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Author Topic: Thoughts on circling ("circling" or "drifting" in radio logs)  (Read 8555 times)

Jeff Carter

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I read the pages on how "circling" in the radio logs was typed over "drifting", and how experts suspect that AE actually said "listening".  I wonder if AE said "searching" -- due to AE's terseness on the radio, this might be how AE would say "flying a search pattern", whether square, circular, or some other shape.

A slightly different question:  Is there any navigation reason to fly a circle or square other than a search pattern, perhaps to try to obtain a wind reading by multiple headings?




 
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JNev

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Re: Thoughts on circling ("circling" or "drifting" in radio logs)
« Reply #1 on: July 31, 2012, 06:04:38 PM »

See Ric Gillespie's reply in 'Earhart's First Contact' (reply #1, Dec. 12, 2011) - this post and others in that string -

Quote
I share your doubts about the "100 miles out" notation but I had never run the numbers as you did.  Nice work.
BTW, what you were looking at on the Purdue website is not the Itasca radio log.  It's Thompson's "Radio Transcripts Earhart Flight."  Not at all the same thing.

When trying to reconstruct what happened it's important to use the raw log that Chief Radioman Leo Bellarts salvaged.  The strike-overs and erasures speak volumes.  See Log Jam.  For example, a close examination of the original log makes it clear that the word "circling" was originally typed as "drifting."  Earhart probably actually said "listening."  See Things Not Said.  In that research bulletin I wrote:

"The radio log shows that Amelia probably never said “about one hundred miles out” at all. It is clear from the platen mis-alignment that the phrase was later added to the 0646 entry in which Earhart says she “will make a noise in the microphone” upon which she hopes Itasca will take a bearing. It is also clear from an earlier entry that this operator uses a dash to separate his own comments from the text of the message. With the added knowledge that it was part of the operator’s duty to judge distance based on the strength of reception, it becomes apparent that the “one hundred miles out” estimate is the operator’s, not Amelia’s."

You say - "Another interesting note of the only change in signal strengths reported other than 5 after 0742."

Others have drawn very specific conclusions about how far way the airplane was at those times based on the signal strengths Thompson included in his report, but those estimates do not appear in the original log.  They are after-the-fact recollections.

You might also find some interesting information in the string "LaPook Hypothesis: Box Search around 157-337" in the "Celestial Choir" panel -

Gary LaPook has written a great deal about the potential for a search pattern, among others.  Some of his information in that string may spur your thoughts a bit.

LTM -
- Jeff Neville

Former Member 3074R
 
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Gary LaPook

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Re: Thoughts on circling ("circling" or "drifting" in radio logs)
« Reply #2 on: August 01, 2012, 03:20:26 AM »

I read the pages on how "circling" in the radio logs was typed over "drifting", and how experts suspect that AE actually said "listening".  I wonder if AE said "searching" -- due to AE's terseness on the radio, this might be how AE would say "flying a search pattern", whether square, circular, or some other shape.

A slightly different question:  Is there any navigation reason to fly a circle or square other than a search pattern, perhaps to try to obtain a wind reading by multiple headings?
You fly three different headings, usually for two minutes each, and measure the angle of drift on each of them. With this information you can compute the wind. For more detail on this procedure see :
https://sites.google.com/site/fredienoonan/topics/measureing-and-determining-wind-speed-and-direction-while-in-flight
on my website.

gl
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pilotart

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Re: Thoughts on circling ("circling" or "drifting" in radio logs)
« Reply #3 on: August 01, 2012, 08:59:13 AM »

If you have a single ground (or water) reference point; you just start one 'Standard-Rate' (three degrees per second or "two minute turn") from over that reference point and when you finish one complete circle (at a constant airspeed), you can note your displacement from that reference point and that was the movement of the wind in two minutes.  This is referred to as a "Wind Circle".

A 'quick and dirty' way to get a rough idea of wind direction is a 'turn about a point' where you will see that to compensate for the wind, you must increase your rate of turn (bank angle) when downwind from the point and reduce rate of turn when upwind.  You use greater bank angles (and power to maintain constant airspeed) and complete this turn in much less than two minutes.

This is one of the first things you teach to a beginning student pilot. And you must make sure they 'get' it before a Solo Flight.  One danger in a turn towards the wind (downwind turn) is the visual increase in your groundspeed could cause you to reduce your airspeed without realizing it...

It depends on the airspeed, but this is usually done at a fairly 'low' altitude (like 500/1000') for most training planes (maybe 1000/1500' in an Electra).  The relationship between your heading/airspeed & direction/groundspeed is the winds movement.

Over the land, a student would begin by tracking along straight lines on the ground (like the three different headings that Gary mentioned) and noticing the different headings required in different directions as well as increase/decrease in ground speed when flying in different directions.
'Boxing' a Section is ideal for this.

Over water, if the 'point' is moving with the current it would add/subtract from the wind's movement and you would need to know that current to apply the correction.  Usually not very significant over open water unless you are over the Gulf Stream or similar current ...
Art Johnson
 
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Gary LaPook

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Re: Thoughts on circling ("circling" or "drifting" in radio logs)
« Reply #4 on: August 01, 2012, 10:15:02 PM »

If you have a single ground (or water) reference point; you just start one 'Standard-Rate' (three degrees per second or "two minute turn") from over that reference point and when you finish one complete circle (at a constant airspeed), you can note your displacement from that reference point and that was the movement of the wind in two minutes.  This is referred to as a "Wind Circle".

That works and you can see which direction the wind is blowing but it is difficult to quantify the strength of the wind, did you ever try to do that? A two minute circle in a ten knot wind will displace the plane only one-third of a nautical mile downwind at the end of the circle. You might be able to estimate this at low altitude over land with many land marks and a large scale chart but it doesn't work over the ocean, no LAND marks. Noonan had  "bombs" (filled with aluminum powder) and flares that ignite when they hit the ocean that make a visible spot on the ocean surface so why wouldn't he just use the Mk 2 driftmeter he had installed in the plane for this purpose, it produces a much more accurate wind than your circle? (I know, someone many years later claimed he found the bombs under Noonan's bed but there is not much of a reason to give this story much weight because, if it were true, he would have told it, and would have produced the bombs, when the search was on.)   During the day, if the wind is strong enough to make whitecaps, you don't even need the bombs.
gl
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Jeff Victor Hayden

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Re: Thoughts on circling ("circling" or "drifting" in radio logs)
« Reply #5 on: August 05, 2012, 12:45:50 PM »

'circling'/'drifting'/'searching' and similar terms would give you a good birds eye view of Howland from all points of the compass. this would eliminate the problem of low cloud/sun glare/haze etc... from obscuring Howland, as in looking for it from ONE point on the compass. Some objects can be seen better from a different vantage point. What better way to obtain a different vantage point...circling, drifting, searching.
Would it not?
Of course, you would have to be in visual range of Howland for this theory to work.

IMHO of course
This must be the place
 
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