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Author Topic: The Last Takeoff Footage.  (Read 79901 times)

Gary LaPook

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Re: The Last Takeoff Footage.
« Reply #15 on: December 04, 2011, 10:35:49 PM »

I recently realised that I may have been mistaken to assume that a broken antenna would still be attached at the front connection point, at least initially.  The problem with this scenario is explaining how the aft end magically hooks on something on the field and is yanked off to create the "puffs" seen during the takeoff film.  Is this what others assumed happened?  What do you think the loose end hooked on?  Most airfields are preferred to be free of obstructions and objects that might hook airplane parts, and a loose, floppy antenna, possibly with a broken section of mast still attached, will not "hook" on the ground by itself. Note that I do a lot of vehicle tests that include dragging cables along the ground, and I've never seen a cable "hook" on bare ground, even when dragging failed ground anchors, tent pins, instrumentation boxes, etc.  However, there is a different scenario that makes hypothetical sense to me, so I'll throw it out here:
Let's say that during the taxi at Lae, the aft mast contacted the ground, bending it back, tensioning the antenna wire enough to cause it to fail at the forward end.  The loose section of cable was then dragged along the ground, still connected to the bent aft mast, and possibly to a bent intermediate mast.  When the tailwheel rolled over the loose end of the antenna, the remaining connection point abruptly failed.  I've seen a similar action take place when a vehicle wheel rolls over a moving cable - the cable abruptly acquires the velocity of the ground, rather than the velocity of the vehicle (caveat: I test vehicle barriers for a living, not aircraft antennas).
But there's a problem - this scenario would have to occur while the tail wheel was still firmly on the ground, not during the takeoff run when the tail is in the air.  If so, then the puffs are not from the antenna getting yanked off - it was already gone earlier in the taxi or takeoff.
The simple explaination for the puff(s) is the plane passing over the hypothesized dirt road.
OK, let the flames begin.
I think that everyone has always assumed that Lae was a sleepy little backwater airport, maybe one or two planes a day. It turns out that in the '30s Lae was one of the busiest airports in the world! The airplanes flying in and out of Lae carried more air freight than ALL THE OTHER AIRLINES IN THE WORLD PUT TOGETHER!
http://www.airwaysmuseum.com/Junkers%20G31%20VH-UOW.htm
This was due to the gold rush in New Guinea which could only be carried out with air transport since there were no roads. Several months ago I brought up the question of why Earhart didn't takeoff from Rabaul which was almost 400 miles closer to Howland. Ric did not know that there was an airport at Rabaul (there were actually three) in 1937 and expressed the opinion that there was no reason to believe that Earhart knew about them. There were many flights every day between Rabaul and Lae so it is impossible that Earhart did not know about Rabaul. It would be like being at the Cincinnati airport and not knowing that there was an airport in Chicago.

So, I agree with you, the TWO puffs of dust were created by the TWO main wheels hitting the road crossing the runway. Ric's explanation that it was just one puff broken into two by prop wash reminds me of the old story about the new guy on his first day working at the airport. An old timer sends him off with a bucket to get some "prop wash" and he is run all around the airport by the other old timers in search of the mysterious prop wash.

It is highly unlikely that at an airport that handled that much traffic that somebody would not have detected and removed every obstruction from the runway and from the taxiway that was large enough and strong enough to break the belly antenna of Earhart's plane. Because of this, it is an unlikely event that the belly antenna mast was broken off while taxiing and impossible after the tail was up. Then, in Ric's scenario, the dragging antenna gets snagged a second time, on a different obstruction, another unlikely event for the same reasons already mentioned. Two unlikely events in series results in a very unlikely event. And then there is the question (assuming for the sake of argument that Ric is right) of just where the antenna would fail if it did get snagged. There is no reason to believe that the antenna wire was more likely to fail at the forward end than at the back end where it was connected to the rear antenna mast. In fact, it is more likely that the wire would fail where it was connected to the rear mast resulting in the rear mast being torn off but leaving the antenna wire still connected to the forward mast. This is due to the stress risers created by twisting or tieing off the wire at the rear mast and these stress risers lead to a weakness and a failure at that point.


Then there is also the likelihood that the belly antenna was not used for HF radio reception in the first place. Since a tuned transmitting antenna is the most effective antenna for reception it is most likely that the receiver utilized the transmitting antenna on the top of the plane.

gl
« Last Edit: December 05, 2011, 01:33:54 AM by Gary LaPook »
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Martin X. Moleski, SJ

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Re: The Last Takeoff Footage.
« Reply #16 on: December 05, 2011, 02:44:56 AM »

... So, I agree with you, the TWO puffs of dust were created by the TWO main wheels hitting the road crossing the runway. ...

I'm the one who introduced the possibility that there was a "road" crossing the runway--and I did so without checking where that idea came from.

I see that it is a controverted point in the old Forum.

The Lae Gallery contains a 1943 aerial photograph of the runway:



There does seem to my eye to be a "road" across the runway, not far from the red rectangle on the right. 

Please note that I am not a qualified interpreter of aerial photographs. I also don't know how closely the conditions pictured in 1943 matched those of 1937.

I'm still under time pressure, so I don't have time to review other arguments about the purported "road." 
LTM,

           Marty
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Ric Gillespie

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Re: The Last Takeoff Footage.
« Reply #17 on: December 05, 2011, 07:14:24 AM »

I think that everyone has always assumed that Lae was a sleepy little backwater airport, maybe one or two planes a day.

I can't speak for everyone but I've been aware that Lae was active in supporting the gold mining industry.  Note that the Chater Report is addresses to M.E.Griffin at Placer Management Limited.  Placer was (and is) a mining company. 

Several months ago I brought up the question of why Earhart didn't takeoff from Rabaul which was almost 400 miles closer to Howland. Ric did not know that there was an airport at Rabaul (there were actually three) in 1937 and expressed the opinion that there was no reason to believe that Earhart knew about them. There were many flights every day between Rabaul and Lae so it is impossible that Earhart did not know about Rabaul. It would be like being at the Cincinnati airport and not knowing that there was an airport in Chicago.

I didn't know there was an airport in Rabaul and you haven't shown that Earhart knew either.  Yes, once she got to Lae she undoubtedly found out but by then it was too late to change her departure point for Howland even if she wanted to.

So, I agree with you, the TWO puffs of dust were created by the TWO main wheels hitting the road crossing the runway. Ric's explanation that it was just one puff broken into two by prop wash reminds me of the old story about the new guy on his first day working at the airport. An old timer sends him off with a bucket to get some "prop wash" and he is run all around the airport by the other old timers in search of the mysterious prop wash.

We can disagree about about what the photos show but, as I've said before, it ultimately doesn't matter whether there is one puff of dust caused by the dragging antenna mast snagging in the dirt or two puffs of dust caused by the wheels.  The simple fact is that the belly antenna is there when the airplane taxis out and it's gone when it comes back by on the takeoff run.  All of the discussion about how that happened is speculation.  Fun to puzzle over but we'll never know for sure.

It is highly unlikely that at an airport that handled that much traffic that somebody would not have detected and removed every obstruction from the runway and from the taxiway that was large enough and strong enough to break the belly antenna of Earhart's plane.

Who said anything about "obstructions?"  It was a heavily-used dirt/turf runway. In my experience, heavily-used unpaved runways tend to get beat up. The aircraft was heavier than it had ever been.  You can see in the film that when the plane taxied out, the aft antenna mast barely cleared the ground.  It's not hard for me to believe that it could have been knocked off by striking the ground, especially if Earhart taxied into the over-run at the end of the runway to turn around so as have as much runway as possible.  And it's not hard for me to believe that the mast being dragged along the ground by the still-attached wire might, at some point, snag in the dirt (maybe where the road went across the runway) and tear the antenna loose. But again, it's all speculation.

Because of this, it is an unlikely event that the belly antenna mast was broken off while taxiing and impossible after the tail was up. Then, in Ric's scenario, the dragging antenna gets snagged a second time, on a different obstruction, another unlikely event for the same reasons already mentioned. Two unlikely events in series results in a very unlikely event.

I would argue that the first event (the ground strike of the aft antenna mast) was not an unlikely event due to its proximity to the ground, the weight of the aircraft, and the nature of the field.  Once that happens and the mast if being dragged along the ground, the second event (the mast catching on something) is almost inevitable.

And then there is the question (assuming for the sake of argument that Ric is right) of just where the antenna would fail if it did get snagged. There is no reason to believe that the antenna wire was more likely to fail at the forward end than at the back end where it was connected to the rear antenna mast. In fact, it is more likely that the wire would fail where it was connected to the rear mast resulting in the rear mast being torn off but leaving the antenna wire still connected to the forward mast. This is due to the stress risers created by twisting or tieing off the wire at the rear mast and these stress risers lead to a weakness and a failure at that point.

I have no idea what you're talking about.  All I'm suggesting is that the aft mast struck the ground during taxi resulting in the broken-off mast being dragged along the ground by the wire antenna. When the mast ultimately snags on something the wire pulls free.

Then there is also the likelihood that the belly antenna was not used for HF radio reception in the first place. Since a tuned transmitting antenna is the most effective antenna for reception it is most likely that the receiver utilized the transmitting antenna on the top of the plane.

By that logic, Earhart and Noonan surely were adept at sending and receiving Morse code since code was the standard method of radio communication at that time. 
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John Ousterhout

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Re: The Last Takeoff Footage.
« Reply #18 on: December 05, 2011, 08:40:21 AM »

Regarding part of Gary's post, Ric sez: "...I have no idea what you're talking about..."
I think Gary is referring to points I raised in my message #17, in which I propose that the antenna may have broken at the forward end, rather than at the aft end.  If this happened, then I know of one means that explains how the antenna would subsequently be pulled completely free of the aircraft by the tail wheel if it ran over the loose end of the antenna.  This would explain how the antenna wet missing between the taxi out, and the takeoff run.  It does not explain the puffs, which may in fact be unrelated.
In my experience, a loose wire, with or without a broken mast on the end, is unlikely to catch on anything when dragged along the ground.  I've seen no suggestions for what the antenna might have caught on, and I believe it unlikely that an antenna could have hooked on something, so I offered a different scenario to explan how the antenna went missing, based on something I've observed in practice.
I think it may be more important to concentrate on the antenna than on the puffs.  The photographic evidence supports the conjecture that the belly antenna went missing between taxi and takeoff.  The puffs might offer some indirect supporting evidence to explain how that happened, but the missing antenna is a fact that stands alone without requiring further explanation.
Cheers,
JohnO
 
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Ric Gillespie

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Re: The Last Takeoff Footage.
« Reply #19 on: December 05, 2011, 11:32:01 AM »

The photographic evidence supports the conjecture that the belly antenna went missing between taxi and takeoff.

Call it conjecture if you want to but the antenna was not there when the plane left Lae.

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Friend Weller

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Re: The Last Takeoff Footage.
« Reply #20 on: December 05, 2011, 11:39:02 AM »

I can see why the antenna and any remaining attached support may have just dragged behind NR16020 until it simply broke free; either attached to the aircraft by the front or rear mast.  But what if the now-broken antenna and mast went "Twang!"?  As AE approached the end of the taxi strip, would it have been prudent or necessary (as the 10-E was a tail-dragger) to come a full stop after aligning with the center line of the runway prior to running up the engines and releasing the wheel brakes to begin her take-off roll?  Or would she have allowed the aircraft to roll through and begin it's take off roll directly from taxiing (as sometimes takes place today)?  If she came to a full stop, what would been the fluidity of motion as the aircraft rolled forward from that full stop?  Would it been uneven enough from the derelict mast's point-of-view between the propwash and the release of the brakes so as to tip the remaining portion of the mast upward at some point, resulting in it's bouncing along over the ground still secured to the airframe?  Alternatively, if she rolled through at the beginning of the take-off run, would centrifugal forces have whipped the antenna sideways causing it to have to bound along as it regained it's fall position under the centerline of the fuselage?  Either way, the "tipping" action could happen while the antenna mast was being dragged slowly at first but at an increasing rate of speed over an uneven surface or striking a small crevasse or rock (or ruts from the possible cross-runway road), being jerked forward as the aircraft begins to gather speed and repeating the process.  Instead of it sliding along on the ground, it is bouncing along, until the repeated physical shocks to the wire break it free (with or without the other mast) from the airframe.  We should also consider the changing geometrical relationship of the wire with the aircraft as the tail wheel came up off the ground.  Admittedly this is all a guess but if it were the aft mast that had failed during taxiing and the mid-point mast broke off during the take-off roll, that could explain the puff (or puffs) of dust we see in the film.  If the runway had been paved, it is conceivable the antenna might have remained attached to the aircraft as it left the ground, sliding down the runway then trailing along in the air until it failed from being jerked around in the conflict between gravity and propwash.

It almost makes me want to get in a truck in the sub-freezing temps and drag a length of similar copper wire down a graded but unimproved dirt road at the same speed with an appropriately-sized and weighted aluminum "mast" behind it to simulate the scenario in this hypothesis.....except most of the county roads near me right now are under a few inches of snow!

LTM,
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« Last Edit: December 05, 2011, 02:59:29 PM by Friend Weller »
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John Ousterhout

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Re: The Last Takeoff Footage.
« Reply #21 on: December 05, 2011, 12:54:00 PM »

Below is the address to a Purdue picture showing the belly aft antenna mast(s), at some earlier date.  At one time there was a second antenna that was part of the Hoven ADF system.  The second mast may be part of that system, although I don't see a second wire.  The fat dangling object behind the masts appears to be the weighted the end of the retracted long wire antenna.  I've read that its location was moved from the tail, to the belly (as I think is shown here), then finally removed entirely.  The mast(s) do not appear to be substantial structural items, so a ground contact would reasonable be expected to break it off.  Would it have been visible if it were dragging along on the ground? Only with luck that positioned the greatest cross section to the camera lens at the right instant. Otherwise it would have been a rapidly bouncing stick on a skinny string, neither of which are likely to show up easily in the photo  The mast and stretched wire are obviously missing from where they're supposed to be. 

http://earchives.lib.purdue.edu/cdm4/item_viewer.php?CISOROOT=%2Fearhart&CISOPTR=802&DMSCALE=25.00000&DMWIDTH=600&DMHEIGHT=600&DMMODE=viewer&DMFULL=0&DMOLDSCALE=2.80269&DMX=0&DMY=0&DMTEXT=%2520b12f9i2&DMTHUMB=1&REC=1&DMROTATE=0&x=115&y=106
Cheers,
JohnO
 
« Last Edit: December 05, 2011, 01:03:20 PM by John Ousterhout »
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Chuck Varney

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Re: The Last Takeoff Footage.
« Reply #22 on: December 05, 2011, 02:15:06 PM »

Call it conjecture if you want to but the antenna was not there when the plane left Lae.

Ric,

Help me understand your thought process.

There are three numbered statements below. Which, if any, do you consider to be fact?

1.  The aft ventral antenna mast has not been detected in still or motion photography of AE’s final takeoff from Lae.

2.  The aft ventral antenna mast was torn free of the fuselage at some point during AE’s final departure from Lae.

3.  The ventral antenna was separated from the aircraft at some point during AE’s final departure from Lae.

(This is not intended to be a trick quiz.)

Chuck
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Heath Smith

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Re: The Last Takeoff Footage.
« Reply #23 on: December 05, 2011, 04:34:17 PM »

Ok, another crazy theory.... the rear mast did indeed snap off. There was slack in the wire with the rear mast dangling. When they throttled up, the wire eventually was swept up and wrapped around one of the props and a piece violently smacked the pavement (I am sure someone did mention this already). The rear mast was pulled against the mast in the middle deforming it or ripping it off completely.

Has anyone ever noticed a faint line in the LaeT-Odet.jpg photo under the left wing? That seems out of place. I inversed the image so that it is easier to see. Strange how the line intersects exactly where the center mast is supposed to be.

It sure would be nice to have a higher resolution image than the 8-bit jpg image to work with.
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Tim Collins

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Re: The Last Takeoff Footage.
« Reply #24 on: December 06, 2011, 06:56:11 AM »

Is there something visable on the plane's belly just aft of the rear window in the take off picture? Or is it simply lint or something on the negative?
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Dan Swift

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Re: The Last Takeoff Footage.
« Reply #25 on: December 06, 2011, 08:41:09 AM »

As far as missing antenna mast:  A picture is worth a thousand words.  It simply isn't there on the takeoff roll picture.  No amount of high resolution is going to make it re-appear! 

As far as Lae vs Rabaul:  An instrument rated pilot myself, 'trying' to think in terms of a poorly trained (she had vitrually none) instrument pilot, with 1937 navigation technonlogy, and considering where they were, 'personally' I would want as much "dead reconing" as possible during this last leg.  Better to calculate wind drift and ground speed early in the flight....before going out over the vast....nothingness!  But, that's just me trying to think like a VFR pilot having to go over the ocean....in 1937.  I want to fly over as much land as possible.....
TIGHAR Member #4154
 
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Martin X. Moleski, SJ

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Re: The Last Takeoff Footage.
« Reply #26 on: December 06, 2011, 10:36:52 AM »

As far as missing antenna mast:  A picture is worth a thousand words.  It simply isn't there on the takeoff roll picture.  No amount of high resolution is going to make it re-appear! 

There are limits to what pictures can say.  No picture, for example, can say, "A picture is worth a thousand words."

"The Lost Antenna II"
says, "It could be argued, however, that our inability to see the mast does not prove that it wasn’t there. (You cannot prove a negative hypothesis.)"

I very strongly disagree with the unproven negative assertion, "You cannot prove a negative hypothesis."  Nevertheless, I grant that it is difficult to prove some negatives.  On the basis of the photographic analysis and the fact that the radio transcripts show that AE and FN only heard one transmission from the ''Itasaca,'' I'm willing to say that it is not unreasonable to think that the antenna was lost on takeoff.  Because the interpretation of the photo relies on certain assumptions about the reliability of the lens and the quality of the film, I'm not willing to say that we know for certain that "the antenna was not there when the plane left Lae."

The putative loss of the antenna on takeoff would account for the problems with radio reception during the fatal flight.  There might be other causes (such as a blown receiver fuse?) that could have kept the receiver from working.  It may well be the best explanation available for the receiver failure on 3105 kcs and 6210 kcs.  If there was only one receiver on board, then it was in working order when the repeated transmission of the letter "A" was heard on 7500 kcs.


The Niku Hypothesis is independent from the Lost Antenna Hypothesis.  Evidence for or against one theory does not confirm or discredit the other.
LTM,

           Marty
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Mona Kendrick

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Re: The Last Takeoff Footage.
« Reply #27 on: December 06, 2011, 11:42:52 AM »


 'trying' to think in terms of a poorly trained (she had vitrually none) instrument pilot, with 1937 navigation technonlogy, 

    If you mean simply that she was poorly trained in the use of the particular radio equipment she had for the world flight, that's true.  But this is not a good characterization of her instrument skills as a whole.  She'd learned attitude instrument flying between 1929 and 1932, and later added radio navaids; from late 1934 onwards she used radio compasses, which were early versions of the ADF, to navigate U.S. airways.

LTM,
Mona
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Ric Gillespie

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Re: The Last Takeoff Footage.
« Reply #28 on: December 06, 2011, 05:37:52 PM »

There are three numbered statements below. Which, if any, do you consider to be fact?

1.  The aft ventral antenna mast has not been detected in still or motion photography of AE’s final takeoff from Lae.

The aft ventral mast IS visible in motion picture photography when the airplanes taxis out at Lae.  It is NOT visible in still photography taken during the actual takeoff. I consider these statements to be fact.

2.  The aft ventral antenna mast was torn free of the fuselage at some point during AE’s final departure from Lae.

I consider that statement to be fact. For the statement to be false the mast would have to be present but not visible in the still photo taken during the takeoff run.  All of the other antennas are visible in that photo and a forensic imaging specialist confirmed that the aft ventral mast is not visible.  That's good enough for me.

3.  The ventral antenna was separated from the aircraft at some point during AE’s final departure from Lae.

I consider that statement to be fact.

Ric
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Irvine John Donald

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Re: The Last Takeoff Footage.
« Reply #29 on: December 07, 2011, 09:16:47 PM »

I think Ric just solved it.  John you're right on the money with that idea. Who wants to lead that one?  It probably shouldn't be someone who believes the TIGHAR theory. Maybe Gary
Respectfully Submitted;

Irv
 
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