Could Earhart’s Transmitter Operate If Her Plane Was Afloat?

[h.a.c. van asten]

F.A.A. files on Electra , I possibly have it from Lovell but do not remember exactly . The text was " At least 10 Electra´s ..etc" .

[Matt Revington]

I have a question that is peripherally related to this thread as it deals with the source of post-loss transmissions please move it if you know of a more appropriate one.  I have read a couple of places that the engineers who built the Electra stated that radio transmission from that plane in the water would not be possible but have not seen a clear explanation as to why that was.  If one assumes a non-castastrophic water landing ( i.e. the plane was floating upright in one piece) with empty fuel tanks supplying plenty of buoyancy. My understanding is that batteries ( if fully charged) could operate the radio for 90 minutes ( I assume there was no chance, of running the engine on the water).  I think it was also suggested that the electra was front heavy and would tilt forward in the water, perhaps submerging the cockpit which would also of course make using the radio difficult.  However in life and death situations people can often find ways to jury rig something not spelled out in the engineering specifications, was there another reason why it would be impossible to transmit from the surface of the ocean ?

The reason I ask is that post loss signals that were used to get directional bearings in the Pacific ( not the Betty transmissions) are the most convincing evidence for the Niku hypothesis ( IMHO), if there is no chance of those coming from a floating place then either they were hoaxes from someone in the area of gardner at that time ( extremely unlikely) or the plane was on land and in shape to transmit for those few days.

[pilotart]

Water, especially salt water would have 'shorted-out' the electricity needed for the radio to work.

It is truly sad that All of the messages were deemed to be 'hoaxes' at the time or they would have put more effort into looking on 'land' locations beyond single fly-overs.

[Martin X. Moleski, SJ]

... I have read a couple of places that the engineers who built the Electra stated that radio transmission from that plane in the water would not be possible but have not seen a clear explanation as to why that was.  If one assumes a non-castastrophic water landing ( i.e. the plane was floating upright in one piece) with empty fuel tanks supplying plenty of buoyancy. ...

The question about how well and how long the Electra would float has been pursued in another thread: "Might Electra have floated some distance off-shore?"

A brief FAQ reads, "The opinon of supposed experts at the time was that, with all those empty fuel tanks, the Electra would float 'indefinitely.' We actually had some calculations run by Oceaneering International in 1991. There were 12 individual fuel tanks aboard NR16020 – three in each wing and six in the cabin. If all the tanks were empty and intact, the 7,000 lb (empty weight) airplane would be 1,200 pounds buoyant. Damage to one, or even all, of the tanks in one wing should not be sufficient to sink the airplane."

See also "Ditching into Water" for more considerations about CG and how the plane might float.

[Matt Revington]

A fairly detailed study of the likelyhood of the survival of ditching is also available here

http://www.wingsoverkansas.com/earhart/article.asp?id=1054

They conclude that she would likely have survived the ditching however they also say she would have had only 8 minutes to get out of the plane based on the time another Electra took to sink showing a lack of attention to the particulars of this case.

[Matt Revington]

Pilotart, I understand that seawater is devastating to electronics but It seems to me that if the outer skin of the Electra was not breached in the ditching that they would have period of time to transmit before the batteries ran out, I was asking about the arbitrary way the engineerS are quoted about there being no possibility of any radio messages sent if they ditched

[John Ousterhout]

Keep in mind that the outer skin of the Electra isn't water-tightf enough to float like a boat. It would quickly settle deeper into the water as it flooded through the various openings built-in (door, hatches, inspection covers, cooling ducts, etc).  The battery and the dynamoter were very low in the fuselage and would be some of the first parts of the "electronics" to submerge and be rendered inoperable.
You're right that there would be some time after first contact with the water and the radio becoming unservicable.  The amount of time might even be slightly longer than it takes a car crashing into water to submerge it's battery and electronics.  The ability to float depends on the buoyancy of empty tanks remaining intact and sealed inside the fuselage, which means the lower parts of the aircraft would be submerged. I'd be surprised if the radio might remain functional for as long as a minute after ditching.  It certainly would not have been functional hours or days after ditching.

[Gary LaPook]

Keep in mind that the outer skin of the Electra isn't water-tightf enough to float like a boat. It would quickly settle deeper into the water as it flooded through the various openings built-in (door, hatches, inspection covers, cooling ducts, etc).  The battery and the dynamoter were very low in the fuselage and would be some of the first parts of the "electronics" to submerge and be rendered inoperable.
You're right that there would be some time after first contact with the water and the radio becoming unservicable.  The amount of time might even be slightly longer than it takes a car crashing into water to submerge it's battery and electronics.  The ability to float depends on the buoyancy of empty tanks remaining intact and sealed inside the fuselage, which means the lower parts of the aircraft would be submerged. I'd be surprised if the radio might remain functional for as long as a minute after ditching.  It certainly would not have been functional hours or days after ditching.

The main problem is the dynamotor that converts 12 volts to the very high voltages needed to run a tube type radio mounted on the floor. This is an electric motor that turns a generator, ever try running an electric motor under water?

gl

[John Ousterhout]

"...ever try running an electric motor under water?"  That's the dynamotor mentioned.  They don't work when damp, let alone when submerged.  Likewise the lead-acid battery would quit working when submerged in salt water.

[Matt Revington]

My point in this thread has not been a lack of understanding of what seawater would do to a radio but in establishing that the engineers statement of no possibility of radio transmission after a ditching is correct.  As I understand it the batteries could power the radio for a while but there would be zero chance of recharging after the Electra hit the water, it's a bit of a stretch but say Fred and Amelia were running out of fuel after searching for Howland and knew they were going to have to ditch, would they realize that moving the radio and batteries would give them a chance to transmit after a water landing.  To be clear I don't think this happened but if post loss radio transmission after a ditching can be completely eliminated then, as I said a couple of posts ago, the rf directional signals that track to gardner island area become very convincing evidence, they could only have originated from fn and ae on land at Gardner, then Betty's notebook, freckle cream bottles etc do not matter in making the case for the niku hypothesis.  Of course one could still blame a mischievous native with a radio in his canoe or that a series of experienced radio operators across the pacific all misidentified transmissions and made mistakes in tracing their sources to the Gardner area.

[John Ousterhout]

Matt sez: " I was asking about the arbitrary way the engineerS are quoted about there being no possibility of any radio messages sent if they ditched"
sorry if I wasn't clear in my posts - I was trying to give the reason the radios wouldn't work after a ditching, rather than trying to answer your question.  Let me try to clarify -  the Lockheed Engineers knew that the battery and dynamotor would be covered/filled with sea water almost immediately in a ditching, ending any chance of further radio use.  The Harney drawings don't provide enough detail to see how the battery and dynamotor were accessed, but they are shown under the fuel tank area, so my guess is there was an access panel in the bottom of the fuselage.  It would not have been water-tight, and would likely collapse in a ditching.  Perhaps Gary can provide some details of what happens to hatch covers and inspection covers in a ditching?  I'm no expert.

[Matt Revington]

Thanks John, I'm not trying to be a pain but to me this seems important in the establishment of the niku hypothesis.  You have come very close to answering my question, I realize that chances of the radio working is very small but we have people on these forums arguing for a million to one probability radio transmissions occuring and the electra flying back to New britain when it reasonably didn't have the fuel, it would be good to be able to say that any post loss radio transmissions had to have come from land.  I may be missing something, does the radio require the dynamotor/generator for operation or just battery charging?

[C.W. Herndon]

Matt, you have to remember that the Electra probably would not have floated the same way that the Airbus that "Sully" landed in the river did.
His fuel tanks were in the wings and "belly" of the aircraft. The cabin and a good part of the wings were above at least a good part of the flotation that was available for the Airbus.

The only tanks in the Electra that were below the cabin were those in the wings and they would not have prevented the ship from sinking. Sea water, and quite a bit I would guess, would have had to enter the cabin of the electra before enough flotation would be provided by the internal tanks to prevent the aircraft from sinking. Most estimates that I have seen think that the nose of the airaraft would have settled more than the rest of the cabin which would most  likely mean more water up front. Up front was where the radio receiver, located under the copilot's seat, one of the batteries (the only access to which was through an outside hatch in the belly of the aircraft) and the dynamotor, located under the pilot's seat, that provided the AC electrical power for both radios were located. The transmitter and the second battery were both mounted on the floor of the aircraft near the navigator's station in the rear of the aircraft. They might have also been in the water, but if not, the items up front and most of the electrical wiring would probably have been quickly shorted out by the water.

Moving the battery and radios would  not have been enough to make them work. The electrical wiring would have had to have been moved too. AE couldn't make the RDF work. Do you really think she could have rewired the electrical system? I don't think Fred could have done it either.

Below is one of the Harney drawings that shows where everything was located. Maybe that will give you abetter understanding of the problems.

[C.W. Herndon]

Thanks John, I'm not trying to be a pain but to me this seems important in the establishment of the niku hypothesis.  You have come very close to answering my question, I realize that chances of the radio working is very small but we have people on these forums arguing for a million to one probability radio transmissions occuring and the electra flying back to New britain when it reasonably didn't have the fuel, it would be good to be able to say that any post loss radio transmissions had to have come from land.  I may be missing something, does the radio require the dynamotor/generator for operation or just battery charging?

Matt, the generator and dynamotor are two separate things. The generator was mounted on and driven by the right engine to provide DC power to charge the batteries and to run the dynamotor. The dynamotor produced AC power to run the radios. Simple explanation.

[Matt Revington]

Thanks CW
That does finally get it through my thick head, a ditched engine can't run, a non-functioning engine means the generator doesn't run, no generator and the dynamotor doesn't run, no dynamotor and the radio won't work. Therefore if any of the post loss radio transmissions are real then AE was on land ( or beach or reef).  And if the transmissions used to do the rf bearings were real then niku is the only reasonable piece of land that they could have been on.
Thanks