Northern navigation...

Northern Skies · Post by **Northern Skies** » Wed Jul 07, 2004 8:31 pm

Can anyone help me find some in-depth info on navigating where a mag compass is useless? I've always been interested in how it was done before everyone had GPS. I'm planning to fly up between 65-70 degrees north in a few months, so i think it'd be good to know.

Also, any thoughts and references to info about a shadow-pin pelorus? An astrocompass is way too awkward for my situation.

thanks.

ahramin · Post by **ahramin** » Wed Jul 07, 2004 11:51 pm

U.S. Air Force Publications Website

Manual of air navigation

http://www.e-publishing.af.mil/pubfiles ... 11-216.pdf

PT6-114A · Post by **PT6-114A** » Thu Jul 08, 2004 8:27 pm

GMT X 15 minus West Longitude = True bearing to the sun
put GMT as (eg) 1515 = 15.2
1530 = 15.5 once you get the answer just point into the sun and reset your DG an old dog showed me this

Cat Driver · Post by **Cat Driver** » Fri Jul 09, 2004 5:38 am

It has been many years since I used that method of finding true heading, but it works until the sun goes down for the winter in the high Arctic.

Cat

onceacop · Post by **onceacop** » Fri Jul 09, 2004 7:33 am

You can navigate by using the Rule of 60. I read about it in a bush flying book but need to refresh my memory before posting the rest. Maybe other here know what this is. Will post again after looking up the info.

just curious · Post by **just curious** » Fri Jul 09, 2004 11:29 am

Navigation while on the continent is a little dependent on where you will be flying. Along the Mackenzie Valley, and in the western arctic say wet of the mag anomoly at ......, operation is feasable in Mag. NDBs are to be found at every YK and GNWT airport, and winds in the west are given in Mag. All of the middle runs in true.

An astro compass is extremely useful, but if you don't have the panel mount, and a little practice...

Fifteen X GMT minus W Long will be your best method for setting gyros. Something else in this GPS age is to select your ADF to a nearby facility, and select your GPS to the same NDB. Ensure your GPS is set to variation zero and note the Relative bearing of the facility on your GPS, and rotate your gyro so that the ADF needle points to the GPS derived bearing.

Get the maps for your trip before you get up north, since map stores north of YK or YXY are few and far between, and usually claened out by the pilot that preceeded you.

Some useful links:
http://map.aeroplanner.com/mapping/chart/smartchart.cfm

Online maps showing a bit of the western arctic

http://aa.usno.navy.mil/data/

Sunrise/Sunset plus astronomical data... useful if you find an astro compass

http://www.airrouting.com/content/tdcalc.html

Time Distance Calculator[/code]

Northern Skies · Post by **Northern Skies** » Fri Jul 09, 2004 1:37 pm

PT6-114A wrote:GMT X 15 minus West Longitude = True bearing to the sun
put GMT as (eg) 1515 = 15.2
1530 = 15.5 once you get the answer just point into the sun and reset your DG an old dog showed me this

Cool! That works really well. I Just tried it on my balcony and it was off by 0.7 degrees. The sun is almost directly overhead, too. I dont understand why they really didnt want to teach this to us in college.

ahramin · Post by **ahramin** » Fri Jul 09, 2004 1:59 pm

Northern: Where did you get a compass that is accurate to 0.1°?

Northern Skies · Post by **Northern Skies** » Fri Jul 09, 2004 3:16 pm

It's not.

It's a Suunto MC-1. The markings on the rose are every 2 degrees.
When I took that bearing, I eyeballed it to be a bit more than a quarter, but a bit less than half way between the two markings. Hence the approximation of 0.7 degrees.

However, there are at least 5 possible errors I didnt account for.

Northern Skies · Post by **Northern Skies** » Fri Jul 09, 2004 4:15 pm

Thanks Just Curious, that helps. The Navy one is really interesting.

One Problem though, does the 15gmt-lon method have any exceptions? I just tried it again: (23x15)-125.2=219.8 but the chart data on that website says it should be 241.5 and my compass bearing read 219 magnetic which works out to 240. What went wrong?