LINUX flight software

[Bill Daniels]

Apparently, there are a few people out there working with Linux for gliding
applications. (Thanks for the links) Maybe it's a good thing.

I keep thinking that the potential user base in this space is so small that
if the PDA based apps split it, there won't be all that much profit to
support a commercial business - especially with a price war. So, we are
back to the hobbyist/enthusiast hacker who tends to like Linux/GPL anyway.
This person just wants some recognition for expertise and contribution made.
Gliding software might make a good resume entry.

Should someone take up the challenge, I'd like to see something along the
lines of an x86 based (lots of small, cheap, powerful, highly configurable,
12V boxes like those from Via) with the in-flight software developed on a
very small, hard real-time Linux kernel with an API like DIAPM RTAI. This
removes all the constraints of the PDA platform. (Somehow, I just don't
think a pocketable device designed for to-do and a contact lists is a great
platform for advanced soaring software, even if they are widely available.)

This approach offers the chance to do the entire panel in a gliding specific
"glass cockpit" with a screen size that's actually big enough to read at a
glance.

Bill Daniels

[André Somers]

Bill Daniels wrote:

> Apparently, there are a few people out there working with Linux for
> gliding
> applications. (Thanks for the links) Maybe it's a good thing.
Yes, there are. I am one of them.

> I keep thinking that the potential user base in this space is so small
> that if the PDA based apps split it, there won't be all that much profit
> to
> support a commercial business - especially with a price war. So, we are
> back to the hobbyist/enthusiast hacker who tends to like Linux/GPL anyway.
> This person just wants some recognition for expertise and contribution
> made. Gliding software might make a good resume entry.
It does, actually. I am currently in contact with a potential employee who
seems to be very interested in my work. I'm not sure what you are
suggesting though, that I am undermining the commercial glidersoftware
business?

> Should someone take up the challenge, I'd like to see something along the
> lines of an x86 based (lots of small, cheap, powerful, highly
> configurable, 12V boxes like those from Via) with the in-flight software
> developed on a
> very small, hard real-time Linux kernel with an API like DIAPM RTAI. This
> removes all the constraints of the PDA platform. (Somehow, I just don't
> think a pocketable device designed for to-do and a contact lists is a
> great platform for advanced soaring software, even if they are widely
> available.)
>
> This approach offers the chance to do the entire panel in a gliding
> specific "glass cockpit" with a screen size that's actually big enough to
> read at a glance.
Problem is: these devices are:
-too powerhungry
-too hard to install in a cockpit.

I am working on an application called Cumulus on the PDA platform. But, it's
easy to port to x86. In fact, most of the development work is done on x86.

André
projectleader of Cumulus

[Bill Daniels]

"André Somers" > wrote in message
...
> Bill Daniels wrote:
>
> > Apparently, there are a few people out there working with Linux for
> > gliding
> > applications. (Thanks for the links) Maybe it's a good thing.
> Yes, there are. I am one of them.
>
> > I keep thinking that the potential user base in this space is so small
> > that if the PDA based apps split it, there won't be all that much profit
> > to
> > support a commercial business - especially with a price war. So, we are
> > back to the hobbyist/enthusiast hacker who tends to like Linux/GPL
anyway.
> > This person just wants some recognition for expertise and contribution
> > made. Gliding software might make a good resume entry.
> It does, actually. I am currently in contact with a potential employee who
> seems to be very interested in my work. I'm not sure what you are
> suggesting though, that I am undermining the commercial glidersoftware
> business?

Nope, just pointing out that it's likely to be a labor of love rather than a
serious effort to get rich. Nothing wrong with getting paid for your work.
>
> > Should someone take up the challenge, I'd like to see something along
the
> > lines of an x86 based (lots of small, cheap, powerful, highly
> > configurable, 12V boxes like those from Via) with the in-flight software
> > developed on a
> > very small, hard real-time Linux kernel with an API like DIAPM RTAI.
This
> > removes all the constraints of the PDA platform. (Somehow, I just don't
> > think a pocketable device designed for to-do and a contact lists is a
> > great platform for advanced soaring software, even if they are widely
> > available.)
> >
> > This approach offers the chance to do the entire panel in a gliding
> > specific "glass cockpit" with a screen size that's actually big enough
to
> > read at a glance.
> Problem is: these devices are:
> -too powerhungry
> -too hard to install in a cockpit.
>
> André
> projectleader of Cumulus
>

Really? I see systems that pull less than 750ma. That would go for more
than 8 hours on a 7.5AH battery. Spend a little more for a Li-Ion polymer
battery and 10 - 15 hours are possible. The systems are about the same size
as a CD drive (5.5 inch form factor). I've got plenty of room for that and
the battery. As for the screen, I have dry-fitted a 15" screen over my
panel and I have room to spare. It just needs to hinge at the top so I can
flip it up out of the way if I need to see the old round gauges.

>
> I am working on an application called Cumulus on the PDA platform. But,
it's
> easy to port to x86. In fact, most of the development work is done on x86.

I read your web page and I'm really impressed. Waaay cool!

Bill Daniels

[André Somers]

Bill Daniels wrote:

>> I'm not sure what you are
>> suggesting though, that I am undermining the commercial glidersoftware
>> business?
> Nope, just pointing out that it's likely to be a labor of love rather than
> a
> serious effort to get rich. Nothing wrong with getting paid for your
> work.
I didn't start this project to get rich. I like OpenSource. That concept has
allready made Cumulus far better than I had ever been able to make myself,
because we now have a number of contributors and we are free to use code
from other GPL projects. Cumulus will always remain OpenSource. So yes, It
is a labor of love. Nothing wrong with that either, is there?

>> Problem is: these devices are:
>> -too powerhungry
>> -too hard to install in a cockpit.
> Really? I see systems that pull less than 750ma. That would go for more
> than 8 hours on a 7.5AH battery. Spend a little more for a Li-Ion polymer
> battery and 10 - 15 hours are possible. The systems are about the same
> size
> as a CD drive (5.5 inch form factor). I've got plenty of room for that
> and
> the battery. As for the screen, I have dry-fitted a 15" screen over my
> panel and I have room to spare. It just needs to hinge at the top so I
> can flip it up out of the way if I need to see the old round gauges.
And how much power does your (touch) screen draw? I would be really
interested to see such a setup, and I must say I find the concept
intreaging. Maybe you can fit, say, a 10" screen in your pannel. That would
allready be a huge improvement over a PDA screen, and I must say that the
additional CPU power of an x86-based system would give some *very* nice
options indeed...

>> I am working on an application called Cumulus on the PDA platform. But,
> it's
>> easy to port to x86. In fact, most of the development work is done on
>> x86.
>
> I read your web page and I'm really impressed. Waaay cool!
Thanks. The webpage is a bit outdated, and the screenshots are pretty old...
Stuff looks better now, and 1.2 will be a lot cooler feature-wise :-)

André

[Bill Daniels]

"André Somers" > wrote in message
...
> And how much power does your (touch) screen draw? I would be really
> interested to see such a setup, and I must say I find the concept
> intreaging. Maybe you can fit, say, a 10" screen in your pannel. That
would
> allready be a huge improvement over a PDA screen, and I must say that the
> additional CPU power of an x86-based system would give some *very* nice
> options indeed...
>
> André

Some of these screens draw about 650ma @ 12V with the brightness all the way
up. I don't know if this is a good number or if there are better screens.
A narrow viewing angle would reduce the demands on the backlight.

What are your thoughts on Real-Time Linux for this application?

Bill Daniels

[André Somers]

Bill Daniels wrote:

>
> "André Somers" > wrote in message
> ...
>> And how much power does your (touch) screen draw? I would be really
>> interested to see such a setup, and I must say I find the concept
>> intreaging. Maybe you can fit, say, a 10" screen in your pannel. That
> would
>> allready be a huge improvement over a PDA screen, and I must say that the
>> additional CPU power of an x86-based system would give some *very* nice
>> options indeed...
>>
>> André
>
> Some of these screens draw about 650ma @ 12V with the brightness all the
> way
> up. I don't know if this is a good number or if there are better screens.
> A narrow viewing angle would reduce the demands on the backlight.
>
> What are your thoughts on Real-Time Linux for this application?
I guess that depends on what you want to do with it. For one, you can't use
it for primairy instruments, at least not here. The greatest power of using
a computer is where it is used now too: navigational aid and flightcomputer
functions. For that, you don't really need a RT system IMHO.

André

[Bill Daniels]

"André Somers" > wrote in message
...

> > What are your thoughts on Real-Time Linux for this application?

> I guess that depends on what you want to do with it. For one, you can't
use
> it for primairy instruments, at least not here. The greatest power of
using
> a computer is where it is used now too: navigational aid and
flightcomputer
> functions. For that, you don't really need a RT system IMHO.
>
> André
>

Well, you probably couldn't CERTIFY a computer display for the primary
instruments (without a lot of money) but by displaying the primary
instrument data on the computer screen, all the flight data would be in one
place and easy to read. Keep the old primary instruments in the panel to
keep things legal and just hinge the thin computer screen over them so that
if you need to peek just lift the screen.

Bill Daniels

[André Somers]

Bill Daniels wrote:

>
> "André Somers" > wrote in message
> ...
>
>> > What are your thoughts on Real-Time Linux for this application?
>
>> I guess that depends on what you want to do with it. For one, you can't
> use
>> it for primairy instruments, at least not here. The greatest power of
> using
>> a computer is where it is used now too: navigational aid and
> flightcomputer
>> functions. For that, you don't really need a RT system IMHO.
>>
>> André
>>
>
> Well, you probably couldn't CERTIFY a computer display for the primary
> instruments (without a lot of money) but by displaying the primary
> instrument data on the computer screen, all the flight data would be in
> one
> place and easy to read. Keep the old primary instruments in the panel to
> keep things legal and just hinge the thin computer screen over them so
> that if you need to peek just lift the screen.
Apart from the legal aspects, I don't really see many advantages to making
the primairy instruments electronic (or obscuring them with a screen,wich
is illegal here I think). The "normal" instruments are very easy to
interpret (it has been shown that round dials are by far the easiest to
comprehend for the human brain: judging angles is easier than judging a
distance or reading and interpretting a figure.) That doesn't say that you
couldn't use the data also on the screen, but I would not make it primairy.
An electronic system *is* more likely to fail, if only due to poor battery
conditions.
Having said that, I haven't found a useable x86 system yet. Maybe I'm
looking in the wrong place, but a system like a VIA EPIA board still takes
about 30W. Using a 12V battery, that means 2,5A. That's a heavy load; my
battery would last maybe two, max three hours. And that is without a
screen...

André

[Robert Ehrlich]

André Somers wrote:
> ...
> The "normal" instruments are very easy to
> interpret (it has been shown that round dials are by far the easiest to
> comprehend for the human brain: judging angles is easier than judging a
> distance or reading and interpretting a figure.)
> ...

Not obviuous for me. Head up displays use rather vertical scales with
a moving index. I remember some Mercedes cars about 40 years ago had
also a speed indicator of this type, a colored bar filling less or more
of a vertical slot with a scale on the border. The color changed when
your speed was above the max allowed inside towns. At that time it was
purely mechanical, just a colored disc behind the slot rotating like
the usual needle around a pivot at the bottom of the slot, with a boundary
that was a spiral rather than a circle. Such an airspeed indicator in
a saiplane would probably easier to comprehend than some round dials
with more than one turn and 2 different values under the needle.
However the limitation of space to that of a standard instrument
would not allow it.

[Bert Willing]

So how comes that these linear indicators can't be found anymore ? All car
manufacturers on this planet ignoring human perception ?
I also had something like this on a Citroën GS...

--
Bert Willing

ASW20 "TW"


"Robert Ehrlich" > a écrit dans le message de
...
> André Somers wrote:
> > ...
> > The "normal" instruments are very easy to
> > interpret (it has been shown that round dials are by far the easiest to
> > comprehend for the human brain: judging angles is easier than judging a
> > distance or reading and interpretting a figure.)
> > ...
>
> Not obviuous for me. Head up displays use rather vertical scales with
> a moving index. I remember some Mercedes cars about 40 years ago had
> also a speed indicator of this type, a colored bar filling less or more
> of a vertical slot with a scale on the border. The color changed when
> your speed was above the max allowed inside towns. At that time it was
> purely mechanical, just a colored disc behind the slot rotating like
> the usual needle around a pivot at the bottom of the slot, with a boundary
> that was a spiral rather than a circle. Such an airspeed indicator in
> a saiplane would probably easier to comprehend than some round dials
> with more than one turn and 2 different values under the needle.
> However the limitation of space to that of a standard instrument
> would not allow it.

[tango4]

The major problem with current HUD systems is that they are projected onto a
screen screwed to the instrument panel turtledeck. Fine if you are a fighter
jock and want to keep your eye on the bandit in front of you. Also good for
IFR types who actually don't need to look out the window anyway.

What is really needed in sailplanes are head mounted displays that keep an
image hovering in front of the pilot wherever his head is. A sailplane pilot
only looking out ahead is almost as bad as one focussed on a PDA strapped to
his leg.


Ian

[Finbar]

Robert Ehrlich > wrote in message >...
> André Somers wrote:
> > ...
> > The "normal" instruments are very easy to
> > interpret (it has been shown that round dials are by far the easiest to
> > comprehend for the human brain: judging angles is easier than judging a
> > distance or reading and interpretting a figure.)
> > ...
>
Also I found, on returning from hang gliding to the world of
conventional aircraft, that conventional altimeters are MUCH harder to
read than a digital output. It took me a while to get used to them
again, and I'd still much prefer digital output.

[Bob Kuykendall]

Earlier, Robert Ehrlich > wrote:

> > The "normal" instruments are very easy to
> > interpret (it has been shown that round dials are by far the easiest to
> > comprehend for the human brain: judging angles is easier than judging a
> > distance or reading and interpretting a figure.)

> Not obviuous for me...

The assertion that angular guages are easier to read is backed up by
countless perception and human factors studies. It is also
corroborated by studies of the stimulation network pre-processing that
takes place right in the retina at the back of the eye.

Human factors texts such as McCormick's, and physiology texts on
sensation and perception deal with this topic at great length.

Thanks, and best regards to all

Bob K.

[Kirk Stant]

"tango4" > wrote in message >...
> The major problem with current HUD systems is that they are projected onto a
> screen screwed to the instrument panel turtledeck. Fine if you are a fighter
> jock and want to keep your eye on the bandit in front of you. Also good for
> IFR types who actually don't need to look out the window anyway.
>
> What is really needed in sailplanes are head mounted displays that keep an
> image hovering in front of the pilot wherever his head is. A sailplane pilot
> only looking out ahead is almost as bad as one focussed on a PDA strapped to
> his leg.
>
>
> Ian

Your description of current HUDs is somewhat misleading. HUD work by
projecting images, collimated to infinity, on a clear "combining
glass" on top of the instrument panel, in the pilots normal line of
sight. The projected symbology - attitude, heading, airspeed,
altitude, etc. is superimposed on the real world with a direct
correlation - in other words a 5 degree pitch up using the HUD scale
is a true 5 degree pitch, not a shrunk symbolic display as on a small
attitude indicator. Newer HUDs also allow projecting FLIR or LLTV
images - also collimated at infinity - on the HUD, so you have a
"virtual reality" display; cool at night. The importance of the
infinity collimation of the display is that you do not have to refocus
your eyes when looking at a HUD, you see the symbology when focused at
long distance. That is absolutely not true when "coming inside" to
read old fashioned steam gauges!

The downside is all the optics are HEAVY and power hungry, so don't
count on seeing them in a glider soon.

The newer fighters have Helmet-mounted displays that project all the
HUD symbology on their helmet visor. Still heavy, big, and power
hungry.

What I think we need for gliding is a nice big color navigation
display to replace the sectional chart that is becoming more and more
difficult to fold in our small cockpits - something that I can pull
out, look at, then put away to continue flying. Let's face it, after
awhile you can fly any glider by feel and audio vario, anyway.


Kirk

[Bill Daniels]

"Kirk Stant" > wrote in message
om...
> "tango4" > wrote in message
>...
> > The major problem with current HUD systems is that they are projected
onto a
> > screen screwed to the instrument panel turtledeck. Fine if you are a
fighter
> > jock and want to keep your eye on the bandit in front of you. Also good
for
> > IFR types who actually don't need to look out the window anyway.
> >
> > What is really needed in sailplanes are head mounted displays that keep
an
> > image hovering in front of the pilot wherever his head is. A sailplane
pilot
> > only looking out ahead is almost as bad as one focussed on a PDA
strapped to
> > his leg.
> >
> >
> > Ian
>
> Your description of current HUDs is somewhat misleading. HUD work by
> projecting images, collimated to infinity, on a clear "combining
> glass" on top of the instrument panel, in the pilots normal line of
> sight. The projected symbology - attitude, heading, airspeed,
> altitude, etc. is superimposed on the real world with a direct
> correlation - in other words a 5 degree pitch up using the HUD scale
> is a true 5 degree pitch, not a shrunk symbolic display as on a small
> attitude indicator. Newer HUDs also allow projecting FLIR or LLTV
> images - also collimated at infinity - on the HUD, so you have a
> "virtual reality" display; cool at night. The importance of the
> infinity collimation of the display is that you do not have to refocus
> your eyes when looking at a HUD, you see the symbology when focused at
> long distance. That is absolutely not true when "coming inside" to
> read old fashioned steam gauges!
>
> The downside is all the optics are HEAVY and power hungry, so don't
> count on seeing them in a glider soon.
>
> The newer fighters have Helmet-mounted displays that project all the
> HUD symbology on their helmet visor. Still heavy, big, and power
> hungry.
>
> What I think we need for gliding is a nice big color navigation
> display to replace the sectional chart that is becoming more and more
> difficult to fold in our small cockpits - something that I can pull
> out, look at, then put away to continue flying. Let's face it, after
> awhile you can fly any glider by feel and audio vario, anyway.
>
>
> Kirk

I have to agree with "tango4" that good glider pilots don't spend much time
looking straight ahead or "heads down" inside the cockpit.

Kirk, you are right that the current generation of HUD is heavy and power
hungry but it doesn't have to be. I once built a benchtop breadboard HUD
with semi-mirrored Mylar and plastic Frenel lenses - it worked great and
weighed less than 4 ounces including the LED light source. That little
experiment convinced me that there is a better way even though it was
technically possible.

Head mounted displays are coming fast and I think they will find a place in
glider cockpits. The latest from LeadTek
http://www.leadtek.com.tw/hmd/x_eye_1.shtml is a SVGA OLED display that
could be used with the 12V "car computers" now available. It appears that
the X-Eye would interfere with the pilots vision, however. We would need
"see-through" displays mounted on sunglass frames that give full peripheral
vision. It's nice to see an 800x600 OLED display though.

For now, I think I would find the panel mounted display a better solution,
but if sunlight readability remains a problem, eyeglass mounted displays may
be the interim solution. The neat thing about the modular x86 computers is
that the display can be replaced at will just like changing desktop
monitors.

Bill Daniels

[Bill Daniels]

"Bill Daniels" > wrote in message
...
>
> "Kirk Stant" > wrote in message
> om...
> > "tango4" > wrote in message
> >...
> > > The major problem with current HUD systems is that they are projected
> onto a
> > > screen screwed to the instrument panel turtledeck. Fine if you are a
> fighter
> > > jock and want to keep your eye on the bandit in front of you. Also
good
> for
> > > IFR types who actually don't need to look out the window anyway.
> > >
> > > What is really needed in sailplanes are head mounted displays that
keep
> an
> > > image hovering in front of the pilot wherever his head is. A sailplane
> pilot
> > > only looking out ahead is almost as bad as one focussed on a PDA
> strapped to
> > > his leg.
> > >
> > >
> > > Ian
> >
> > Your description of current HUDs is somewhat misleading. HUD work by
> > projecting images, collimated to infinity, on a clear "combining
> > glass" on top of the instrument panel, in the pilots normal line of
> > sight. The projected symbology - attitude, heading, airspeed,
> > altitude, etc. is superimposed on the real world with a direct
> > correlation - in other words a 5 degree pitch up using the HUD scale
> > is a true 5 degree pitch, not a shrunk symbolic display as on a small
> > attitude indicator. Newer HUDs also allow projecting FLIR or LLTV
> > images - also collimated at infinity - on the HUD, so you have a
> > "virtual reality" display; cool at night. The importance of the
> > infinity collimation of the display is that you do not have to refocus
> > your eyes when looking at a HUD, you see the symbology when focused at
> > long distance. That is absolutely not true when "coming inside" to
> > read old fashioned steam gauges!
> >
> > The downside is all the optics are HEAVY and power hungry, so don't
> > count on seeing them in a glider soon.
> >
> > The newer fighters have Helmet-mounted displays that project all the
> > HUD symbology on their helmet visor. Still heavy, big, and power
> > hungry.
> >
> > What I think we need for gliding is a nice big color navigation
> > display to replace the sectional chart that is becoming more and more
> > difficult to fold in our small cockpits - something that I can pull
> > out, look at, then put away to continue flying. Let's face it, after
> > awhile you can fly any glider by feel and audio vario, anyway.
> >
> >
> > Kirk
>
> I have to agree with "tango4" that good glider pilots don't spend much
time
> looking straight ahead or "heads down" inside the cockpit.
>
> Kirk, you are right that the current generation of HUD is heavy and power
> hungry but it doesn't have to be. I once built a benchtop breadboard HUD
> with semi-mirrored Mylar and plastic Frenel lenses - it worked great and
> weighed less than 4 ounces including the LED light source. That little
> experiment convinced me that there is a better way even though it was
> technically possible.
>
> Head mounted displays are coming fast and I think they will find a place
in
> glider cockpits. The latest from LeadTek
> http://www.leadtek.com.tw/hmd/x_eye_1.shtml is a SVGA OLED display that
> could be used with the 12V "car computers" now available. It appears that
> the X-Eye would interfere with the pilots vision, however. We would need
> "see-through" displays mounted on sunglass frames that give full
peripheral
> vision. It's nice to see an 800x600 OLED display though.
>
> For now, I think I would find the panel mounted display a better solution,
> but if sunlight readability remains a problem, eyeglass mounted displays
may
> be the interim solution. The neat thing about the modular x86 computers
is
> that the display can be replaced at will just like changing desktop
> monitors.
>
> Bill Daniels
>
p.s. I just got this link by e-mail:
http://www.electronicproducts.com/ShowPage.asp?SECTION=3700&PRIMID=&FileName=janema1.jan2002

[tango4]

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

They're commercial military systems and cost about as much as Nimbus 4dM's

Ian

[John Gilbert]

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.

Regards,
John


(Bob Kuykendall) wrote in message >...
> Earlier, Robert Ehrlich > wrote:
>
> > > The "normal" instruments are very easy to
> > > interpret (it has been shown that round dials are by far the easiest to
> > > comprehend for the human brain: judging angles is easier than judging a
> > > distance or reading and interpretting a figure.)
>
> > Not obviuous for me...
>
> The assertion that angular guages are easier to read is backed up by
> countless perception and human factors studies. It is also
> corroborated by studies of the stimulation network pre-processing that
> takes place right in the retina at the back of the eye.
>
> Human factors texts such as McCormick's, and physiology texts on
> sensation and perception deal with this topic at great length.
>
> Thanks, and best regards to all
>
> Bob K.

[Kirk Stant]

"Bill Daniels" > wrote in message >...

> Head mounted displays are coming fast and I think they will find a place
> in glider cockpits.

Oh, I agree that a head-mounted display is the optimum solution for
exactly the reason stated - no need to look forward and refocus to
check the panel instruments. The key is images that are focused at
infinity and do not require refocusing the eyes; do the current "low
cost" displays (and emerging technologies) support that?. If the
technology develops, one could imagine an instrument setup that would
consist of a head-mounted display for airspeed, AOA, altitude, vario,
basic nav, speed to fly, thermal center, etc.; a heads-down big color
map display for siturational awareness, tactical planning, navigation,
weather (blipmaps!), and collision avoidance; an integrated radio/mode
S transponder/GPS/datalinik; and small backup airspeed, altimeter,
vario at the bottom of the panel. Controls would all be by HOSAF
(Hands On Stick And Flaps) after initial settings via windows on the
big display.

Then add usual aural cues for vario, and possibly (my wish) AOA when
the gear is down - so when landing out I could concentrate on flying
while controlling speed based on the optimum AOA tone. I loved that
in the F-4, it makes flying approaches in gusty or tight situations
really easy - much better than trying to sneak a peek at the airspeed
indicator!

Funny about all the studies that say that round dials are easier to
read than digital meters - I've read them too, and from personal
experience, I have to disagree - I end up using the digital readouts
for vario a lot more than the jumping needle, with of course audio for
trend info. 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.

Give me BIG NUMBERS anyday!

Kirk

[Dave Nadler YO]

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

PS: Not covered in the references: You can pick up motion trends during
a scan off analog meters, but not discrete indicators (LCD). All the above
is why we (ILEC) continue to use mechanical round dials despite their being
the highest cost single component and not as reliable as the alternatives...

(Bob Kuykendall) wrote in message >...
> Earlier, Robert Ehrlich > wrote:
>
> > > The "normal" instruments are very easy to
> > > interpret (it has been shown that round dials are by far the easiest to
> > > comprehend for the human brain: judging angles is easier than judging a
> > > distance or reading and interpretting a figure.)
>
> > Not obviuous for me...
>
> The assertion that angular guages are easier to read is backed up by
> countless perception and human factors studies. It is also
> corroborated by studies of the stimulation network pre-processing that
> takes place right in the retina at the back of the eye.
>
> Human factors texts such as McCormick's, and physiology texts on
> sensation and perception deal with this topic at great length.
>
> Thanks, and best regards to all
>
> Bob K.

[André Somers]

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

[Tony Verhulst]

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"

[Bill Daniels]

"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

[tango4]

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
>

[Martin Gregorie]

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 :

[Martin Gregorie]

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 :

[André Somers]

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

[Andy Durbin]

(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)

[Robert Ehrlich]

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.

[Steve Bralla]

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

[Bill Daniels]

"Steve Bralla" > wrote in message
...
> 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

Maybe this is what we are headed toward:
http://www.brighthand.com/article/Technologies_That_Could_Change_Handhelds?site=Lear n

Bill Daniels