I was looking at my aircraft realism settings and saw the option "Gyro drift" was checked. What affect does gyro drift have on planes and is it best to have that option checked or un checked?

Gyro drift causes the compass (and other navigational instruments like INS systems) to loose precision over time.

Make the "precess" as in precession. Of course, with precession, one could also say that after a while the DG/HSI will not give a "precise" reading when compared to the mag compass! ;-)If you turn drift off, it will be like having a gyro slaved to a remote compass, which is what I wish I could afford on my plane! Almost all larger aircraft, and some smaller ones also, have a remote compass system installed. Simply put: This is a magnetic compass (more substantial than the one in the cockpit) that is installed out of sight, and is wired to the heading indicator (DG or HSI). It sends a signal to the heading indicator to keep it in sync. Thus no precession or "drift".With drift turned on, you will need to adjust the DG periodically to match the mag compass heading. In FS, this effect is greatly exagerated, and seems to simulate a DG that is due for overhaul (perhaps overdue!).FS allows simulating a remote compass, but my suggestion is just to turn gyro drift off.Here's the section from an aircraft.cfg that that shows this:{direction_indicators}//1 Type: 0=None, 1=Vacuum Gyro, 2=Electric Gyro, 3=Electro-Mag Slaved Compass, 4=Slaved to another//2 Indicator number of slaving indicator if Type = 4direction_indicator.0=3Regards,http://www.dreamfleet2000.com/gfx/images/F...R_FORUM_LOU.jpg

Hi there.I use the default 'b' and 'd' keys to simulate the necessary adjustments which would need to be made to keep things accurate. It fascinates me that this part of flight is simulated, among all the other small details which make up the whole immersive virtual world.Andy.

Just a couple of clarifications.An HSI is by its very nature slaved. If the slaving device fails then it can be used like a DI.INS systems don't suffer from the same problems as a DI. Precssion and drift are not the same thing. An INS rate gyro uses the effect of precession to provide rate of a/c drift laterally, longitudinally and vertically. The error comes from mechanical wander, friction and tolerances within the system and the need to keep the gyro platform at Earth horizontal. Anyway, INS systems are stuff of Victors, Tristars and 727s. Modern computerised aircraft use strapdown IRS (Inertial Reference Systems) that use ring laser gyros and do not suffer from machanical wonder, are lighter, quicker to align and do not need a level platform.A DI drifts (also called wander) because Earth gyros (aligned to Earth horizontal) like to remain constant in space, but are forced to follow the curvature of the earth. Therefore the rate of drift or wander (if you remain stationary) is 15*sin(latitude) with the heading decreasing in the N hem +/- east/west ground speed * tan(lat)/60. Again, the properties of prcession are used to provide information on the change of heading. So precission is not, in its self, the cause of the error.

Sorry, but some HSI's are not slaved by their very nature. I'm pricing an HSI for my Dakota. They come in two flavors, air and electric. I used to use an air driven Century NSD360 HSI in the Archer I used to fly, and you certainly had to adjust it to the compass. Century also has an electric unit, just as Bendix-King has, and both have slaved, un-slaved, and boot strap versions (for use with and RMI usually). Yes, most (the electric versions)are usually slaved to a remote compass, but this is not mandatory, as the remote compass is an extra cost option.My friend's Mooney as an older Narco HSI, air driven and un-slaved. When they start to precess badly, throw them out, as overhaul for them is almost impossible to find. Even Narco doesn't do it.So, just to correct, while often slaved, they are not by their narture slaved. They can be nothing more than fancy, air-driven DG's with VOR/LOC/GS info, subject to precession just as a DG is.Needless to say, based on cost, if I get one for the Dakota, it will be an un-slaved Century unit. We'll use the several thousand dollars we save over the slaved unit for something else. ;-)Regards,http://www.dreamfleet2000.com/gfx/images/F...R_FORUM_LOU.jpg

Ah, something I can sink my professional teeth into."Modern computerised aircraft use strapdown IRS (Inertial Reference Systems) that use ring laser gyros and do not suffer from machanical wonder, are lighter, quicker to align and do not need a level platform."Among error sources for Ring Laser Gyros (RLG's), and in particular, strap down systems (definition of strap down = the gyro cluster and acceleromters (referred to as the Inertial Measurement Unit or IMU) are "hard" mounted to a horizontal plane within the object they are installed upon) are velocity error growth (i.e., undamped operation), Schuler and RLG white noise, to name just a few. Without a reset mechanism, for example a GPS, the error growth will increase over time until the navigation function of the strapdown RLG system becomes unuseable for in-flight navigation. The quality of the INS/IRS determines the speed at which that error growth occurs in the absence of a reset system, and when it ultimately becomes unusable as a navigation sensor. The three primary RLG INS/IRS systems in use today are manufactured by Honeywell, Northrop Grumman (formerly Litton + its Germany subsidiary LITEF) and Sagem.The only way to eliminate or greatly reduce the effects of common mode errors is to index the IMU in one, two or three axis. This then removes the "strap down" hard mount to the horizontal plane, and makes the predominent error source RLG white noise. The down side to indexing is that the system becomes much larger than that seen on a/c today (they are typically associated with Naval platforms). You would have to build an a/c around the thing, and a typical example is the Sperry Marine systems (the MK49, NATO SINS and the WSN-7) which typically weigh in at about 750 pounds.

Without a lot of detailed explanation, simply put, you set your HSI by your magnetic compass. This is done before takeoff and periodically during flight when flying stright and level. The gyro will drift over a period of time and has to be re-aligned with the mag compass. My flight instructor told me to reset it about every 15 minutes. Hope this helps.Jim

Helloits funny how fast i get used to such comfortable things like a slave system :-)my last flight i did with a warrior, normaly i take an archer but the archer was booked so i had to take the warrior.The archer has a slave system, the warrior not! guess what happend:-) :-) :-)just a little ofcourse :-)GreetsMcDaniel

I stand corrected! :)

My point was the RLG does not suffer from mechanical error. I didn't entend to get deep into INS/IRS other than explain the reason why they arn't relevant to the issue of Earth rate and Transport wander; which can be tuned out without any difficult in both INS and IRS systems.BTW, to my knowledge White noise is quntifiable and can be tuned out by the navigation computer as can the 84.4min Schuler oscillation period. In addition Schuler error is bounded meaning that although the instantaneous position maybe wrong, the error does not grow.Also, you say that a stable platform helps counter the errors, but the point of strapdown is that you have a suitable corresponding computer that does that for you, which has only recently (relatively speaking) been possible because of the hard sums involved. These computer systems do a better job than gyro stablised platforms...so I'm told.In order to complete any self respecting Smart Alec response I need to say: You forgot coriolis and centripedal errors...yes I did just look them up! :D

Yes, but when you consider that the angle of the dangle equals the droop of the root then the cosign of the widget requires recalibration of the whatsit!!Kidding! Your disertation was brilliant. It MUST have been since I didn't understand a word of it!!!!(: