On Sat, Jan 3, 2009 at 7:49 AM, Torsten Dreyer tors...@t3r.de wrote:
The CDI needle can move a little further out, than the outermost dot on the
scale. Here, also the receiver detects offsets of more than 10deg, just the
display is limited to full deflection.
That is the sensible approach.
On 2 Jan 2009, at 22:28, Alex Perry wrote:
No. The standard design is based around 3 degrees slope. With that
design, the usable range is 1.4 degrees high, from 2.1 to 3.7 degrees
and offers 0.35 degrees per dot. Therefore, a dot equals 50ft per
mile range from the touchdown zone of the
On 01/03/2009 06:58 AM, James Turner wrote:
- everyone seems agreed that the GS is a 1.4 degree volume, so 0.7
degrees above and below the GS line.
I concur.
And the '0.35' degrees per dot
comes up, which basically implies 2 dots from the center line to the
0.7 degree limit.
On 3 Jan 2009, at 15:04, John Denker wrote:
On 01/03/2009 06:58 AM, James Turner wrote:
- everyone seems agreed that the GS is a 1.4 degree volume, so 0.7
degrees above and below the GS line.
I concur.
Please let's not confuse ICAO (which is quite general) with
Mk-VIII (which is just
On 01/03/2009 08:34 AM, James Turner wrote:
snip Lots of stuff we agree on /snip
No, the *deflection* properties really are broken, because they're in
ambiguous units, I think (especially the magic factor-of-5 multiple
that started this thread).
As always, I look at things primarily
/instruments/navradio[n]/heading-deviation-deg: [-10.0 to 10.0 for a
VOR, -2.5 to 2.5 for a LOC] (i.e no 'magic 4' multiple for LOCs)
/instruments/navradio[n]/heading-deviation-norm: [-1.0 .. 1.0]
/instruments/navradio[n]/gs-deviation-deg: [-0.7 to 0.7]
On 3 Jan 2009, at 16:17, John Denker wrote:
They don't care what local units are used to communicate
between the tuner and the CDI head. It could be gallons
as Torsten mentioned.
The existing code uses [0 ± 10] gallons for the left/right
needle and [0 ± 3.5] gallons for the up/down needle.
On 01/03/2009 08:49 AM, Torsten Dreyer wrote:
So my question is: why clamp the xxx-deviation-deg properties at all?
Shouldn't it be a duty of the instrument to define where it hits the border?
I completely agree with TD.
Currently there is no clamp on the GS deflection in
navradio.cxx. The
On 3 Jan 2009, at 17:12, John Denker wrote:
Is there anything unrealistic about item (B)? Is there
any instrument/system in the world that expects the
nav tuner to put out the GS angle in degrees?
The only MK-VIII known to me is a GPWS, and I very much
doubt it needs to know any GS info
On 01/03/2009 10:04 AM, James Turner wrote:
I.e, let's just normalise to [-1.0 .. 1.0] and be done with it.
(Except, as Torsten just noted, the values can probably go slightly
beyond that, since any clamping should be done at the panel-instrument
level, not the receiver level).
OK
On 3 Jan 2009, at 17:38, John Denker wrote:
A) We are now agreed that deflection as a fraction
of full scale is a supported feature, not deprecated,
not scheduled to rot, right?
Err, I would say that we don't have that as a current feature, but I
think that's getting into semantics of
On Sat, Jan 3, 2009 at 7:49 AM, Torsten Dreyer tors...@t3r.de wrote:
/instruments/navradio[n]/heading-deviation-deg: [-10.0 to 10.0 for a
VOR, -2.5 to 2.5 for a LOC] (i.e no 'magic 4' multiple for LOCs)
/instruments/navradio[n]/heading-deviation-norm: [-1.0 .. 1.0]
On 2 Jan 2009, at 05:59, John Denker wrote:
On 01/01/2009 10:05 PM, syd adams wrote:
I think i assumed long ago that the GS deflection had a limit of
-10 to 10
like the heading-needle-deflection , and so scaled the needle to the
outermost dot accordingly.
That is not consistent with
For the GS, John states that the 'usable' part is only 0.7 degrees
thick. I'm unsure what usable means in that context, but given then
+/- 0.8 DDM range used by the Mk-VIII GPWS, and their dots-to-DMM
factor of 0.0875 for the GS, maximum deviation is 9.142 **dots**.
Clearly that's a much
Going through the Primus manaul again , and one section states that capture
occurs at +- 0.5 degrees , and an approach illustration states typical
capture point at 1/3 dot ... so for the Primus it looks like each dot is 1.5
degrees deviation...
attachment:
On 01/02/2009 11:37 AM, syd adams wrote:
Going through the Primus manaul again , and one section states that capture
occurs at +- 0.5 degrees , and an approach illustration states typical
capture point at 1/3 dot ... so for the Primus it looks like each dot is 1.5
degrees deviation...
Which
On Fri, Jan 2, 2009 at 11:32 AM, John Denker j...@av8n.com wrote:
On 01/02/2009 11:37 AM, syd adams wrote:
Going through the Primus manaul again , and one section states that
capture
occurs at +- 0.5 degrees , and an approach illustration states typical
capture point at 1/3 dot ... so for
Further online searching turned up this
This deflection corresponds to the direction the pilot must fly to intercept
the glide path and is proportional to the angular displacement from the
glide path angle. As with the localizer, the full scale deflection is 150
microamperes. Typically, the
Ok , Im getting closer...i think
Another manual i have states min glideslope angle = 2.5 degrees , maximum =
3.25 degrees,
so does that mean the needle animation range should be 0.25 at the upper
second dot, and -0.5 for the bottom second dot ?
That approach illustration is really confusing me now
No. The standard design is based around 3 degrees slope. With that
design, the usable range is 1.4 degrees high, from 2.1 to 3.7 degrees
and offers 0.35 degrees per dot. Therefore, a dot equals 50ft per
mile range from the touchdown zone of the runway. When the standard
design is scaled for
OK , so my needle animation is far too insensitive , but the needle
deflection property shows 0 at dead center (3 degrees). What I was asking is
what amount of deflection per dot the needle should move based on the
existing property , so I'll go with 0.35 and try some approaches.
Thanks everyone
On 01/02/2009 03:28 PM, Alex Perry wrote:
From the point of view of implementation in a simulator, just take the
actual slope number for a specific runway and combine that with the
aircraft's position to generate a ratio. Repair the ratio to allow
for the side lobes (which as I recall are the
On Fri, Jan 2, 2009 at 3:12 PM, John Denker j...@av8n.com wrote:
On 01/02/2009 03:28 PM, Alex Perry wrote:
From the point of view of implementation in a simulator, just take the
actual slope number for a specific runway and combine that with the
aircraft's position to generate a ratio.
On 12/31/2008 11:46 PM, Alex Perry wrote:
I've observed this variation in sensitivity in practical operations. We
can get away with using the 0.5 degree rule, but I'd prefer us to
perform the divide-and-constrain that John describes.
I've got most of the code to do this.
In the absence of
On 12/31/2008 11:46 PM, Alex Perry wrote:
If you want more
detail than the handwave that the AIM contains, go read the FAA
technical manual on how to design and deploy LOC antenna arrays ..
Found it.
In such matters, the FAA defers to the ICAO.
So, it seems like at least Syd may have been assuming the deflection
was in 'dots * 5' rather than 'degrees * 5' - I'd love Syd to confirm
or deny that. The upshot of this is that the GS indicator in Primus
is, **I think**, about 1/3rd as sensitive as it should be. However, I
could easily
On 01/01/2009 10:05 PM, syd adams wrote:
I think i assumed long ago that the GS deflection had a limit of -10 to 10
like the heading-needle-deflection , and so scaled the needle to the
outermost dot accordingly.
That is not consistent with what is implemented in navradio.cxx
That instrument,
(sorry for the long email, but please read if you are involved with
panel creation, or can shed light on nav-radios)
I have had an entertaining afternoon, and now morning, with the Mk-VIII.
Along the way, I believe I have discovered some genuine bugs in the
code, and some odd assumptions
On 31 Dec 2008, at 13:09, James Turner wrote:
...as giving a value of 0.32 degrees GS deviation per dot. I'd love to
know if this is correct, and what the VOR/HSI deviation is (in degrees
per dot) (I believe the 'LOC is 4x the sensitivity of VOR' rule is
indeed correct, but again, please
On 12/31/2008 06:23 AM, James Turner wrote:
Reckons 5 degrees per-dot for a VOR, 1.25 for a LOC (yay, the 4x
factor is sane) and 'about a quarter of a degree per dot' for a GS
indicator, so the 0.32 term is plausible.
Standard dogma in IFR training is that the VOR CDI indicates
two
On 12/31/2008 10:29 AM, I wrote:
Standard dogma in IFR training is that the VOR CDI indicates
two degrees per dot, while the LOC CDI indicates half a degree
per dot. These numbers are quite believable. Good practice
is to check them as part of the 30-day IFR receiver check.
Important
John Denker wrote:
On 12/31/2008 10:29 AM, I wrote
Standard dogma in IFR training is that the VOR CDI indicates
two degrees per dot, while the LOC CDI indicates half a degree
per dot. These numbers are quite believable. Good practice
is to check them as part of the 30-day IFR receiver
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