Sextant Tutorial Video Part 2 - Following along on a flight

The "Queen of the Skies"
new reply
Stearmandriver
Senior Airman
Posts: 174
Joined: 12 Mar 2017, 22:33

Sextant Tutorial Video Part 2 - Following along on a flight

Post by Stearmandriver »

Hi all,

This is the sequel to that first video tutorial on navigating with the sextant gauge. I don't know if it's needed since folks seem to be doing just fine with the gauge now, but I've had it recorded for a while and finally got the time to publish it. It's a flight from Christmas Island to Bora Bora, using only dead reckoning and the sextant. The video consists of an intro / explanation of the setup, then cuts away and picks back up for the various checkpoints, finding land, and the arrival. It's still pretty long, but I put the timestamps of each section in the description, so you can just watch one section until you understand, then skim on to the next etc... so if you don't have almost 2 hours to watch the whole thing (which I don't expect most people do) you can hopefully still find some value to it.

I made some dumb mistakes and did some rambling - it was late and I was tired, but I knew it'd be my only available chunk of time to record it for a while, so I pressed on. Bear with me ;-).

https://www.youtube.com/watch?v=3M-IJ7h0vQM&t=5456s

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Sextant Tutorial Video Part 2 - Following along on a fli

Post by TreeTops »

Thanks mate. Look forward to watching it.
Cheers
Trev

User avatar
Lewis - A2A
A2A Lieutenant Colonel
Posts: 33284
Joined: 06 Nov 2004, 23:22
Location: Norfolk UK
Contact:

Re: Sextant Tutorial Video Part 2 - Following along on a fli

Post by Lewis - A2A »

Brilliant job man, thanks for sharing with the fs community, I know I cant be the only one that learns best via video type tutorials over text.

thanks,
Lewis
A2A Facebook for news live to your social media newsfeed
A2A Youtube because a video can say a thousand screenshots,..
A2A Simulations Twitter for news live to your social media newsfeed
A2A Simulations Community Discord for voice/text chat

User avatar
Adam_NZ
Technical Sergeant
Posts: 603
Joined: 03 Feb 2011, 01:00
Location: Auckland, NZ
Contact:

Re: Sextant Tutorial Video Part 2 - Following along on a fli

Post by Adam_NZ »

Lewis - A2A wrote:Brilliant job man, thanks for sharing with the fs community, I know I cant be the only one that learns best via video type tutorials over text.
+1 from me!!!

I've worked my way through #1 (thanks) but need to brush up on my dead-reckoning skills before I have a go at #2!

Adam.
--
Image--Image

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Sextant Tutorial Video Part 2 - Following along on a fli

Post by TreeTops »

Great stuff mate. For me the most interesting was the analysis at the end. What was the tracking program you were using. That looks really useful for looking back over a flight.
The track clearly shows when calculating course to correct that the distance used is not what the sextant shot but the present location minutes after the plot.
An interesting situation with this flight is the sun LOP for Bora Bora being close to parallel to the flight course. So the previous speed shot and calculated speed become very important to give a decent point to begin descent due to the time gap between last shots using stars and then the sun being up far enough.
Was there any significant wind on this flight? It has sent me on a search for what they used to estimate winds aloft away from visual location. Having an island 1-2 hours into the flight gives a good fix, but leaving a coast straight out into 5 hours of ocean is a different thing all together.
Cheers
Trev

User avatar
Adam_NZ
Technical Sergeant
Posts: 603
Joined: 03 Feb 2011, 01:00
Location: Auckland, NZ
Contact:

Re: Sextant Tutorial Video Part 2 - Following along on a fli

Post by Adam_NZ »

I can answer some of these! The tracking utility is "Tiny Flight Tracker": https://www.aero.sors.fr/GE.html

For calculating wind drift, I use "Driftmeter" by Pierre Verster/Dave Bitzer and "Kill Drift" by Glenn Copeland.
https://library.avsim.net/esearch.php?C ... DLID=83525
https://library.avsim.net/esearch.php?DLID=75975

Both are old FS2004 gauges, but they seem to work fine in my P3Dv3.

I've had some really interesting flights in the Connie - using no modern navaids whatsoever - only the sextant plus these two (and no shift-z or shift-5 cheating!!).

I also use real weather (as injected by OPUS) so find I often have to check that the wind hasn't shifted. Very often, the wind conditions at cruise altitude can be very different to that at take-off/climb.

The "Killdrift" gauge is a bit of a cheat - and I suppose if you can see the ground well enough when using the "Driftmeter" then you can probably work out where you are visually(!!) but they're both good fun to use.

I suppose the *proper* way to do it would be to use dead reckoning and the correction calcualtions as described in the 2nd video.

Does anyone know any utility that can read off magnetic deviation from a point (that saves you manually querying the website)? Ideally a Google Earth add-on. I did find one overlay but it was for North America only.

Adam.
--
Image--Image

Stearmandriver
Senior Airman
Posts: 174
Joined: 12 Mar 2017, 22:33

Re: Sextant Tutorial Video Part 2 - Following along on a fli

Post by Stearmandriver »

Thanks Adam. Yep, it is Tiny Flight Tracker, I meant to put that in the description, sorry. The app tracks wind too, and it showed some shifting for sure, as you'd expect over that distance. As far as I know, pure dead reckoning checked with sextant shots is the only accurate way to get a wind check over open ocean without radio navaids.

On earlier flights I cheated somewhat during planning and used ASNs predicted winds aloft at each point. They still changed a bit from what was planned to what was experienced, but struck me as representative of the level of accuracy a modern flight plan would have. Of course they wouldn't have had that data in the 40s, much less the 30s, which is earlier than the Connie but roughly the era I'm modeling - the early Pan Am clippers. So, for this flight I used only current winds aloft at departure and destination, which would have been observable via weather balloon, and interpolated for the rest of the points. Next time, maybe I'll just plan a zero wind flight plan and take the winds as they come - just for a challenge.

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Sextant Tutorial Video Part 2 - Following along on a fli

Post by TreeTops »

They used a drift meter but I don't know if one of them is available in the sim, nor how to use it.
I agree about the departure and destination weather only would have been known unless it was a busy route and navigators would have exchanged information where possible in the air.
I tend to cheat and look at the SHFT Z wind numbers. I will try without next time. Just another step away from the precision mentality that modern aviation brings hey!! :)
Cheers
Trev

Stearmandriver
Senior Airman
Posts: 174
Joined: 12 Mar 2017, 22:33

Re: Sextant Tutorial Video Part 2 - Following along on a fli

Post by Stearmandriver »

Hey you're right, I forgot about dropping drift markers since I've been focusing on night flights. I heave tested the drift meter gauge over land and found it to not be entirely accurate, but still useful. So.. I wonder if this guy's technique could be used to create a droppable drift marker mod? Beyond my coding abilities, but if someone's interested..

http://www.sim-outhouse.com/sohforums/s ... alpha-test

new reply

Return to “Lockheed Model 049 Constellation”

Who is online

Users browsing this forum: No registered users and 8 guests