviation's history
   and some observation of truly modern and (more important)
   UNREGULATED evolution of aviation technology proves that
   "the devil you don't know" is really a pretty nice guy.


     Bob . . .
     --------------------------------------------
     ( Knowing about a thing is different than  )
     ( understanding it. One can know a lot     )
     ( and still understand nothing.            )
     (                     C.F. Kettering       )
     --------------------------------------------
           http://www.aeroelectric.com



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