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Post by connieguy on Dec 24, 2018 15:22:46 GMT -5
Some years ago I abandoned flight simulation of modern jets as too boring and took up flying propliners because there seemed to me to be simply more to it. This was particularly the case once I discovered the Manfred Jahn/Connie Team Constellations, where the various statistics available on the engine information panels often tally very closely with those given in flight manuals for the real aircraft. Some simmers take the view that they are the pilot and that as navigating the aircraft was the role of the navigator they are therefore fully entitled to use a modern GPS or the display in a program such as the freeware Plan G to tell them where to go. I have no argument with this, because it is for them to do as they wish, and indeed it is what I have done hitherto. However, as time has passed I have become increasingly uneasy about it. One has only to read works like Gann's 'Fate is the Hunter' to realise how dangerous flying propliners could be, and that part of this was the danger of getting lost. Thus, there were times when the navigator was not simply a subordinate to the pilot, but the most important person on board, upon whose professionalism the lives of all the others depended. There are other threads on this forum which discuss the navigation aids used on multi-engine aircraft in the 1950s, including the system known as Loran. However, there is no simulation of Loran available for FS9 and even if there were it is clear that it was not always as effective as was desirable, even in the limited areas where it was available. In these circumstances aircraft navigators crossing large expanses of sea and desert fell back, like mariners in the case of the seas, upon celestial navigation, based upon a knowledge of the heavens which went back thousands of years. In this context two of the vital instruments were the driftmeter and the sextant, both of which are available for FS9 thanks to the efforts of members of the virtual airline DC3 Airways and especially those of Dave Bitzer and Mark Beaumont. My skills have never included things remotely mathematical. When I was at school Algebra seemed to me to be complete fantasy and even today I have only to look at the simplest mathematical formula to remember the sense of panic which often gripped me sitting at a school desk fifty years ago. Hence I have approached 'real' navigation with considerable trepidation, downloading the Beaumont-Bitzer sextant several times, looking at it, leaving it on my hard drive without doing anything with it, and then eventually deleting it. Now that I have made some real progress I have realised that I was right not be satisfied with the gps, because real navigation is exciting and when you get it right extremely satisfying. I have also realised that while I would not describe it as easy, nor is it as difficult as I anticipated. Of course this thread is not intended for those determined to stick to the gps or for those who are already expert navigators, for I know that among the forum's members may well be people who navigated real aircraft before the age of gps. It is intended for people who, like myself, might be interested if they can be shown how to do it in a way which is accessible and reasonably easy to understand. If experts wish to chip in that will be good and much appreciated, but whether they do or not here goes:
Firstly, there will need to be some modifications to FS9. A utility which I have used for some time and which is absolutely essential is Nils Meier's PDFKneeboard, which allows pdfs to be read in the cockpit without even going out of full screen. Also essential if you are going to be looking at stars (and you are) is a better representation of them than that in stock FS9. I am using one called MyFSStars which was done by Juergen Haible some years ago and displays the stars you need to see in an uncluttered way. Unfortunately, the website from which I obtained it is no longer in existence. Another version with a lot more stars is available from Norbert Pachner, but the greater number of stars tends to make the important ones stand out rather less well, at least on my system. A very good free and portable astronomy program is Stellarium, and it is easy to see the night sky from any geographical location and date that you want. Iceland in December 1956? No problem. The Pachner stars are available here:
Then there is the Dave Bitzer driftmeter, which is readily available. I believe Version 7 to be the latest and that is the one I have. On the sextant I recommend the version reworked for FSX (it works in FS9 too) by Kronzky:
This contains a very clear explanation of how to take a series of three sextant shots, although you will get a fuller manual if you also download the version of the gauge issued by Mark Beaumont and Dave Bitzer in 2008 and the first version of (I think) 2005. However, I have found the clickspots for changing the digits rather confusing, at least on my system, in the 2008 version, while in the Kronzky edition things are more straightforward. The link above will also take you to two rather good You Tube videos done by someone who has navigated the A2A Constellation in the Pacific in FSX. All these things have to be installed, of course, and I give below an image of the modified virtual cockpit of my Jahn/Connie Team L 1049H.
Quite some time ago I removed the autopilot from the glareshield and replaced it with: firstly, on the right the analogue clock with adjustable hours by Pierre Fasseaux which will not change as the aircraft crosses FS time zones. It can therefore be set to Zulu/UTC/GMT time and will remain there, avoiding at a stroke the problems caused by FS9's inadequate treatment of time zones. Correct local times can nearly always be found in airline timetables from the period, and I set these on the two clocks on the main panel. Zulu time is also available on the sextant; secondly, a magnetic compass. This one, on trial at the moment, is from the MAAM DC3; thirdly, a little panel which allows me to switch the rmi indicator between VOR and ADF signals. This is adapted from the Connie Team L 1649 Starliner. Important things - the autopilot, engine information panel, sextant, driftmeter and flight engineer's station - are summoned by means of invisible clickspots over some of the gauges (the engineer's and engine panels are also available from icons provided by the Connie Team). I use the freeware FSRecorder to move around the virtual cockpit and have added two new views - the first simulates what would have been the view from an astrodome and the second produces the view below the aircraft necessary to use the driftmeter. The simulated sextant can in fact be used without looking outside at all, but nevertheless a very clear view of the heavens can in certain circumstances come in extremely useful - see below.
Then there is a certain amount of hardware and literature beyond the sextant manual. I think probably essential if one is going to replicate the old methods fairly fully is a Dalton E6B Flight Computer. I got mine on E-Bay but they and similar things are still in use by pilots and available new, for example from Flightstore. Something else that is almost priceless is the introduction to navigation issued by the Army Air Forces Training Command in 1944 and available here:
It can be downloaded complete or in individual sections. The latter are rather easier to handle and of course particularly important pages, such as that on calculating double drift, can be printed out. Not all have the gift of explaining reasonably complicated things which they understand perfectly to complete novices, but the authors of this manual made a pretty good job of it, and the descriptions of how to use the Dalton E6B I have found easy to follow. The sextant gauge includes a chart but even so I have found it difficult understanding where a star shot is actually placing the aircraft and as a result have created a physical chart. Lines of longitude and latitude have been drawn on a piece of graph paper and a piece of clear plastic fastened down on top of it. Each square of latitude represents five nautical miles and varying distances in longitude. This can be used to plot courses and parts of courses with a dry wipe pen (using whatever lines of latitude and longitude are appropriate) and everything can be wiped clean when done ready for the next use.
You will also need a timer. This can be done within FS, but I have preferred to buy a kitchen timer which will count upwards and therefore act as a stopwatch. This might all seem a lot of effort, but it is worth it. Let us now get to a real flight. My early efforts saw basic errors such as not realising that the course offered by the sextant gauge after a star shot is a reciprocal course and that therefore 046 means actually steering 226, with whatever allowance is necessary to convert this True Heading to Magnetic. However, I am now hopeful that I can do rather better.
My chosen route is from Burtonwood (US designation S590) near Manchester in the UK (Prestwick would do just as well) to Keflavik, Iceland. First of all, it is a route I have flown both ways a number of times and I am familiar with the sort of winds one might encounter, especially quite strong south westerlies but also quite strong easterlies, sometimes both on the same flight. Also, at nearly 900 nm and about four hours it is a suitable length and as there are radio beacons at both ends the distance which needs serious navigation is considerably less. The first thing to do is plot a flight plan, using the freeware Plan G which calculates automatically various things that real navigators would have had to do manually. As the flight is taking place in 1956 I am not using radio aids which were not present then, so there is no VOR at Benbecula or at Keflavik. There is one at Dean's Cross and also an NDB with a range of 75 nm at Barra. After that we are on our own until we pick up the 112.5 nm range NDB at Vestmannaeyjar off the southern coast of Iceland. The plan is of course routed through these points, and also through two user waypoints created in Plan G in the north Atlantic, waypoints which I have called ICO13 and ICO10. The Plan G flightplan tells me the True Heading and Magnetic Heading from one point to another and distance between them, as well as the time it will take to fly these distances assuming a cruising speed of 240 knots. I have gone for 240 even though I know that a Super Constellation flying at FL160 with a relatively light fuel load will probably be doing something between 250 and 260 knots true airspeed. A screenshot can be taken of this flight plan, it can be converted into a pdf and as such consulted through the pdf viewer during the flight.
It is mid December and we shall take off at about 14:30 Zulu (and Local) Time. By the time we reach Barra night should be falling and we shall be able to see the crucial stars, but prior to that views of the ground should enable us to see what we make of the driftmeter. The next thing is that we need a weather forecast. I use FS Global Real Weather and opt for a dynamic file starting about 2pm on the afternoon of 22nd December 2018. Once downloaded I put in the flight plan and am given the winds for all the points upon it, including ICO13 and ICO10. This I copy and paste into Word and then save as a pdf, so that it too can be consulted in the cockpit. And it has an interesting tale to tell. Over the British Isles we can expect strong westerlies - 41 knots at 279 degrees at 17,500 feet at Dean's Cross and 22 knots at 269 degrees at Barra. However, by ICO13 there has been a change to a 9 knot wind from 029 degrees and this is maintained at ICO 10 with a 12 knot wind from 031 degrees, while Vestmannaeyjar is not too dissimilar. Of course, these winds may have changed by the time we get to the points concerned.
The first part of the flight is straightforward. On what is a dark afternoon we take off from Burtonwood runway 27 and turn north for Dean's Cross. Climb to FL160 is uneventful and I set the engines for cruise in high blower at 1700 BHP. Fuel to air ratio is 0.064 after I have pulled the mixture levers right back, which is ideal. Once on the autopilot I shall need to check the engine settings periodically but it is time for the real business to begin. Fortunately we are high enough to pass over a thunderstorm raging below. I have connected the flight to Plan G and can see it proceeding there, but as I approach Barra I cover the monitor so that I can see nothing. After we land, if we get there, I will eventually be able to see on the Plan G track exactly what happened. The Barra NDB will get us off to a good start, because I can follow the correct course by aligning a needle now pointing backwards on the right heading. I know that somewhere between Barra and ICO13 the wind is likely to change and this is where the driftmeter comes in very useful. The multiplicity of small islands down below reveal that we are initially drifting right to the tune of 5 degrees on the driftmeter, as is consistent with a westerly wind. But quite quickly we are not, because the driftmeter now shows a drift of 1 degree left. Clearly we have now picked up the forecast easterly winds. I adjust the aircraft heading to what I hope is the correct one and wait for the star shot in the vicinty of ICO13, quite a long wait. In the meantime we have lost the islands but the driftmeter seems to operate not too badly on clouds and strongly suggests that the easterly wind is holding. If we were doing things strictly by the book I would now go to the appropriate website from the FS9 kneeboard and look up three suitable stars with their elevations and azimuths. However, the sextant gauge will work perfectly well if one simply pretends there are stars where one wants them to be, and as this is very much an experiment I decide to take the easy option. Thus I take one shot at an imaginary star directly off the starboard beam, another at one almost dead ahead and a third of one at an azimuth of 225 degrees. It is important with these shots to centre the stars in the sextant bubble accurately, because if one does not the resultant position will be inaccurate, possibly seriously so. However, the signs are good. The first shot places me only 5nm from my assumed position and the three together cross each other at a fairly definite point - if the crossing forms a distinct triangle something has probably gone slightly wrong. ICO13 is at N59 54 W12 18 and the sextant tells me that the plot has produced N60 20 W11 60 (the latter I take to mean W12 00). Plotting these coordinates on my physical chart (see the illustration of that chart above) shows that I have gone slightly too far north and am a little too far east, but not by very much at all. I turn the heading of the aircraft to port by what I guess is the right amount and wait for the plot at ICO10, a plot which is never made. Why? Because the stars are obscured by clouds, just as they might be in real life. All I can do is wait, and wait I do until I suddenly see the ADF needle jump into action and hear the welcome beeps which tell me that we have picked up the NDB at Vestmannaeyjar. The needle is about 5 compass points to the left of where it should be. After that everything is straightforward, although ATIS comes in rather late and tells me that landing is on Keflavik Runway 11 rather than 24, as one might have expected from the fact that the wind is about 5 knots from 241 degrees. I resist the temptation to land on 24 anyway and go round for 11, making a good landing on a clear night. After the long taxi in (Keflavik is a big place) and engine shut down there are 3,420 lbs of fuel left from the 15,084 lbs originally loaded. Flight time 4 hours and 7 minutes.
Then I take the cover off the monitor to look at the Plan G track, which generally confirms what I think has happened.
After Barra we held the course pretty well until the NDB gave out but then drifted east fairly slowly. In future I shall take shots more frequently than every 250 nm, although in this case that distance was effectively reduced by the use of the Barra NDB. The Plan G track only turns left some way after ICO13 but that is probably because it took me some minutes to take the star shots, get the result, plot it on my physical chart and work out what to do. If I had been able to take shots at ICO10 I would have been very near it, but as it was went slightly too far west until I picked up the Vestmannaeyjar NDB. Have I been navigating? I think so.
Just one more point before this rather long post concludes. On an earlier attempt at this flight I looked out of the astrodome and could see The Plough (aka The Big Dipper) and the Pole Star quite clearly. However they were slightly to port of the aircraft nose when I knew they ought to be to starboard for me to be travelling north west as I needed to be. Once the correction had been made all was well, although I was well off course. However, the amended stars for FS9 show the constellations quite clearly and the next thing is to become much more familiar with them. To be continued (perhaps).
Addendum: This is part of the night sky at Keflavik at 17:21 on 21st December, 1956, as seen in FS9 with the stars by Juergen Haible. I have identified them by setting the same time and location in the program Stellarium. Constellations in red. An experienced navigator must have been able to recognise them at a glance, but what the novice is looking for is easily recognisable patterns. Altair, for example, is the central one of a distinctive group of three stars which I have often noticed without knowing what it was. Near it is the distinctive grouping of the constellation Delphinus.
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Post by Tom/CalClassic on Dec 25, 2018 14:26:57 GMT -5
Hi,
Glad to hear you're having fun with the propliners. As you say, there is so much more you can do than with the modern day aircraft.
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Post by warbaby on Dec 25, 2018 23:19:37 GMT -5
Fabulous account connieguy. This report is a great inspiration.
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Post by connieguy on Dec 26, 2018 5:55:07 GMT -5
Thank you very much indeed. That is what I hoped some would find it.
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Post by Erik on Dec 26, 2018 18:42:24 GMT -5
Absolutely Ken, thanks for taking us along on this adventure. I admire the way you took this on, including the real equipment on your navigators' table. I find a lot of useful tips and resources in your account here, that is fascinating enough to keep me away a while from Gann's standard work that I am actually reading myself now, at long last. Perhaps I can offer some bits in return but be aware I certainly am not an expert. Also just ignore me for the time if I'm thinking of steps you did not get to taking yet.
Your star shots do not have to be taken in the vicinity of waypoints, I think. If you get a good fix, you know your position at the time you took it. Combined with the data from your previous fix or passing over a beacon, you can determine your true track and ground speed.* Those enable you to calculate the wind's influence when combined with your airspeed and heading. Based on that 'wind vector', you can adjust heading if necessary and estimate where you will be after the next time interval you set. The next fix then will update the data et cetera. This way you can do without waypoints where there are no beacons. You are, after all, now truly employing a form of GPS in the sense FSAviator explained the concept. * Obviously averaged since the previous fix. If a wind shift is suspected in between than you'll want to take another fix not very long thereafter, but long enough to get a good average for the new values. Using the drift meter on clouds would give you the drift relative to those clouds, if my interpretation of what you meant is correct. Clouds themselves however have a habit of drifting over the earth's surface so this merely gives you the drift relative to the air mass at lower altitude. That lower air's movement can vary in every possible way from the layer you're flying in, so I think it could be more confusing than having no drift figures. There are some things about the use of Plan G too, which is my favourite planner as well. I'm not at my FS machine now so I'd better check those before I put down nonsense here. Will try and have a look tomorrow.
Cheers, Erik
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Post by connieguy on Dec 27, 2018 5:17:15 GMT -5
Hi Erik,
Good to hear from you. I thought it very likely I would. What I am hoping might happen is that the people interested in this - and there could easily be no more than two or three of us - will share experiences and learn together, so any thoughts about different or better ways of doing things are most welcome. With reference to what you say, in order to take star shots you first enter an 'assumed position' into the sextant. If you are actually more than 350 nm from that position the sextant won't work at all. But even if you are not it seems easiest to use the coordinates of the waypoints which are provided for you on the Plan G flight plan. It is true, however, that if you plot the course on a piece of graph paper you can then read your assumed positions from that. Still, I'm not sure I would do that unless I thought something fairly serious had gone wrong. I have read somewhere that experienced navigators took star shots once an hour, but I would be nervous at the moment about leaving it that long, and doing it more frequently might safeguard you to some extent from the danger of the sky clouding over. It is quite true, as you say, that navigators used fixes to work out winds and groundspeeds, but it seems to me that the most critical thing is getting an accurate statement about where you actually are, because things could go desperately wrong. Lew Price, who navigated with MATS in the early 1960s, tells how on one occasion the head winds were far stronger than had been forecast and they came very close to running out of fuel and having to ditch. Fortunately he was able to persuade the pilot that the sensible thing to do in these circumstances was to increase speed, even though it meant that fuel consumption rose. As a result, they just made it. I'm sure that he was working out groundspeeds as accurately as he could, but in a broader sense the fixes alone would have told him that they simply weren't travelling fast enough.
On the use of clouds with the driftmeter I should have been more precise. For the reasons you give, 'the driftmeter seems to operate not too badly on clouds' would have been better phrased as 'the driftmeter seems to operate not too badly on clouds in this instance'. I think that to some extent navigating may have been a matter of making educated guesses. I was encouraged that the driftmeter and clouds together suggested the easterly wind had not changed, but I would not have changed course if they had suggested something different, because the evidence would not have been strong enough. By North Atlantic standards I was lucky with the winds on that flight, avoiding both strong side winds and strong head winds. I was also lucky that the winds seem not to have changed significantly between the forecast and me actually getting to the areas concerned. I think that a likely reason I drifted east so steadily after losing the Barra NDB was that the course I set was out by a point or two. My next flight is Keflavik to Goose Bay. This is quite a lot further, but on the way there are two of Tom's Atlantic weather ships and two long range NDBs on the southern tip of Greenland. I shall do it at night again so that there are plenty of stars. What I have not yet understood at all - though I have yet to finish reading the AAF manual - is how far it was possible to navigate satisfactorily during the day by taking sextant shots of the sun alone. Many thanks again for your input and support, Best wishes, Ken
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Post by connieguy on Dec 27, 2018 17:18:11 GMT -5
I give above the flight plan for my flight from Keflavik to Goose Bay. What is not evident from the plan is that the route brings me into contact with two Atlantic weather ships and that it crosses the southern tip of Greenland where there is a long range NDB. Once on the Canadian coast there is a 75nm NDB quite early and then the 112.5nm one at Goose Bay itself. There is a VOR there today but I do not make use of that. As in other flights the route is via waypoints I have created in Plan G. These waypoints I enter on my physical charts (it needed four of them, but as I only have three I wiped the first one eventually and then used it as the fourth) and I also put the weather ships on the charts. It is only during the flight that I realise that I should have put the NDBs on too. I download a dynamic weather file starting at 7:00 Zulu on 27th December 2018 in the belief that a take-off at about 7:30 will mean that dawn occurs as I am crossing the Canadian coast. In fact, I have miscalculated this and it breaks a little earlier than I anticipated, taking the stars with it.
As in the past I download a weather report and look at it carefully before departure. Cruising at FL160 the wind is forecast to be 47 knots from 178 degrees at 17,500 feet at the first waypoint - a fairly strong side wind. By the second - ICO 21 - it will be (or may be) 32 knots from 147 degrees, not as strong and more of a tail wind. ICO 22 sees 26 at 122 and ICO 23 - Greenland - 26 at 119. Unlike my earlier flight there is no warm up period while I get to cruising height, I shall have to start navigating straightaway, and this may be why I make a basic error on take off by leaving the mixture in Full Rich rather than moving it to Auto Rich. By the time I near FL100 there is a distinct lack of power and blue warning lights appear on the Engine Status panel. At that point I realise what has happened, but my climb to FL160 is delayed. To counter the side wind I steer 270 rather than the plan's 277,* and I also use the long range Keflavik NDB so that when its signals go silent I know that I have travelled 112 nm. This is probably something of a cheat, because historical accounts suggest that radio beacons behaved nothing like as predictably as they do in FS9. After waiting 7 or 8 minutes I then take my first sextant shot, since although the sky is partly covered in cloud stars are certainly visible. My assumed position is N63 23 W27 58 and the sextant returns N63 5 W27 33. My plot on the graph shows that my adjustment for the wind has been rather overdone and I am a little south of the track but still pretty near to where I should be. So far so good. Then the stars disappear in cloud and mist and I am not able to use the sextant again until I reach Greenland. This is where Ocean Station Alfa comes in very useful, as it was no doubt intended to. The radio picks it up fairly soon after the first waypoint and before I left I measured on Plan G that I would be in the right place if when my heading is W and the needle points south my distance from it is 35.6 nm. In fact it is about 33nm so I am still a little south of track, but not seriously so. My next star shot is not until ICO23 where an assumed position of N60 30 W42 44 produces N60 0 W42 40 - still a little south of track but still pretty close, largely thanks to the Ocean Station, of course. By now a tail wind is having an effect and at ICO24 and 25 I am close to the track but some way to the west (i.e. ahead) of the assumed positions. However by the time I am near ICO25 I am picking up the signal from Ocean Station Bravo. Using the same technique as I employed with Alfa I should pass no nearer than 65 nm and this time it is about 63nm. With the star shot for ICO26 I take account of the fact that I have got ahead of myself and take the shot not after 36 minutes from the last waypoint but 26. This delivers a fix which is almost dead on - assumed position N56 18 W54 35, fix N56 5 W54 44. I think this was also the one where I wasn't satisfied that I had done the third shot properly and re-did it, with a much better result. I perhaps should not have done these shots at all, because when I looked outside dawn had come and the stars had gone. But all the hard work has been done anyway. I maintain my course and duly pick up the outer NDB and then the Goose Bay one.
It is only then that things go wrong, for reasons which have nothing to do with navigation. I leave descending too late (easy when there is no VOR to give you a distance, though of course it could have been calculated) and have to do a full circle to lose height. All seems well but in the course of going to Flaps 60 and lowering the gear I must have lowered it at too high a speed, because when I command Flaps 80 nothing happens. I am not duly unconcerned because I have flown and landed this beautiful aircraft a lot and am confident I can land it without the proper flaps. Nor am I wrong, because I flare and the wheels kiss the runway most gently. And then there is a most unpleasant noise rather like a horn and the brakes don't seem very effective. It is only when I go to the outside view that I see that the undercarriage has partly collapsed. My dreams of taxiiing in and being surrounded by admirers as I explain how I have flown from Keflavik with only radio aids and a sextant are brought to nothing. Instead I cut the engines and wait for the emergency services to arrive... Addendum. This is the real thing and it is quite hard work. There is no going out into the garden for half an hour having set a suitable heading by looking at a GPS track. You are sitting there working things out with only short breaks, although this may well be less arduous with repeated practice. I am already realising (or think I am realising) that it is not necessary to be dead on all the time, because there is a substantial margin for error providing that you are careful. I suspect real navigation was like this too. When I eventually look at the track as recorded by Plan G it replicates the one I have seen from my plots. This looks like progress.
* I guessed the heading but should not have done. As I knew my magnetic heading and true airspeed and thought I knew the direction and speed of the wind my Dalton E-6B could have been used to give me my groundspeed - 253 knots - and the course I should have flown - 266 magnetic, although in the event this would have pulled me further off track than the 270 I actually used. Probably, therefore, the wind direction and speed were not accurate, or they varied. There is an online E-6B at the following link and it is worth pointing out that as far as I can see the physical E-6B would be unable to calculate the effect of winds much above 55 knots whereas the electronic one can.
My thanks to Manfred Jahn and the Connie team for the aircraft, to Tom for the Ocean Stations and to Dave Bitzer and Mark Beaumont for the sextant.
Almost there - ready to land on Runway 26 at Goose Bay. The ILS for Runway 08 works in reverse.
Pride goes before a fall. On the runway at Goose Bay. Excellent scenery by Flight Ontario, although unfortunately you can't see much of it. Paint of my MATS C-121C by Eric Joiner. The Plan G tracks:
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Post by Erik on Dec 27, 2018 18:49:28 GMT -5
Hello Ken, Thanks again for the account of the second leg and the reply above it. The end of your second flight report definitely has a certain "Gann style" to it! Impressive how you used the weather ships even if you did not route overhead those. Your earlier replies are clear. You won't be surprised that I too read all of Price's tales of being a navigator, very fascinating. Meanwhile I checked Plan G on two points: magnetic variation and winds aloft. The variation in Plan G often differs from that in FS9. For instance Plan G has BIKF at 19°W where FS9 has it at 22°W. It's 14°W nowadays so Plan G's data set is probably from around 2009. On long flight legs a few degrees can make a difference. As for the winds, I thought Plan G enables the user to enter winds aloft per leg, but it does so 'only' for the complete flight. On short flights that seems useful but not on long ones. I usually print my Plan G files through FS9 by the way, because that layout (albeit not ideal) gives me a bit more room to enter the values for my fuel planning and estimates, corrected with actual values, followed by new estimates et cetera. Meanwhile, I still hardly ever get to virtual flying so I am something of an armchair desktop flyer. As said, I very much enjoy your reports and insights, and yes there is definitily progress to be seen!
Erik
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Post by connieguy on Dec 28, 2018 9:39:25 GMT -5
Hello Erik, Thank you for your further contribution. I had not realised about the divergences on Keflavik. According to Sky Vector magnetic variation at Keflavik is now 14 degrees west, although it is true that Plan G gives it as 19 degrees west. What we really need to know is what it is in FS9,* but I don't know whether that is discoverable. However, there are people offering updates to FS9 magnetic declination files because otherwise you get problems with the latest navaid updates. In our case I suppose FS9 is best left as it is, although what we really need is the magnetic declination of the 1950s. I shall probably report on future sextant flights and am working my way towards Shannon - Gander (one weather ship and what happens if there are no stars?), but shall not do anything further for the next few days, as I feel rather drained from yesterday! Best wishes, Ken
* I have edited this post to take into account what is said further down the page, but it will be clear from this sentence that I didn't originally realise that you had told me the declination in FS9.
Also of interest is this. Could one go back to the 1950s?
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Post by Tom/CalClassic on Dec 28, 2018 11:00:30 GMT -5
I guess you could go back to the 50s if you were willing to edit every runway and navaid on the planet.
The way I get local FS9 magvar is to go into slew mode (Y key) and press the space bar. This aligns you to true north and your magnetic heading gives you the magvar.
There is also an FS variable that could display the current magvar in a panel gauge.
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Post by Defender on Dec 28, 2018 12:27:03 GMT -5
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Post by connieguy on Dec 28, 2018 12:30:38 GMT -5
Thanks, Tom. Using your method the magnetic variation at Keflavik in FS9 seems to be about 21 degrees i.e. when the aircraft is facing True North the compass reading is 021 degrees. The utilities offered on the second site I linked to above seem to make it possible to change the settings for individual airports fairly easily and I suppose this would allow the use of 1950s charts for those airports, but personally that is not a road I am interested in going down. In the two flights I describe above the magnetic headings given by Plan G got me where I wanted to go, and that is good enough for me, Ken
Thanks, Bill. Your post went up as I was replying to Tom. That does look a very interesting site. The declination at Keflavik was 21 degrees in 1990.
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Post by connieguy on Dec 29, 2018 14:14:24 GMT -5
The AstroCompass in FS9 The AAF navigator's manual (link above) has a long section (pp. 288ff.) on the instrument called an AstroCompass, which was clearly important as a way of finding true rather than magnetic heading. There is such an instrument available for FS9 made by Alexander Belov and available on both Avsim and Flightsim. In another thread I said I had not been able to get this to work, but have now rather belatedly understood the reason. The image below shows the panel of my L1049H parked at Keflavik where magnetic declination, as established above, is 22 degrees in FS9. However, the aircraft is facing True North as a result of using the procedure described by Tom, and the gyro shows an error in line with the magnetic declination.
My confusion arose from the fact that in his instructions Mr Belov has transposed the words latitude and longitude. First the instrument, like the real one, needs to be levelled and I have left the levelling window open. Then, as this is daylight, one should go to the lower longitude scale and set W22 for Keflavik, not the latitude N64 as I was doing previously. The letters W and E on the gauge ought, of course, to have told me that these were in fact longitude scales. Then one adjusts the azimuth scale at the bottom until the yellow line is central between the two black ones. The result, quite correctly, is N, and if one clicks on the yellow arrow this connects with the aircraft's gyro, which then shows the true heading. According to Mr Belov, once set the true heading will remain on the gyro for the rest of the flight, but I have not tried this yet. This part of the gauge only works during the day, and during the night one needs to sight stars in a similar way to the Beaumont and Bitzer sextant, although I think in this case they have to be real stars looked up in the astronomical sources. The upper longitudinal scale is used for that. How much use I shall make of this gauge I am not sure, but I still think it is a wonderful thing to have, and the fact that there was such an instrument available during the war has come as something of a revelation.
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Post by Erik on Dec 29, 2018 17:29:28 GMT -5
Hi all,
Just a short comment on the magvar, although the AstroCompass seems a fascinating piece of equipment indeed! To determine local magvar in FS9, I too go into slew and hit the space bar to align with true north, but then simply read the heading off the top of the screen. In the above example, it is indeed 022 ('east') so the magvar is 22° west. I have not tried to modify the variation in FS9 and don't think I will. I just correct charts that I may have to the FS9 headings where applicable. That said, my nav skills obviously produce greater deviations than a few degrees of magvar but hey, one has to start somewhere. ;-)
Erik
Edit: P.S. Essentially the same approach as Bill I just realise - thanks for that link!
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Post by connieguy on Jan 4, 2019 7:41:27 GMT -5
Following my flight to Goose Bay I attempted to do the return to Keflavik without using any of the radio aids. This was probably too ambitious, but at any rate the flight was a failure. Doing trips over the North Atlantic in winter is always likely to be a challenge and in this case there were strong southerly (side) winds on the section between Goose Bay and Greenland. However, the main problem was that the sky clouded over and I was unable to use the sextant for more than two hours. When I eventually conceded defeat and looked at the track on Plan G I was not as far off course as I expected, but I had lost any real sense of where I was or what heading to set. How far my inability to use the sextant for such a long period replicated real conditions I am not sure, while remembering that two weather ships were probably not placed in this area without good reason. As a result of this I made one or two changes before trying again. What seemed to me a curious feature of the last flight was that although I could not see any stars for a long time I could often see the moon quite clearly, and this raised doubts in my mind as to whether the stars.dat file in my main FS9 folder was necessarily producing an accurate result. At the same time I discovered that it can be opened in Notepad and edited, so I changed the line on Intensity from a value of 230 to one of 430. I was also aware that the physical charts I am using are drawn on graph paper and do not represent the curvature of the earth, so I produced a flight plan on Google Earth which I guess could possibly be used with a protractor to work out true headings. Certainly the bearings to be read in Google Earth seem to match those produced by Plan G. Thus armed, I tried a flight from Keflavik to Burtonwood using a weather file for 3rd January, 2019. It was timed to reach Barra at dawn, i.e. around 8:00 Zulu and thus have stars available in the most important stretch - if they were visible. The weather report was for strong winds south of Iceland, moderating as I flew further south. Thus a 57 knot wind at 205 degrees would (or might) be followed at the waypoint IC010 by one of 40 knots from 215 degrees and then at ICO13 by one of 15 knots at 234 degrees. All assuming, of course, that the forecasts would prove accurate. The Plan G and Google Earth plans It was raining quite hard as I took off from Keflavik although the rain stopped quickly to be followed by a brief bout of carburettor icing. However, I reached Vestmannaeyjar just as I got to cruise level of FL170. Using the Dalton E6-B I worked out that I needed to allow 11 degrees of drift to cope with the wind and thus set a course of 158 degrees. No stars were visible at all until the flight was 42 minutes old, when the sky beyond the clouds became clear. However, it was not yet time to use the sextant to check I was on course at ICO10 and by the time I got to that area the sky had clouded over again. At this point things were looking rather like the previous flight, and I can see that there is a case for taking sextant shots when you get the chance. However, one hour and 14 minutes into the flight the sky cleared. Knowing that I was beyond ICO10 I used the coordinates of ICO13 as the assumed position and the sextant returned a reading of N61 30 W14 36. This showed me to be about a third of the way to ICO13 but rather north of the correct track. In other words, the compensation I had allowed for the wind had not proved to be enough. Fortunately the sky then remained clear, I adjusted the heading to 156 magnetic to correct the error and when I was fairly sure I was near ICO13 used the sextant again. This reading was N60 25 W12 50, almost at ICO13 and nearer the track, but still slightly north of it. I then changed the course to 150 degrees and eventually using Barra as my assumed position tried the sextant a further time, getting a reading of N58 25 W9 20 - just over half way between ICO13 and Barra and still slightly north of track. As a result I changed course to 154 degrees but shortly thereafter picked up the Barra NDB, the needle confirming that I was very slightly off track in the way suggested by the last sextant shot. At the same time the first signs of dawn were appearing in the eastern sky.
The point where I picked up the Barra NDB, with the needle on the rmi pointing almost exactly at it. Dawn is just breaking in the east.
Once in range of the radio beacons, of course, the last part of the flight was straightforward and I was able to enjoy the sunrise. This was therefore more encouraging. While I am not sure, I think it possible that the change I made to the stars.dat file did make the stars more visible, and although I looked at the Google Earth flight plan once or twice the plots made on my physical charts were adequate in terms of telling me where I was and what to do next. As I have said before, this feels like the real thing, exciting and satisfying but also rather draining. Don't assume you will follow it with a good night's sleep, because you may dream of the roar of Curtiss-Wrights and the silence of the stars.
Landing on Burtonwood runway 09. Scenery by Glen Broome modified by myself. The size of this air base, of which almost nothing now remains, is clear.
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