TIGHAR
Amelia Earhart Search Forum => Aircraft & Powerplant, Performance and Operations => Topic started by: Brian Tannahill on August 19, 2018, 08:03:24 PM
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The crashed-and-sank advocates say that Amelia reported she only had 30 minutes of fuel left.
It's questionable (https://tighar.org/Projects/Earhart/Archives/Research/Bulletins/37_ItascaLogs/analysis.html) whether Amelia actually said that (https://tighar.org/Projects/Earhart/Archives/Research/Bulletins/49_LastWords/49_LastWords.html), but it makes me wonder just how precisely Amelia could monitor her fuel supply.
The standard Electra had several fuel gauges -- this cockpit diagram (https://www.flightglobal.com/pdfarchive/view/1937/1937%20-%201027.html) shows six gauges on the panel.
NR16020 was modified, with 13 separate fuel tanks (https://tighar.org/Projects/Earhart/Archives/Research/Bulletins/61_FuelSystem/61_FuelSystem.htm). Were there also additional fuel gauges? And would the gauges be calibrated so that the pilot could make a ball-park estimate of remaining flight time?
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The crashed-and-sank advocates say that Amelia reported she only had 30 minutes of fuel left.
It's more than questionable. I didn't happen. It's one of many myths the Crashed-and-Sankers cling to. See Chapter Ten of Finding Amelia.
it makes me wonder just how precisely Amelia could monitor her fuel supply.
Good question.
NR16020 was modified, with 13 separate fuel tanks (https://tighar.org/Projects/Earhart/Archives/Research/Bulletins/61_FuelSystem/61_FuelSystem.htm).
The attached schematic shows the fuel tank layout in NR16020. As you can see, the aircraft actually had a total of 12 fuel tanks (it was delivered with 13 but a tank was removed when the fuel system was re-done in August 1936). The two smaller tanks in the front of each wing were serviced from a single filler neck and treated as one tank.
Were there also additional fuel gauges? And would the gauges be calibrated so that the pilot could make a ball-park estimate of remaining flight time?
I'll address that question in the following post.
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As shown in the attached illustrations, Earhart could check the indicated fuel level in each tank. How accurate the indicated level was is a different question. The only way to be sure you have used all of the available fuel in any particular tank is to run it dry. When you know it's getting low, keep a sharp eye on the fuel flow meter. When the pressure drops, switch to a different tank and hit the boost pump. If deftly done, the engine won't miss a beat.
My guess is that, from experience during the world flight, Earhart had a pretty good feel for how accurate the fuel quantity gauges were.
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So, just to clarify - the fuselage 1-6 and wing left/right/font/rear selector switches shown are for the purposes of reading the fuel quanity only, not for actual tank selection?
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So, just to clarify - the fuselage 1-6 and wing left/right/font/rear selector switches shown are for the purposes of reading the fuel quanity only, not for actual tank selection?
That's correct. Wing tank selection was made using the left-hand selector switch below the throttle quadrant. Fuselage tank selection was apparently made using the large handles visible in some cockpit photos. I say "apparently" because the system for selecting fuselage tanks is not described in the literature.
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Thanks Ric :)
So it looks like both engines' fuel supply is controlled with that one rotary switch, and in that aircraft it wasn't possible to feed the engines from different tanks?
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So it looks like both engines' fuel supply is controlled with that one rotary switch, and in that aircraft it wasn't possible to feed the engines from different tanks?
I'm not sure, but if it was not possible to feed the engines from different tanks, why would the selector valve have left and right engine positions?
Attached is a schematic of the fuel system.
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Looking at the schematic, there appears to have been selector valves on the floor for the fuselage tanks.
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I'm not sure, but if it was not possible to feed the engines from different tanks, why would the selector valve have left and right engine positions?
I don't see selector positions for the individual left/right engines Ric, - just for the left/right wing tanks for both the front & rear tank positions. Looks like the selected tank feeds both engines (twin feeds at the top of the schematic).
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I don't see selector positions for the individual left/right engines Ric, - just for the left/right wing tanks for both the front & rear tank positions.
The engine selector is not shown in the fuel system schematic. It's the selector switch on the lower instrument panel just below the mixture controls.
Ric
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Okay - thanks Ric.