Print

[JNev]

The dust covers don't do much for me but they may be as substantial as your own evidence in the reader's eye - I agree, let the reader decide.

Fresh consideration of 'fuel usage' however yields much to think about.

[Ric Gillespie]

Fresh consideration of 'fuel usage' however yields much to think about.

What new information do you have about fuel usage?

[JNev]

Not to flog anyone's nag, dead or otherwise, but in response and as to room for doubt hereabouts -

I didn't say I had 'new information', just 'fresh consideration' -

One can 'do the math' in bookend cases:

Bookend ONE:

Using a fuel burn rate reported in a February 13, 1937 wire by "Putnam to De Sibour, London" - 310 pounds per hour (around 6.02 pounds per gallon at 59 degrees F): 310/6.02 = 51.495 gallons / hour - which is close to the "51.6" GPH and "52 GPH" as offered by Neff Jacobs (among other details) per below quoted posts:

...Having spent 40 years in engineering I will observe items become a commercial success or failure for more reasons than working well or not.  Case in point Kelly Johnson measured significant improvement in fuel economy using the Cambridge Meter.   It never seemed to catch on.  Was that because Earhart didn't make it, or because the filters seemed to plug a lot, or because according to an article in a Darwin paper Noonan reported Earhart habitually burned 52 gallons per hour or because it used a leaner burn than Pratt and Whitney recommended?    I strongly suspect a glittering endorsement form a successful Earhart could well have made the Cambridge Meter a must have item in all airplanes.
...

Neff

And -

I dug in my notes and found a quote from Sound of Wings, no page number. A Wire dated Feb 13 , 1937 ,Putnam to De Sibour ,  London , " Fuel consumption normal cruising speed per hour by weight 310 lb."   310/6=51.6 GPH These notes are yellow so from way back.  Context justifying heavy fuel loads over British Territory.   Max cruse for the engines would be 64 gph so it is not simply a claim for all it could burn.

Still looking for Darwin news papers.
Neff

Given that 1100 gallons were aboard at take-off in Lae per Chater, the Putnam/Noonan numbers yield roughly (splitting the difference between my more conservative 51.495 GPH and Noonan's least conservative 52 GPH = 51.7475 GPH) 21.257 hours of flight.

Bookend TWO:

Considering briefly Lockheed 487 Report by Kelly Johnson and The Kelly Johnson Telegrams per your comment upstring -

It depends on altitude, weather conditions (headwinds or tailwinds), throttle and mixture settings, engine performance, etc.

Yes.  If Earhart followed Kelly Johnson's recommendations (and there's no way to know whether she did) she reached the LOP with about 190 gallons of gas left or about 5 hour's flying time at 38 gph - but that was at 10,000 feet pulling 24 inches manifold pressure at 1,600 RPM which delivered a true airspeed of 130 kts.
At last report, Earhart was flying at 1,000 feet presumably to get below he scattered cloud deck to look for Howland.  If she wanted to keep her speed up at the low altitude he would have to bump up her power setting and therefore her fuel consumption.  If she wanted to minimize her fuel consumption she would have to accept a lower airspeed...

Means something of around 38 GPH at best (at the end of all that fuel burn-off at the point of the LOP), or 26 hours out of 1100 gallons (roughly five hours remaining upon reaching the LOP) - which neither of us is likely to believe since as you point out she was not able to have such an optimum condition throughout the flight and because there are many unknowns, because as you say -

...What did she do? How far did she run north on the LOP before turning around and running south?  Did she climb  or did she stay low? How much power was she carrying.  How fast was she going? What was her fuel burn?  Nobody knows.

In sum we have two 'witnesses' (Noonan and Putnam) giving nearly identical 'reports' - if we dare trust that the wire and article written of exist (I'm going strictly by Jacobs' post at moment, having not seen that material - but he does cite notes in at least one case taken from the source) - of close to 52 gallons per hour, or roughly 21 and one quarter hour's worth of flying as a 'habit', AND we have the optimum Kelly Johnson case -

Split the middle if one will, etc. - that may be reasonable if we can believe that Johnson's pleas were sinking into Earhart's behavior, but we're stuck guessing. 

As to running 'slower' to 'save fuel' - in increases endurance (time in the air), yes - but not range.  Long explains that phenomenon well: if one is stuck trying to cover 'ground' (or open sea) to find a place, one is stuck using higher speeds to gain more ground for fuel burned.  Johnson's curves show this if studied.

---

So what is 'new'?  A realization that at best (for the Niku hypothesis) 'we don't know' BUT IF Earhart were somehow on the LOP remarkably far south such as to not find even Baker by flying north (how far must one stand off to miss seeing that island at 1000' and skies no more than 3/10's if we can believe the area was generally as clear as Itasca reported?), and then stumble upon Gardner off to the west by a few miles of the extended LOP, she MIGHT have had 2 or 3 hours of fuel aboard.

My concern is that this is fairly optimistic - but 'nobody knows'.

My other concern is that at 52 GPH +/-, thunk and dunk comes eerily close to her 'last known call' ("we are on the line...").  When I consider the reports of her fuel burn habit (and that Johnson may have realized the problem and had been trying to get her attention, much as did Hooven in other matters) and the simplicity of it, I do not see crashed and sank as so 'irrational', even in today's light - in part because 'nobody knows'.

So there's nothing 'new' here - we've known these 'numbers' for years.  Hence 'fresh consideration' lends room for huge doubt: I simply disagree that Long's notion has been rendered irrelevant.

Yes many things have been studied by TIGHAR over the years - but of even most recent study now are things like what role the island store may have played in supplying certain things to the seven site (as found by Betchart passengers under Tom King's supervision), that the 'camp zero' idea is an apparent no-go, and that we still lack airplane-defining hardware (I do look forward to TIGHAR's technical response to come on 22V1 (sorry, I've tired of keying the dashes in...)).

So, damn Putnam and Noonan for putting out that nagging commentary about 52 GPH anyway (26 GPH per engine), it creates a hellish outlier for us.  It doesn't help that perusing the net for R1340 fuel burn rates turns up that it is not unusual for the AT-6 (similar engine - same displacement and HP as on Earhart's plane, but single engine of course) to burn around 32 GPH in cruise - which would equate to a whopping 64 GPH on the Electra ("x 2") - the ridiculously high 'max rate', BTW, that we would not expect.

So the freshest consideration is that 'nobody knows', but arrival at Gardner with enough juice to transmit for 5 days is no shoo-in.  Fresh consideration reveals that arrival at Gardner would depend very much on a very serendipitous alignment of what some might consider to be a too-long string of improbable things: fuel burn rates closer to Johnson's recommendations than not against reports of the time - split the difference if you will; arrival way far south on the LOP - which given the offset of that line being NNW - SSE means more 'ground' covered to reach it (which in the allotted time means more speed which means more fuel burned), thence missing the moon and sun for 'shots' in what reasonably were around 3/10th's sky cover conditions - AND being so far south so as to miss Baker at the very least on the north-bound leg.

None of which is to say "no way", Ric.  It is simply to note that there remain rational reasons among many reasonable people to differ, that's all.  And thanks, I realize you didn't accuse me of dishonesty or a lack of intelligence.  Hats off for your efforts to turn up new things more lately than most others (no, I have zero confidence in the dust covers of whatzit island); and this isn't a 'pitch' for the 'other possibility(ies)' - it is merely to point out that others still 'hold water' (lots of it - that is a problem: the Pacific does occupy a huge basin).

Sorry for using so much space, but I hope something has been said.

All the best -

[Ric Gillespie]

I didn't say I had 'new information', just 'fresh consideration' -

Actually they are old considerations. The fuel issue is far more complex than you describe.  You have to start with Lockheed Report 487 "Range Study of Lockheed Electra Bimotor Airplane" dated June 19, 1936.  Written by Lockheed engineers Kelly Johnson and William Nelson, Report 487 was Lockheed's attempt to verify that the 10E Special being built for Earhart could be flown 4,500 miles unrefueled - enough to go nonstop from Honolulu to Tokyo as was her original plan.

Bookend ONE:

Using a fuel burn rate reported in a February 13, 1937 wire by "Putnam to De Sibour, London" - 310 pounds per hour (around 6.02 pounds per gallon at 59 degrees F): 310/6.02 = 51.495 gallons / hour - which is close to the "51.6" GPH and "52 GPH" as offered by Neff Jacobs (among other details) per below quoted posts:

On February 13, 1937 Earhart and Putnam were in New York having just announced her plan to fly around the world. None of her Electra flying at that point had been at high weights over great distances.  52 GPH is a typical economical cruise for the 10E in normal operations. Kelly Johnson's recommendations for the long over-water legs were derived from test flights conducted in NR16020 in early March 1937.

...according to an article in a Darwin paper Noonan reported Earhart habitually burned 52 gallons per hour

Assuming such an article exists, Noonan was probably right.  During the world flight up to that time the Electra had never flown a leg longer than 1,961 miles (South Atlantic crossing). Most of the legs were under 500 miles. No need for Kelly Johnson's special long range full management profile.

And -

I dug in my notes and found a quote from Sound of Wings, no page number. A Wire dated Feb 13 , 1937 ,Putnam to De Sibour ,  London , " Fuel consumption normal cruising speed per hour by weight 310 lb."   310/6=51.6 GPH

Again, this was before Kelly Johnson's test flights in early March 1937

Bookend TWO:

Considering briefly Lockheed 487 Report by Kelly Johnson and The Kelly Johnson Telegrams per your comment upstring -

It depends on altitude, weather conditions (headwinds or tailwinds), throttle and mixture settings, engine performance, etc.

Yes.  If Earhart followed Kelly Johnson's recommendations (and there's no way to know whether she did) she reached the LOP with about 190 gallons of gas left or about 5 hour's flying time at 38 gph - but that was at 10,000 feet pulling 24 inches manifold pressure at 1,600 RPM which delivered a true airspeed of 130 kts.
At last report, Earhart was flying at 1,000 feet presumably to get below he scattered cloud deck to look for Howland.  If she wanted to keep her speed up at the low altitude he would have to bump up her power setting and therefore her fuel consumption.  If she wanted to minimize her fuel consumption she would have to accept a lower airspeed...

Means something of around 38 GPH at best (at the end of all that fuel burn-off at the point of the LOP), or 26 hours out of 1100 gallons (roughly five hours remaining upon reaching the LOP) - which neither of us is likely to believe since as you point out she was not able to have such an optimum condition throughout the flight and because there are many unknowns, because as you say -

...What did she do? How far did she run north on the LOP before turning around and running south?  Did she climb  or did she stay low? How much power was she carrying.  How fast was she going? What was her fuel burn?  Nobody knows.

In sum we have two 'witnesses' (Noonan and Putnam) giving nearly identical 'reports' - if we dare trust that the wire and article written of exist (I'm going strictly by Jacobs' post at moment, having not seen that material - but he does cite notes in at least one case taken from the source) - of close to 52 gallons per hour, or roughly 21 and one quarter hour's worth of flying as a 'habit', AND we have the optimum Kelly Johnson case -

No.  As shown above, your Bookend One is meaningless with regard to the Lae/Howland leg. Earhart apparently followed Johnson's recommendations for the Oakland/Honolulu flight.  I see no reason to suppose that she ignored them on an even longer flight.

So there's nothing 'new' here - we've known these 'numbers' for years.  Hence 'fresh consideration' lends room for huge doubt: I simply disagree that Long's notion has been rendered irrelevant.

So much for your fresh consideration.  The bottom line remains the same. Nobody knows how Earhart managed her fuel on the Lae/Howland flight but it's clear that if she simply followed Johnson's recommendations as she had done in the past when she needed maximum range she should have had plenty of fuel to reach Gardner.  The abundant evidence that she did reach Gardner with fuel to spare suggests that she did what any reasonable person would do. 

Sorry for using so much space, but I hope something has been said.

I'd say that's a safe bet.

[JNev]

I realize the true complexity of the thing - hence, 'nobody knows'.

Earhart also had Mantz aboard for Oakland-Honolulu -

Why would she not bother with the practice on the shorter legs and suddenly expect success with it when it really counted?  Doesn't make sense to me, but to each his own.

[Ric Gillespie]

Why would she not bother with the practice on the shorter legs and suddenly expect success with it when it really counted?

Why would she not make sure her RDF was working properly and suddenly expect success with it when it really counted?

[Neff Jacobs]

From P&W Suggested Engine operation table.  Calculations after GPH for single engine mine.
600 HP 66 GPH .65 lbs/hp/hr   .61 LSC*   132 GPH for 2 engines.
550 HP 55 GPH .60 lbs/hp/hr   .55 LSC     110 GPH
500 HP 47 GPH .56 lbs/hp/hr   .49 LSC     100 GPH
400 HP was the Maximum  Setting that did not require rich mixture.
400 HP 32 GPH .48 lbs/hp/hr   .48 LSC      64 GPH
350 HP 28 GPH .48                                   56 GPH
300 HP 24 GPH .48                                   48 GPH
250 HP 21 GPH .50                                   42 GPH
The McRobertson Racer Lady Southern Cross was operated extra lean at high power settings.  The pounds per HP hour are included here to show other operation was possible.

Note:  As I read the Lockheed test report leaning resulted in fewer pounds of Gas per hour and therefore less power.   What the Cambridge meter did was allow Earhart to keep the engines accurately leaned as she changed altitude.  Gas contains a number of BTU per pound.  Leaning puts more air and less gas in per unit of time.  Fewer pounds = fewer HP.   LSC was leaned at high power setting were the recommended mixture was rich for cooling.  Kingsford Smith worked out the extra mixture for cooling the engine was not necessary at cool temperatures and high speed.

Work thru the Johnson Telegrams and adjust for 1100 gallons and you should come up with an average 45 GPH, or 24.4 hours.
Work thru report 487 for maximum hang time and you should come up with 33 GPH at an average speed of 103 mph, or 33.3 hours endurance.

To convert GPH to HP multiply GPH x 6 to convert to pounds.   Divide the number by the lbs/hp/hr. 
Example
52 GPH, 26 GPH for one engine.
26x6=156 pounds  156/.48 = 325 HP per engine.

To convert HP/engine to speed multiply x 2 for both engines.
325*2=650 Engine HP
to Convert to Thrust HP  Multiple by .75 for prop efficiency
650*.75= 487
Turn to Page 26, 27 or 28 of Report 487 depending on the weight you want to consider.  Hint the middle weight should get you close to Average performance.
and look up Thrust HP on the Sea Level curve should give you true air speed for that power setting.

Be careful of ramifications.
52 GPH gives 21.1 hrs endurance but also implies 325 hp, 160 mph Airspeed  around 16 hrs to Howland in still air.

33 hours at  33 GPH and 103 mph is 3430 miles.
25 hours at  44  GPH and 135 mph is 3375 miles.
21 hours at 52   GPH and 160 mph is 3360 miles

Conclusion.   Within limits range vs speed balance.
Have fun with this one and all
Neff

[Ric Gillespie]

Work thru the Johnson Telegrams and adjust for 1100 gallons and you should come up with an average 45 GPH, or 24.4 hours.

Exactly.  "..BUT GAS IS RUNNING LOW" at 19 hours 12 minutes into the flight.  She has 5 hours of fuel left.  She has just begun to burn into her 20% reserve.

[Neff Jacobs]

There is always crashed and sank.   She really did run at 52-54 GPH and had an hour fuel left at that point.

Earhart Arrived from Darwin with something like 335 gallons.  1100 - 785 = 315 gallons  plus 20 or so used for the 30 minute flight.  This put her into Lea with roughly a 50% fuel margin.  So smack in the middle of the Pacific with the receiver not working, the DF not working and the Navigator unable to make landfall 200 gallons may have been "RUNNING LOW." 

If you look at tankage the 6 wing tanks plus the 2, 118 gallon tanks comes to 634 gallons which is very close to twice 315.   The weight and balance work out right.  The Electra would be a little nose heavy with Fred up front and only fuel in the Original wing tanks.  So Fuel in the 102 gallon baggage compartment tanks and the 118 gallon fuselage tanks make sense.

Then there is the possibility as Tighar has pointed out that having not heard from Earhart for about 40-45 minutes after they believed they heard 30 minutes fuel left  they quit listening and missed a couple of transmissions and they did a CYA on the log book.

Does Tighar have any fuel receipts that Purdue does not?  I would love to know if 634 gallons was her usual fuel load unless she needed more.

Neff

[Joshua Doremire]

Now, now...

Now, now is right.  We don't need anyone filling over half a page without saying anything.
Posting arguments from 14 years ago is pointless.  Since then we have concluded a twelve year analysis of the post-loss radio signals, discovered the correlation between the credible signals and the water levels on the reef at Gardner, discovered and analyzed the object in the Bevington Photo, etc., etc.  Meanwhile, not only Nauticos but also Waitt have done multi-million dollar deep water searches around Howland without finding anything.  Crashed & Sank may not have been an irrational hypothesis in 2001 but it is today.  For those who want to flog that dead horse there are other places to do it.

Wasn't a member 14 years ago.

I find it interesting to see how we got here/now. So it is entertaining and educational to see the fuel usage revisited especially in the current context of now. Think of the new members. I see this as a debate more than an argument and in debate facts come up to help others better see why one holds the position (theory) they do.

Fine line between "go search for the info" and having a discussion/debate over it even if it is just rehashing old facts. After all coffee with friends would get quiet and boring if you asked about today's weather and got told to go Google it. (Edit: Asking about 'the weather' in context of 1937 is a Google it.)       

Maybe I misread your intent by the way it's lumped together, however, it is not evidence to use "multi-million dollar deep water searches" as proof the plane isn't there or Crashed & Sank theory isn't sound. It simply means the plane hasn't been found. (By limits of technology used, invalid data from search areas covered, etc.)  Other reasons, as you listed, would better doubt the Crashed & Sank theory.

[Ric Gillespie]

Maybe I misread your intent by the way it's lumped together, however, it is not evidence to use "multi-million dollar deep water searches" as proof the plane isn't there or Crashed & Sank theory isn't sound.

Yes, I think you misread my intent. 
The fact that deep water searches around Howland haven't found the airplane does not disqualify Crashed & Sank.  After all, TIGHAR hasn't found the airplane either but that doesn't mean it isn't in the water off Nikumaroro.
What eliminates Crashed & Sank as a viable theory are the post-loss radio messages.

[Alfred Hendrickson]

What eliminates Crashed & Sank as a viable theory are the post-loss radio messages.

^^^ This ^^^

[Ric Gillespie]

There is always crashed and sank.   She really did run at 52-54 GPH and had an hour fuel left at that point.

At what point? 

Earhart Arrived from Darwin with something like 335 gallons.
  1100 - 785 = 315 gallons  plus 20 or so used for the 30 minute flight.

Okay.  I can see where you get that.

  This put her into Lea with roughly a 50% fuel margin.

I don't see where you get that.  She took on 365 (presumably Imperial) gallons in Darwin according to the fuel receipt in the Purdue archives. That's 438 U.S. gallons.  How do you know how much fuel was in the airplane when they began fueling in Darwin?  Without knowing how much fuel they had aboard when they left Darwin how can you know that she arrived in Lae with a 50% fuel margin? 

If you look at tankage the 6 wing tanks plus the 2, 118 gallon tanks comes to 634 gallons which is very close to twice 315.   The weight and balance work out right.  The Electra would be a little nose heavy with Fred up front and only fuel in the Original wing tanks.  So Fuel in the 102 gallon baggage compartment tanks and the 118 gallon fuselage tanks make sense.

What are you saying?
  Chater says:
July 1st — after the machine was tested the Vacuum Oil Co.’s representatives filled all tanks in the machine with 87 octane fuel with the exception of one 81 gallon tank which already contained 100 octane for taking off purposes. This tank was approximately half full and it can be safely estimated that on leaving Lae the tank at least 40 gallons of 100 octane fuel – (100 octane fuel is not obtainable in Lae). A total of 654 imperial gallons was filled into the tanks of the Lockheed after the test flight was completed. This would indicate that 1,100 US gallons was carried by the machine when it took off for Howland Island.

The airplane had a total capacity of 1,151 U.S. gallons.  According to Chater all of the tanks were full except for one "81 gallon" tank which was about half full.  Chater talks in Imperial gallons unless he specifies otherwise.  81 imperial gallons is 97 U.S. gallons.  There is no 97 gallon tank aboard NR16020.  The closest are the two 102 gallon baggage compartment tanks.  If one of those tanks was half empty she left Lae 51 gallons short of a full load.  In other words, 1,100 U.S. gallons.

Then there is the possibility as Tighar has pointed out that having not heard from Earhart for about 40-45 minutes after they believed they heard 30 minutes fuel left  they quit listening and missed a couple of transmissions and they did a CYA on the log book.

Say what?  When did TIGHAR ever suggest that?   If we did we've long since rejected that idea. There's no evidence to support it.  Itasca never stopped listening for her including all afternoon and into the evening when they believed they started hearing her again.

Does Tighar have any fuel receipts that Purdue does not?

No.

[Craig Romig]

Wait. A single engine uses say as example 26 gph. It would make sense that two engines would be double 26. 26X2=52.
If similar weight and aerodynamicly comparable planes had one engine vs two engines. The two engine plane would burn less fuel than the single engine because of power produced. The twin engines wouldn't have to work as hard as a single engine plane.
So a twin engine plan wouldn't use double the fuel as a single engine. In my scenario above.
Also the cooler the fuel is the more efficiently it burns.

[Monty Fowler]

Craig ... oh, never mind.


LTM,
Monty Fowler, TIGHAR No. 2189 EC