Electra Fuel Tanks

C.W. Herndon · June 12, 2012, 06:50:27 AM

I had often looked at the size of the added fuel tanks inside the Electra and wondered how they got them in there. I was scanning the pictures in the Purdue Earhart e-collection yesterday and found this picture of a skin panel over the starboard wing that appears to have been removed and replaced. Could this have been the entry way for the fuel tanks?

http://earchives.lib.purdue.edu/u?/earhart,899

John Ousterhout · June 12, 2012, 07:06:06 AM

Why wouldn't they fit through the door? They look like they were sized with the doorway in mind - narrow and tall. Isn't that also the reason to have 5 of them, because 1 or 2 bigger ones couldn't pass through the door? Too bad we don't have detailed drawings of their construction - there are some important questions they might answer. Would they float, how did the dump valves work, etc...
The odd-colored panel is interesting in its own right. If it were an opening, then the underlying structure (ribs, stringers, etc) would also need to be removed, which either compromises strength, or adds weight of reinforcements.

C.W. Herndon · June 12, 2012, 07:37:04 AM

I agree that there are some unanswered questions about the fuel tanks and I don't know if they would have fit through the door or not since we do not know their dimensions. I have found that sometimes, when moving large objects, after they go through the doorway they cannot be turned. Could this have happened here?

John Ousterhout · June 12, 2012, 07:21:53 PM

There wouldn't be any need to turn the tanks once passed-though the door. They would already be oriented correctly.

C.W. Herndon · June 12, 2012, 09:06:40 PM

Maybe, maybe not.

Bruce Thomas · June 12, 2012, 09:24:29 PM

Quote from: C.W. Herndon on June 12, 2012, 07:37:04 AM
I agree that there are some unanswered questions about the fuel tanks and I don't know if they would have fit through the door or not since we do not know their dimensions. I have found that sometimes, when moving large objects, after they go through the doorway they cannot be turned. Could this have happened here?

The Harney drawings provide a good way to estimate the width of those fuel tanks (using the scale at the bottom, it looks like no more than 20", with the one aft being a tad smaller), with the door width being 24".

Chris Johnson · June 13, 2012, 01:50:55 AM

What were the tanks made of?

C.W. Herndon · June 13, 2012, 03:56:29 AM

Quote from: Bruce Thomas on June 12, 2012, 09:24:29 PM
Quote from: C.W. Herndon on June 12, 2012, 07:37:04 AM
I agree that there are some unanswered questions about the fuel tanks and I don't know if they would have fit through the door or not since we do not know their dimensions. I have found that sometimes, when moving large objects, after they go through the doorway they cannot be turned. Could this have happened here?

The Harney drawings provide a good way to estimate the width of those fuel tanks (using the scale at the bottom, it looks like no more than 20", with the one aft being a tad smaller), with the door width being 24".

Bruce, I did not measure the 4 rear fuel tanks but I did use your Harney drawing to very hastily measure the 2 large, forward fuel tanks and the door.

The measurements I got for the door were 2' x 3' 8".

The front fuel tanks 2' 6" x 2' 10" x 4'6".

I will admit these were hasty approximations but I ask again, how did they get the fuel tanks inside the Electra?

C.W. Herndon · June 13, 2012, 04:50:53 AM

Bruce, I went back and re-measured and discovered my hasty measurements were off.

I came up with:

door 2' x 3' 7"
large tanks 1' 8" x 2' 4" x 4' 3"

It would have been tight but maybe could have been done. I still have a little problem with getting them around the corner but my mind is too tired to work on that right now.

Sorry about that. So why was the aircraft skin replaced?

C.W. Herndon · June 30, 2012, 02:40:16 PM

A little more on the Electra fuel tanks.

Richie posted a link to this article about the Electra fuel system that included a drawing showing the location of the tanks. See drawing at bottom.

http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/61_FuelSystem/61_FuelSystem.htm

I have been going through the Purdue e-archives for AE and have chanced on the items below. Somewhere, and I have not been able to find it again yet, I remember reading about there being "baggage lockers in the wings" of the Electra.

I discovered this picture of the port wing, and there is another one for the other wing that is not as clear, that shows a door with handle where I remembered the baggage locker being shown. See picture 2 below.

http://earchives.lib.purdue.edu/u?/earhart,331

From looking at the drawing for the fuel tanks, it appears that fuel tanks were installed in the wing baggage lockers.

From this picture of the underneath of the port wing, it also appears that the panel that formed the bottom of the baggage locker may have been removable. Maybe to allow for inspections? See picture 3 below.

Maybe a convienent piece of aluminum for an alert islander to remove for his own use after the aircraft broke up on the reef?

http://earchives.lib.purdue.edu/u?/earhart,344

Comments or ideas anyone?

Jeff Victor Hayden · July 01, 2012, 05:20:25 PM

The material the ferry/extra fuel tanks was made from was extremely thin. I understand they don't even need to use metal these days. Not much chance of the ferry/extra fuel tanks surviving for very long IMHO
http://www.turtlepac.com/en/photo-gallery/aircraft-ferry-tanks.html

Chris Austin · July 02, 2012, 09:39:11 AM

Quote from: Jeff Victor Hayden on July 01, 2012, 05:20:25 PM
The material the ferry/extra fuel tanks was made from was extremely thin. I understand they don't even need to use metal these days. Not much chance of the ferry/extra fuel tanks surviving for very long IMHO
http://www.turtlepac.com/en/photo-gallery/aircraft-ferry-tanks.html

Use of non-metallic tanks is not new. The drop tanks used during WWII on P-51 Mustangs (and probably others) were made of laminated and shellacked cardboard; perfectly serviceable in the short term.

C.W. Herndon · July 02, 2012, 09:49:05 AM

The temporary tanks that they use today look very similar to the fuel bladders that the US Army used in Viet Nam to establish field refueling stations when we had large helicopter operations in remote locations. They were set up with hoses and pumps all brought in by transport helicopters. Very effective.

It appears, from looking at the pictures, that the newer ones are made from lighter, more durable materals.

C.W. Herndon · July 09, 2012, 01:39:47 PM

Bruce Thomas pointed out to me the article below from a previous addition of TIGHAR Tracks.

I found it very interesting and possibly related to the fuel tank issue as well as the water problem. I thought I would share it with everyone.

See the PDF pages 3-5.

C.W. Herndon · July 11, 2012, 01:04:46 PM

Quote from: J. Nevill on July 10, 2012, 04:57:11 PM
Quote from: C.W. Herndon on June 13, 2012, 04:50:53 AM
...So why was the aircraft skin replaced?

Woody, I think it was to cover the RH window(s). I can't say for sure how they got the tanks in - always thought they were sized to go in through the door. If it were up to me, I would do that and avoid having to disturb the structural frames behind that side skin panel. Mighty good question, but I suspect we can find that the door would work.

Thanks!

LTM -

Jeff, I have found a picture of the port side of the Electra that seems to have two skin panels of a different color. One is the same panel that is a different color on the right side. Maybe they were just from a different lot of aluminum when the aircraft was built. ???

http://earchives.lib.purdue.edu/u?/earhart,768