View Full Version : Compass and Declination.
Hello, All.
Just a few questions for those who know.
Does every map in rotation account for the declination between magnetic north and true north?
I'm pretty sure Fall Rot has it. What would it be from Abbeyville in this map?
Is the declination historic to 1940?
~S~
are you talking about magnetic variation?
are you talking about magnetic variation?
Yes.
I thought it was 10 degrees?
235 Sqn. Coldstreamer (QJ-X)
Mar-14-2014, 13:41
d.rock
Magnetic variation for Great Britain July 1940 was. 10 Degrees 8 minutes, West of Grid North. With a annual change of 12 minutes east per annum
d.rock
Magnetic variation for Great Britain July 1940 was. 10 Degrees 8 minutes, West of Grid North. With a annual change of 12 minutes east per annum
10 degrees west makes sense. So +10 to the heading should do it.
Thanks for the answers.:thumbsup:
I'm not sure about this. Over at ACG we're on a campaign break so tomorrow night we are going to trial having a real ground controller. This means a single ground controller (actually me), is going to use our RDF to scramble the RAF and provide vectors and angels to intercept the incoming LW force. Should be an interesting experience... anyway, the thing is, as part of the preparation we've been checking out the vectors and timings and last night we did a bit of practice.
I've used real aeronautical maps to work out the direct headings (T) to fly between a number of RAF airfields and some key landmarks. There was no wind so that didn't need to be factored in.
Interesting results...
Biggin Hill to Dover is 104T. We flew 114M thinking that Magnetic Variation in 1939/40 was 10W - but this took us about 10 degrees off course! Timing was OK though.
Turning around, we flew an uncorrected track of 298T to RAF Gravesend. Timing was spot on at 11 minutes - and it was only in the last couple of minutes that we had to make a correction of about 10 degrees left - which could have been attributable to natural errors. Had we flown a 308M track we would have been way off.
It could be investigated further but initial indications are that Magnetic Variation is not modelled.
Would be interested in anybody else's findings.
In FMB set a wind 0 to 180 and place a Spit.
Play the mission, align the plane compass with North.
Open map, and using map tools trace a line over plane direction - is the line on plane icon - with protractor measure the angle, a plane with compass pointed to N is aligned on map a 10 degrees left.
I do a lot of 14 - 22 minute channel crossings.
On Autopilot in the Blennie.
Usually using Tom's Vintage Map: Link to the vintage map. (http://theairtacticalassaultgroup.com/forum/showthread.php?t=12895)
and a stopwatch.
I always make the 10 degree correction.
I always end up where I was going. (set up errors and Too Much Beer notwithstanding).
In fact My Flight planner has a spot for the correction so I don't have to figure it out on the fly.
Bombing Flight Plan Blanks: LapBoardPlannerBlanks.pdf (https://dl.dropboxusercontent.com/u/24241061/LapBoardPlannerBlanks.pdf)
https://dl.dropboxusercontent.com/u/24241061/Clipboard%20Center%20Planner.jpg
3./JG51_Heiden
Nov-24-2014, 02:37
I don't really account for the variation when I fly. Everything is VFR, so if you're +/- 10 degrees on heading and using terrain association, you'll be able to get where you need to go.
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