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Post by Jorge on Jan 4, 2022 18:51:58 GMT -5
Thanks for the help on this. I should elaborate that I don't have a google account -- at least not for personal use. I have no Facebook, Twitter, etc, either. I use a flip-phone for personal communications with friends and family. I have a feeling I may be alone in the "communications world" in a few years, which would be fine by me. I've never given in to peer pressure ever in my life, and don't expect to do so at this stage. That said, I do have an android phone for work purposes that I can't use for this. Sorry. Thanks for the help, though! ![;)](//storage.proboards.com/forum/images/smiley/wink.png) Jorge
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Post by Tom/CalClassic on Jan 4, 2022 19:59:39 GMT -5
Ah, I'm not sure why they would hide the PDF download choice in the Settings menu, but there is was. Thanks!
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Post by Defender on Jan 5, 2022 11:58:32 GMT -5
Jorge, I haven't found the paper you refer to but as Ken mentions it this is the goldmine site I often search. dotlibrary.specialcollection.net/SearchSelect a section in the left hand margin then click contents top left. Or if that offers a dataset then click on the listed dataset item, then search which will then give a list of contents. It can be addictive! Bill
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sas1548
DC-3
"Back in the piston-engine days, when airplanes were airplanes. None of this jet malarkey."
Posts: 9
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Post by sas1548 on Feb 5, 2022 17:33:01 GMT -5
This was a big enough deal that back in the piston-engine days there were several Weather Ships in the Atlantic, putting up balloons twice a day to measure winds aloft. Surface weather really doesn't tell you much about winds aloft. Good numerical prediction models and weather satellites made the ships no longer worth the expense. I speculate that jet power reduced the life-and-death aspect of headwinds, too.
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Post by mrcapitalism on Feb 7, 2022 2:06:46 GMT -5
This post might perhaps be considered off topic for the idea discussed in the thread, but it's certainly appropriate for it's title. Found an interesting find over at the PMDG forums. Check out the function on this flight computer, specifically near the center and the bottom of the center. ![](https://ids.si.edu/ids/deliveryService?id=NASM-B27BCE9B8F832_003&max=3000) It's a calculation of the "geostrophic" a.k.a. "pressure pattern" wind. The process described in the documentation is performed using the flight computer and values from the constant pressure chart. The heavy math is eliminated (or automated) resulting in an incredibly easy process that was probably quick and easy to perform. Pretty amazing to actually recognize that after studying this topic. So easy even a pilot or navigator could do it ![:P](//storage2.proboards.com/forum/images/smiley/tongue.png)
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Post by Jorge on Feb 7, 2022 9:57:35 GMT -5
Nice find!
Just to be clear, you mean the section where it speaks of the crosswind component and "D1" and "D2" as well as latitude, right? Just above the line, but below the metal knob?
I've never seen this on any E6B or CR-2 I ever used. Probably because this one is a MilSpec E6B and not GA?
Jorge
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Post by mrcapitalism on Feb 7, 2022 10:06:01 GMT -5
Just to be clear, you mean the section where it speaks of the crosswind component and "D1" and "D2" as well as latitude, right? Just above the line, but below the metal knob? Exactly correct! If you didn't see it, the latitude is on the innermost scale below the "Hour" arrow (big black triangle), marked with the word "latitude." Yes, I've never seen this before either. I bought a "high speed" E6-B for the crosswind grid on the wind side, because that's used for celestial computations as well. Robert, EDIT: The modern, still commercially available circular style E6-B's still have this pressure pattern latitude scale. Such as the ASA AirClassics E6-B Circular Flight Computer.
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Post by blockwood on Feb 7, 2022 11:19:58 GMT -5
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Post by Jorge on Feb 11, 2022 8:14:28 GMT -5
Found my old CR-2. Surprise, surprise, surprise! It has the PP scale! I never even noticed it before!
I then looked through all my books in the various shelves I have and found the manual for it as well!
I'll scan the pages for the procedure on how to do this over the next few days and see how to get them on here. I was thinking a PDF since that would be easier for most, but I can try and do pictures on my flickr account as well. Not sure if I can upload PDF over there or not.
Short description of last night's reading: The procedure tells of using two (2) altitude readings at thirty (30) minutes apart. Eventually you can get the crosswind component and various other things so that you can correct your course.
It also had instructions on doing 45* offsets to base course, intercepts, etc.
We'll see what I can do. Give me a few days.
Jorge
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Post by mrcapitalism on Feb 11, 2022 17:40:24 GMT -5
Jorge,
There are a number of flight computer manuals already available online, hosted by their manufacturer. Is your CR-2 from Jeppesen?
Robert.
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Post by Jorge on Feb 11, 2022 19:34:14 GMT -5
Jorge, There are a number of flight computer manuals already available online, hosted by their manufacturer. Is your CR-2 from Jeppesen? Robert. Sure is. Bought it in 1993 while a cadet at Florida Air Academy my senior year. Ended up getting a standard E-6B as well and used that for my training since that's what the instructors were using. Didn't use the CR-2 again until 2006 when flying the B-1900 around FL and the Bahamas. Never used it for this particular purpose, though. Haven't used it at all in several years. Hadn't thought about checking online for manuals. Found this one at Jeppesen: CR-2 / CR-3 / CR-5 ManualIf you go to page 13 in the PDF (page 23 in the actual manual) you have all the instructions you need to properly use this for pressure pattern flying. It's what I was going to scan tonight. Still trying to wrap my head around some of the math, though. It's been a while since I did anything even close to this level. Now I can concentrate on finalizing some gauge work instead. ![:D](//storage2.proboards.com/forum/images/smiley/grin.png) I'm fairly sure the "meat and potatoes" of the thing can be used with any circular computer that has pressure pattern info on it since the math is the math, regardless of platform. Would be fun to try and do a flight in an airship from Europe using the methods in the manual. It would definatly not be a short flight! ![:D](//storage2.proboards.com/forum/images/smiley/grin.png) Jorge
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Post by connieguy on Dec 15, 2022 7:18:01 GMT -5
Ventusky is a marvellous site for giving a general impression of weather patterns and can deliver wind direction and gust speed at particular airports, but as far as I can tell (and subject to correction) there is no information on another crucial matter when flight planning - that is, visibility. The site linked below will do this: metar-taf.com/It is possible to access metar records which are up to date and also extend back for some years. These include visibility. At Gander, on 14th December 2022, for example, visibility varied between 1 mile and 5 miles. This information was essential for those planning propliner transatlantic flights in the late 1940s and 1950s, and for those simulating them now. Although Gander had GCA from an early date it was notorious for its fogs and if visibility was bad enough aircraft went elsewhere. A flight from London to Bermuda might go via Keflavik and it might also use other alternatives, like Goose Bay, Ernest Harmon (Stephenville), Sydney (Nova Scotia) and Moncton (New Brunswick). Sydney had been a RCAF airfield during the war but was later designated as an alternate for the North Atlantic air route, with a licence issued in March, 1947. In 1950 runway 07-25 was extended to 7070 feet. By 1953 runway 01-19 had an ILS and by 1955 07-25 had one too. This probably gives a good indication of its importance (information from Wikipedia and charts for 1953 and 1955 generously supplied by John Hewson). Visibility at Sydney on 14th December 2022 fell as low as 2.5 miles just after midnight local time, but for much of the day was 10-15 miles. Not a great distance from Gander, it would have been the obvious choice on that day.
Approach to Sydney 07 with the weather of 14th December 2022. Winds. Calm. Visibility 15 miles. Their large fin apparently made aircraft of the Stratocruiser family particularly vulnerable to side winds.
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Post by Tom/CalClassic on Dec 15, 2022 10:52:54 GMT -5
Thanks for another good resource.
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Post by connieguy on Dec 22, 2022 15:23:56 GMT -5
It has just come to my attention that this site, which is run from Malaga in Spain, only gives metar histories for the last three days. However. by making a one off payment which can be as low as £5 one gets permanent access to their records extending back for years.
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Post by Erik on Jan 23, 2023 18:33:30 GMT -5
Ah, navigation and flight/fuel planning, two of my absolute favourite subjects along with the extent to which we can replicate them in our beloved, nearly two decades-old, sim! For a visualisation of pressure systems and winds, I can recommend Windy.com. Among many other options, the site can show isobars together with wind direction and speed. This nicely demonstrates how the air mostly flows approximately parallel to the isobars and certainly not directly from high to low pressure. ![](https://i.imgur.com/YdCgQXx.jpg) Here I chose the surface because the colour coding makes it a bit overwhelming to view this whole area at altitude. Near bottom right is a slider, enabling you to choose up to FL450. Many thanks for all the resources everybody, even if partly quite technical. I am certainly going to try and read through them. As Ken so nicely quoted: 'We skippers became meteorologists first, pilots second' and I'm among those who feel attracted by that aspect. I am sorry for Flight Literacy that Google won't show them anymore, but their articles on this subject are direct copies from the FAA manual, without due credit. They should have done better there; I don't know anything about their other content though. For relatively recent historic weather data, I still turn to Weather Underground. If you take this link www.wunderground.com/weather/EHAM and modify the identifier correctly, it takes you to the airport page of your choice, if it exists (most do). I just had a quick look and Gander goes back to 2014, Heathrow to 2000. The search box goes back to 1930, not sure if they have data even nearly that old! There are no fees, login or whatsoever involved. Finally, be advised that metar-taf.com tends to make a few things up and report them as facts. They will suggest a runway in use but that is just a projection of wind direction over runway heading. The actual situation may well differ - although FS9 uses the same principle of course. They will also use data from other stations if the airfield you look up does not have a METAR or TAF. I noticed this with EHTW that I live close to: metar-taf.com uses the data of EDDG for that, which is 56km / 35mi away, and pretends it is EHTW. All in all, lots of intersting reading to do, and maybe at some point bring it into sim practice. Many thanks again. Erik
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