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raaaid
05-13-2006, 05:36 AM
only the gyro marks true north magnetics can fail up to 20º

so planes used gyrocompass right?

p-11.cAce
05-13-2006, 06:35 AM
Depends - most general aviation aircraft use a mag compass and some have a gyro as well - though to be honest I'm a GPS baby and doubt I could navigate anymore without one. A gyro compass though has its own issues - namely gyro drift - and has to have a mag compass or GPS to cross check it against at regular intervals. When you use a mag for navigation you account for the magnetic north angle anyway so no worries.

Taylortony
05-13-2006, 06:47 AM
Both

The Direct reading compass is magnetic snd the gyro compass is either pnuematic or electric....

The reason for this if you flew by the magnetic compass when you turn onto a heading it would carry on turning past the direction you were intending to go then settle... you would end up making lots of little turns to finally get onto your correct heading.....

so you use the gyro compass for that as it will turn to the heading without and tendancy to swing, but for flying a heading you would fly it on the magnetic compass and reset the gyro compass to it about every 15 minutes, this is due to precession.... The Gyro compass does not display accurate heading information for a limitless period of time. Because of "precession,". but you would set the Gyro compass to the magnetic compass on the ground before you set out. you correct your magnetic readings for variance when navigating.

a good link to read is this

http://flyawaysimulation.com/contentid-5.html

raaaid
05-13-2006, 07:03 AM
yes but what a bout wwii birds did they use magnetic or gyroscopic compasses

im just curious

that would explain many things on bermuda trinagle for ex

Snow_Wolf_
05-13-2006, 07:08 AM
both are there

The magnetic there to give you a basic reference for heading information. (Can be affected by errors such as acceleration error and turning error which are only valid in flights in the northern Hemishpere (that why up at the northern area they don't use magnetic headings but true headings.)

Heading Indicator Gyroscopic instrument has no magnetic qualities of its own and therefore must be set periodically by reference to the magnetic compass. Its main asset is that it provides a stable directional reference and (unlike the magnetic comass) is relatively free of errors during turns accelerations and deceleration in normal flight

also compasses must be swing every year...

so don't read your damn compass when you are turning diving climbing etc.. lol

Taylortony
05-13-2006, 07:14 AM
Originally posted by Snow_Wolf_:
both are there

The magnetic there to give you a basic reference for heading information. (Can be affected by errors such as acceleration error and turning error which are only valid in flights in the northern Hemishpere (that why up at the northern area they don't use magnetic headings but true headings.)

Heading Indicator Gyroscopic instrument has no magnetic qualities of its own and therefore must be set periodically by reference to the magnetic compass. Its main asset is that it provides a stable directional reference and (unlike the magnetic comass) is relatively free of errors during turns accelerations and deceleration in normal flight

also compasses must be swing every year...

so don't read your damn compass when you are turning diving climbing etc.. lol


Compasses are now Swung every 3 years in the UK, http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

My job........ http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Snow_Wolf_
05-13-2006, 07:18 AM
Originally posted by Taylortony:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Snow_Wolf_:
both are there

The magnetic there to give you a basic reference for heading information. (Can be affected by errors such as acceleration error and turning error which are only valid in flights in the northern Hemishpere (that why up at the northern area they don't use magnetic headings but true headings.)

Heading Indicator Gyroscopic instrument has no magnetic qualities of its own and therefore must be set periodically by reference to the magnetic compass. Its main asset is that it provides a stable directional reference and (unlike the magnetic comass) is relatively free of errors during turns accelerations and deceleration in normal flight

also compasses must be swing every year...

so don't read your damn compass when you are turning diving climbing etc.. lol


Compasses are now Swung every 3 years in the UK, http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

My job........ http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

lol Lucky you us canucks still need to swing them every year..

VW-IceFire
05-13-2006, 07:29 AM
Originally posted by raaaid:
yes but what a bout wwii birds did they use magnetic or gyroscopic compasses

im just curious

that would explain many things on bermuda trinagle for ex
Both.

One of the issues with flying a big bomber for instance was that the bombload would be a possible cause for magnetic disturbance and would throw the readings off. So they had a gyro compas up in the front cockpit as well as a magnetic compass that would actually be located at the back of the plane (in the tail) that would then relay the signals up to the front. If battle damage cut this line then the gyro would be their best bet.

raaaid
05-13-2006, 07:35 AM
i realize the problem, on sea gyrocompass is limited to move on the horizontal plane so it always shows the north

but what when on air? how do you make the gyroscopic move in only one plane? by levelling the plane i guess

or on the other hand do you use it as a fixed point indicator?

i hope to have been clear on my question:

gyroscopic working limited to move on a plane by levelling the plane or gyroscopic pointing a fixed point in space taken as a reference

i love gyros

raaaid
05-13-2006, 07:36 AM
what about the 109 compass is it magnetic or gyroscopic?

anybody knows?

BrassEm
05-13-2006, 08:59 AM
In the PTO they used a beaufighter as a navigation escort for fighters such as spitfires traversing over long hauls. I guess bigger the aircraft better the compasses, plus a dedicated nav to steer.

luftluuver
05-13-2006, 09:38 AM
I once worked for Sperry Gyroscope, O/H, repair and calibration of the gyro compass (3 axis) for the auto pilot used in the CF-5 and SeaKing. At the end of the 4.5hr test, the deviation was something ~5-6 degrees off what it started at (after stabilization - ~10min) to be in spec.

mortoma1958
05-13-2006, 07:09 PM
There is only a magnetic compass in planes. The directional gyro is a gyro, technically not a compass. A compass is always magnetic. A gyro is a gyro, is a different animal. Least that's what I learned during pilot training. A DG may function similar to a compass, but the the main difference is a magnetic compass works when the engine is turned off, while the DG needs a vacuum or electric pump to operate ( to turn the gyroscope at high speeds ) and therefore the engine must be running for it to function. It is also called a "direction indicator" or "DI".
A DG/DI does not suffer from magnetic "dip" during banks/turns or acceleration/decelleration, unlike a magnetic compass.

georgeo76
05-14-2006, 01:43 AM
In 1946 Germany developed a compass that could determine position and heading by subtracting where it was from where it isn't and comparing the difference between the two.

This remained in military service until the more accurate GPS system was developed.

WTE_Galway
05-14-2006, 06:09 PM
basically what everyone else said

the mag compass looses track in hard manouvres but eventually settles back to give an accurate reading

the DG doesnt get thrown out by manouvres but when you first start the plane its random and has to be set and in real life needs to be reset every once and a while to match the mag compass on longer flights

in game .. some planes have both .. I think the P40 is an example



.. irrelevant bit of trivia .. WWII bombers often had a sextant in the cabin roof to allow navigation by the stars