Point to Point Navigation question

[mx22]

Hi guys,

 

I'm trying to teach myself Point to Point Navigation in F-5 and having a bit of a problem. Or perhaps just a question...

 

I've created a custom mission with some navigation points, screenshot below. But basically:

 

1) take off from Kobuleti, TACAN - 67X

2) WP1: Kutaisi airport - 56 degree radial, 32 miles

3) WP2: Senaki-Kolkhi airport - 18 degree radial, 21 miles

4) etc (left out to keep things brief)

 

I'm using this link to teach myself how to fly:

http://code7700.com/1979_fix-to-fix.htm

 

WP1 is straight forward, it's pretty much a straight line from take-off to the waypoint.

For WP2, after drawing a line between current radial and the one I'll be going, if I turn the 'card' counter clockwise (just as shown in the link above) until the line that connects two radials is vertical, my new course is incorrect - I'll be heading in the wrong directions:

 

- current radial: 56

- upcoming radial: 18

- desired heading after turning 'circle' counter clockwise is around 95 degrees or so.

 

But 95 degrees is an opposite direction from where I need to be heading. It looks like I need to be turning 'card' clockwise instead, which gives me a heading of 275.

 

To me it looks like difference between the example in the link above and my mission is that author goes from 270 to 305 radial (ie higher radial), where I'm going from 56 to 18 radial (lower radial). Am I correct in assuming that any time I go to a lower radial I will need to be turning 'the card' clockwise and when to a higher radial 'the card' goes counterclockwise?

 

Thanks!

Edited April 28, 2017 by mx22

[VampireNZ]

Nvm

 

Edit: - Thread with a TACAN nav video, haven't watched it myself but Bunyap does some pretty good vids. - https://forums.eagle.ru/showthread.php?t=186376

Edited April 29, 2017 by VampireNZ

[mx22]

Sorry, I should have been a bit more clear - all navigation is done through original TACAN (Kobuleti, 67X). The point of exercise is to fly along predetermined route using original TACAN only. So 18 degrees radial, 21 miles is calculated off original TACAN. I chose the other airfields as navigation points simply because it makes it easier for me to see if I messed up somewhere in my calculations.

 

PS. Between the fields in the screenshot, I can obviously navigate by dialing TACAN frequencies of the airfields I'll be heading for. For airfields without TACAN stations​, I can use NDB frequencies. But exercise here is to fly through points that are not located over any beacons forcing me to use original TACAN station only for navigation.

[aaron886]

Oof. Don't know why you'd want to put yourself through the pain of point to points in a sim but...

 

That link is exactly how I was taught. We call it the Pencil Method.

 

These are the two most important things to keep from getting mixed up, and I think they'll solve your problem:

1. YOU are on the tail of the bearing pointer! (This is the most common early mistake)
   
2. The NAVAID is the airplane symbol at the middle of the HSI
   

 

I believe what you've done is mentally place yourself on the 018 bearing from Kobuleti, and Senaki on the tail of the bearing pointer (050)... that's backwards! I like to build it like a picture, step by step. Start by locating yourself first, then the NAVAID, and then the desired point. (Make a triangle and mentally check it.)

 

 

Note that I set the CRS to represent the desired bearing from Kobuleti (ish?) "Scale" is 32nm, since that is the larger of the two distances.

 

Estimate the location of Senaki along the desired bearing. I aimed for about 2/3rds

 

Start the line from your position toward Senaki's position. This is what you got backwards.

 

Now, if we make the turn to our estimated required heading from overhead Kutaisi, we have to remember that you need to continually update your solution to get a direct course. (It's worse with wind!) If we make a 30 degree bank turn at 250 knots, it takes up quite a bit of space:

 

...and by the time we roll out, our HSI looks like this:

 

Time to take a new estimate.

 

One more thing to add: we can make this slightly easier on ourselves if we get an even rougher estimate first and then refine it. To that end, you can "split the heads" of the needles initially by turning to a heading roughly between the heads of the needles. To make this reasonably accurate, slightly favor the needle head with the larger DME instead of precisely splitting the heads. If you're quick enough, you can skip the second step or even avoid this entirely.

Edited April 29, 2017 by aaron886

[Ramsay]

Thanks for the clear explanation

[Rudel_chw]

Amazing explanation, thanks a lot ... i'm saving this thread on my 'dcs tips' bookmark folder :) ... and going to practice it.

[mx22]

Oof. Don't know why you'd want to put yourself through the pain of point to points in a sim but...

 

Thank you very much for such an informative post!