1. #1
    Tully__'s Avatar Global Moderator
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    I've seen a number of people asking about long range navigation by ded reckoning so I thought I'd give it a try. On the GoF map (Leningrad) I set up a mission taking off from Helsinki and landing at a reasonably obscure field some way south east of Leningrad. The destination was next to a small town, so reasonably easy to spot of I got close.

    The results, after 51 minutes at 300km/h IAS & 5000m, 8.35km off target (about 6km south and about 4km overshoot). Navigation was entirely precalculated for climb to 5000m, set up on heading 106 directly over takeoff field @ 300km/h IAS, fly bearing 106 degrees @ 300km/h IAS for 51 minutes and I should be directly over the target.

    I had icons, map icons & minimap path turned off and didn't check for landmarks until the clock hit the 51 minute mark. Altitude deviation was less than +/- 600feet (have to keep it fairly close to the intended alt or TAS varies too much ) and speed deviation was less then 10km/h through most of the trip. Heading variation was less than +/- 4 degrees and for most of the trip less than +/- 2 degrees.

    Once at the target, it took me about 30 seconds to find how far out of line I was.

    When flying this sort of navigation for carrier missions I would plan the mission slightly differently. Ships tend to be a bit hard to see from 5km up so cruise altitude would be lower, at least for the final 30km or so. This would allow the pilot to spend the last 5 minutes looking for the ship rather than hoping he hasn't overshot .

    If anyone is interested I would be happy to put up an explanation of working out the navigation. It's actually easier in the game than in real life as the maps are flat (unlike the earth which is round) making distance and direction calculations much easier.

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  2. #2
    Tully__'s Avatar Global Moderator
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    I've seen a number of people asking about long range navigation by ded reckoning so I thought I'd give it a try. On the GoF map (Leningrad) I set up a mission taking off from Helsinki and landing at a reasonably obscure field some way south east of Leningrad. The destination was next to a small town, so reasonably easy to spot of I got close.

    The results, after 51 minutes at 300km/h IAS & 5000m, 8.35km off target (about 6km south and about 4km overshoot). Navigation was entirely precalculated for climb to 5000m, set up on heading 106 directly over takeoff field @ 300km/h IAS, fly bearing 106 degrees @ 300km/h IAS for 51 minutes and I should be directly over the target.

    I had icons, map icons & minimap path turned off and didn't check for landmarks until the clock hit the 51 minute mark. Altitude deviation was less than +/- 600feet (have to keep it fairly close to the intended alt or TAS varies too much ) and speed deviation was less then 10km/h through most of the trip. Heading variation was less than +/- 4 degrees and for most of the trip less than +/- 2 degrees.

    Once at the target, it took me about 30 seconds to find how far out of line I was.

    When flying this sort of navigation for carrier missions I would plan the mission slightly differently. Ships tend to be a bit hard to see from 5km up so cruise altitude would be lower, at least for the final 30km or so. This would allow the pilot to spend the last 5 minutes looking for the ship rather than hoping he hasn't overshot .

    If anyone is interested I would be happy to put up an explanation of working out the navigation. It's actually easier in the game than in real life as the maps are flat (unlike the earth which is round) making distance and direction calculations much easier.

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  3. #3
    heywooood's Avatar Senior Member
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    Tully.... The X MOD

    Nicely done... yes dead reckoning is good in FB.




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  4. #4
    In real life ships are quite easy to spot from 5,000, m (bout FL 200) presuming they are not hiding under a cloud. Because of the low scattered to broken cloud bases often found over the Pacific, searches by PBY's etc. were often flown at low altitude (eg. 1500')

    The big variables are if the carrier is going to be at "point option" when you return and the winds aloft. In a plane crusing at say, 160 kts, a 30 knot wind makes a big diference! Ships would send up weather balloons to make estimates, however many skippers discouraged this as it of course provided a visible clue to the presence of the ships, possibly to be seen from some distance.

    Sounds like a good excersize, one from which everyone could learn much.
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  5. #5
    Suppose you departed for your carrier after a furball session, from an unknown position, and your carrier had been steaming all the while, after you left it?

    Can you work an interception calculation?

    Is the chart you used based on lat/long or is it the silly grid that they have been using?

    I do not fly FB so I don't know what the scale of the map is, thus how you meassure distances. (The US Navy used blank Mercators with their plotting boards in WWII.) Is there any wind? Any variation? Is TAS calculated on standard day lapse rate in this sim?

    Do you have to convert from meters of altitude to feet to find flight level temperature for TAS calculations? The E6b is set up on feet, Knots and Nautical miles, as you no doubt know.

    What navigation habits do I need to unlearn? Or do I just have to convert a lot of stuff to get everything over into the same terms as RL navigation uses?

    The grid maps are "for the birds" not for fast flying aircraft, flying long distances over water, in my opinion.

    I think they should use standard navigation charts and instrumentation, not grids and the metric system for PF.
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  6. #6
    What would be very nice is a calculator that would calcualte the same type of "data" for Nav, but just plug in the "numbers", so to speak. It gets complicated as you have to figure time elapsed (in combat) and estimate of location if only over the ocean. It would need to be automated to some degree if they can even do it, which I doubt.You could have a plotting board come up, but with windows for plugging in the #s, for auto calculation.

    Pilots would fly LOW because the wind variation is less under 1000ft.

    Also, grid type map would be helpful, to plot carrier course.

    I have actual Navy WW2 Navigation books in the mail, on the way. I may post some of this stuff.
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  7. #7
    Did you adjust TAS from IAS when you flew higher? and 8 km isn't that far off after 51 mins. But Generally you would look for landmarks inbetween that time yes? That was the problem in the Pacific, you needed a Point of Reference, Like an Island, to Navigate Anywhere.


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  8. #8
    Tully__'s Avatar Global Moderator
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    To fly this mission I used the coordinates used by the game. The waypoint/object data in the mission files includes coordinates (in metres) for distance east and north of the soutwest corner of the map. The map grid is in km or km x 10, depending on zoom level. In addition to the alphanumeric reference at the top & right of the map, there is another set of reference in the bottom & left edges of the map. Every tenth grid line has a number which is distance from the bottom or left edge of the map in km. The grid corresponds exactly to the coordinates in the mission files once you take into account the metre/kilometre conversion.

    Using basic geometry I calculated trip distance and using basic trigonometry (arctan) I got heading. For TAS calculation I used the table supplied in the "MANUAL" folder on FB game disc 2.

    I chose 5000m because it gave me very close to 400km/h TAS (a round number ) at 300km/h IAS. That wasn't necessary, any speed would do.

    Simply dividing planned TAS by distance gives time @ heading to reach intended destination. All that remains is setting up heading/speed/altitude at the right place to start the timer.

    As I mentioned above, FB maps are flat and "great circle" nav can be ignored in favour of basic cartesian geometry. The only tricky bit is taking the difference between TAS & IAS into account at altitude. If you were prepared to fly the whole mission at sea level even that could be mostly ignored .

    ------

    For carrier missions, total mission time and planned carrier heading would have to be factored in when choosing your heading for the home leg. It would be similar to planning for a round trip mission with landing at a field different to but near your takeoff point. I've flown a couple of those some years ago in CFS2 and for those I simply flew to a point that I knew the carrier had already passed then turned onto the same heading the carrier was supposed to be on. With about 150knots more than the carrier can manage, it doesn't take long to catch up and you're more or less on a landing approach heading when you find it (provided your LSO allows straight in approaches ).

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  9. #9
    Tully, how did you figure your ground speed during the climb? As I understand it, the game has no wind modeled, so TAS would be the same as ground speed during cruise flight, but for a climb to 5Km, there would probably be a lot of room for error if the difference between climb speed and actual ground speed weren't taken into account.

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  10. #10
    <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by IV_JG51_Razor:As I understand it, the game has no wind modeled, <HR></BLOCKQUOTE>

    Try loading up a mission with a fully laden He-111 in a thunderstorm. Then you'll experience some wind!!!! Last time I tried it, I couldn't even line up to taxi, never mind take off!!

    whit ye looking at, ya big jessie?!?!


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