Post by Tom/CalClassic on Aug 26, 2019 9:37:48 GMT -5
I have always wondered if the DCs with their hot air deicing were better at keeping ice free than the Connies with their rubber boots, but I've never heard much either way. In fact, once the planes became pressurized and flew above 10,000 ft it seems there was a much reduced mention of icing in the typical aircraft disaster story. In fact, it seems that icing is a bigger problem on the jets with their swept wings, especially at takeoff.
Tom my assessment would be the hot air would be more efficient rather than expanding and collapsing boots which they do in a rhythmical pulse. But boots are a cheaper fit and hot air requires a lot more plumbing whereas the boot is fixed and only requires pneumatic pressure to work. Your right about icing once you get above 10,000 it drops considerably but you can get a mix of clear and rime both but it drops off above 15.000 to basically rime ice. Whats the difference as I explain to my students look in the fridge, that light white frosty stuff is rime ice and the hard heavy cubes in the icetray that is clear ice. The simple explanation is that ice forms because supercooled water droplets (water can stay as water down to -20C which is why you get cloud in the artic) the hit the aerofoil and smear backward instantly freezing on an airframe at freezing temperatures, does not take long for those droplets to start to form into a veneer of hard ice that increases in depth, the other thing people also forget about is ice is heavy, so if you accumulate ice then the weight of the aeroplane is increasing as well.
Yes correct about the wing and swept wings and icing. The aerodynamic tests show that ice on a wing destroys lift to the equivalent of about 25% loss of lift, you need to increase the angle of attack (up to a point you can only raise the nose so high) and you need to increase the power to keep the speed up. Ice on a swept wing is a serious issue if not cleared because of the change in the aerofoil shape and loss of lift, so if you dragged out the TOLD card and had a V1 of say 130 knot with ice it will actually be about 155 knots big difference on take off, countless accidents over the years as we know of crews attempting take off and having not properly deiced and then the inevitable crash as the aircraft either stalls or fails to get airborne.
Connieguy - This has been very informative and a pleasure to go along with. Your research and planning is great and I really like the attention to detail or realism both in operating the Constellation and your flight planning and navigation. This Southern Atlantic crossing is one I have not done (so many one could do so little time) but I got prepared awhile ago and was going to do it in the C124 (It was one of the MATS C124s regular routes across from the US to Europe via the Azores) but it went on hold. All the background information and other material is a great help.
Some very nice screenshots as well. Great contribution.
Thank you for your comments Mike, and for your interesting information on aircraft icing. The Azores - Bermuda route, on this limited experience, seems to have been pretty good from the point of view of weather. I am aware that Shannon - Gander might be another matter, and intend turning my attention to that next.
Last Edit: Aug 28, 2019 9:47:30 GMT -5 by connieguy
Ken, I am just rereading parts of this great topic because it is so informative in many ways, complete with very fine screen shots. I hope we will see G-AHEK back in London to complete the journey. Thanks very much.
Mike H, I hope you read this and will be back. Thank you too for confirmation on the weather reporting and other info.
Hi Erik, Thank you for your post. I realise that it might look as though I have abandoned the thread,but in fact I have not. There were strong side winds on the first attempted flight from the Azores to Lisbon and there was a failure in navigation as a result, so I need to have another go with a rather more refined method. I should be able to do this in the next few days - I have been away from home too. I do, further, intend doing the more northern route via Gander, where strong and changing winds may be an even bigger problem. I believe that crews did get updated weather forecasts during these flights, sometimes from other aircraft, and I need a way of simulating this.
I would also like to reinforce what you say to MikeH, and to thank Tom for keeping the thread on topic
Last Edit: Sept 6, 2019 1:57:37 GMT -5 by connieguy
So now we come to the 770nm flight from the Azores to Lisbon, which gave more trouble than I expected, partly because of initial methods which could have been improved upon. BOAC scheduled this flight to leave Santa Maria at 09:10 LT (UTC-1) and arrive in Lisbon at 14:45 (UTC+1). Even taking place completely over the sea, a flight of this distance would not normally be expected to be difficult from a navigational point of view, especially as Lisbon has an NDB with a range of 112.5nm waiting with welcoming arms. The outward bound flight had gone smoothly and so had the very similar flights from Bermuda to Nassau and back, although my post on the latter did point out that I was fortunate that there had not been stronger side winds. When I looked at the FSGRW weather report for this flight to Lisbon it was clear that my luck had run out, because side winds of 40 knots were reported at FL110, the level at which I decided to cruise because the winds at higher altitudes were even stronger. If you go the link below and enter 18 October 2018 you will see a pressure chart for 00:00 UTC on that day (not 10:00, when we took off).
Of course I was able to work out the necessary adustments to my heading on my Dalton computer, but even so the flight went wrong, as the Plan G breadcrumb shows. My track was too far to the north from the start and as I flew out on the reciprocal of the Santa Maria NDB for 112.5nm I find this impossible to understand unless I made some kind of error. I was well to the north by the time I got to waypoint AZ02, there had been no further drift by AZ01, but there was further drift after that and by the time I abandoned the flight because I had to switch off the computer and be elsewhere I had still not picked up the Lisbon NDB. The breadcrumb shows why. The NDB has a range of 112.5nm and I was 116nm away from it. There are two more long range NDBs to the north of Lisbon which I would have picked up had I troubled to write down their frequencies beforehand, although even so this is not the standard I try to achieve and there was nothing for it but to do the flight again.
The Plan G breadcrumb from the first flight:
At the second attempt I used the same weather file (for 18th October, 2018) but added more waypoints to the plan so that the forecast would be a little more detailed. I also recorded the frequencies of the other NDBs I mentioned above and had realised by this time that I could check my track by taking sextant shots of the sun, which around mid-day would be off the starboard beam - the ideal place for sextant course shots. The screenshots below show my second monitor (with the Plan G flight plan obscuring the Plan G screen so that I cannot see the location of the aircraft and the Voice Bot program which provides my virtual flight crew), the FSGRW weather report with the winds highlighted, and the intended track shown on Google Earth, along with a line of position derived from the sun at 12:00 UTC.
Take-off was exactly on time at 10:10 UTC. Ready to go, as one of Mike Stevens's classic ships rounds Santa Maria.
And the passenger view to starboard just after take-off. I do not normally look outside at this stage, but this view shows that I am on the northern edge of Santa Maria as my examination of the flight plan before take-off confirmed that I needed to be.
With a light fuel load and a third of the passenger seats empty climb to FL110 took 12 minutes and initial cruise at 65,700 lbs gw and an OAT of +4C was at BHP1005, BMEP 113, RPM 2106, FF 445, f/a 0.064, Mix 19, KTAS 225. The breadcrumb (see below) shows that this time I tracked out on the NDB reciprocal accurately and I noticed that to keep the NDB needle in the right place I needed a heading of 085, which showed that the northerly wind was not yet in full swing. At waypoint AZ02 it was forecast to be 41 knots at 354, requiring an offset of -8, but I only changed to this setting when I was half way there and in fact, as the breadcrumb shows, even this was a little too much as it took me slightly too far north. I took sextant sun shots at AZ01A and AZ01, which I did not interpret correctly. The first returned -10 miles which I took to mean I was slightly south of track when actually I was slightly north of it. The second returned -5 miles - so I was obviously doing quite well - but I interpreted this the same way and altered the heading from 080 to 082 - the heading with no adjustment was turning more south-east by this time (see the flight plan above). If I had altered it to 084 or more that would have been better. Still this was far better than the first flight. The breadcrumb shows that I was in fact 10nm north of track for much of the time.
The sextant shots. The two assumed positions can be seen on the flight plan.
I am somewhere on the blue line. but this is to the left of the centre of the chart, which represents the assumed position entered in the sextant. I am therefore to the north of the track, not the south as I concluded in two senior moments. The second shot at 12:34 suggests I was only 5nm north of the track, but I suspect this sextant reading was not as accurate as the first one (i.e. I didn't place the bubble completely accurately). As a result of this incorrect change of heading I drifted further north and when I picked up the Lisbon NDB at 13:16 UTC the needle was pointing some way to the right. Still, the second sextant shot had shown that everything was going to be fine on this flight and on the strength of it I decided to give the passengers lunch. Beatrice announced that it would be chocolate pudding and custard for dessert. Great. My favourite.
The Plan G breadcrumb for the second flight.
That was the most difficult part of the flight over, until it came to landing. The site to which Erik linked in an earlier post in this thread shows that the winds at Lisbon blew consistently from the north on that day (18th October, 2018). Hence I approached on the basis that the landing would be on Runway 03. Then ATIS came in and told me that the wind direction was 144 and landing would be on Runway 17. I would have been better ignoring this, but didn't, and made for R 21, the one with ILS. Then I got within ATC range and was told that landing was on R 03. This I did ignore, but came in too tight and ended up doing a visual landing on R 17 after all, gently enough in the end. Touchdown was 16 minutes later than the schedule required, partly caused by the difficulties with ATIS, although cruise should probably have been at 1100 BHP rather than 1000 BHP.
Lisbon at last. Scenery of LPPT by Cal Classic.
Last Edit: Sept 8, 2019 10:02:17 GMT -5 by connieguy
Thank you, Chris. Here is the final leg of this particular trip. BOAC scheduled departure from Lisbon at 16:00 (UTC+1) and arrival at The London Airport (now Heathrow) at 20:10, a flight time of 4:10, five minutes less than the outward bound leg of 4:15. On that leg I cruised at FL200 at 950BHP, landing with seven minutes to spare after taking off four minutes early. When I looked at the weather report for this one the strong northerlies of earlier in the day had gone, the winds at FL190 being north-easterly but never higher than 13 knots, while the weather site found by Erik reported that north-easterlies prevailed in London all day. I loaded 13,167 lbs of fuel and again carried a two-thirds passenger load, so I used the lower cruise climb setting of 123 BMEP which allowed me to delay blower shift until FL165. Taking off from R03 I reached FL100 in 10:05 and FL190 in 22:30, with initial cruise at an OAT of -17C and gw of 68,250 lbs at BHP 1094, RPM 2203, BMEP 118 (full throttle), FF 480, f/a 0.064, Mix 15 and KTAS of 244. This was as a result of a hunch that I would need maximum cruise on this flight, which turned out to be correct. Shortly after cruise began there was a bout of propeller icing which I noticed fairly quickly but thereafter I was above most of the cloud and there was no further problem.
The view from the astrodome over Spain, 18th October, 1950.
Eventually night fell, a clear night with a great galaxy of stars which I did not need as navigation of this flight was entirely by radio aids. Even so, I looked at the sky occasionally and thought it a pity that so many good stars were going to waste. The Plough and Polaris were clearly visible off the port bow, just where they should be given that my course was 030 degrees magnetic. Not unnaturally, I was determined that there was not going to be the confusion about the landing runway which had attended my arrival in Lisbon. This one was going to be at The London Airport of the early 1950s with its six runways, so I anticipated the use of 05L or 05R. ATIS confirmed this when I picked it up and so did ATC a little later, assigning me to 5L. I began the descent when just over 90nm away, which was not quite enough for a descent rate of 500 fpm and I eventually found myself trimming the nose down slightly to achieve nearer 1000 fpm. This served its purpose and the only difficulty as I came in was being sure that what I thought was 05L was not in fact a taxiway (there are no centre lights, but all these runways were 300 feet wide). However, it was not, and after a little manoevering there was a gentle touch down.
Lining up (notice the angle of the horizon) for 05L.
The Happy Return. Seconds before touchdown.
I was 24 minutes ahead of schedule but had taken off eight minutes early and was fortunate that the north-easterly wind had given me a straight-in landing when westerlies and south-westerlies are far more common in this location, and they would have meant doing a downwind leg and the expenditure of more time. The relatively rapid descent must also have saved some minutes. The scheduling of these flights was far less generous than those of the New York to Nassau and Bermuda services, on a route where the winds can do almost anything. Strong south-westerlies are always a possibility, but so are north-westerlies and the resultant formidable headwinds. In this case it looks as though BOAC scheduled for 'normal' winds and accepted that in other circumstances flights would arrive late and perhaps sometimes distinctly late.
Parked. London Airport scenery by myself. Thanks to all those who have followed and contributed to this thread. The North Atlantic route, which I tend to regard as the ultimate test from a navigational point of view, is next.
Last Edit: Sept 10, 2019 6:41:31 GMT -5 by connieguy
BOAC Flight 13A, 2-3 November, 1947. The London Airport - Shannon - Gander - New York La Guardia.
Aircraft. G-AHEN Balmoral. Construction Number 1980. Originally built for the USAAF, it was flown by BOAC in the USA and formally delivered to them at Dorval, Canada on 31 May, 1946. Converted to 049-46-26 configuration, it entered service on 31st August and inaugurated BOAC's service to Canada in April 1947. It also flew BOAC's last First Class Constellation service from London to New York on 1st April, 1950. Wrecked in a training accident on 8th January, 1951, it was withdrawn from BOAC service but subsequently rebuilt, whereupon it served with other airlines until eventually being broken up in May 1965.
The BOAC Constellation service to New York began in July 1946. By the timetable isued for September 1947 there were five flights a week routed via Shannon and one routed via Prestwick. Our flight is on 2nd November and took off on a Sunday evening at 20:00 (UTC +1), being scheduled to arrive in Shannon at 22:15 (UTC +1), a generous allotment for a flight of only 323 nm. However, I suspect that the passengers ate before they boarded, and there was no hurry. The flight plan shows the waypoints which are all radio aids and below it is my chart for Shannon Rineanna, which at this date may have had four available runways. My sources (Erik's weather site) suggest that the wind upon landing will be SE or SSE, while the historic pressure charts for 2-3 November, 2018 (the weather I am using) show a deep depression moving eastwards to the north of my flight plans.
The flight plan
The weather at 00:00 UTC, 3rd November. You will need to enter this date into the relevant boxes to see it.
I am carrying a half passenger load on this trip - 3,424 lbs including crew - and load 6,771 lbs of fuel for the first leg. We are assigned to R 23L for take-off, which means no more than a short taxi from the apron, and then a brief turn to starboard when airborne to head for the VOR at Compton.
Contact Three. G-AHEN in the fine paint by Frank Gonzalez.
I usually climb with the Team Connie Engine Information Gauge open, because I need the pilot's view although at this stage I am really acting as the flight engineer, who I suspect controlled the throttles even though duplicates were supplied for the pilots. Lightly loaded, we are using a climb BMEP of 124 and an RPM of 2300. I use dual throttles mapped firstly to 1 and 4 and secondly to 2 and 3, and as is clear some readings vary between the two. RPM is synchronized by the synchroniser thoughtfully provided by the Connie Team, although the first Constellation to actually have this feature was the L 1049. My trim should have been slightly flatter, as I am not quite at the 150 IAS which is advised for climb. Even so, note the rate of climb.
I decided to cruise at FL100 and initial cruise at an OAT of -3C and gw of about 63,000 lbs was at BHP 960, RPM 1998, BMEP 114, FF 415, f/a 0.064, Mix 20 and KTAS 217. Shortly after the cruise began I noticed that the aircraft nose was trimming up under the autopilot and on going to the flight engineer's panel to turn on propeller anti-ice found that the Wing Ice gauge was illuminated too. Turning on the anti-icing boots cleared this immediately and only one bout of the propeller anti-ice was needed for things to return to normal.
I reached the VOR at Brecon after flying for 36 minutes, which my Dalton computer showed to have been an average groundspeed (including climb, of course) of 188 knots. It took another 21 minutes to reach Strumble, an average of 194 knots, but the headwind must then have strengthened because the speed to Tuskar Rock was 186 knots. When over the English and Welsh mainland I looked through the driftmeter - an aid I tend to neglect - at lights below and there was no drift at all at that stage, something which was confirmed by the fact that the radio needles showed no tendency to wander. In due course ATIS advised me that landing would be on R18, which was later confirmed by ATC. This created a problem, because unlike some of the other runways R18 had no navaids at all and I can only assume that in real life aircraft using this runway were vectored in by ground control. My substitute for this is Manfred Jahn's GCA gauge, which I try to use (without the voice element) only as a last resort. However, it brings me in accurately although the Plan G breadcrumb shows that my circuit to the N was wider than it need have been. The runway is not generous in terms of length and as I am keen to get down quickly there is a slight bounce on landing. After that it is a very short taxi from the end of the runway to the terminal. Although I cruised fairly economically I was well within schedule and had 3,196 lbs of fuel left. As the passengers disappear into the terminal, the tanks are filled to the brim for the flight to Gander.
The runway in the distance as correctly shown by the GCA gauge.
Abour to land.
At the terminal. Shannon Rineanna must have been a hive of activity in 1947 at this time in the evening.
The big one next, but as I am going away for a shorter version of Tom's trip it will not be for at least a week.
Last Edit: Sept 15, 2019 12:12:04 GMT -5 by connieguy
Post by mrcapitalism on Sept 17, 2019 19:16:45 GMT -5
This created a problem, because unlike some of the other runways R18 had no navaids at all and I can only assume that in real life aircraft using this runway were vectored in by ground control.
You can consider an instrument approach to another runway, then circle to RWY 18. Or, you might consider asking ATC for a runway change if the winds will allow using one with a "straight-in" approach. FSAviator remarks in the Propliner Tutorial that circling approaches were common heyday of propliners
Post by connieguy on Sept 18, 2019 11:52:15 GMT -5
Thank you for your response and appreciation. Quite likely circling approaches by night would have been possible in real life, but I wouldn't have fancied my chances of pulling off such a thing in FS where what you see out of the window is far less informative than it would have been in reality. The obvious alternative would have been to use R22 which had navaids and would have been compatible with the wind direction. As far as I know FS9 will not allow you to choose an alternative unless it is parallel to the first one you were offered. During the Second World War aircraft which had no real navigation equipment - e.g. single seat fighters - were given approach vectors by ground control based on radar plots. Given the likelihood of bad weather at Shannon and what must have been intensive use of the airport at this date it seems to me very likely that such methods were used there. However, I do not know this. Does anybody here know?
Almost certainly Shannon had GCA and the common way of finding the airport was the tower based DF, direction finder, which FS replicates quite well. Not sure about radar vectoring in the early 50's but can't say for sure.