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doug.ilg(at)verizon.net
Guest

Posted: Wed Jan 04, 2012 7:01 am Post subject: AeroElectric-List:

Bob (Noffs),

Most GPS units made over the last 10 years, or so, have that exact feature.  The difference being that they don't display on a separate instrument.

Of course, the likely reason that this hasn't been marketed as a replacement for the old DG is that it's not really the same as a DG.  A DG shows heading, while a GPS only knows track (derived from successive positions).  Depending on wind conditions and your airspeed, those two can differ by a considerable amount.



 

Doug Ilg

Grumman Tiger N74818, College Park Airport (KCGS), Maryland

Challenger II LSS LW  (N641LG reserved) - kit underway at Laurel Suburban (W18)

do not archive



 



[quote]       From: bob noffs <icubob(at)gmail.com>

 To: aeroelectric list <aeroelectric-list(at)matronics.com> 

 Sent: Wednesday, January 4, 2012 6:59 AM

 Subject: AeroElectric-List:

   

seems what this world[or at least me] needs is a gps driven directional gyro. i know that most gps units have part of a compass rose displayed but for the price of a mechanical one i would think a plain simple dg that mounts in a conventional 3'' hole and is gps driven would be cheap and popular. 

   or at least a program to drive a palm pilot, tapping off the gps of another unit.

   bob noffs



 



 

 [b]

klehman(at)albedo.net
Guest

Posted: Wed Jan 04, 2012 7:59 am Post subject: AeroElectric-List:

Some rnav units that have airspeed inputs calculate drift and simply use

a lookup table to convert track to magnetic dg info.



In some cases these headings have gone out of acceptable tolerance due

to variation changes and lookup tables that have not been updated for

tens of years.  Several degrees of error can become problematical for

things like an RNAV NDB approach.



Ken



 	  Quote: 	
		   

 Bob (Noffs),

 

 Most GPS units made over the last 10 years, or so, have that exact

feature.  The difference being that they don't display on a separate
	


instrument.

 	  Quote: 	
		   

 Of course, the likely reason that this hasn't been marketed as a

replacement for the old DG is that it's not really the same as a DG.  A
	


DG shows heading, while a GPS only knows track (derived from successive

positions).  Depending on wind conditions and your airspeed, those two

can differ by a considerable amount.

 	  Quote: 	
		   

  

 Doug Ilg

 Grumman Tiger N74818, College Park Airport (KCGS), Maryland

 Challenger II LSS LW (N641LG reserved) - kit underway at Laurel

Suburban (W18)
	


 	  Quote: 	
		   do not archive

 

  

 

 

 

 >________________________________

 > From: bob noffs <icubob(at)gmail.com>

 >To: aeroelectric list <aeroelectric-list(at)matronics.com> 

 >Sent: Wednesday, January 4, 2012 6:59 AM

 >Subject: AeroElectric-List:

 > 

 >

 >seems what this world[or at least me] needs is a gps driven

directional gyro. i know that most gps units have part of a compass rose
	


displayed but for the price of a mechanical one i would think a plain

simple dg that mounts in a conventional 3'' hole and is gps driven would

be cheap and popular. 

 	  Quote: 	
		   >  or at least a program to drive a palm pilot, tapping off the gps of

another unit.
	


 	  Quote: 	
		   >   bob noffs

 >

BobsV35B(at)aol.com
Guest

Posted: Wed Jan 04, 2012 8:34 am Post subject: AeroElectric-List:

Good Morning Ken,

  

 You said:

 "Several degrees of error can become problematical for things like an RNAV  NDB approach."

  

 While this is getting quite far away from a subject for the Aeroelectric  list, I would like to comment. 

  

 If we are flying IFR, it would seem we need a legal method of shooting an  NDB approach and the only method currently legal is to use an ADF combined with  a legal compass heading.

  

 Once upon a time, we were legal to shoot that approach with just a fixed or  manually rotatable loop and compass. 

  

 No longer true. We must have an ADF and a compass. 

  

 If we are cheating and want to use a GPS, even a legal GPS, to execute the  approach, it would be pertinent to set the airport location as the 'go to'  destination and fly the track to the airport. While heading is always nice to  know, (it helps us determine where to look when visibility is marginal,) it  pales in importance to staying on track toward the airport.

  

 Just sayin' nothin' else <G>

  

 Happy Skies,

  

 Old Bob



  In a message dated 1/4/2012 10:01:16 A.M. Central Standard Time,  klehman(at)albedo.net writes:

  	  Quote: 	
		  Several    degrees of error can become problematical for

things like an RNAV NDB    approach.



	


 [quote][b]

email(at)jaredyates.com
Guest

Posted: Wed Jan 04, 2012 9:06 am Post subject: AeroElectric-List:

Hmmm.... I thought we could substitute an ifr gps for adf in ndb approaches. When you say compass, do you mean magnetically derived heading?



On Jan 4, 2012, at 11:27, BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote:



[quote]     Good Morning Ken,

  

 You said:

 "Several degrees of error can become problematical for things like an RNAV  NDB approach."

  

 While this is getting quite far away from a subject for the Aeroelectric  list, I would like to comment. 

  

 If we are flying IFR, it would seem we need a legal method of shooting an  NDB approach and the only method currently legal is to use an ADF combined with  a legal compass heading.

  

 Once upon a time, we were legal to shoot that approach with just a fixed or  manually rotatable loop and compass. 

  

 No longer true. We must have an ADF and a compass. 

  

 If we are cheating and want to use a GPS, even a legal GPS, to execute the  approach, it would be pertinent to set the airport location as the 'go to'  destination and fly the track to the airport. While heading is always nice to  know, (it helps us determine where to look when visibility is marginal,) it  pales in importance to staying on track toward the airport.

  

 Just sayin' nothin' else <G>

  

 Happy Skies,

  

 Old Bob



  In a message dated 1/4/2012 10:01:16 A.M. Central Standard Time,  klehman(at)albedo.net (klehman(at)albedo.net) writes:

  	  Quote: 	
		  Several    degrees of error can become problematical for

things like an RNAV NDB    approach.



	


  	  Quote: 	
		  

	


[b]

Mauledriver(at)nc.rr.com
Guest

Posted: Wed Jan 04, 2012 9:38 am Post subject: AeroElectric-List:

Yes, what Bob said.

     

     I'm thinking that track is better than heading.  And if I recall     correctly, when many of those NDB approaches had GPS overlays a few     years ago, you didn't require an ADF (or the ability to fly a mag     heading), you just used a certified GPS to fly the NDB tracks.  (do     any of those still exist - the ones I used to fly are all replaced     by RNAV T approaches)

     

     I guess what you are getting at is that you'd like to avoid having     to install a DG by using a GPS driven instrument.

     

     My glass panel gives me mag headings from the EFIS's AHRS system and     allows me to easily follow vectors.  Otherwise, I don't have a     whiskey compass or vacuum driven heading instrument.  The key     question is what happens with an electronics failure... well I have     a GRT ADI instrument with a GPS and an independent backup battery.      It just gives me a digital track readout along with turn coordinator     function and a quasi-horizon.  I can't follow a mag heading but I     can fly a track pretty darn accurately.

     

     Bill "not completely off-topic" Watson

     

     On 1/4/2012 11:27 AM, BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote:     [quote]                              Good Morning Ken,

          

         You said:

         "Several degrees of error can become problematical for           things like an RNAV NDB approach."

          

         While this is getting quite far away from a subject for the           Aeroelectric list, I would like to comment. 

          

         If we are flying IFR, it would seem we need a legal method           of shooting an NDB approach and the only method currently           legal is to use an ADF combined with a legal compass heading.

          

         Once upon a time, we were legal to shoot that approach with           just a fixed or manually rotatable loop and compass. 

          

         No longer true. We must have an ADF and a compass. 

          

         If we are cheating and want to use a GPS, even a legal GPS,           to execute the approach, it would be pertinent to set the           airport location as the 'go to' destination and fly the track           to the airport. While heading is always nice to know, (it           helps us determine where to look when visibility is marginal,)           it pales in importance to staying on track toward the airport.

          

         Just sayin' nothin' else <G>

          

         Happy Skies,

          

         Old Bob

         

                    I

           

         

       [b]

BobsV35B(at)aol.com
Guest

Posted: Wed Jan 04, 2012 10:46 am Post subject: AeroElectric-List:

Good Morning Bill,

  

 Just a little bit more off topic if I may.

  

 The overlay program was instituted to get a lot of early use out of GPS  approaches. When you executed an overlay approach. all the guidance was strictly  via GPS. The only thing used from the ADF approach was the minima.  Many  divisions of the FAA were strongly against the overlay program and the FAA is  now removing the overlays as fast as practical. Very few still exist. In most  cases, the new approach which replaces the overlay will have better minima, bit  not always.

  

 To pat myself on the back just a bit, I do have some expertise on that  program. I was an early adopter and fought hard for the use of GPS In Lieu of  ADF and DME. With the help of Randy Kenagy and Phil Boyer of ALPA . We got it  done. I was contacted by a gentleman named Bob Wright who was in the position  within the FAA to get the job done. It took almost a year, but we did get that  permission and I am VERY proud of what we got done. If you get to the correct  FAA FED, things can work correctly

  

 Happy Skies.

  

 Old Bragging Bob

  

  In a message dated 1/4/2012 11:39:45 A.M. Central Standard Time,  Mauledriver(at)nc.rr.com writes:

  	  Quote: 	
		  Yes,    what Bob said.



I'm thinking that track is better than heading.     And if I recall correctly, when many of those NDB approaches had GPS overlays    a few years ago, you didn't require an ADF (or the ability to fly a mag    heading), you just used a certified GPS to fly the NDB tracks.  (do any    of those still exist - the ones I used to fly are all replaced by RNAV T    approaches)



I guess what you are getting at is that you'd like to avoid    having to install a DG by using a GPS driven instrument.



My glass panel    gives me mag headings from the EFIS's AHRS system and allows me to easily    follow vectors.  Otherwise, I don't have a whiskey compass or vacuum    driven heading instrument.  The key question is what happens with an    electronics failure... well I have a GRT ADI instrument with a GPS and an    independent backup battery.  It just gives me a digital track readout    along with turn coordinator function and a quasi-horizon.  I can't follow    a mag heading but I can fly a track pretty darn accurately.



Bill "not    completely off-topic" Watson



On 1/4/2012 11:27 AM, BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote:     	  Quote: 	
		            Good Morning Ken,

      

     You said:

     "Several degrees of error can become problematical for things like an      RNAV NDB approach."

      

     While this is getting quite far away from a subject for the      AeroElectric list, I would like to comment. 

      

     If we are flying IFR, it would seem we need a legal method of shooting      an NDB approach and the only method currently legal is to use an ADF      combined with a legal compass heading.

      

     Once upon a time, we were legal to shoot that approach with just a      fixed or manually rotatable loop and compass. 

      

     No longer true. We must have an ADF and a compass. 

      

     If we are cheating and want to use a GPS, even a legal GPS, to execute      the approach, it would be pertinent to set the airport location as the 'go      to' destination and fly the track to the airport. While heading is always      nice to know, (it helps us determine where to look when visibility is      marginal,) it pales in importance to staying on track toward the      airport.

      

     Just sayin' nothin' else <G>

      

     Happy Skies,

      

     Old Bob



          I





ist href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List

s.matronics.com/">http://forums.matronics.com

p://www.matronics.com/contribution">http://www.matronics.com/contribution



	
	


 [quote][b]

ainut(at)knology.net
Guest

Posted: Wed Jan 04, 2012 10:53 am Post subject: AeroElectric-List:

Yeah, until the 4G phones get installed. <sigh>

bob noffs wrote:

 	  Quote: 	
		   seems what this world[or at least me] needs is a gps driven 

 directional gyro. i know that most gps units have part of a compass 

 rose displayed but for the price of a mechanical one i would think a 

 plain simple dg that mounts in a conventional 3'' hole and is gps 

 driven would be cheap and popular.

   or at least a program to drive a palm pilot, tapping off the gps of 

 another unit.

    bob noffs

 *

 *


	


-- 

Tell the truth.  Be honest.  Be responsible to and for yourself.



I liked America when it was free and it's people were responsible and had morals.



Every gram of cocaine you buy from elsewhere contributes to an innocent being murdered in Central and South America.  Grow your own or Stop taking it.

BobsV35B(at)aol.com
Guest

Posted: Wed Jan 04, 2012 11:28 am Post subject: AeroElectric-List:

Good Morning -- Is it Jared?

  

 The GPS cannot be used in lieu of an ADF for an ADF approach.

  

 It can be used for all other functions of the ADF, but not when the ADF is  the basis for the approach. 

  

 If there is a published overlay, then the overlay approach can be executed.  We tried to get permission to use it as you suggest, but the FEDs were firm.  They told us that all ADF approaches would either get an overlay or a GPS  approach that had better minima. While most have been handled that way,  many have not. 

  

 Does NOT make sense, but them's the rules.

  

 Happy Skies,

  

 Old Bob

  

 PS Incidentally, there are no longer any NDB approaches. They were all  converted to ADF.

  

  In a message dated 1/4/2012 11:07:31 A.M. Central Standard Time,  email(at)jaredyates.com writes:

  	  Quote: 	
		     Hmmm.... I thought we could substitute an ifr gps for adf in ndb    approaches. When you say compass, do you mean magnetically derived    heading?



   

   

On Jan 4, 2012, at 11:27, BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote:

   

    	  Quote: 	
		                 Good Morning Ken,

      

     You said:

     "Several degrees of error can become problematical for things like an      RNAV NDB approach."

      

     While this is getting quite far away from a subject for the      Aeroelectric list, I would like to comment. 

      

     If we are flying IFR, it would seem we need a legal method of shooting      an NDB approach and the only method currently legal is to use an ADF      combined with a legal compass heading.

      

     Once upon a time, we were legal to shoot that approach with just a      fixed or manually rotatable loop and compass. 

      

     No longer true. We must have an ADF and a compass. 

      

     If we are cheating and want to use a GPS, even a legal GPS, to execute      the approach, it would be pertinent to set the airport location as the 'go      to' destination and fly the track to the airport. While heading is always      nice to know, (it helps us determine where to look when visibility is      marginal,) it pales in importance to staying on track toward the      airport.

      

     Just sayin' nothin' else <G>

      

     Happy Skies,

      

     Old Bob



          In a message dated 1/4/2012 10:01:16 A.M. Central Standard Time, klehman(at)albedo.net (klehman(at)albedo.net) writes:

      	  Quote: 	
		  Several degrees of error can become problematical for

things        like an RNAV NDB approach.



	


 	  Quote: 	
		  

	




	
	


 [quote][b]

BobsV35B(at)aol.com
Guest

Posted: Wed Jan 04, 2012 11:36 am Post subject: AeroElectric-List:

Good Afternoon,

  

 Just realized you asked a second question which I failed to address.

  

 ADF approaches are based on having good magnetically derived heading  information. The approaches are not based on true courses as back when such  approaches were developed, there was no practical way to get other than a  magnetically derived heading in the airplane. When we use a Directional Gyro, we  set it by the magnetic compass. Many modern units use a flux gate compass, but  that is still magnetic. The DGs just provide stability that is difficult to get  using a pure magnetic compass.

  

 Happy Skies,

  

 Old Bob

  

  In a message dated 1/4/2012 11:07:31 A.M. Central Standard Time,  email(at)jaredyates.com writes:

  	  Quote: 	
		     Hmmm.... I thought we could substitute an ifr gps for adf in ndb    approaches. When you say compass, do you mean magnetically derived    heading?



   

   

On Jan 4, 2012, at 11:27, BobsV35B(at)aol.com (BobsV35B(at)aol.com) wrote:

   

    	  Quote: 	
		                 Good Morning Ken,

      

     You said:

     "Several degrees of error can become problematical for things like an      RNAV NDB approach."

      

     While this is getting quite far away from a subject for the      Aeroelectric list, I would like to comment. 

      

     If we are flying IFR, it would seem we need a legal method of shooting      an NDB approach and the only method currently legal is to use an ADF      combined with a legal compass heading.

      

     Once upon a time, we were legal to shoot that approach with just a      fixed or manually rotatable loop and compass. 

      

     No longer true. We must have an ADF and a compass. 

      

     If we are cheating and want to use a GPS, even a legal GPS, to execute      the approach, it would be pertinent to set the airport location as the 'go      to' destination and fly the track to the airport. While heading is always      nice to know, (it helps us determine where to look when visibility is      marginal,) it pales in importance to staying on track toward the      airport.

      

     Just sayin' nothin' else <G>

      

     Happy Skies,

      

     Old Bob



          In a message dated 1/4/2012 10:01:16 A.M. Central Standard Time, klehman(at)albedo.net (klehman(at)albedo.net) writes:

      	  Quote: 	
		  Several degrees of error can become problematical for

things        like an RNAV NDB approach.



	


 	  Quote: 	
		  

	






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eroElectric-List"' href='mip://0aa914f8/3D"http://www.matronics.com/Navigator?AeroElectric-List"'>http://www.matronics.com/Navigator?AeroElectric-List

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 [quote][b]

Mauledriver(at)nc.rr.com
Guest

Posted: Wed Jan 04, 2012 11:51 am Post subject: AeroElectric-List:

Well thanks Bob!  

     

     I for one fully exploited the overlay program.  It allowed me to     upgrade my Maule panel with a G300XL and not include an ADF.   I did     my training without ever having to learn to use and ADF and yet was     able to take great advantage of all the ADF/overlay approaches for     both training and travel.

     

     Now they seem quaint with RNAV T approaches, WAAS, and a 2 axis AP.     

     

     Bill

     

     [quote]         Good Morning Bill,

          

         Just a little bit more off topic if I may.

          

         The overlay program was instituted to get a lot of early           use out of GPS approaches. When you executed an overlay           approach. all the guidance was strictly via GPS. The only           thing used from the ADF approach was the minima.  Many           divisions of the FAA were strongly against the overlay program           and the FAA is now removing the overlays as fast as practical.           Very few still exist. In most cases, the new approach which           replaces the overlay will have better minima, bit not always.

          

         To pat myself on the back just a bit, I do have some           expertise on that program. I was an early adopter and fought           hard for the use of GPS In Lieu of ADF and DME. With the help           of Randy Kenagy and Phil Boyer of ALPA . We got it done. I was           contacted by a gentleman named Bob Wright who was in the           position within the FAA to get the job done. It took almost a           year, but we did get that permission and I am VERY proud of           what we got done. If you get to the correct FAA FED, things           can work correctly

          

         Happy Skies.

          

         Old Bragging Bob

          

                    In a message dated 1/4/2012 11:39:45 A.M. Central             Standard Time, Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com) writes:

            	  Quote: 	
		  Yes,               what Bob said.

               

               I'm thinking that track is better than heading.  And if I               recall correctly, when many of those NDB approaches had               GPS overlays a few years ago, you didn't require an ADF               (or the ability to fly a mag heading), you just used a               certified GPS to fly the NDB tracks.  (do any of those               still exist - the ones I used to fly are all replaced by               RNAV T approaches)

               

               I guess what you are getting at is that you'd like to               avoid having to install a DG by using a GPS driven               instrument.

               

               My glass panel gives me mag headings from the EFIS's AHRS               system and allows me to easily follow vectors.  Otherwise,               I don't have a whiskey compass or vacuum driven heading               instrument.  The key question is what happens with an               electronics failure... well I have a GRT ADI instrument               with a GPS and an independent backup battery.  It just               gives me a digital track readout along with turn               coordinator function and a quasi-horizon.  I can't follow               a mag heading but I can fly a track pretty darn               accurately.

               

               Bill "not completely off-topic" Watson

               

               On 1/4/2012 11:27 AM, BobsV35B(at)aol.com (BobsV35B(at)aol.com)               wrote:                	  Quote: 	
		                                                       Good Morning Ken,

                    

                   You said:

                   "Several degrees of error can become                     problematical for things like an RNAV NDB approach."

                    

                   While this is getting quite far away from a                     subject for the AeroElectric list, I would like to                     comment. 

                    

                   If we are flying IFR, it would seem we need a                     legal method of shooting an NDB approach and the                     only method currently legal is to use an ADF                     combined with a legal compass heading.

                    

                   Once upon a time, we were legal to shoot that                     approach with just a fixed or manually rotatable                     loop and compass. 

                    

                   No longer true. We must have an ADF and a                     compass. 

                    

                   If we are cheating and want to use a GPS, even a                     legal GPS, to execute the approach, it would be                     pertinent to set the airport location as the 'go to'                     destination and fly the track to the airport. While                     heading is always nice to know, (it helps us                     determine where to look when visibility is                     marginal,) it pales in importance to staying on                     track toward the airport.

                    

                   Just sayin' nothin' else <G>

                    

                                    	
             	
         

            [b]

BobsV35B(at)aol.com
Guest

Posted: Wed Jan 04, 2012 1:03 pm Post subject: AeroElectric-List:

Good Afternoon Bill,

  

 That GNC300XL is a very good box at a reasonable price. Garmin did  discontinue production about a year ago, but it is still supported and current  data base updates are available. I have one in my Stearman and am very happy  with it.

  

 You can still shoot all of the LNAV approaches. Every WAAS approach I know  of has either an LNAV associated with it or there is a standalone LNAV to the  same runway. Those Advisory Only glide paths are fun to fly, but it is my  contention that the classic dive and drive technique will result in many more  safely completed approaches.  

  

 Check out the Advisory Only glide path on the  N23 Rwy 7 approach. If  someone should happen to follow that glide path below the MDA, they will hit  solid rock prior to the runway threshold.

  

 The 300XL should be good for several more years.

  

 Happy Skies,

  

 Old Bob

  

  In a message dated 1/4/2012 1:53:06 P.M. Central Standard Time,  Mauledriver(at)nc.rr.com writes:

  	  Quote: 	
		  Well    thanks Bob!  



I for one fully exploited the overlay program.     It allowed me to upgrade my Maule panel with a G300XL and not include an    ADF.   I did my training without ever having to learn to use and ADF    and yet was able to take great advantage of all the ADF/overlay approaches for    both training and travel.



Now they seem quaint with RNAV T approaches,    WAAS, and a 2 axis AP. 



Bill



    	  Quote: 	
		       Good Morning Bill,

      

     Just a little bit more off topic if I may.

      

     The overlay program was instituted to get a lot of early use out of GPS      approaches. When you executed an overlay approach. all the guidance was      strictly via GPS. The only thing used from the ADF approach was the      minima.  Many divisions of the FAA were strongly against the overlay      program and the FAA is now removing the overlays as fast as practical. Very      few still exist. In most cases, the new approach which replaces the overlay      will have better minima, bit not always.

      

     To pat myself on the back just a bit, I do have some expertise on that      program. I was an early adopter and fought hard for the use of GPS In Lieu      of ADF and DME. With the help of Randy Kenagy and Phil Boyer of ALPA . We      got it done. I was contacted by a gentleman named Bob Wright who was in the      position within the FAA to get the job done. It took almost a year, but we      did get that permission and I am VERY proud of what we got done. If you get      to the correct FAA FED, things can work correctly

      

     Happy Skies.

      

     Old Bragging Bob

      

          In a message dated 1/4/2012 11:39:45 A.M. Central Standard Time, Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com) writes:

      	  Quote: 	
		  Yes,        what Bob said.



I'm thinking that track is better than        heading.  And if I recall correctly, when many of those NDB        approaches had GPS overlays a few years ago, you didn't require an ADF (or        the ability to fly a mag heading), you just used a certified GPS to fly        the NDB tracks.  (do any of those still exist - the ones I used to        fly are all replaced by RNAV T approaches)



I guess what you are        getting at is that you'd like to avoid having to install a DG by using a        GPS driven instrument.



My glass panel gives me mag headings from        the EFIS's AHRS system and allows me to easily follow vectors.         Otherwise, I don't have a whiskey compass or vacuum driven heading        instrument.  The key question is what happens with an electronics        failure... well I have a GRT ADI instrument with a GPS and an independent        backup battery.  It just gives me a digital track readout along with        turn coordinator function and a quasi-horizon.  I can't follow a mag        heading but I can fly a track pretty darn accurately.



Bill "not        completely off-topic" Watson



On 1/4/2012 11:27 AM, BobsV35B(at)aol.com (BobsV35B(at)aol.com)        wrote:         	  Quote: 	
		                    Good Morning Ken,

          

         You said:

         "Several degrees of error can become problematical for things like          an RNAV NDB approach."

          

         While this is getting quite far away from a subject for the          AeroElectric list, I would like to comment. 

          

         If we are flying IFR, it would seem we need a legal method of          shooting an NDB approach and the only method currently legal is to use          an ADF combined with a legal compass heading.

          

         Once upon a time, we were legal to shoot that approach with just a          fixed or manually rotatable loop and compass. 

          

         No longer true. We must have an ADF and a compass. 

          

         If we are cheating and want to use a GPS, even a legal GPS, to          execute the approach, it would be pertinent to set the airport location          as the 'go to' destination and fly the track to the airport. While          heading is always nice to know, (it helps us determine where to look          when visibility is marginal,) it pales in importance to staying on track          toward the airport.

          

         Just sayin' nothin' else <G>

          

	
	






	
	


 [quote][b]

millner(at)me.com
Guest

Posted: Wed Jan 11, 2012 7:37 pm Post subject: AeroElectric-List:

On 1/4/2012 7:55 AM, Ken Lehman wrote:

 	  Quote: 	
		   Some rnav units that have airspeed inputs calculate drift and simply use

 a lookup table to convert track to magnetic dg info.

How would that work, Ken?  Seems like knowing only airspeed and 
	


groundspeed, you don't know if the headwind/tailwind component is 

directly ahead/behind you or off a wingtip... so how does airspeed and 

groundspeed and track allow you to calculate heading?



Paul



-- 

Please note my new email address!

millner(at)me.com

klehman(at)albedo.net
Guest

Posted: Thu Jan 12, 2012 4:39 pm Post subject: AeroElectric-List:

Hello Paul

The GPS gives groundspeed, track, and position.

You can go into a lookup table to find the magnetic variation at your

position. If you know the TAS because you have pitot static info and

temperature, you should be able to solve for the wind vector I believe.

Same as can be done with an E6B computer. I think it goes heading vector

plus wind vector equals track vector. So if you know any two vectors you

can compute the third vector.

Mostly I was just pointing out that many glass PFD/ADI systems already

have all the sensor info they need to display a magnetic heading if the

designer wishes to display it. I often fly an aircraft that does just

that. It has no magnetic sensors but it computes and displays magnetic

heading.

Of course variation does change slightly over a multi year period so

minor changes in the lookup table might be appropriate every few years

if high accuracy is desired.

Ken

 	  Quote: 	

  S> 

 On 1/4/2012 7:55 AM, Ken Lehman wrote:

 > Some rnav units that have airspeed inputs calculate drift and simply use

 > a lookup table to convert track to magnetic dg info.

 How would that work, Ken?  Seems like knowing only airspeed and 

 groundspeed, you don't know if the headwind/tailwind component is 

 directly ahead/behind you or off a wingtip... so how does airspeed and 

 groundspeed and track allow you to calculate heading?

 Paul

 --

bobmeyers(at)meyersfamily
Guest

Posted: Thu Jan 12, 2012 5:16 pm Post subject: AeroElectric-List:

No, you're missing the heading. Your lookup table is just giving you the magnetic adjustment to a 'true' track.  Most GPS's do just that when you tell them you want a magnetic track.

You said your aircraft has no access to magnetic information. Without that it can't tell your plane is pointing in a direction other than the ground track - magnetic or not. Your heading will only match your track in no wind conditions.

You still need something to tell you which way the plane is pointing, not tracking. However if the EFIS has access to magnetic heading data, then you can calculate wind speed and direction in the EFIS.

Bob Meyers

Flying my Sonex N982SX - Building log at http://n982sx.com

Sent from my iPad

On Jan 12, 2012, at 6:36 PM, "Ken Lehman" <klehman(at)albedo.net> wrote:

 	  Quote: 	

 Hello Paul

 The GPS gives groundspeed, track, and position.

 You can go into a lookup table to find the magnetic variation at your

 position. If you know the TAS because you have pitot static info and

 temperature, you should be able to solve for the wind vector I believe.

 Same as can be done with an E6B computer. I think it goes heading vector

 plus wind vector equals track vector. So if you know any two vectors you

 can compute the third vector.

 Mostly I was just pointing out that many glass PFD/ADI systems already

 have all the sensor info they need to display a magnetic heading if the

 designer wishes to display it. I often fly an aircraft that does just

 that. It has no magnetic sensors but it computes and displays magnetic

 heading.

 Of course variation does change slightly over a multi year period so

 minor changes in the lookup table might be appropriate every few years

 if high accuracy is desired.

 Ken

> 

> S> 

> 

> On 1/4/2012 7:55 AM, Ken Lehman wrote:

>> Some rnav units that have airspeed inputs calculate drift and simply use

>> a lookup table to convert track to magnetic dg info.

> How would that work, Ken?  Seems like knowing only airspeed and 

> groundspeed, you don't know if the headwind/tailwind component is 

> directly ahead/behind you or off a wingtip... so how does airspeed and 

> groundspeed and track allow you to calculate heading?

> 

> Paul

> 

> -- 

>

klehman(at)albedo.net
Guest

Posted: Sat Jan 14, 2012 7:13 am Post subject: AeroElectric-List:

Thank you Bob and Paul for taking the time to point this out

and correct my understanding.



The documentation that I have is incomplete and I believed it without 

thinking it through. It may not have any external magnetic sensor but I 

agree that it must at least have an unmentioned internal sensor.



Ken



On 12/01/2012 8:10 PM, Bob Meyers wrote:

 	  Quote: 	
		   

 Meyers<bobmeyers(at)meyersfamily.org>



 No, you're missing the heading. Your lookup table is just giving you

 the magnetic adjustment to a 'true' track.  Most GPS's do just that

 when you tell them you want a magnetic track.



 You said your aircraft has no access to magnetic information. Without

 that it can't tell your plane is pointing in a direction other than

 the ground track - magnetic or not. Your heading will only match your

 track in no wind conditions.



 You still need something to tell you which way the plane is pointing,

 not tracking. However if the EFIS has access to magnetic heading

 data, then you can calculate wind speed and direction in the EFIS.



 Bob Meyers



 Flying my Sonex N982SX - Building log at http://n982sx.com



 Sent from my iPad



 On Jan 12, 2012, at 6:36 PM, "Ken Lehman"<klehman(at)albedo.net>

 wrote:



> 

> Lehman"<klehman(at)albedo.net>

>

> Hello Paul

>

> The GPS gives groundspeed, track, and position. You can go into a

> lookup table to find the magnetic variation at your position. If

> you know the TAS because you have pitot static info and

> temperature, you should be able to solve for the wind vector I

> believe. Same as can be done with an E6B computer. I think it goes

> heading vector plus wind vector equals track vector. So if you know

> any two vectors you can compute the third vector.

>

> Mostly I was just pointing out that many glass PFD/ADI systems

> already have all the sensor info they need to display a magnetic

> heading if the designer wishes to display it. I often fly an

> aircraft that does just that. It has no magnetic sensors but it

> computes and displays magnetic heading.

>

> Of course variation does change slightly over a multi year period

> so minor changes in the lookup table might be appropriate every few

> years if high accuracy is desired.

>

> Ken

>

>> 

>> Millner<millner(at)me.com> S>

>>

>> On 1/4/2012 7:55 AM, Ken Lehman wrote:

>>> Some rnav units that have airspeed inputs calculate drift and

>>> simply use a lookup table to convert track to magnetic dg

>>> info.

>> How would that work, Ken?  Seems like knowing only airspeed and

>> groundspeed, you don't know if the headwind/tailwind component

>> is directly ahead/behind you or off a wingtip... so how does

>> airspeed and groundspeed and track allow you to calculate

>> heading?

>>

>> Paul

>>

mauledriver(at)nc.rr.com
Guest

Posted: Sat Jan 14, 2012 7:39 am Post subject: AeroElectric-List:

FWIW, I recently confirmed that accurate calibration of the mag sensor has a significant impact on wind calculations.  After carefully running the calibration routine on my GRT EFIS, the displayed wind direction and speeds are now spot on.



Bill



Sent from my iPad



On Jan 14, 2012, at 10:10 AM, Ken <klehman(at)albedo.net> wrote:



 	  Quote: 	
		   

 

 Thank you Bob and Paul for taking the time to point this out

 and correct my understanding.

 

 The documentation that I have is incomplete and I believed it without thinking it through. It may not have any external magnetic sensor but I agree that it must at least have an unmentioned internal sensor.

 

 Ken

 

 On 12/01/2012 8:10 PM, Bob Meyers wrote:

> 

> Meyers<bobmeyers(at)meyersfamily.org>

> 

> No, you're missing the heading. Your lookup table is just giving you

> the magnetic adjustment to a 'true' track.  Most GPS's do just that

> when you tell them you want a magnetic track.

> 

> You said your aircraft has no access to magnetic information. Without

> that it can't tell your plane is pointing in a direction other than

> the ground track - magnetic or not. Your heading will only match your

> track in no wind conditions.

> 

> You still need something to tell you which way the plane is pointing,

> not tracking. However if the EFIS has access to magnetic heading

> data, then you can calculate wind speed and direction in the EFIS.

> 

> Bob Meyers

> 

> Flying my Sonex N982SX - Building log at http://n982sx.com

> 

> Sent from my iPad

> 

> On Jan 12, 2012, at 6:36 PM, "Ken Lehman"<klehman(at)albedo.net>

> wrote:

> 

>> 

>> Lehman"<klehman(at)albedo.net>

>> 

>> Hello Paul

>> 

>> The GPS gives groundspeed, track, and position. You can go into a

>> lookup table to find the magnetic variation at your position. If

>> you know the TAS because you have pitot static info and

>> temperature, you should be able to solve for the wind vector I

>> believe. Same as can be done with an E6B computer. I think it goes

>> heading vector plus wind vector equals track vector. So if you know

>> any two vectors you can compute the third vector.

>> 

>> Mostly I was just pointing out that many glass PFD/ADI systems

>> already have all the sensor info they need to display a magnetic

>> heading if the designer wishes to display it. I often fly an

>> aircraft that does just that. It has no magnetic sensors but it

>> computes and displays magnetic heading.

>> 

>> Of course variation does change slightly over a multi year period

>> so minor changes in the lookup table might be appropriate every few

>> years if high accuracy is desired.

>> 

>> Ken

>> 

>>> 

>>> Millner<millner(at)me.com> S>

>>> 

>>> On 1/4/2012 7:55 AM, Ken Lehman wrote:

>>>> Some rnav units that have airspeed inputs calculate drift and

>>>> simply use a lookup table to convert track to magnetic dg

>>>> info.

>>> How would that work, Ken?  Seems like knowing only airspeed and

>>> groundspeed, you don't know if the headwind/tailwind component

>>> is directly ahead/behind you or off a wingtip... so how does

>>> airspeed and groundspeed and track allow you to calculate

>>> heading?

>>> 

>>> Paul

>>>

bobmeyers(at)meyersfamily
Guest

Posted: Sat Jan 14, 2012 9:14 am Post subject: AeroElectric-List:

Hi Ken,



Yes, you probably have an internal compass.



I assume you don't have an inertial navigation system with ring laser gyros!!!



Not too many of those in the OBAM market. The accelerometers and gyro pkgs in our EFIS units are pretty good though.



Bob Meyers



Flying my Sonex N982SX - Building log at http://n982sx.com



Sent from my iPad



On Jan 14, 2012, at 9:10 AM, Ken <klehman(at)albedo.net> wrote:



 	  Quote: 	
		   

 

 Thank you Bob and Paul for taking the time to point this out

 and correct my understanding.

 

 The documentation that I have is incomplete and I believed it without thinking it through. It may not have any external magnetic sensor but I agree that it must at least have an unmentioned internal sensor.

 

 Ken

 

 On 12/01/2012 8:10 PM, Bob Meyers wrote:

> 

> Meyers<bobmeyers(at)meyersfamily.org>

> 

> No, you're missing the heading. Your lookup table is just giving you

> the magnetic adjustment to a 'true' track.  Most GPS's do just that

> when you tell them you want a magnetic track.

> 

> You said your aircraft has no access to magnetic information. Without

> that it can't tell your plane is pointing in a direction other than

> the ground track - magnetic or not. Your heading will only match your

> track in no wind conditions.

> 

> You still need something to tell you which way the plane is pointing,

> not tracking. However if the EFIS has access to magnetic heading

> data, then you can calculate wind speed and direction in the EFIS.

> 

> Bob Meyers

> 

> Flying my Sonex N982SX - Building log at http://n982sx.com

> 

> Sent from my iPad

> 

> On Jan 12, 2012, at 6:36 PM, "Ken Lehman"<klehman(at)albedo.net>

> wrote:

> 

>> 

>> Lehman"<klehman(at)albedo.net>

>> 

>> Hello Paul

>> 

>> The GPS gives groundspeed, track, and position. You can go into a

>> lookup table to find the magnetic variation at your position. If

>> you know the TAS because you have pitot static info and

>> temperature, you should be able to solve for the wind vector I

>> believe. Same as can be done with an E6B computer. I think it goes

>> heading vector plus wind vector equals track vector. So if you know

>> any two vectors you can compute the third vector.

>> 

>> Mostly I was just pointing out that many glass PFD/ADI systems

>> already have all the sensor info they need to display a magnetic

>> heading if the designer wishes to display it. I often fly an

>> aircraft that does just that. It has no magnetic sensors but it

>> computes and displays magnetic heading.

>> 

>> Of course variation does change slightly over a multi year period

>> so minor changes in the lookup table might be appropriate every few

>> years if high accuracy is desired.

>> 

>> Ken

>> 

>>> 

>>> Millner<millner(at)me.com> S>

>>> 

>>> On 1/4/2012 7:55 AM, Ken Lehman wrote:

>>>> Some rnav units that have airspeed inputs calculate drift and

>>>> simply use a lookup table to convert track to magnetic dg

>>>> info.

>>> How would that work, Ken?  Seems like knowing only airspeed and

>>> groundspeed, you don't know if the headwind/tailwind component

>>> is directly ahead/behind you or off a wingtip... so how does

>>> airspeed and groundspeed and track allow you to calculate

>>> heading?

>>> 

>>> Paul

>>>

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