Long range navigation in the Vega

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Tailspin45
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Long range navigation in the Vega

Post by Tailspin45 » 27 Jun 2018, 18:40

This marvelous Vega was designed and first built before radio navigation was available--before aircraft electrical systems existed, for that a matter. Over the next few years, however, advances were rapid and early low-frequency ranges and radio direction finders changed the game and were installed in the aircraft along with batteries and generators. Regardless of the advances, though, if you were flying thousands of miles across an ocean, no radio navigation was possible until LORAN and GPS became available decades later.

In short, if you're going to make long flights in the Vega across oceans or continents you need to know how to use deduced reckoning (ded-reckoning, aka dead-reckoning, also called DR) and celestial navigation using the stars.

Dead-reckoning

DR is amazingly accurate over moderate distances. Use a chart to plot your course, figure in wind to deduce your heading to fly, figure your ground speed to deduce how long it will take to get there, and voilá. Point 'er in that direction, fly until the clock says you're there, and by George, there you are!

Using a drift meter, first used in a Vega, the Winnie Mae, you can even peer through the floor of your bird, make sure the wind forecast was correct, and change course if your drift isn't as predicted--in other words, use reality not prognostication, to reach your destination.

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Here's a course plot for a flight from Easter Island to Tahiti. Each leg is about 2 hours in the Vega. The course changes were used to approximate a great circle route instead of longer rhumb line (aka loxodrome).

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Of course, if the wind forecast is off and you don't correct your drift, if you forget to figure in magnetic variation and compass deviation, or if you don't do a very good job of holding your heading, things won't work out so well. But even then, experience has shown, you'll be pretty darn close. It's almost spooky how well DR works if your trust it.

Offset navigation

In any case, one way to improve your chances of finding a destination when using DR or celestial, early pilots learned, was to navigate to a point that was 10% (in miles) offset 90º from your actual destination. That way, when you arrive and don't find the island or airport you're looking for, you know which way to turn. "I know I'm northeast so if I turn left I'll be headed toward my destination. I know it can't be the other way unless I've made a huge mistake." You've reduced the possible solutions to your problem and it really does work. Usually.

It didn't work for pilot Amelia Earhart and navigator Fred Noonan in a twin-engine Lockheed Electra in 1937. She radioed at 8:43 a.m. on July 2nd, to the Itasca, a U.S. Coast Guard cutter awaiting Earhart at Howland Island: "KHAQQ [her aircraft's call letters] to Itasca. We are on the line 157 337." 157-337 was the line from the offset point to Howland. The Itasca received the transmission but couldn't get any bearings on the signal and (so far) she has not been found.

Noonan, by the way, was one of the most famous navigators in the world. He had extensive experience in both marine navigation (he was a licensed ship's captain) and aerial navigation (he'd worked for Pan American Airways, where he'd been responsible for training navigators for the routes between San Francisco and the Pacific islands). But he had a serious weakness.

According to a fella by the name of Smella, Noonan had an, um, beverage problem. I bought a 1929 Travel Air biplane back in the late '80s. It was at wonderful grass strip north of Philadelphia called Van Sant (9N1) run by ol' Billy Smella who knew Travel Airs and who knew Noonan.  Seems Noonan flew a Travel Air into trees on takeoff with Smella aboard back in the mid-'30s because he was hung-over. Smella said Noonan drank when he was nervous or upset. That was the way Noonan might have felt, Smella suggested, during a long over-water flight when he was cooped up in the tail of the Electra and his skill most needed because they were running out of fuel.

But I digress. For Wiley Post, Amelia on earlier flights, and many others, DR and celestial worked great. It worked for sailors of old, and it was the best navigation system golden-age aviators had.

Celestial Navigation

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Celestial navigation has a reputation for being a fussy mathematical nightmare, but the concept is actually simple. And it isn't inherently difficult nor does it require extensive mathematics. It's more a procedure that requires meticulous attention to detail. Most of the math has been, and was even back in the '30s, converted to tables so the job was looking up the right number in the right place so you could take a star shot, measure the angle of a star above the horizon, and convert the result to a line of position or a fix. Here's how it works:

Every bright star (that includes the Sun, remember) has a geographic position (GP) on earth that is directly below it at a given time. Stand on that spot at that time and look straight up and you'll see the star at night or the Sun during the day (clouds permitting). Use an almanac, a book of tables of star positions, and you can find, for any time and place on earth, where to find a particular star. Good chance you aren't directly under it, of course, so you'll get an angle above the horizon and a direction to look to see the star (again, at a particular time and place). But here's the rub, if you see the star at exactly the angle predicted you still don't know where you are. You only know that you're someplace on a circle under the star.

Think of a star that's an ornament on top of a Christmas tree at an outdoor lighting ceremony. You see the star, say, 60º above the street, so you call a friend on your cell phone to come find you in the crowd. Just keep the star 60º above you, and you'll find me, you tell her. Get too close to the tree and the star will be almost overhead. Get too far from it, and it'll be much lower and you'll be too far away.

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But your bright friend says that's not much help because she could be anywhere on a circle around the tree and the star on top will always be 60º above her head. No worries, you say. There's a street lamp on the south side of the plaza, keep that light 47º above you and you'll find me.

Nuh-uh, says she, I could be anywhere on a circle under the lamp and the light will be 47º above me. If I do that and I keep the star on the tree 60º above me, too, those two circles of position intersect at two places and I still won't find you in the crowd unless I'm lucky.

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Okay, fine, you tell your friend, go to a spot where the anti-collision light on top of the church steeple is 73º above your head. There, find the circle around the Christmas tree, and the circle around the street lamp. They'll all intersect right where I'm standing.

And it worked, of course. She pushed through the crowd, threw herself into your arms, and promised to follow you anywhere, smart navigator that you are.

Using a bubble sextant to calculate the altitude (angle) to a star, and tables to find the position line you can, if you use three stars, get a small triangle, the middle of which is your position or fix.

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DR and LOPs

Which takes us to sun shots. No, that's not tossing back Christmas cheer, it's the angle you get with the sextant when you shoot the sun during the day. You can't see other stars to get a fix because the one close to us is so darn bright. But you can find the circle you're on under it. And you'll recall from high school math that a short segment of a circle, for all practical purposes, is a line. Take a sun shot, find the circle that crosses your planned route and you have what's called a line of position or LOP. You won't know where on that line you are, but it's bound to be pretty close to your course line so you'll know how you're progressing and if the wind forecast is close to predicted.

So now you know how long range navigation works, at least in principle. In the Vega, the process is actually quite simple, and it will give you something to do as you drone along.

Add-on gauges for your Vega

Add-on driftmeter and sextant gauges, available at DC-3 Airways, will give you the tools you need to navigate by DR and celestial.

An excellent tutorial for the sextant is available here.

You'll find that the sextant doesn't work exactly like a real one. It is a simulation, after all, just like our aircraft. But it comes close enough to give you a real sense of satisfaction when you find the tiny island after hours and hours of flying over a featureless ocean.

A final word

If this kind of thing interests or excites you, you'll love an old (1954) book titled Song of the Sky by Guy Murchie.

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It's a wonderful documentary, comparable to Rachel Carson's The Sea Around Us and every bit as good St. Exupery's Wind, Sand and Stars.

Murchie, a DC-4 navigator by profession, tells how those who ride the winds find kinship with the navigators of Columbus' day. He casts light on the close comparison between the making of a calendar with its 360 odd days and navigating the globe which has 360 degrees, and explains in lucid terms how celestial navigation was first put to work by sailors and perfected by aviators.
Blue skies and tailwinds - Tailspin Tommy (aka Tom)

Mgchristy
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Re: Long range navigation in the Vega

Post by Mgchristy » 20 Jul 2018, 20:07

According to a fella by the name of Smella, Noonan had an, um, beverage problem. I bought a 1929 Travel Air biplane back in the late '80s. It was at wonderful grass strip north of Philadelphia called Van Sant (9N1) run by ol' Billy Smella who knew Travel Airs and who knew Noonan.
Tom,
Thanks for the excellent (and entertaining) write-up. I grew up in Bucks County and took my first PPL lessons at Doylestown back in the early '90s. I haven't been to Van Sant in about 10 years, but I'm sure it's still a gem of an airfield. I used to love going there and just relaxing in a beach chair on a nice summer's day. I had no idea of the local link with Noonan via Smella, though. Fascinating stuff!

I've never particulary excelled at DR even in real life, so I've always have an immense amount of respect and admiration for the men & women who flew using such methods over vast expanses of featureless ocean. The DC-3 Airways site is definitely a treasure-trove of info and utilities on this and other vintage ops. It's just a pity the Radio Range addon will probably never migrate to FSX/P3D!

-Mark

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Tailspin45
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Re: Long range navigation in the Vega

Post by Tailspin45 » 20 Jul 2018, 22:26

Hey Mark,

Glad you enjoyed it. Small world that you know Bucks county and Van Sant. The place is better than ever now. For more on my connection with the place go here.

The radio range add-on (or one like it) is included in the MILVIZ Cessna Bobcat package. I bought it just for that and have had fun trying to shoot a safe approach using it—so far unsuccessfully, to be honest. In any case, it's not a bad aircraft, but I wish they'd make the package available as a separate add-on. I did write to them and tried to sell them on the idea, but....

Mgchristy
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Re: Long range navigation in the Vega

Post by Mgchristy » 22 Jul 2018, 06:06

You're a lucky man, Tom. She's a beautiful machine. Great pics, too. The one of NC3242 flying over the multi-hued field is fantastic. My new background on my desktop....

I've had my eye on the Bobcat for a while but haven't pulled the trigger yet. I'll probably pick it up on the next big Milviz sale. I always enjoyed the RR4 in my old FS2004 Golden Wings setup, particularly installed in the MAAM DC-3 or Uiver DC-2 in Allegheny or AA colors, respectively...while bouncing around PA. I never had much success flying approaches with the radio range either, but I could at least hold a course for point-to-point navigation with a modicum of success. Emphasis on "modicum"! My wife constantly says I'm a man who was born 50+ years too late, and I'm inclined to agree with her. Whether it's planes, cars, music or clothing styles, I've always felt an odd kinship with the "olden days"...and that's the reason I gravitate towards vintage ops in FSX...and why I'm eternally grateful that talented folks like Otmar dedicate their efforts towards planes such as the Vega. Anyone can punch buttons and track a magenta line, but my (admittedly pathetic) attempts at recreating vintage ops in FS have convinced me that men & women really were cut from a different cloth back in days gone by. They don't make 'em like this anymore:

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Take care.

MatsH
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Re: Long range navigation in the Vega

Post by MatsH » 28 Jul 2018, 00:58

I just got Radio Range working in FSX:SE!

I found it here: http://dca1013.com/

I installed it in Manfred Jahns C-47 and tried a few circles around the Tampa station. I can hear the code change as i circle: Dit-dah, dit-dah, daaaaah, daaaah, dah-dit, dah-dit...

I don't think I will use it in the Vega. I fly IFR (I-follow-roads) in the Vega. :-)

No luck in P3D3 or P3D4!

I did a self calculating nav log that I use with the Vega as well as other Aircraft. Read more here if you are interested: http://a2asimulations.com/forum/viewtop ... 33&t=61102

I'd be happy if you tried it out and helped me find bugs or gave me feedback!

/Mats

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Tailspin45
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Re: Long range navigation in the Vega

Post by Tailspin45 » 28 Jul 2018, 01:49

Woohoo! That's fantastic!

You simply installed the FS9 range in the FSX C-47, and it worked?

I certainly will try it out on the Vega.

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Re: Long range navigation in the Vega

Post by Tailspin45 » 28 Jul 2018, 02:09

Merrill Wien

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Re: Long range navigation in the Vega

Post by Tailspin45 » 28 Jul 2018, 15:41

Oh, gosh, I missed those entirely. Didn't realize DCA had new FSX versions! Yay!

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Re: Long range navigation in the Vega

Post by Tailspin45 » 30 Jul 2018, 02:01

Mgchristy wrote:
22 Jul 2018, 06:06
My wife constantly says I'm a man who was born 50+ years too late, and I'm inclined to agree with her. Whether it's planes, cars, music or clothing styles, I've always felt an odd kinship with the "olden days"...and that's the reason I gravitate towards vintage ops in FSX...and why I'm eternally grateful that talented folks like Otmar dedicate their efforts towards planes such as the Vega.
Just realized I never responded to this part of your message, Mark.

I, too, feel like I was born in the wrong era. I would love to have been one of those boys that signed up in '40-'41 to learn in a Stearman, BT-13, and AT-6 before flying a Wildcat and then a Hellcat. I grew up addicted to the TV series Victory At Sea, probably the main reason I signed up with the Navy in 1969. My Dad flew A-20s and A-26s for the USAAC in Okinawa and the Philippines, but--to his chagrin--I was Navy all the way.

My first flight in a Navy aircraft was as a passenger in C-118 from Albuquerque to NAS Dallas, and I loved every minute of it. I was sent off to the Philippines before I got to go to Pensacola. But I did get to fly in an HU-16 Albatross and a C-121 WarningStar while I was over there.

When I showed up for flight training a couple years later the first aircraft I touched was a Beechcraft UC-45J and I loved that old bird (way older than I was), too. The martinet Marine flight instructor, not so much. He featured himself a jet jockey and his assignment to a Bugsmasher was a slam to his fragile ego.

Anyway, when I was in flight school I did have the opportunity to ride along from Pensacola to New Orleans in the Navy's very last Douglas AD that belonged to the Naval Air Medical Insitute. The pilot delighted in showing off what it, and he, could do and I was delighted too. I have a clear recollection of hanging in the straps in an almost vertical dive, falling like a bag of hammers, at a constant 180 knots through a hole in the undercast. Not exactly a stabilized approach, but it worked!

I have had some fun creating some environments from "back when" thanks to the great Solomons terrain package, and the Fantasy of Flight package.

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All that said, I can't wait for the opportunity to recreate some of the famous flights that featured the Vega! Hawaii here we come!

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