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1. 04:16 PM - Re: KIS-List Digest: 1 Msgs - 10/21/13 (SUSAN TRICKEL)
2. 04:16 PM - Re: KIS-List Digest: 1 Msgs - 10/21/13 (SUSAN TRICKEL)
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Subject: | Re: KIS-List Digest: 1 Msgs - 10/21/13 |
=0A =0A=0A________________________________=0A From: KIS-List Digest Server
<kis-list@matronics.com>=0ATo: KIS-List Digest List <kis-list-digest@matron
ics.com> =0ASent: Tuesday, October 22, 2013 3:00 AM=0ASubject: KIS-List Dig
est: 1 Msgs - 10/21/13=0A =0A=0A*=0A=0A===========
===============0A- Online Versions of Today'
s List Digest Archive=0A=================
=========0A=0AToday's complete KIS-List Digest can also be
found in either of the =0Atwo Web Links listed below.- The .html file inc
ludes the Digest formatted =0Ain HTML for viewing with a web browser and fe
atures Hyperlinked Indexes =0Aand Message Navigation.- The .txt file incl
udes the plain ASCII version =0Aof the KIS-List Digest and can be viewed wi
th a generic text editor =0Asuch as Notepad or with a web browser. =0A=0AHT
ML Version:=0A=0A- - http://www.matronics.com/digest/digestview.php?Sty
le=82701&View=html&Chapter 13-10-21&Archive=KIS=0A=0AText Version
:=0A=0A- - http://www.matronics.com/digest/digestview.php?Style=82701
&View=txt&Chapter 13-10-21&Archive=KIS=0A=0A=0A======
==================0A- EMail Version of
Today's List Digest Archive=0A==============
==========0A=0A=0A- - - - - ------------------
----------------------------------------=0A- - - - - - - -
- - - - - KIS-List Digest Archive=0A- - - - - - -
- - - - - - - - - - - - ---=0A- - - - -
- - - - - Total Messages Posted Mon 10/21/13: 1=0A- - -
- - ----------------------------------------------------------=0A=0A
=0AToday's Message Index:=0A----------------------=0A=0A- - 1. 11:04 P
M - TAS Error with my new EFIS- (Galin Hernandez)=0A=0A=0A=0A____________
____________________- Message 1- _____________________________________
=0A=0A=0ATime: 11:04:20 PM PST US=0AFrom: Galin Hernandez <galinhdz@gmail.c
om>=0ASubject: KIS-List: TAS Error with my new EFIS=0A=0APardon the long wr
ite-up.=0A=0AAfter buying my airplane several years ago I did a series of m
aneuvers at=0Adifferent power settings and, by using GPS groundspeeds, I ma
de a fairly=0Aaccurate calibrated airspeed chart. For the next few years I
used the CAS=0Achart often and found that, at normal power settings, I cons
istently=0Acruised at 143KTAS.=0A=0A=0AFast forward to this year when I ins
talled a complete DYNON Skyview EFIS=0Asystem which automatically calculate
s TAS. But, at normal cruise power=0Asettings, the Skyview consistently sho
wed me cruising at 156KTAS. The=0ASkyview also showed that no matter which
direction I was flying, I always=0Ahad a headwind. Knowing that the Skyview
did not change the aerodynamics of=0Athe airplane and the system had just
passed an IFR check, something was not=0Aright.=0A=0A=0AOn subsequent fligh
ts I calculated my TAS using my old CAS chart and came=0Aback to 143KTAS no
t the 156KTAS the Skyview was displaying. The plots on my=0ACAS chart shows
that as my airspeed increases, IAS and CAS spread apart=0Awith IAS being a
lmost 20KT faster at full power. Since the Skyview does not=0Ahave a method
of factoring in a CAS, it uses IAS for the calculations. With=0Athe signif
icantly higher IAS used by the Skyview it would display a higher=0ATAS than
actual matching what I was seeing.=0A=0A=0ATalking with the engineers at D
YNON, they told me that in a =93well designe=0Ad=94=0Asystem the differ
ence between IAS and CAS should not be more than a few=0Aknots. If my IAS a
nd CAS was that far apart, there is a problem with either=0Athe pitot or st
atic source position. Having IAS significantly higher than=0ACAS meant that
either the pitot tube is in an area of =93higher=94 pressure=0Aor=0Ath
e static source is in an area of =93lower=94 pressure. If the pitot is
in=0Aan=0Aarea of =93higher=94 pressure the error would only be in airs
peed. But if t=0Ahe=0Astatic source is in an area of =93lower=94 pressu
re, altitude indications w=0Aill=0Ashow me flying at a higher altitude than
I really am. This is a potentially=0Adeadly situation when flying real IMC
, which I do.=0A=0A=0ATo isolate if the error was in the pitot or static, I
flew to different=0Aairports with ILS approaches over the next few months.
I found that when at=0Athe FAF on the glideslope of each airport, the Skyv
iew displayed a=0Aconsistent 100-110=92 higher than what the approach pla
te showed. In order =0Ato=0Aconfirm what I found, I did several high speed
passes, over different=0Aairports, trying to stay about 10=92 above the r
unway. At each airport the=0ASkyview displayed a consistent 100-110=92 hi
gher than what the runway reall=0Ay=0Awas . This matched what I found with
the FAF experiment. Since my CAS chart=0Ashowed the IAS and CAS getting fur
ther apart the faster I flew, the data=0Aobtained from the test flights was
consistent with the static source being=0Ain an area where pressure drops
as airspeed increases. So I needed to=0Acorrect the static source placement
.=0A=0A=0AThe dual static source I have was installed by Rich Trickel back
in 2008=0Aand I really didn=92t want to change where they were located. S
o in order t=0Ao=0Acorrect for a possible changing static pressure situatio
n I experimented by=0Aplacing a piece of Gorilla tape just behind each stat
ic port hole and doing=0Athe flight checks again. With one piece of tape, t
he FAF and high speed=0Arunway checks altitude error dropped to about 40=
92. My displayed TAS error=0A,=0Abased on my CAS chart, had also dropped to
about 10kts.=0A=0A=0AI figured I was on the right track so I added a secon
d piece of tape=0Aeffectively doubling the thickness behind the static port
hole. The next=0Aseries of flights showed my FAF and high speed runway che
cks had dropped to=0Awithin a few feet. My TAS error had also dropped to wi
thin 2Kts at normal=0Acruise. A third piece of tape caused the FAF and high
speed runway checks=0Ato show the altitude difference was about 40=92 bu
t in the opposite=0Adirection. Now the TAS error was back to about 10Kts, a
lso in the opposite=0Adirection than before. Armed with this information, I
went back to using=0Atwo pieces of Gorilla tape just behind the static sou
rce hole.=0A=0A=0ADuring the next flights the FAF and high speed runway che
cks showed the=0Aaltitude error was within 10 feet of what I was expecting.
Additionally I=0Adid a series of maneuvers at different power settings and
, by using GPS=0Agroundspeeds, calculated that my TAS was within a few knot
s of what the=0ASkyview was displaying. During my final test flight (Octobe
r 21, 2013) I=0Afound that normal approach speed (90Kts) and normal cruise
(143Kts) speeds=0Awere within 2Kts of calculated. I also found that as I ap
proached to land,=0Athe wind aloft display matched very closely to what the
tower was=0Areporting. Now I know what I have to do to correct my static s
ource=0Aposition error. I can complete the work by making a piece of alumin
um the=0Athickness of two pieces of Gorilla tape and permanently attach it
just=0Abehind to the static source hole.=0A=0A=0ASo, if your EFIS show an a
irspeed higher than what the =93book=94 shows you=0Ar=0Aairplane should
be doing, check it out. You may have a pitot/static source=0Aerror that ca
n be corrected. Overall I think I corrected a possibly serious=0Asituation
and now completely trust my Skyview is displaying correct=0Ainformation.=0A
=================
Message 2
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Subject: | Re: KIS-List Digest: 1 Msgs - 10/21/13 |
=0A =0A=0A________________________________=0A From: KIS-List Digest Server
<kis-list@matronics.com>=0ATo: KIS-List Digest List <kis-list-digest@matron
ics.com> =0ASent: Tuesday, October 22, 2013 3:00 AM=0ASubject: KIS-List Dig
est: 1 Msgs - 10/21/13=0A =0A=0A*=0A=0A===========
===============0A- Online Versions of Today'
s List Digest Archive=0A=================
=========0A=0AToday's complete KIS-List Digest can also be
found in either of the =0Atwo Web Links listed below.- The .html file inc
ludes the Digest formatted =0Ain HTML for viewing with a web browser and fe
atures Hyperlinked Indexes =0Aand Message Navigation.- The .txt file incl
udes the plain ASCII version =0Aof the KIS-List Digest and can be viewed wi
th a generic text editor =0Asuch as Notepad or with a web browser. =0A=0AHT
ML Version:=0A=0A- - http://www.matronics.com/digest/digestview.php?Sty
le=82701&View=html&Chapter 13-10-21&Archive=KIS=0A=0AText Version
:=0A=0A- - http://www.matronics.com/digest/digestview.php?Style=82701
&View=txt&Chapter 13-10-21&Archive=KIS=0A=0A=0A======
==================0A- EMail Version of
Today's List Digest Archive=0A==============
==========0A=0A=0A- - - - - ------------------
----------------------------------------=0A- - - - - - - -
- - - - - KIS-List Digest Archive=0A- - - - - - -
- - - - - - - - - - - - ---=0A- - - - -
- - - - - Total Messages Posted Mon 10/21/13: 1=0A- - -
- - ----------------------------------------------------------=0A=0A
=0AToday's Message Index:=0A----------------------=0A=0A- - 1. 11:04 P
M - TAS Error with my new EFIS- (Galin Hernandez)=0A=0A=0A=0A____________
____________________- Message 1- _____________________________________
=0A=0A=0ATime: 11:04:20 PM PST US=0AFrom: Galin Hernandez <galinhdz@gmail.c
om>=0ASubject: KIS-List: TAS Error with my new EFIS=0A=0APardon the long wr
ite-up.=0A=0AAfter buying my airplane several years ago I did a series of m
aneuvers at=0Adifferent power settings and, by using GPS groundspeeds, I ma
de a fairly=0Aaccurate calibrated airspeed chart. For the next few years I
used the CAS=0Achart often and found that, at normal power settings, I cons
istently=0Acruised at 143KTAS.=0A=0A=0AFast forward to this year when I ins
talled a complete DYNON Skyview EFIS=0Asystem which automatically calculate
s TAS. But, at normal cruise power=0Asettings, the Skyview consistently sho
wed me cruising at 156KTAS. The=0ASkyview also showed that no matter which
direction I was flying, I always=0Ahad a headwind. Knowing that the Skyview
did not change the aerodynamics of=0Athe airplane and the system had just
passed an IFR check, something was not=0Aright.=0A=0A=0AOn subsequent fligh
ts I calculated my TAS using my old CAS chart and came=0Aback to 143KTAS no
t the 156KTAS the Skyview was displaying. The plots on my=0ACAS chart shows
that as my airspeed increases, IAS and CAS spread apart=0Awith IAS being a
lmost 20KT faster at full power. Since the Skyview does not=0Ahave a method
of factoring in a CAS, it uses IAS for the calculations. With=0Athe signif
icantly higher IAS used by the Skyview it would display a higher=0ATAS than
actual matching what I was seeing.=0A=0A=0ATalking with the engineers at D
YNON, they told me that in a =93well designe=0Ad=94=0Asystem the differ
ence between IAS and CAS should not be more than a few=0Aknots. If my IAS a
nd CAS was that far apart, there is a problem with either=0Athe pitot or st
atic source position. Having IAS significantly higher than=0ACAS meant that
either the pitot tube is in an area of =93higher=94 pressure=0Aor=0Ath
e static source is in an area of =93lower=94 pressure. If the pitot is
in=0Aan=0Aarea of =93higher=94 pressure the error would only be in airs
peed. But if t=0Ahe=0Astatic source is in an area of =93lower=94 pressu
re, altitude indications w=0Aill=0Ashow me flying at a higher altitude than
I really am. This is a potentially=0Adeadly situation when flying real IMC
, which I do.=0A=0A=0ATo isolate if the error was in the pitot or static, I
flew to different=0Aairports with ILS approaches over the next few months.
I found that when at=0Athe FAF on the glideslope of each airport, the Skyv
iew displayed a=0Aconsistent 100-110=92 higher than what the approach pla
te showed. In order =0Ato=0Aconfirm what I found, I did several high speed
passes, over different=0Aairports, trying to stay about 10=92 above the r
unway. At each airport the=0ASkyview displayed a consistent 100-110=92 hi
gher than what the runway reall=0Ay=0Awas . This matched what I found with
the FAF experiment. Since my CAS chart=0Ashowed the IAS and CAS getting fur
ther apart the faster I flew, the data=0Aobtained from the test flights was
consistent with the static source being=0Ain an area where pressure drops
as airspeed increases. So I needed to=0Acorrect the static source placement
.=0A=0A=0AThe dual static source I have was installed by Rich Trickel back
in 2008=0Aand I really didn=92t want to change where they were located. S
o in order t=0Ao=0Acorrect for a possible changing static pressure situatio
n I experimented by=0Aplacing a piece of Gorilla tape just behind each stat
ic port hole and doing=0Athe flight checks again. With one piece of tape, t
he FAF and high speed=0Arunway checks altitude error dropped to about 40=
92. My displayed TAS error=0A,=0Abased on my CAS chart, had also dropped to
about 10kts.=0A=0A=0AI figured I was on the right track so I added a secon
d piece of tape=0Aeffectively doubling the thickness behind the static port
hole. The next=0Aseries of flights showed my FAF and high speed runway che
cks had dropped to=0Awithin a few feet. My TAS error had also dropped to wi
thin 2Kts at normal=0Acruise. A third piece of tape caused the FAF and high
speed runway checks=0Ato show the altitude difference was about 40=92 bu
t in the opposite=0Adirection. Now the TAS error was back to about 10Kts, a
lso in the opposite=0Adirection than before. Armed with this information, I
went back to using=0Atwo pieces of Gorilla tape just behind the static sou
rce hole.=0A=0A=0ADuring the next flights the FAF and high speed runway che
cks showed the=0Aaltitude error was within 10 feet of what I was expecting.
Additionally I=0Adid a series of maneuvers at different power settings and
, by using GPS=0Agroundspeeds, calculated that my TAS was within a few knot
s of what the=0ASkyview was displaying. During my final test flight (Octobe
r 21, 2013) I=0Afound that normal approach speed (90Kts) and normal cruise
(143Kts) speeds=0Awere within 2Kts of calculated. I also found that as I ap
proached to land,=0Athe wind aloft display matched very closely to what the
tower was=0Areporting. Now I know what I have to do to correct my static s
ource=0Aposition error. I can complete the work by making a piece of alumin
um the=0Athickness of two pieces of Gorilla tape and permanently attach it
just=0Abehind to the static source hole.=0A=0A=0ASo, if your EFIS show an a
irspeed higher than what the =93book=94 shows you=0Ar=0Aairplane should
be doing, check it out. You may have a pitot/static source=0Aerror that ca
n be corrected. Overall I think I corrected a possibly serious=0Asituation
and now completely trust my Skyview is displaying correct=0Ainformation.=0A
=================
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