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Author Topic: The flight plan, magnetic course, headwinds.  (Read 455780 times)

JNev

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Re: The flight plan, magnetic course, headwinds.
« Reply #330 on: February 05, 2012, 04:53:16 PM »

Gary,

I tend to agree with your view of Hooven's commentary - while some of his points may be valid, there does seem to be some self-serving bias there.  I got an impression from it that he was implying that his equipment could have dealt with the higher freqs - which is not the case, as you point out.

I did find that his impression of AE was consistent with that of some others.  He was a bit harsh in it, I thought - but maybe just be straightforward.  He was passing on what was told him by others about her behavior in the familiarizaiton effort, but AE wasn't the brightest bulb on the tree when in came to this stuff - that we know.

Heath,

I think your analysis and chart-work is excellent - and you make a point we should always remember and apply - none of us can really establish 'fact' about where the flight really tracked - even if we finally find wreckage we'll only know where it came to rest.  But I think the ideas you are kicking around help us understand more about the how things could have come to a loss.

I don't know exactly how to constrain your boundaries - I think what you've put up for visual constraints are a good start.  But even though we 'know' conditions were 'good' that day and that visibility ought to allow spotting smoke and islands at the distances you mention, lots of variables can still play into the equation.  It is not likely, for instance, but possible, that AE came within 10 miles and never spotted or was spotted or hear: Howland and Baker aren't the type to 'stick-out' so well.

As I read over your thoughts I am again confounded at the loss.  Even with RDF off the table it is very hard to understand how a guy like FN missed on his end of it.  Which is not to blame FN personally - just the opposite, in fact: given the RDF shortcoming, something must have prevented him from using all of his tools as effectively as he normally would have, or he should have been able to get the flight within one of your circles by all I understand.

Irv,

I dunno - the manual Gary cites does come some years later than FN and AE's last effort, but FN probably could have 'written the book' on those things - I don't think they were new ideas, but maybe newly codified and put into easily consumed format for military fliers of whom there were so many.

But your comment underscores a peculiar aspect of the mystery for me: FN, so far as we can tell, was all over those things - what he was all about as a navigator.  Recall the report of him calmly folding his charts away in the back of the Electra after the Luke Field crack-up, for instance.

I hope I don't get in trouble for this again, I've been accused of trying to 'profile' FN before - and that's really not where I'm goin - but was something different this time?  Probably not - but it's tough to understand the 'miss' after all the navigation I've waded through here.

As Heath noted, not trying to establish the 'fact' of such a thing - just trying to understand as much of the picture and possible reasons for the loss as I can.

Gary and some others may think me a fool - but I am still convinced the flight found Gardner after my own 'preponderance' - and I still respect many other opinions put up here about 'how' or 'how not'.  The mystery that will be left after we do find 'proof' at Gardner (if we do - and I've seen enough, personally - due to Dr. King's work mainly) - is 'how they got there'.  Short of finding a sealed bottle with FN's last log pages in it, I doubt we'll ever know for sure.

LTM -
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #331 on: February 06, 2012, 04:39:25 AM »



As to its meaning to the case at-hand, I think it's been noted that the Vidal sidebar was a 'third hand' discussion (if that's the root of the need to understand the state of communications between mainland U.S. and Lae in 1937, etc.).  Maybe one day Gore Vidal himself can shed more light as a living link of sorts, or maybe not.
LTM -
I wonder when Gore Vidal first started telling this story. If he told it in the '30s people would have been familiar with the state of communications of the era, including the extremely high cost of telephone calls and the sparsity of overseas phone links, so the story would not have been accepted at that time. If Vidal waited until the '70s, then the state of '30s communications would have been forgotten and he could have gotten away with telling a made up story. Also waiting until after George Putnam had died (1950) and after his father had died (1969), those who could dispute his story were gone. It is fairly common for people to try to insert themselves into famous events, it brings some sense of fame to themselves and this is a possible explanation for Gore Vidal to make up a story like this.

So, does anyone know when Gore Vidal first started telling the story about the impossible phone call from Lae to Putnam?

gl
This is what Gore Vidal said on a recent TV show:

"Narrator: Earhart flew over Africa without incident and continued over Arabia to Karachi and Calcutta. She fought monsoons that beat the paint off her airplane en route to Singapore. Then in Java, she took a short rest before flying onto Australia and finally to Lae, New Guinea. This would be her last stop before the long Pacific leg to Howland Island. Amelia called the Herald Tribune office in New York where G.P. and Gene Vidal were waiting to hear from her.

Gore Vidal, author: Well, just the night before the final flight, she reported in and they had a code phrase, “personnel problems,” which meant Noonan was back drinking. And my father said, “Just stop it right now and come home,” and G.P. agreed and said, “Come back, abort the flight, forget it, come home.” And then she said, “Oh, no,” and she said, “I think it’ll be all right,” something like that. So you may put that down to invincible optimism or it may have been huge pessimism."

-------------------------------------------------------------

Well, Putnam was in California at the time, anybody know where Gene Vidal was?

And what does it mean, night before the final flight, is it the night in the States or the night in Lae? Let's explore if it was the night in Lae, say 9:00 p.m., Thursday night, July 1st.  That would make it 6:00 a.m. in New York July 1st, and 3:00 a.m. in California, were Putnam and Gene Vidal in the Herald Tribune office that early? Would they have described this early morning call as "the night before" the final flight?

Let's say it was night in New York, 9:00 p.m.(6:00 p.m. in Oakland), making it noon in Lae the next day. So we know the call couldn't have been received on July 1st in New York, the "night before the final flight", because the Electra was rolling down the runway at Lae at that very moment. So it would have had to have been at least one day sooner, Noon on Thursday in Lae and 9:00 p.m. in New York (6:00 p.m. in Oakland) on Wednesday, June 30th.  The personnel unfitness radiogram was received at 5:53 p.m. on June 29th in Oakland (8:43 p.m. New York time)after being sent out from Lae at 6:30 a.m. on June 30th, (12:30 p.m. June 29th in Oakland.) so it only took five hours and 23 minutes to  make it to Oakland, pretty good time since we have seen that other radiograms took a lot longer. Is it possible that it was actually received on June 30th instead of June 29th in Oakland making the travel time 29:23? If so, then Vidal's description seems to match the radiogram. We know that the "Denmark's a prison" radiogram took to a whole lot longer than 5:23 to travel from Lae to the Oakland. It took a minimum of 11:23 and that is if Earhart had tossed it out the window of the plane as they were taking off. It is actually datelined Lae, July 1 so it must have gone out considerably sooner.

So it wasn't a telephone call that Gore Vidal was describing but the radiogram that we all knew about.

gl

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Heath Smith

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Re: The flight plan, magnetic course, headwinds.
« Reply #332 on: February 19, 2012, 08:50:54 AM »

I seem to be having issues with Google Earth and I am hoping that someone could point out the problem.

If I plot a course from Howland to Lae in Google Earth, the heading is 257°42' (257.7 decimal).

If I then use GE plot the course from Lae to Howland, it reports a heading of  79°39' (79.65  decimal).

So if I take the heading from Howland to Lae (257.7), I should be able to subtract 180 to obtain the heading from Lae to Howland:

257.7 - 180 = 77.7

This does not equal the 79.65 computed by GE.

What gives?

Thanks.

Update - I found this note on a great circle calculator page: "If you need a BACK BEARING from the distant site back to home do the calculation again, you can't just add 180 deg. The reason for this is that lines of longitude are not parallel to one another, particularly towards the north and south pole.  The errors are small however near the equator and over short distances."

« Last Edit: February 19, 2012, 08:58:28 AM by Heath Smith »
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Heath Smith

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Re: The flight plan, magnetic course, headwinds.
« Reply #333 on: February 19, 2012, 09:02:57 AM »

Ok, the next question...

GE calculates a heading of 257.7 from Howland to Lae. The original flight plan shows 257°3' (257.05).

The difference between the two is then 0.65 degrees. While this seems like an insignificant error in the heading, over 2556SM miles, this could lead to a 29SM error over the distance traveled.

Am I missing something?

Another question I have is whether the reversed flight plan suffer from this same small error? Was this perhaps due to tiny errors in trig tables or navigation tables of the day?

Thanks.

« Last Edit: February 19, 2012, 09:15:42 AM by Heath Smith »
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John Ousterhout

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Re: The flight plan, magnetic course, headwinds.
« Reply #334 on: February 19, 2012, 09:22:08 AM »

Heath,
I don't think you're missing anything.  What you're doing is learning to appreciate just how many variables there were to navigating over long distances in 1937! An aircraft compass card doesn't need to show fractions of degrees - keeping the nose pointed within a degree is the best that can be managed.  Add the need to allow for winds, which can only be estimated within a few degrees at best, then allow for some magnetic variation, then occasional land marks and star shots that have their own variables, and you can appreciate the difficulty of finding Howland.  AE and FN weren't ignorant of those variables - those were the kinds of things pilots and navigators had been learning to deal with for decades.  The actual methods used on the last flight are the source of endless speculation here.
Cheers,
JohnO
 
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Harry Howe, Jr.

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Re: The flight plan, magnetic course, headwinds.
« Reply #335 on: February 19, 2012, 10:13:59 AM »


John
What you post is correct and many have said similar things in the past.  What I can't understand is the failure to mention the fact that AE/FN had an autopilot and a drift indicator on the plane. Certainly AE would have set the autopilot to maintain her heading  (I assume it was slaved to the directional gyro) and checked periodically with her two compasses and the directional gyro to assure that she was "on course".  That's standard practice on a plane with autopilot.  If ya drift one way or the other, the drift indicator would show that and the aurtopilot would be correcting, that's what they do.
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Jeff Victor Hayden

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Re: The flight plan, magnetic course, headwinds.
« Reply #336 on: February 19, 2012, 01:11:09 PM »

Don't know if it has ever been mentioned before but, has the possibility that they overshot Howland island ever been considered?
This must be the place
 
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #337 on: February 19, 2012, 01:44:05 PM »


John
What you post is correct and many have said similar things in the past.  What I can't understand is the failure to mention the fact that AE/FN had an autopilot and a drift indicator on the plane. Certainly AE would have set the autopilot to maintain her heading  (I assume it was slaved to the directional gyro) and checked periodically with her two compasses and the directional gyro to assure that she was "on course".  That's standard practice on a plane with autopilot.  If ya drift one way or the other, the drift indicator would show that and the aurtopilot would be correcting, that's what they do.
Just how do you think a drift indicator works?

gl
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #338 on: February 19, 2012, 01:58:49 PM »



What gives?

Thanks.

Update - I found this note on a great circle calculator page: "If you need a BACK BEARING from the distant site back to home do the calculation again, you can't just add 180 deg. The reason for this is that lines of longitude are not parallel to one another, particularly towards the north and south pole.  The errors are small however near the equator and over short distances."
That's what makes a great circle, the true course changes as you cross meridians. For an exercise, use Google Earth to plot a course from Los Angles to London and see the change. A rhumb line course maintains a constant course for the whole flight so you can just add 180 degrees to reverse course. The rhumb line from Lae to Howland is only one-tenth of a nautical mile longer than the great circle and the two are so close together that no navigator could tell the difference prior to GPS.

gl
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Harry Howe, Jr.

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Re: The flight plan, magnetic course, headwinds.
« Reply #339 on: February 19, 2012, 02:00:00 PM »


Gary
My thought re Drift Indicator is that it displays any deviation from the desired course set on the autopilot/DG from say, wind component.
I would be pleased if you would enlighten me, as I am sure you are amply capable of doing.  Thanks in advance.
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #340 on: February 19, 2012, 02:07:02 PM »


Gary
My thought re Drift Indicator is that it displays any deviation from the desired course set on the autopilot/DG from say, wind component.
I would be pleased if you would enlighten me, as I am sure you are amply capable of doing.  Thanks in advance.
Did you have one on your plane? Maybe you could figure out to build one that did that, nobody else could. Read these manuals for the answer to your question.

gl
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #341 on: February 19, 2012, 02:13:25 PM »

Ok, the next question...

GE calculates a heading of 257.7 from Howland to Lae. The original flight plan shows 257°3' (257.05).

The difference between the two is then 0.65 degrees. While this seems like an insignificant error in the heading, over 2556SM miles, this could lead to a 29SM error over the distance traveled.

Am I missing something?

Another question I have is whether the reversed flight plan suffer from this same small error? Was this perhaps due to tiny errors in trig tables or navigation tables of the day?

Thanks.
Where did you find that number ? Both William's strip map and flight plane give the initial course from Howland to Lae as 257° exactly.

Btw. have you ever worked with logarithms of trigonometric functions as Williams had to do to do his computations?

gl
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Harry Howe, Jr.

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Re: The flight plan, magnetic course, headwinds.
« Reply #342 on: February 19, 2012, 02:16:04 PM »


Gary
Didn't have an autopillot on my Warrior.  Nor an RNAV either.  Sure would have been nicee though.  Was studying (ground and flight) for Instrument Rating when had to start taking meds and that put the kabosh on solo flying  sigh
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Heath Smith

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Re: The flight plan, magnetic course, headwinds.
« Reply #343 on: February 19, 2012, 02:27:33 PM »

Quote
Where did you find that number ? Both William's strip map and flight plane give the initial course from Howland to Lae as 257° exactly.

It is on the original flight plan, not the strip chart. See attached. See the TC (True Course) at the lower right of the left pane.

While I have not worked with tables for trig functions or navigation tables, I think that is something that I need to study to understand how errors and rounding (perhaps excessive) that maybe have entered in to the data and flight plan. I have always had the luxury of calculators and computers so I have never had to go back to work with slide rulers and trig tables.

Someone told me recently about errors in trig tables that were not discovered until the 60s and were used as references in both engineering and navigation. I Google'd around a bit but did not find anything on the topic.
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #344 on: February 19, 2012, 02:47:48 PM »

Quote
Where did you find that number ? Both William's strip map and flight plane give the initial course from Howland to Lae as 257° exactly.

It is on the original flight plan, not the strip chart. See attached. See the TC (True Course) at the lower right of the left pane.

While I have not worked with tables for trig functions or navigation tables, I think that is something that I need to study to understand how errors and rounding (perhaps excessive) that maybe have entered in to the data and flight plan. I have always had the luxury of calculators and computers so I have never had to go back to work with slide rulers and trig tables.

Someone told me recently about errors in trig tables that were not discovered until the 60s and were used as references in both engineering and navigation. I Google'd around a bit but did not find anything on the topic.
O.K. I see where you got that number. Nobody can fly headings any better than a few degrees which is why the table only shows the courses in whole degrees. I have checked Williams computations of the great circle course and intermediate points and only one of the intermediate points differed by one-tenth of a nautical mile from my calculation done with a calculator, which is amazingly good work on William's part using trig tables. Of course, it was a lot of wasted time since the rhumb line was indistinguishable from the great circle and is a lot less work to compute.

gl
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