spit compass

[ty1]

Hi does any know how to set the compass if it works in the spit mk1a or procedure thanks in advance

[Whiski]

There is a video on these forums regarding how to set your compass in a spit or hurri, also on you tube.

Whiskey

[fruitbat]

youtube vid is here,

http://www.youtube.com/watch?v=CTRC0sY67Pg

[too-cool]

I've found this to work but if you make any fast braking moves then the compass is off and holding level flight to reset is very difficult. TC

[Skoshi Tiger]

My problem is actually seeing the compas without having to move the joystick out of the way.

How are other people looking at the compas in straight and level flight?

Cheers

[JG52Uther]

I would love the system in RoF, where you can map a certain view to a button. Push the button, and you would be zoomed in on the compass for example. A great workaround for the limitations of a computer game.

Or, and here's a radical idea, the HUD from il2 worked perfectly...

[Sokol1]

My problem is actually seeing the compas without having to move the joystick out of the way.


You can make the same view moves of TrackIR with mouse.
Press the key “Hold to Adjust Field of View” - middle mouse for default - and with mouse slide POV to right or left, with FOV in 60 degrees.
To recenter FOV default key is "/".

Sokol1

[JG52Uther]

Its not so desperate in CoD, England and France is not so hard to navigate. Once we get to the Med and Russia things will get a little more difficult ;)

[_79_dev]

~S~

Any gyroscopic instruments used in airplanes are carrying minor error wich needs to be corrected within flight. Thanks to developers of this brilliant simulator we have chance to experience the same gyro disfuncionalities of gyro instruments. At this stage of development, I did't notice any errors in altimeter yet but I am sure it will be done at some stage... Anyway like in real life remember to correct your directional gyro after vast and rapid changes in altitude, heavy aerobatics or g-loads, eventually every every 15min.

[Skoshi Tiger]

Off topic, what's the point of the gyro compass, isn't a setup like the 109 had much easier and less chance of getting lost? Why bother having a compass that works on the floor, to set up one that messes up every 15 minutes?

The Magnetic compass experience errors when turning.



Errors inherent to compass turns

Several types of errors will affect the heading indication provided by a magnetic compass in a turn. Thus the magnetic compass cannot be used reliably when turning.

[edit] Pitch limits

A limitation imposed by a compass' construction is that the balancing bowl's pin, which is connected to a pivot point, only allows for, in most compasses, a pitch or bank of 18 degrees before the compass will touch the side of the casing. When the compass touches the side of the casing the freedom of the plane to rotate around the compass is lost and the compass becomes unreliable.

[edit] Magnetic dip

A second limitation is magnetic dip. When the aircraft is at any altitude above the Earth's surface, the compass dial will tend to align itself with the geomagnetic field and dip toward the northern magnetic pole when in the northern hemisphere, or toward the southern magnetic pole when in the southern hemisphere. At the equator this error is negligible. As an aircraft flies closer to either pole the dipping error becomes more prevalent to the point that the compass can become unreliable because its pivot point has surpassed its 18 degrees of tilt. Magnetic dip is caused by the downward pull of the magnetic poles and is greatest near the poles themselves. A weight is often placed on the compass of the aircraft on the equatorial side to help negate this effect. Compass navigation near the polar regions, however, is nearly impossible due to the errors caused by this effect.

When in straight and level flight the effect of magnetic dip is of no concern. However when the aircraft is turned to a new heading the following two rules apply for the northern hemisphere:

First, when on an easterly or westerly heading and the aircraft accelerates, the inertia effect of the weight on the compass in the magnet causes the compass to show a false turn towards the north if in the northern hemisphere or vice versa a false turn towards the south if in the southern hemisphere. Also if the aircraft is decelerated the compass will show a false turn towards the south in the northern hemisphere and false turn towards the north in the southern hemisphere. The force is neutralized when the aircraft has reached its velocity and the magnetic compass will then read the proper heading. Pilots in the northern hemisphere remember this by the acronym ANDS; accelerate north, decelerate south. The opposite occurs when flying in the southern hemisphere. This error is eliminated while accelerating or decelerating on heading of exactly North or exactly South.

Second, when on a northerly heading and a turn towards the east or west is made the inertia effect of the weight on the compass in the magnet causes the compass to lag behind the actual heading the aircraft is flying through. This lag will slowly diminish as the aircraft approaches either east or west and will be approximately correct when on an east or west heading. When the aircraft turns further towards South, the magnetic compass needle will tend to lead the actual heading of the aircraft. When a turn is made from south to an east or west heading the compass will lead the actual heading the aircraft is flying through, it will diminish as the aircraft approaches either east or west, and it will lag as the aircraft turns further towards North. The magnitude of the lead/lag will be approximately equal to the aircraft's latitude. (An aircraft at 30° north latitude will need to undershoot 30° while turning directly north, and overshoot 30° while turning directly south) The pilots community uses acronym UNOS (undershoot North overshoot South) to memorize this rule. Some other acronyms which pilots find easier to remember is NOSE (North Opposite, South Exceeds), OSUN (Overshoot South, Undershoot North), and South Leads, North Lags [opposite in the southern hemisphere] This guideline is based not on a standard-rate turn, but on a bank angle of 15°-18°, which would equal a standard rate turn at the airspeeds typical of light aircraft.


Cheers!

[_79_dev]

~S~


Off topic, what's the point of the gyro compass, isn't a setup like the 109 had much easier and less chance of getting lost? Why bother having a compass that works on the floor, to set up one that messes up every 15 minutes?


Take spitfire for 45min ride, try to fly according your gyro ... You will end up somewhere where You don't want to be... Therefore You have to recalibrate gyro. 109 has no problems because gyro error is not simulated yet...

[VBF-12_Gosling]

~S~

Any gyroscopic instruments used in airplanes are carrying minor error wich needs to be corrected within flight. Thanks to developers of this brilliant simulator we have chance to experience the same gyro disfuncionalities of gyro instruments. At this stage of development, I did't notice any errors in altimeter yet but I am sure it will be done at some stage... Anyway like in real life remember to correct your directional gyro after vast and rapid changes in altitude, heavy aerobatics or g-loads, eventually every every 15min.


Totally agree - What a brilliant sim. I started my flying career in a DeHaviland Chipmunk and that had the same compass - Actually it was like the Blenheim with a T shaped double lines on the bezel. It was in the same place as the Spit and hurricane, it was hard to see or to reach the bezel and adjust it while trying to fly straight - essential if you want it to read correctly. I think the Altimeter lags a bit in descent. The DI definately drifts in Hi-G manoeuvres.

Okay - Anyone know if Variation is in the Sim and when we put the Grid in missions, is it aligned with True North?

All in all a BRILLIANT Sim.

Lt Gosling
VBF-12

[CaptainDoggles]

Magnetic declination in the sim is 10 degrees West.

Unsure if the grids are aligned with this or not.

[VBF-12_Gosling]

Magnetic declination in the sim is 10 degrees West.

Unsure if the grids are aligned with this or not.

Outstanding, Thanks. That sounds about right. Its about 2 degree west now and was about 4 degrees west when I started flying 25 years ago so 10W adds up.

Gosling
VBF-12

[IvanK]

Grids point to Grid North. So any angles measured then need to be adjusted for 10W variation.
(Add 10 degrees) to get Mag.

[VBF-12_Gosling]

Grids point to Grid North. So any angles measured then need to be adjusted for 10W variation.
(Add 10 degrees) to get Mag.

Thanks, but are you sure you meant to say that.

I think you meant - Grids point to True North. Otherwise, your next sentance does not make sense.

CADET = Compass ADd East to True

[jf1981]

Hi does any know how to set the compass if it works in the spit mk1a or procedure thanks in advance

You have to set keys for magnetic compass & for gyro.

Basically most people use to move the bottom one (magnetic) until indicated north and real north (the yellow T marker) are parallel then read the indicated heading and set gyro at same. Then you would follow the gyro.

For myself, I have an easier & faster trick.

Just keep the magnetic indicator as it is. Read the indication in front of the yellow T marker, and set the gyro to the symmetric value.

For example, if the magnetic compass points to 350, you are heading 10.
If it points to 270 you are heading 90.
If it points to 30 your heading is 330.
If it points to 150 you are heading 210.
0 is 0 and 180 is 180 but for other readings make the symmetry.

Also remember to recalibrate sometimes and always after strong maneouvers as the gyro will deviate. Only the magnetic will remain. And finally, the geographic north has 10 degree difference with magnetic north. So if you read on the map heading 90 you have to head 100 magnetic compass. Just add 10 degree to get the magnetic heading, the only one which you have access to.

[Skoshi Tiger]

Here's my take on it.

http://www.youtube.com/watch?v=O9ZRDkt6ODw


Cheers!

[Osprey]

I tend to just read the magnetic these days because even the slightest move upsets the DI. The DI is about as useful as the artificial horizon - is this broken in game or was it just a useless instrument?

[IvanK]

So once the 109's gyro distortion gets implemented, how did they take care of it? The whole compass thing gets me, glad I can dead reckon almost everywhere on the map! :)

No Gyro to it in the 109 just a straight out Raw Mag compass with all the usual errors associated with such. "ONUS" Nippy on North Sluggish on South plus the acceleration errors :)

As for those with Gyro instruments I think the Gyro precession is a little overdone.

[phoenix1963]

As for those with Gyro instruments I think the Gyro precession is a little overdone.
I agree. Most of the reason for having a gyro direction indicator is surely that it is MORE immune to aircraft movements than the magnetic compass!

I also think this is an area where the limitations of being a PC based sim need a palliative. A real pilot would simply lean forward, twiddle the compass ring then set the gyro DI. An operation taking maybe 10 seconds.

In this sim, it's painfully hard and the aircraft usually rolls and turns a little while you zoom-in on the instruments, immediately introducing serious inaccuracy.

What we need is a "synchronise compass and DI" button or command, which does this action, maybe taking 10 seconds to do so, while we try and keep the 'plane level. That way it would introduce realistic error rather than unrealistic error.

My twoha'pworth,
56RAF_phoenix

[IvanK]

"What we need is a "synchronise compass and DI" button or command, which does this action, maybe taking 10 seconds to do so, while we try and keep the 'plane level. That way it would introduce realistic error rather than unrealistic error."

That is a good idea .... Devs informed directly.