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Author Topic: FAQ: Electra bouyancy, Ditching at sea  (Read 74881 times)

Gary LaPook

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #15 on: October 24, 2011, 12:40:39 AM »

Gary,

This is all reminding me ...Did some crucial part deteriorate over time?  What part?  How long did it take to deteriorate?  Hours?  Days?  Weeks?  Months?  If the airplane ditched anywhere near Howland and floated indefinitely, why didn't Itasca spot it?  If Itasca somehow missed it, why didn't the planes from the Lexington find it? 

If the intact and indestructible plane you describe floated far away from Gardner (or was never there) why was there such a strong and consistent tradition among the islanders that there was airplane wreckage on the reef when the first settlers arrived in 1938?  ...debris on the reef in the same spot where a former-resident described seeing wreckage from an aircraft.  Stories of airplane parts being found on the reef or shoreline are corroborated by aircraft artifacts found in the abandoned village that are consistent with a Lockheed 10.

Theoretical calculations suggesting that the intact airplane could have floated far away from the island and sunk in very deep water are trumped by the abundant evidence that it sank in the near-shore environment in water shallow enough for it to be, to some degree, broken up in later storms with some lighter components being cast up onto the reef and shoreline.
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If they ditched near Howland then there would have been a much higher likelihood of damage to the fuel system components so a greater likelihood that it would sink more quickly than in your scenario of a controlled landing on a smooth reef surface, soft enough to leave the plane standing on its landing gear.

The pieces you have found are also "consistent with" other aircraft. The only way the aluminum would not be "consistent with" Earhart's Electra is if the pieces were stamped "MANUFACTURED IN 1938" or later. I have cross-examined many adverse expert witnesses who have tried to use that "consistent with" terminology to cover up the weaknesses in their theories, its SOP for many plaintiff's experts.

As for being "trumped" I don't think you are there yet. When you find any piece that can be positively connected to NR16020 (and you haven't yet) then you will have the trump card. Until then, I calls 'em as I sees 'em.

As for a "tradition" of islanders  seeing aircraft parts on the reef, I have been a lawyer for a long time and almost all of my cases involved airplane crashes. Based
on my experience I have come to be distrustful of “eyewitness testimony.” Even if a witness is
trying to be truthful it doesn’t mean that they actually saw what they think they saw. I’ll give you
an example. A number of my cases involved airplane crashes involving fires with the wreckage
badly burned up. We would take the testimony of 3 or 4 and in one case 6 eyewitness who
testified under oath “I looked up and I saw the airplane on fire, fire was coming out of the front
of the plane!” If islanders' "tradition" was sufficient then this testimony from so many eye witnesses would
establish the fact that the plane was on fire while it was still up in the sky, case closed.

Well, not so fast. When a plane catches fire after it impacts the ground, the fire and smoke goes
upward, just like the fire in your fireplace. When a plane is on fire while in flight the smoke trails
back and deposits soot on the tail of the plane, no soot on the tail, no in-flight fire. All these
witnesses that testified under oath (not just a "tradition") that they saw a plane on fire up in the air were wrong. They
weren’t lying, they were just wrong. This is just a sample but when you take sworn testimony
many times you start to realize that eyewitness testimony is not all that reliable. And these
witnesses were testifying shortly after the accidents, not many years later. It is also quite common for witnesses to give you the answer you are looking for unless you are careful to ask the questions in such a way that the witnesses can't guess what you are looking for.

"Did you see aircraft wreckage on the reef?"

"Oh, yes."

I have a suggestion for you for an experiment to test your theory on your next trip to Niku.  Bring a bunch of pieces of aircraft aluminum, say four feet by four feet. Inscribe each piece "NOT FROM EARHART PLANE." On the first day go to many places along the edge of the reef and chuck them over the edge. Record the locations from your GPS.  Then on the last day see where those pieces ended up. Did they slide all the way down to the abyssal plain? Did they get caught in shallower water by protuberances on the side of the reef? Did they end up on the various shelves on the side of the reef that you showed in your recent movie? Were they cast back up on top of the reef?

Then on the following trip look for them again, see if they have moved from their original resting places.

It's a good experiment. If they get tossed back on top of the reef then it supports your explanation for the bits found on the island. If they disappear down all the way to very deep water then it also supports your theory since it explains why you haven't been able to find pieces in the shallow water on the side of the reef. I'll predict that they don 't slide very far down the side of the reef before getting caught in pretty shallow water where they will stay forever, but I could be wrong. It shouldn't cost very much for the pieces of aluminum so an inexpensive experiment that might help with your theory.

Ric, do you have diagram or drawing showing where the vent line for the cabin tanks led?

Another question for you. After Earhart landed on the flat reef is there some reason that she couldn't taxi up onto the beach to get away from the tide?

gl

« Last Edit: July 20, 2012, 12:36:07 PM by J. Nevill »
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John Ousterhout

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #16 on: October 24, 2011, 07:10:05 AM »

Gary - thankyou for catching my errors.  I respondeded too quickly and didn't take the time to read your analysis carefully, or to check my own figures - my bad.  You're right that the tanks would need an entry, as well as an exit to fill with water.  I'm not convinced they would withstand crushing, but only because I'm ignorant of the design of their internal bracing.  I've seen many examples of slab-sided tanks that begin to crush at trivial pressures - a foot of water depth is suffiicient in some cases, yet only develops about 1/2 psi.  There are a lot of square inches being pushed upon, and the skin and bracing were not designed with external pressure in mind. Internal baffles for example are simply flat metal sheets spanning the tank width in several places.  Holes in the baffles allow slow liquid flow and reduce weight.  Forces from the action of fuel (sloshing, sudden deceleration, turbulence, etc) are resisted by shear and tension in the baffles.  There are no significant compression loads on the baffles in normal operation.  A flat sheet with holes in it is not capable of withstanding significant compression loads without buckling.  If the baffles have stiffening features, then they can resist buckling and can carry compression loads.  I'm anxious to learn more about the tank design, since it might be important to define the search area. 

I'm inclined to assume the internal bracing of the extra tanks used simple flat sheets with lightning holes, welded or riveted to the skins.  Such a design provides almost no resistance to crushing by submersion in water, but the displaced air would still need to escape for the a/c to sink.

As Ric points out, there was a tradition of an airplane wreck on the reef at one time.  What is known about the ways aircraft breakup on reefs over time?  Surely it wouldn't take much wave and wind action to move an aircraft around on the reef - one modest storm would be enough.  What would be damaged first  - the landing gear getting caught in a crack, anchoring it to one spot?  If so, then the aircraft would "weather-vane" about the stuck wheel, damaging the attach points and nearby structure.  At what point are the empty fuel tanks compromised to an extent they can't float the wreckage?  They would seem to be well protected inside the main fuselage. Would it take a year or two of constant saltwater exposure and pounding by waves to break the stuck parts free of the main body, which then floats away?  I'm guessing something like that could happen, implying there might only be a few pieces deposited near the reef - the larger pieces containing the buoyant tanks might have drifted miles away. 
Cheers,
JohnO
 
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Gary LaPook

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #17 on: October 24, 2011, 06:23:01 PM »

Thanks Gary.  Very interesting.  The pilot did a beautiful job. 
So a low wing, twin engined airplane with empty long-range ferry tanks in the cabin (safe assumption) remained afloat for 15 minutes after a well-executed ditching.

A Lockheed 10E with standard in-the-wings tanks ditched off Cape Cod in 1967 and remained afloat for 8 minutes.  In each case we're probably looking at the amount of time it took for the tanks to loose their buoyancy.

The Cessna 310, although smaller than an Electra, should be roughly proportional in terms of weight versus buoyancy.  I think 15 minutes is a pretty good estimate for how long NR16020 would float.
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BTW, I worked on a case in which a Navajo ditched just off shore of Hilo, it sank in about one minute taking one passenger to the bottom of the ocean. One engine had failed and the plane wouldn't maintain altitude on the remaining engine although it should have been able to, since the single engine service ceiling was about 8,000 feet at the weight of 7,000 pounds, so this did not make any sense. We found out the reason when we took the deposition of the mechanic. It turned out he had not used the proper procedure in adjusting the wastegate controller which then prevented the good engine from actually producing full power.

See:
http://dms.ntsb.gov/aviation/AccidentReports/gsoirwf4xfbwxlflxz02foj21/O10182011120000.pdf

gl

...or at least what you got out of the mechanic was not 'inconsistent with' what happened... but it's hardly 'proof'.

Sounds like your 'proof' is still on the ocean floor, but that you were able to make your case via preponderance. 

Some days that's the best one can do.

I rest.
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The proof was when we had our mechanic expert adjust the wastegate controller on an exemplar engine using the procedure described by the A&P who had worked on the accident plane and then test running the exemplar and determining that it put out significantly less power than it should have. Lycoming's engineers also testified the same way.

gl
« Last Edit: October 24, 2011, 09:32:27 PM by Gary LaPook »
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Gary LaPook

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #18 on: October 25, 2011, 12:46:44 PM »

Thanks Gary.  Very interesting.  The pilot did a beautiful job. 
So a low wing, twin engined airplane with empty long-range ferry tanks in the cabin (safe assumption) remained afloat for 15 minutes after a well-executed ditching.

A Lockheed 10E with standard in-the-wings tanks ditched off Cape Cod in 1967 and remained afloat for 8 minutes.  In each case we're probably looking at the amount of time it took for the tanks to loose their buoyancy.

The Cessna 310, although smaller than an Electra, should be roughly proportional in terms of weight versus buoyancy.  I think 15 minutes is a pretty good estimate for how long NR16020 would float.
----------------------------------------------

BTW, I worked on a case in which a Navajo ditched just off shore of Hilo, it sank in about one minute taking one passenger to the bottom of the ocean. One engine had failed and the plane wouldn't maintain altitude on the remaining engine although it should have been able to, since the single engine service ceiling was about 8,000 feet at the weight of 7,000 pounds, so this did not make any sense. We found out the reason when we took the deposition of the mechanic. It turned out he had not used the proper procedure in adjusting the wastegate controller which then prevented the good engine from actually producing full power.

See:
http://dms.ntsb.gov/aviation/AccidentReports/gsoirwf4xfbwxlflxz02foj21/O10182011120000.pdf

gl

...or at least what you got out of the mechanic was not 'inconsistent with' what happened... but it's hardly 'proof'.

Sounds like your 'proof' is still on the ocean floor, but that you were able to make your case via preponderance. 

Some days that's the best one can do.

I rest.
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The proof was when we had our mechanic expert adjust the wastegate controller on an exemplar engine using the procedure described by the A&P who had worked on the accident plane and then test running the exemplar and determining that it put out significantly less power than it should have. Lycoming's engineers also testified the same way.

gl

You certainly proved that was ONE WAY to get that particular result - and kudos, perhaps it was the most LIKELY way -

Just as TIGHAR has made a most credible case regarding the AE disappearance... except TIGHAR seems to hold more probable physical evidence today than you managed to regain from the Navajo, and has done so before what is likely a far more technically-critical and qualified 'jury' than the typical civil case would face ;D

Now maybe you can understand how TIGHAR has won the positive opinion of so many of us.

LTM -
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Since a Navajo flies fine on one engine  (especially at sea level, I have quite a few hours in them) the other possibility was that the pilot did not use the proper procedure in dealing with the loss of the engine, which was our first thought. But the wreckage was recovered and the prop was feathered and the pilot described using the correct procedure. It wasn't until we took the deposition of the A&P that we got the clue to the actual cause which was confirmed by testing.

gl
« Last Edit: October 25, 2011, 12:56:21 PM by Gary LaPook »
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Gary LaPook

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #19 on: October 25, 2011, 03:21:09 PM »

Since the photos of the tanks appear to show all of the vent lines manifolded together, an air leak in any one tank would allow air to escape from all of the tanks, through the vent lines to the damaged tank.  This also assumes the external vent is line is routed to the bottom of the aircraft.  If it's out the top, then nothing will prevent the tanks from filling or crushing.

Gary wrote"...This means that it would take damaging many of the tanks to make the plane sink.", to which I would add "...to sink quickly", but even a single damaged tank would eventually result in sinking, if the tank vents are indeed all manifolded together.

Assuming any initial submersion does not generate any significant pressure in the the tanks, and assuming one vent line is open to the atmosphere, and assuming 1/2 inch ID vent line, how long would the tanks provide net positive buoyancy?  At a modest 125 ft/sec velocity of escaping air (a bit faster than the maximum recommended velocity in compressed-air systems), through a single 1/2 inch diameter tube, it would take about 17 minutes for 1251 gallons/167 cu.ft of air to escape.  To just reach zero net buoyancy only needs the loss of 393 gallons/53cu.ft, which would take just 5 minutes.

It seems unlikely that a tank could be ruptured by any successful landing, so there would be no obvious way for the tanks to lose their buoyancy unless the vent(s) were open to atmosphere somehow.  If the vents were in the top of the aircraft, and if the tanks could flood or crush, then the a/c might be expected to lose buoyancy and sink within a very short time/distance.  If the vents were in the bottom, or otherwise not open to the atmosphere, then the tanks might provide buoyancy indefinitely.

Knowing where the vent was located might narrow the search area significantly.

Where are the best photos to study that might show vent locations?
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It looks like possible vent lines along the bottom of the cabin in the attached photo.

gl


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Chuck Varney

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #20 on: October 25, 2011, 07:48:50 PM »

It looks like possible vent lines along the bottom of the cabin in the attached photo.

Gary,

If you're talking about the two lines in the photo that run along the starboard wall below the pelorus, I think you'll find that they're electrical cables--typically shown as connecting to the auxiliary battery.

See the attached photo for how the cabin tank venting was arranged--at least early on. There are port and starboard vent manifolds, the aft ends of which bend downwards 90 degrees. Each of the four transverse tanks has a pair of vent lines; one connecting to the port manifold, the other to the starboard manifold. The port and starboard tanks forward of the transverse tanks each have a single connection to a manifold.

Chuck 
« Last Edit: October 25, 2011, 07:52:26 PM by Chuck Varney »
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Gary LaPook

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #21 on: October 25, 2011, 09:16:10 PM »

It looks like possible vent lines along the bottom of the cabin in the attached photo.

Gary,

If you're talking about the two lines in the photo that run along the starboard wall below the pelorus, I think you'll find that they're electrical cables--typically shown as connecting to the auxiliary battery.

See the attached photo for how the cabin tank venting was arranged--at least early on. There are port and starboard vent manifolds, the aft ends of which bend downwards 90 degrees. Each of the four transverse tanks has a pair of vent lines; one connecting to the port manifold, the other to the starboard manifold. The port and starboard tanks forward of the transverse tanks each have a single connection to a manifold.

Chuck
------------------------

There is also this diagram that appears to show the same arrangement with the vent lines going down to the floor aft of the last fuel tank. This photo also shows the vent lines. I have attached a second photo showing Manning doing some plotting. Is that a vent line running under the platform along the left side of the cabin?

gl

gl
« Last Edit: October 25, 2011, 11:24:14 PM by Gary LaPook »
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Gary LaPook

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #22 on: October 25, 2011, 10:50:02 PM »

It looks like possible vent lines along the bottom of the cabin in the attached photo.

Gary,

If you're talking about the two lines in the photo that run along the starboard wall below the pelorus, I think you'll find that they're electrical cables--typically shown as connecting to the auxiliary battery.

See the attached photo for how the cabin tank venting was arranged--at least early on. There are port and starboard vent manifolds, the aft ends of which bend downwards 90 degrees. Each of the four transverse tanks has a pair of vent lines; one connecting to the port manifold, the other to the starboard manifold. The port and starboard tanks forward of the transverse tanks each have a single connection to a manifold.

Chuck
------------------------

There is also this diagram that appears to show the same arrangement with the vent lines going down to the floor aft of the last fuel tank. This photo also shows the vent lines.

gl

gl
-------------------
I have attached a frame from a movie showing the plane taking off. You can see three objects projecting from the belly aft of the trailing edge of the wing.  Two are rear antenna masts for the two belly antennas but the third may be the vent line or possibly the mast for the longwire antenna. Any idea which is correct?
gl
« Last Edit: October 25, 2011, 10:52:31 PM by Gary LaPook »
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John Ousterhout

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #23 on: October 26, 2011, 06:58:38 AM »

The Aircraft-diagram clearly depicts the manifolded vents connecting the extra fuel tanks along their tops.  The one shown turns down and disappears from view behind the aft-end of the tanks.  This would be consistant with the idea that they eventually route to the bottom of the a/c, approximately in the vicinity of the mystery projections apparent in the PDVD_009 video still.
Also, The amelia-earhart-equipment_tn photo shows what appear to be the port and starboard vent lines routing to the tops of the two tanks on either side of her, but not visibly connecting to any external vent(s) at those ends.  It is not shown whether the filler connections(?) for those two tanks are external through the upper skin, nor whether such fillers had vented caps.  In an earlier post I refered to those tanks as "header tanks".  They are also shown in the Aircraft-diagram, the port one even showing the vent line connection, as well as what appears to be an access cover over the filller neck.  I've seen no protruberances in photos in those areas, so I assume the access covers are flush, and the filler neck ends are in boxed assemblies, similar to the sider filler arrangements on the aux. tanks. Such "boxes" are barely visible in the Aircraft-diagram drawing, but not in the photo.  The inside surface of the fuselage above AE appears to be covered in fabric, which may hide any box structure.  Would it be likely that the covered filler ends or the "boxes" were connected to the vent lines, providing a vent to the atmosphere in the top of the a/c?  Then what does the aft line connect to?
I'd conclude from these photos and drawings that the most likely vent location for the extra tanks was through the bottom of the fuselage.
While studying the photos (btw, thanks for posting them gary and chuck), the visible surface of the aft-most tank can be clearly seen to be dented and bulged, giving the impression of very light-gage sheet metal construction.  Rivets connecting the skin to their internal structure are clearly visible.
Cheers,
JohnO
 
« Last Edit: October 26, 2011, 07:04:30 AM by John Ousterhout »
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Ric Gillespie

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #24 on: October 26, 2011, 07:19:56 AM »

These are valuable discussions.  I'm going to post a number of photos that should help us answer some important questions.
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Friend Weller

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #25 on: October 26, 2011, 07:48:36 AM »

All,

I hope I haven't overlooked this already being mentioned and if so, apologies in advance.  That said, it was mentioned by John that the interior of the aircraft appears to be covered by some sort of fabric as seen in the amelia-earhart-equipment_tn photo.  Compare that to the vent_lines photo posted by Chuck where the "fabric" does not appear to be installed as the bulkheads/formers are clearly visible.  I wonder which of these photos was taken earlier and/or if the fabric was removed as a lightening measure after the Luke Field accident.  Vent lines aside, perhaps this might provide insight into modifications made before the 2nd World flight attempt.

LTM,
Friend
Friend
TIGHAR 3086V
 
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Chuck Varney

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #26 on: October 26, 2011, 07:56:07 AM »

There is also this diagram that appears to show the same arrangement with the vent lines going down to the floor aft of the last fuel tank. This photo also shows the vent lines.

Gary,

Yes. (There’s a color illustration in Women Aloft on pp130-131 identical to your drawing.)

I’ve attached a larger version of your Amelia-in-cabin photo (yours, BTW, is a .png file mislabeled as a .jpg).

Quote
I have attached a second photo showing Manning doing some plotting. Is that a vent line running under the platform along the left side of the cabin?

I can’t say for certain, but I doubt it, as the vertical runs from the aft ends of the manifolds lie between the cabin liner and skin. (I’ve attached a copy of your compressed Manning photo, stretched to approximately the right proportion.)

Chuck
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Chuck Varney

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #27 on: October 26, 2011, 08:02:11 AM »

I have attached a frame from a movie showing the plane taking off. You can see three objects projecting from the belly aft of the trailing edge of the wing.  Two are rear antenna masts for the two belly antennas but the third may be the vent line or possibly the mast for the longwire antenna. Any idea which is correct?

Gary,

The third item is the trailing wire antenna "fish" (antenna weight) stowed in the fairlead (an insulated tube through which the antenna wire passes).

I've attached a stretched version of your photo.

Chuck
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Chuck Varney

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #28 on: October 26, 2011, 08:06:47 AM »


I hope I haven't overlooked this already being mentioned and if so, apologies in advance.  That said, it was mentioned by John that the interior of the aircraft appears to be covered by some sort of fabric as seen in the amelia-earhart-equipment_tn photo.  Compare that to the vent_lines photo posted by Chuck where the "fabric" does not appear to be installed as the bulkheads/formers are clearly visible.  I wonder which of these photos was taken earlier and/or if the fabric was removed as a lightening measure after the Luke Field accident.

Friend,

In the photos that have been posted so far, the without-liner photos are earlier than the with-liner photos.

Chuck
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Ric Gillespie

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Re: FAQ: Electra bouyancy, Ditching at sea
« Reply #29 on: October 26, 2011, 08:22:43 AM »

I wonder which of these photos was taken earlier and/or if the fabric was removed as a lightening measure after the Luke Field accident.  Vent lines aside, perhaps this might provide insight into modifications made before the 2nd World flight attempt.

It's the other way around.  The photo without the fabric is quite early - probably August or September 1936.  Initially they tried to use a manifold system for filling the fuselage tanks.  Note that there is no filler neck over the starboard 118 gallon tank forward and only two fueling ports on the port side of the cabin.  Later they gave each tank its own fueling port.

Dating the various photos of the cabin interior is important - and tricky.  The aircraft went though many changes in the year between its delivery in July '36 and its disappearance in July '37.  The fuel system was jiggered around, radios and antennas came and went, interior furnishing were added and removed.  Many photos were taken of preparations for the first world flight attempt because Earhart was courting publicity.  Unfortunately, there are no known photos of the cockpit or cabin interior after the April/May repairs.
« Last Edit: October 26, 2011, 08:40:33 AM by Martin X. Moleski, SJ »
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