Is it a habit we prefer mechnical instruments?

------------much snipping----------
Semiconductors fatigue. Their parts don't vibrate. They are not as
susceptible to variations in moisture and other environmental factors.
If I were to go dig out an old 1984 IBM PC from my schools computer lab
closet and flip the switch, it might not start, but that would be due
to rust on the mechanics. I could take the board out, put it in a
non-rusty case, power it, and it will boot. And it will compute up to
4.77 million instructions per second thereafter, and continue to do so
for 1000 years provided I did not drop or fry it.

They are certainly more repeatable over a modest period of time. However,
it is my understanding that the molecules in the critical substrates do
migrate over time, and also due to temperature and electrical events. So,
presuming that "normal" operation was not too close to any critical speed,
voltage, or temperature; the 21 years since 1984, or a few more years into
the future, should not be troublesome. However, 1000 years really is taking
"poetic lecense" over the top.

I think we're being told a lot of digital stuff is "better"
when it really isn't in some ways. Digital stuff is much cheaper to
manufacture, because machines can assemble almost the entire thing,
while analog devices have small moving parts that usually need to be
put together by hand. The profit on digital equipment must be a lot
higher, especially on the cheap stuff.
I can't use digital meters while troubleshooting electrical
problems. The digital VOM I can afford only samples the voltage or
whatever about once a second, making any rapid adjustments or quick
readings impossible. The old analog meter goes immediately to the value
and shows any changes instantly. In cold weather the LCD digital
display gets sleepy but my mechanical needle still works faithfully.

Dan

Good points, one and all. And my experience as well.

Peter

Evan Carew wrote:
could produce a custom electrical package with a nice looking LCD for
~$1000 USD, that you'd still have to arrange to sell it through
distributors, and those guys often want to charge 100% over what you are
charging them. To make matters more interesting, agreements with such
distributors often require you to set a "list price" which is about what
they want to charge at retail (so you don't steal their sales).

Funny enough, this price starts to look awfully like what dynon & the
other workalikes are selling for.

I would distribute over the Internet if that started to happen.

-Le Chaud Lapin-

("Morgans" wrote)
Here, we call that "fly by wire", and for a small airplane, there is no
possible way to make that lighter than you could make conventional
controls. You will need to have back-up, triple redundancy; all of the
controls multiplied times three will start to get heavy.


"Fly by Bluetooth"

Hello, 21st Century calling.


Montblack-and-blue :-)

In article .com,
"Le Chaud Lapin" wrote:

Again, as an electrical/software
engineer (but not a pilot), I am biased.

-Le Chaud Lapin-

And therein lies the crux of the issue. What is possible is one thing.
What is desirable and marketable is another. Try this experiment: Go
find someone riding a motorcycle, and offer him a suitcase full of bus
tickets in exchange for his bike. Or someone waiting in line for a
roller coaster ride, and offer to walk him directly over to the coaster
exit area to save him the bother of doing all that riding just to get
there.

And then, please, go take a few flying lessons. Airliners already have
all the stuff you're talking about, and GA neither needs it, nor, more
importantly, wants it. If we get to the point where people really are
commuting to work by the millions in little skycars, then perhaps your
ideas will have some merit.

wrote:
Thank you Mr. Richard, Denny.
Please not be sick of my more questions.
From your opinion, you like "needle" meters. I want to know why most of
digital manufacturers made numeric readouts. I think they have
investigated markets, and then they done these kinds of products. Since
I browsed aircraftspure catalogues. I found numeric readout digital
meters stand in front of selling catalogue. I guessed there are a lot
of people buy and use them. Maybe I am wrong.

Luo


Digital instruments are easy to program and don't take much computing
resources. Converting the display to a form fit for human consumption
take more computing and programming horsepower.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

--------snip---------

Digital instruments are easy to program and don't take much computing
resources. Converting the display to a form fit for human consumption
take more computing and programming horsepower.

Exactly right. Plus two additional problems:
1) Most modern general purpose computers have voluminous operating
systems and take too much time to cold start (or boot up), even if ROM is
substituted for the disk drive. That means a lot more programming.
2) Presently, there is too little standardization, especially of the NAV
equipment. And integration of the NAV display(s) is a major reason for
considering electronic displays.

So it's not that we necessarily prefer mechanical instruments, but we
certainly have reason to demand that any replacement be at least as good in
all ways important to a pilot, such as:
1) Ease of comprehension.
2) Similarity of controls and displays in aircraft a pilot might fly.
3) Redundancy--at least as good as our old electrical plus vacuum.
4) Immunity from "wash out" in direct sunlight.

On 16 Apr 2006 23:44:47 -0700, wrote:

Who's We?

We used to mechanical instruments when we learnt fly in school. Whether
it is habit we can not accept digital meters. For example quartz

"We" sure can. I took my first lesson in 1963 and I much prefer the
glass panels that are now available.

crystal watch, we almost accept it now. There few people using
mechanical watch. I think it is developing direction for digital
meters.
I just wondered which kinds of digital meters, electric analog or
numeric meter, do pilot can accept. Or we can accept an electric analog
meter with digital number in it?

There are things where analog is easier on the eyes even in a glass
panel. For instance, the AI, is a graphical representation. Glide
slope is graphical while airspeed is digital. Heading can be either
as long is it can be read.

If "we" start out using only the basics of the glass panel and slowly
move up instead of trying to use everything right at the start, they
are relatively simple. I find the flight instruments easier to use
and scan than I do the old steam gages. OTOH there is no
standardization between GPS or MFD manufacturers which can complicate
things a bit and some are a bit less than intuitive.

Still, in the long run they are easier to use and more reliable than
the old mechanical panels. I'd put one in my Deb except the panel
would then be worth more than the airplane.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On Thu, 20 Apr 2006 01:33:50 -0400, "Peter Dohm"
wrote:

--------snip---------

Didn't we just go through this.

Digital instruments are easy to program and don't take much computing
resources. Converting the display to a form fit for human consumption
take more computing and programming horsepower.

But it is still very little compared to a PC. With today's "stuff" an
old 6502 would probably have enough power.

Exactly right. Plus two additional problems:
1) Most modern general purpose computers have voluminous operating

What do general purpose computers have to do with flight displays.

systems and take too much time to cold start (or boot up), even if ROM is

Actually the operating systems can start in seconds. It's all the
other stuff they have to load and interface with that takes the time.

substituted for the disk drive. That means a lot more programming.

Programs for flight displays should be relatively simple. Compared to
a "windows" or "Mac" they should be extremely simple.

2) Presently, there is too little standardization, especially of the NAV

With this I agree to a point, but to say too little? There isn't any!

equipment. And integration of the NAV display(s) is a major reason for
considering electronic displays.

So it's not that we necessarily prefer mechanical instruments, but we
certainly have reason to demand that any replacement be at least as good in
all ways important to a pilot, such as:
1) Ease of comprehension.

Glass panel

2) Similarity of controls and displays in aircraft a pilot might fly.

Actually with most using Garmin there is a lot of similarity, but for
those moving between different systems it can be more than a little
confusing.

3) Redundancy--at least as good as our old electrical plus vacuum.
4) Immunity from "wash out" in direct sunlight.

A properly configured system should have none of these problems.
LCDs can be constructed to be easily viewable in direct sunlight.


Glass panels are more reliable, and once the pilot becomes proficient
with one they are easier to interpret than the old mechanical gages. A
good MFD with The AI, Heading, airspeed and altitude is far easier to
scan than mechanical gages.

Taken in logical order and one step at a time instead of trying to do
everything on the first flight, they are easy to learn as well. The
confusion comes when a pilot jumps into a plane with an unfamiliar
system and then tries to use all the bells and whistles instead of
just flying around for a while getting aquatinted with the system.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Peter Dohm wrote:
--------snip---------

Digital instruments are easy to program and don't take much computing
resources. Converting the display to a form fit for human consumption
take more computing and programming horsepower.

Exactly right. Plus two additional problems:
1) Most modern general purpose computers have voluminous operating
systems and take too much time to cold start (or boot up), even if ROM is
substituted for the disk drive. That means a lot more programming.

I think if you're about to take a trip, waiting the whole 17 seconds
for the OS to boot (Windows) won't hurt too much.

2) Presently, there is too little standardization, especially of the NAV
equipment. And integration of the NAV display(s) is a major reason for
considering electronic displays.

This is true. Also, I have looked at some of the gadgets that are
produced by Garmin (and Raymarine for you boat-lovers). I think it is
important to realize that, when a software engineer at one of these
companies sits down to make software for their gadgets, the complexity
presented to them is often more than that which is presented to someone
who programs a regular PC. This started changing a bit when Microsoft
started selling embedded versions of their OS's, and now, a
full-feature version of XP that is meant for embedded system. Yet
still, there are many devices that uses unconventional hardware, and
then hire programmers to work really hard to tweak it just right.

Compare that to going to a young programmer who knows how to make fancy
graphics on standard PC using C++, and you can see the difference.
S/he would probably be able to create almost anything you can imagine,
with much, much less cost than there would be with custom device. I
cannot emphasize enough that the young people who program and know
computer graphics can create graphical presentations that are far
beyond what Garmin is currently making. And everytime you get into a
simulator that is rendered by a digital display showing analog
controls, you are convincing yourself that it is "ok" that the analog
controls are rendered digitally.

But again, the real power comes from the possibility of letting the
computer open up more of your plane and your environment to you.

So it's not that we necessarily prefer mechanical instruments, but we
certainly have reason to demand that any replacement be at least as good in
all ways important to a pilot, such as:
1) Ease of comprehension.
2) Similarity of controls and displays in aircraft a pilot might fly.
3) Redundancy--at least as good as our old electrical plus vacuum.
4) Immunity from "wash out" in direct sunlight.

True about the redundancy. We can't have a bad transistor bringing
down the aircraft. But digital sensors are cheap, lightweight, and and
accurate. If it fails, the computer will know immediately. With
standard interfaces like USB, it would be a simple matter of finding
the faulty part, throwing it in trash (as opposed to repairing it), and
replacing it with a new one. The computer would tell you if the new
one is OK.

-Le Chaud Lapin-