Breakdown of the Lockheed Electra exposure to the elements

[Randy Conrad]

Several days ago, I was sitting at work trying to avoid the hot temperatures in the building. As I was sitting there the thought of Amelia and Fred trying to manage in the cockpit of the Lockheed Electra at temperatures of 100 degrees or more. I work in a battery manufacturing plant here in Hays, Kansas and everyday I see all sorts of corrosion..mainly from returns of aged old batteries. As I was sitting there I pondered on what would happen if the Electra did sit on the reef of Nikumarro for at least 4 days exposed to extreme heat and then at high tide got hit with cold ocean water. Another scenario is Amelia and Fred were in the Electra at the time it started taking on water at extreme temperatures and things started buckling and aluminum skin popping away from the rivets. With that being said...my question is how long would it take for the Electra to reach its demise before there is nothing left or swept over the reefs edge? Besides the islanders taking possibly pieces of the plane later..what would the timeline be to total deterioration? Do we have the scientific capability to computer generate a time lapse model of the Electra exposed to those particular elements using a piece of the aluminum skin found years ago on the reef. It would be very interesting to see how fast the deterioration would take and how many days,and weeks, and maybe months it would be before anything was left. I believe Amelia and Fred did land on Niku..but the reef led to their demise along with other elements not prepared for. Anyway, I was reading up on aluminum skin exposed to extreme temperatures and then coming in contact with cold ocean water and found it very interesting. Please read the following:



At temperatures of 100°F (38°C) exposed to cold ocean water, a 1937 aluminum airplane skin will experience several phenomena, primarily related to corrosion and stress caused by temperature changes:

1. Thermal Expansion and Contraction:
Metals, including aluminum alloys, expand and contract with temperature changes.
While rapid temperature changes alone don't necessarily cause problems, the rapid transition from hot air (100°F) to cold ocean water can induce stress on the metal skin, especially if the expansion is constrained.

2. Corrosion:
Aluminum, particularly older alloys used in 1937, is susceptible to corrosion, especially in saltwater environments.

Saltwater significantly accelerates corrosion of aluminum alloys due to the presence of chlorides, which can break down the protective oxide layer that naturally forms on aluminum.
Different types of corrosion can occur, including:

Pitting corrosion: Localized formation of pits on the surface.

Galvanic corrosion: If the aluminum is in contact with more noble metals in the presence of saltwater (an electrolyte), the aluminum will degrade.

Exfoliation corrosion: Corrosion products cause the material to swell and peel away in layers, especially in older alloys.
The combination of temperature changes and saltwater exposure can exacerbate corrosion damage.
 
3. Material Properties and Thermal Fatigue:
Elevated temperatures can affect the mechanical properties of aluminum alloys, potentially reducing strength and increasing ductility temporarily.
Repeated temperature cycles (like heating and cooling) can lead to thermal fatigue, which causes localized structural damage and can lead to cracking over time.
The rapid temperature change from 100°F to cold ocean water could contribute to thermal fatigue, potentially accelerating the degradation of the aluminum skin.

In Summary:
The combined effects of temperature changes and saltwater exposure on a 1937 airplane's aluminum skin would likely include:
 
Accelerated corrosion, particularly pitting and galvanic corrosion due to the saltwater.
Thermal stress from the rapid temperature shift.
Potential for thermal fatigue, leading to cracking and other structural issues over time.

Note: The severity of these effects would depend on factors like the specific aluminum alloy used, any protective coatings applied, and the duration of exposure to the saltwater environment. Early aluminum alloys may have been more susceptible to corrosion than modern alloys.

Anyway, it would be neat to take a piece of the airplane skin found on Niku and due further analysis to see how fast the rate of decomposition would take and at what high temperature it would be to advance corrosion.

Whatever the case may be...it will be interesting to find out! Have a great day!!!!

[Martin X. Moleski, SJ]

Howard Alldred, our oceanographer who died tragically young, speculated that the whole airframe would be ground into metallic sand in a short time. He believed in the Niku hypothesis but did not think that we would ever be able to find identifiable parts of it.

This was just his judgment. He did not quote any articles or do any experiments to back it up.

He's not around to defend his view. Peace be upon him. I just mention it as one opinion that I heard from him when I visited with him in New Zealand in 2003.

[Denise Kelsey]

Ric would be a better source on this, but if Niku is like the rest of the South Pacific, water temps average 84F, even in winter. Not exactly cold water, but still a considerable difference to a superheated airplane skin.  Found this on Quora:
"Aluminum has a high thermal conductivity and can absorb heat quickly. On a sunny day, the surface temperature of aluminum can reach between 50°C to 70°C (122°F to 158°F) or even higher."

[Randy Conrad]

Denise...with your comment you just posted....let's just say that the Electra did land with water rising at high tide..and sat there most likely for several days. With the potential for extreme temperatures..how do the fuel tanks react to this environment and do we know what the storage temperature was for these tanks. This is another thing I believe that Amelia and Fred never thought of.