Which is more reliable? the compass or gyro?

[WildBillKelsoe]

I think compass is more reliable.

[KLR Rico]

Gyros drift, but compasses swing due to accelerations and attitude changes. You pretty much have to use them both.

[Ala13_ManOWar]

Both are absolutely reliable if properly working, just Gyro drifts and must be re-set every 15 minutes, and compass works reversed, suffer some gravity and magnetic lines effects and you must be used to it. Gyro usually is more accurate but only because have more dots. Gyro is the main thing to use, easier because works "in the correct direction", but must be re-set with compass so you need both.

 

S!

[Sven2157]

The magnetic compass should only be used as reference, and definitely NOT relied on. In order for it to function correctly you need to be in level, constant speed flight. Banking, Pitch change and even Increase/Decrease in speed, causes the compass to "stick". Coupled with the fact that the P-51 can pull some pretty impressive G's, it sticks more often, than not. Remember that the compass, is floating on a needle, in liquid. Haven't you ever used one? Hand to shake it several times to get it to move?

 

:pilotfly:

 

The compass also relies on your geographical knowledge. You must know the magnetic offset of your location; which can change pretty quick due to man made and natural phenomenon.

 

The gyro is the preferred of the two by the FAA, and the compass is there as a backup unit; I believe that is an actual question in the written part of your private pilot's license in the United States.

 

FAA Instrument Flight Handbook( pgs 5-10 to 5-14 )

 

The Magnetic Compass of an Aircraft by Decoded Science

[Konrad Friedrich]

You should check the manual of the P-51D.

 

Page 68:

Remote Indicator Compass

The Remote Indicator Compass on the P-51D replaces the conventional magnetic compass of previous aircraft, although some models also include a conventional standby magnetic compass as a backup. The remote compass unit is installed in the left wing and transmits its readings electrically to the indicator on the instrument panel. This type of compass doesn’t float around and fluctuate when the aircraft is maneuvered. This provides all of the advantages of the directional gyro without the processions. However, the directional gyro is provided as a backup should the electrical system fail.

The Remote Indicator Compass consists of a stationary compass rose, a current magnetic heading arrow, and a desired magnetic heading arrow. The knob of the instrument is used to adjust (turn) the desired magnetic heading arrow to a desired heading.

 

:smartass:

[Sven2157]

You should check the manual of the P-51D.

 

Page 68:

Remote Indicator Compass

The Remote Indicator Compass on the P-51D replaces the conventional magnetic compass of previous aircraft, although some models also include a conventional standby magnetic compass as a backup. The remote compass unit is installed in the left wing and transmits its readings electrically to the indicator on the instrument panel. This type of compass doesn’t float around and fluctuate when the aircraft is maneuvered. This provides all of the advantages of the directional gyro without the processions. However, the directional gyro is provided as a backup should the electrical system fail.

The Remote Indicator Compass consists of a stationary compass rose, a current magnetic heading arrow, and a desired magnetic heading arrow. The knob of the instrument is used to adjust (turn) the desired magnetic heading arrow to a desired heading.

 

:smartass:

 

I don't own P-51( yet ), so I don't have the manual. But I have to say, what a horrible practice to fall into... Just because the P-51 has a "special" compass doesn't mean that you should accept that as the "golden" rule. I am not even sure that the information provided is valid, as I have never heard of that before; not saying it isn't valid, just have to research it myself.

 

Also, the OP didn't ask about the "Remote Indicator Compass", he asked about the compass... :huh:

[Konrad Friedrich]

Also, the OP didn't ask about the "Remote Indicator Compass", he asked about the compass... :huh:

 

Sure.

But this part of the DCS forum discusses the P-51.

So I think the question was related to that plane? :huh:

 

I did not want to put your comments on aircraft compasses in question, but was referring to the special case of P-51 D.

Especially since I think a lot of people do not know that the P-51 D had a remote indicator compass.

 

Regards,

Konrad

Edited January 27, 2013 by Konrad Friedrich

[Sven2157]

Sure.

But this part of the DCS forum discusses the P-51.

So I think the question was related to that plane? :huh:

 

Did I do something to you? I kind of feel that these statements are personal... By the way, thanks for clarifying where I was posting. :noexpression:

 

Ok, just got the manual...

 

Page 53, shows that the "Radio Indicator Compass #2" is on the top left corner of the front dashboard. This is in fact drive by mechanics, not magnetism. It receives information from the "Remote Indicator Compass", in the left wing( page 24 ).

 

The "Directional Gyro #3" is located left of center, on the front dashboard. This is mechanical also.

 

There is a HUGE difference between a Compass and a RIC. I offered a general opinion on a general question about Gyro vs Compass. Of all the P-51D's I have seen in my life( real ones ), ALL of them have had a magnetic compass on top of the dashboard. Did DCS model this? I guess I will have to wait and see. Where they installed post WWII? Maybe so, but that doesn't negate what I have personally witnessed.

 

So keeping with the P-51D, and not general rules of aviation, there is really no difference between the RIC and the Gyro, as far as accuracy goes; as both are mechanical.

[Konrad Friedrich]

Did I do something to you? I kind of feel that these statements are personal...

 

No, absolutely not.

I have absolutely no reason.

I think you have misunderstood me.

Sorry if my statement was misleading.

[Sven2157]

No, absolutely not.

I have absolutely no reason.

I think you have misunderstood me.

Sorry if my statement was misleading.

 

LOL, ok cool... I was hoping I didn't offend you. :thumbup:

[wolle]

Hi guys,

 

Did I hear you claim that the compass doesn't move as the aircraft maneuvers? I must be misunderstanding something here. In my P51D (I have the latest version installed), the compass needle immediately jumps to an incorrect heading as I initiate the turn, and keeps indicating the wrong heading as long as I am in the turn, then instantaneously jumps back to the correct heading as I level out when the turn is complete. The gyro on the other hands gives smooth heading readings throughout the turn. ???

 

Also, upon start from runway the compass and gyro display a different heading (by 10 degrees or so, don't remember). Which one is the correct one?

 

How often do I have to recalibrate the gyro reading based on the compass reading?

[WildBillKelsoe]

Did I do something to you? I kind of feel that these statements are personal... By the way, thanks for clarifying where I was posting. :noexpression:

 

Ok, just got the manual...

 

Page 53, shows that the "Radio Indicator Compass #2" is on the top left corner of the front dashboard. This is in fact drive by mechanics, not magnetism. It receives information from the "Remote Indicator Compass", in the left wing( page 24 ).

 

The "Directional Gyro #3" is located left of center, on the front dashboard. This is mechanical also.

 

There is a HUGE difference between a Compass and a RIC. I offered a general opinion on a general question about Gyro vs Compass. Of all the P-51D's I have seen in my life( real ones ), ALL of them have had a magnetic compass on top of the dashboard. Did DCS model this? I guess I will have to wait and see. Where they installed post WWII? Maybe so, but that doesn't negate what I have personally witnessed.

 

So keeping with the P-51D, and not general rules of aviation, there is really no difference between the RIC and the Gyro, as far as accuracy goes; as both are mechanical.

 

No, absolutely not.

I have absolutely no reason.

I think you have misunderstood me.

Sorry if my statement was misleading.

 

 

Hey guys, I finally can say the fact that we have to use both. The compass (in the cockpit), for general bearing and the DG for specific bearing. Reason why: compass has 2 degree increments. DG has 5 degree increments. So, it should be the gyro first then compass. NO! compass first!!!!

[Ala13_ManOWar]

Hey guys, I finally can say the fact that we have to use both. The compass (in the cockpit), for general bearing and the DG for specific bearing. Reason why: compass has 2 degree increments. DG has 5 degree increments. So, it should be the gyro first then compass. NO! compass first!!!!

Nice after 2 pages of fighting reach same thing I said in third post :shocking:.

 

 

Did I hear you claim that the compass doesn't move as the aircraft maneuvers? I must be misunderstanding something here. In my P51D (I have the latest version installed), the compass needle immediately jumps to an incorrect heading as I initiate the turn, and keeps indicating the wrong heading as long as I am in the turn, then instantaneously jumps back to the correct heading as I level out when the turn is complete. The gyro on the other hands gives smooth heading readings throughout the turn. ???

Don't know if somebody said compass doesn't move, it's clear compass have to move. At start may be it's simulated drifting so gyro doesn't match compass, compass is always correct (with magnetic error of course) because it's magnetic and gyro should be set with compass reading because it's gyroscopic as his name says and drifts. Just use gyro, it's there for that, and check with compass every certain time gyro keeps correct heading.

 

Anyway, somebody said compass is NOT reliable because FAA says... Well I'm JAR/FCL EASA pilot and EASA says compass is the only absolutely reliable thing as far as everything can fail, so you have to know how to operate with compass and know it's problems. I've flown compass only (for training purposes) and you can be asked to do so in your flight exam and explain and demonstrate what the compass problems are and why. So I don't think compass is just for decoration purposes and not reliable at all :thumbup:.

 

S!

[Merlin-27]

Nice after 2 pages of fighting reach same thing I said in third post .

 

 

Don't know if somebody said compass doesn't move, it's clear compass have to move. At start may be it's simulated drifting so gyro doesn't match compass, compass is always correct (with magnetic error of course) because it's magnetic and gyro should be set with compass reading because it's gyroscopic as his name says and drifts. Just use gyro, it's there for that, and check with compass every certain time gyro keeps correct heading.

 

Anyway, somebody said compass is NOT reliable because FAA says... Well I'm JAR/FCL EASA pilot and EASA says compass is the only absolutely reliable thing as far as everything can fail, so you have to know how to operate with compass and know it's problems. I've flown compass only (for training purposes) and you can be asked to do so in your flight exam and explain and demonstrate what the compass problems are and why. So I don't think compass is just for decoration purposes and not reliable at all .

 

S!

 

This quite a messy thread. lol

 

Firstly lets make sure we are clear what we are referring to. From every thing I've learned about the P-51 (the manual blurb about the compass was posted earlier) we are told the Mustang uses the Remote Indicator Compass. This severely changes the discussion as far as "instrument reliability" is concerned. Normally, the magnetic compass would be a backup i.e. A-10C however in the P-51 they incorporated the Remote compass to avoid typical sources of compass error and conveyed the info to the cockpit via the electrical system. Because of this vital fact, an electrical system failure would render the compass useless. This appears to be why the flight manual notes the gyro as the backup due to normal gyro precession over time. One other note: It mentions an additional standalone compass on some late model Mustangs... apparently that is not us or I'm missing something.

 

Now as far as our Mustangs in DCS. I believe the compass does jump around a bunch when not flying straight and level. Which of course, makes this discussion all kinds of confusing. I'll have to pay close attention to it next time I'm flying.

[wolle]

Don't know if somebody said compass doesn't move, it's clear compass have to move. S!

 

Friedrich did: I quote "Page 68:

Remote Indicator Compass

The Remote Indicator Compass on the P-51D replaces the conventional magnetic compass of previous aircraft, although some models also include a conventional standby magnetic compass as a backup. The remote compass unit is installed in the left wing and transmits its readings electrically to the indicator on the instrument panel. This type of compass doesn’t float around and fluctuate when the aircraft is maneuvered. This provides all of the advantages of the directional gyro without the processions. However, the directional gyro is provided as a backup should the electrical system fail.

The Remote Indicator Compass consists of a stationary compass rose, a current magnetic heading arrow, and a desired magnetic heading arrow. The knob of the instrument is used to adjust (turn) the desired magnetic heading arrow to a desired heading.

"

 

Or do I misunderstand him?

[Merlin-27]

Friedrich did: I quote "Page 68:

Remote Indicator Compass

The Remote Indicator Compass on the P-51D replaces the conventional magnetic compass of previous aircraft, although some models also include a conventional standby magnetic compass as a backup. The remote compass unit is installed in the left wing and transmits its readings electrically to the indicator on the instrument panel. This type of compass doesn’t float around and fluctuate when the aircraft is maneuvered. This provides all of the advantages of the directional gyro without the processions. However, the directional gyro is provided as a backup should the electrical system fail.

The Remote Indicator Compass consists of a stationary compass rose, a current magnetic heading arrow, and a desired magnetic heading arrow. The knob of the instrument is used to adjust (turn) the desired magnetic heading arrow to a desired heading.

"

 

Or do I misunderstand him?

 

In every one of my flights so far the compass is not correct unless in level flight. This does not jive with that statement in the manual shown above describing the RIC...unless I'm misunderstanding the word "maneuvered".

 

Thoughts?

[WildBillKelsoe]

In every one of my flights so far the compass is not correct unless in level flight. This does not jive with that statement in the manual shown above describing the RIC...unless I'm misunderstanding the word "maneuvered".

 

Thoughts?

 

I think we should get general heading in 100's of degrees with the kompass, and follow through with the gyro for 10's of degrees.

[brucewhf]

Quote

This type of compass doesn’t float around and fluctuate when the aircraft is maneuvered.

Pay attention to the specific word 'maneuvered'. I think it stands for 'after you finish the maneuver', which means fly straight and level

By the way, is the Gryro Drift correctly modeled in DCS?