LINUX flight software

John Gilbert wrote:

Angular guages perhaps. Sweeps of 180 to 270 degrees are quite
readable, I agree. But what does the study say about altimeters with
dual needles, that rotate multiple times? How many times have you
misread the altitude or had to think hard to get it right? This has to
be the most confusing instrument to read, unless you don't really care
about knowing about that last +/- 1000 feet.
Well... hardly ever, but maybe that's because our meters are, well, in
meters :-) That means a full spin round is 1000m. Not something you'd
easily misjudge I think.

André

Dave Nadler YO wrote:
Thanks Bob. I'd cite Donald Norman's "The Design of Everyday Things".
Amazing what you read on R.A.S. sometimes ;-)
Best Regards, Dave

Maybe it's just personal preference. I have both a digital and a
traditional altimeter and find myself using the round dial exclusively.
Like wise, my current watch has hands. I much prefer it because I don't
have to read it - just scan it.

Slightly off topic, I remember reading about a (pre-digital) military
transport where the flight engineer's station was designed so that when
everything was operating normally, all dials pointed in the same
direction. It almost trivialized detecting abnormalities.

Tony V "6N"

"André Somers" wrote in message
...
John Gilbert wrote:

Angular guages perhaps. Sweeps of 180 to 270 degrees are quite
readable, I agree. But what does the study say about altimeters with
dual needles, that rotate multiple times? How many times have you
misread the altitude or had to think hard to get it right? This has to
be the most confusing instrument to read, unless you don't really care
about knowing about that last +/- 1000 feet.
Well... hardly ever, but maybe that's because our meters are, well, in
meters :-) That means a full spin round is 1000m. Not something you'd
easily misjudge I think.

André


I've flown airplanes with metric instruments (And Russian placards too).
The airspeed, rate-of-climb, RPM, manifold pressure were no problem.
Numbers is numbers I guess - fly with the needles in the green arc and
everything works. But that damn metric altimeter was impossible - no way to
read trends on an instrument that insensitive. With an altimeter that reads
1000 feet (304.8 meters) per rev of the big hand, you can thermal by
watching the trend of the needle.

Responding to "YO": Some people like analog gauges and some don't.
Ergonomic studies just produce averages which may be useful to marketeers
but what's important individually is what works best for that particular
user. If the data are displayed on an electronic screen, the user can
select the display method in a setup dialog box. i.e. check box one for
round gauge analog, box two for vertical tape with a digit window etc...
Check another box for metric or imperial units. With altitude in meters,
expanding the scale of a vertical tape gives the same sensitivity as with
imperial units.

I've also flown with both vertical tapes and round gauges. At first the
tapes were confusing but once adapted to the idea of having all the "V"
speeds floating alongside the tape with the trend indicators, going back to
round mechanical gauges seemed like the stone age. I vote for computer
graphic displays of primary flight data.

Graphical displays are inevitable anyway since all those little watchmakers
who built and repaired mechanical instruments are all retired or dead now.

Bill Daniels

I used to fly a grob twin that had an altimeter marker 3000m per rotation.
Now that instrument was *really* a pain!

Ian

"André Somers" wrote in message
...
John Gilbert wrote:

Angular guages perhaps. Sweeps of 180 to 270 degrees are quite
readable, I agree. But what does the study say about altimeters with
dual needles, that rotate multiple times? How many times have you
misread the altitude or had to think hard to get it right? This has to
be the most confusing instrument to read, unless you don't really care
about knowing about that last +/- 1000 feet.
Well... hardly ever, but maybe that's because our meters are, well, in
meters :-) That means a full spin round is 1000m. Not something you'd
easily misjudge I think.

André

On Thu, 26 Feb 2004 09:28:30 -0700, "Bill Daniels"
wrote:

I've flown airplanes with metric instruments (And Russian placards too).
The airspeed, rate-of-climb, RPM, manifold pressure were no problem.
Numbers is numbers I guess - fly with the needles in the green arc and
everything works. But that damn metric altimeter was impossible - no way to
read trends on an instrument that insensitive. With an altimeter that reads
1000 feet (304.8 meters) per rev of the big hand, you can thermal by
watching the trend of the needle.

You've just solved a mystery for me: thanks.

The most confusing altimeter I've flown with was a two pointer job but
with 3000 ft per rev of the big hand. I found it difficult to read
rather than insensitive.

I always wondered why anybody would build such a confusing instrument
but now I understand. Looks like they retained the gear train from a
metric instrument while changing the bellows and scale to make it read
in feet, 3000 ft per rev.

--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

On Thu, 26 Feb 2004 12:23:51 -0500, Todd Pattist
wrote:

Tony Verhulst wrote:

Slightly off topic, I remember reading about a (pre-digital) military
transport where the flight engineer's station was designed so that when
everything was operating normally, all dials pointed in the same
direction. It almost trivialized detecting abnormalities.

This is standard in race car instrumentation. The gauges
are rotated when they are installed so that all needles
point up when they're "in the green" during a race.

Trivial point, but why is it that in the US ASIs tend to point down
when 'in the green', but in the UK we mount them the other way up? Its
obviously intentional because the numbers are oriented to suit.


--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

Bill Daniels wrote:

I've flown airplanes with metric instruments (And Russian placards too).
The airspeed, rate-of-climb, RPM, manifold pressure were no problem.
Numbers is numbers I guess - fly with the needles in the green arc and
everything works. But that damn metric altimeter was impossible - no way
to
read trends on an instrument that insensitive. With an altimeter that
reads 1000 feet (304.8 meters) per rev of the big hand, you can thermal by
watching the trend of the needle.
I prefer to thermal on my "butt-feeling" and my audio variometer. I don't
need my altimeter for that. I guess that might be different in regions with
stronger thermals than we have to make due with here. I guess I could get
used to other scales as well (did fly a Sedhberg with Imperial instruments
once, real fun to fly 26 knots or so :-) !)
Personally, I would not trade by old, reliable mechanical primairy
instruments for a computerised system so easily. Not in a glider anyway.
Battery power alone is just not reliable enough for primairy
instrumentation in my opinion. It's fine for navigation, climb optimizing
and other stuff you don't really need to fly safely, but not for altitude
or airspeed.

André

(Kirk Stant) wrote in message

And it seems the military and airlines agree - all big
glass displays and HUDs use ditigal displays, with perhaps a dial for
trend only. I think those studies were all done in pre-digital days,
when the options were a lot more limited.

The CRT and LCD displays used in modern transport aircraft cockpits
allow the display of data in almost any format. Engineer's creativity
is usually limited by conservative certification authorities. In
almost all cases the primary flight display presents altitude and
airspeed as moving vertical tapes with a digital readout included in
the index. Glass cockpit 737 displays software provides an option to
display all instruments as conventional "steam guages". Only one 737
customer bought that option and it was to maintain commonality with
old 737's. Business jet and transport aircraft Head up Displays also
show airspeed and altitude as vertical tapes but may have a declutter
mode that removes the tapes and leaves only the precision digital
index.

Engine indications on most systems I have worked on are round dials
with a digital readout in the center. Vertical tape engine indicators
were selected by a small number of customers.

Round dials with pointers give a good indication that a parameter has
fallen outside a narrow allowed operating range but that is not
applicable to altitude and airspeed that have very large normal
operating ranges.

I have a 57mm winter altimeter and a 302. I look at the 302 altitude
first and back it up with the Winter which is harder to read.

Andy (GY)

Bill Daniels wrote:
...
But that damn metric altimeter was impossible - no way to
read trends on an instrument that insensitive. With an altimeter that reads
1000 feet (304.8 meters) per rev of the big hand, you can thermal by
watching the trend of the needle.
...

This is why I like to fly the few gliders in my club where both type of
altimeters (meter and feet) are installed. By the way, as a quick way
to make the difference between them we call the second one an "altipied",
which could be transtalted as "altifeet". So I look on the metric instrument
when I have anything to think about glide ratios, as vertical an horizontal
distances are so in the same units (and this instrument is set at QFE) and
on the other one for anything about airspace (set at QNH or flight level)
or when I need self encouragement during climb, as the rotation of the
needle is perceptible at a glance when the climbing speed is good.

In article , "tango4"
writes:

Just imagine the comments the first time someone pitches up to the
flightline wearing one of these .....

http://iar-ira.nrc-cnrc.gc.ca/flight_1d.html


Let's see him close his Libelle canopy wearing that thing!

Steve