Forum artHighlights From the Forum

April 9 through 15, 2000

Subject: Black Art Clarification
Date: 4/10/00
From: Birch Matthews

For Skeet Gifford

Your definition of "Black Art" is quite acceptable to me in context with what a pilot faces in the cockpit in a given situation. I cannot argue this as I am not a pilot, just a rapidly aging ex-paratrooper who was usually more than happy to exit a still-flying C-119 or C-46 over Fort Bragg, North Carolina. (That alone may cause many Forum readers to question my capacity for logical thought, especially pilots.)

Once again, I may not have adequately expressed what I was trying to say. Let me try again. I take issue with labeling fuel rate measurement and fuel consumption rate calculation as black art. The former is accomplished in straightforward engineering methods while the latter can be described mathematically and the equations solved. In fact, many weeks ago on the Forum, I outlined in narrative form how to go about this task.

Therefore, I do not take issue with Mr. Gifford's description of "black art" in any way. Conversely, I see no conflict with what he stated and what I intended. I might also suggest that the next time any Forum pilot scans the operating manual for the aircraft he is about to fly, know that some engineer (you might prefer that person was not an old paratrooper with too many hard landings) ran fuel consumption tests and supplemented his data through calculation. I hope this is not too frightening a thought.

Ric, if you feel there has been too much on this subject I certainly won't be offended if you don't post it. Perhaps you would let interested parties contact me at [email deleted; unfortunately, Birch died before finishing his work] if they wish to discuss it further. Thanks.

From Ric

Seems like everyone is in agreement.

Subject: Octane, Performance, and Fuel Economy
Date: 4/10/00
From: Birch Matthews

For Doug Brutlag,

I appreciate your thoughts and comments in your posting of 04/08/00.

You are quite correct in that the aviation fuels of today differ from what Amelia Earhart used in 1937. As Ric noted, she used 80-87 octane aviation gasoline, 100 octane for takeoff. As you know, the antidetonant additive in those days was tetraeythl lead. The amount added was typically 3 cc to 6 cc per gallon.

The lead additive, while dramatically improving detonation resistance, also had some disadvantages when first applied. To counteract lead deposits in the cylinders and on the valves, ethylene dibromide and ethylene dichloride compounds were added to the "ethyl fluid."

I don't know what Linda Finch used in her Electra, but imagine you are correct in assuming it was 100/130 or 100LL, the latter perhaps with an additive. I am not aware of the most recent fuel formulas or antiknock additives. I do know that the T6/SNJs competing at Reno use a maximum power setting on their R-1340s, and I have not heard of any detonation problems with the exception of one year. In this instance it was traced to a bad batch of fuel. This caused problems as you might expect and was the source of many (justified) complaints.

Enriching the mixture has a tendency to cool it and helps reduce the possibility of detonation. Reno Unlimiteds routinely use this technique. The mixture ratio employed depends upon the amount of ADI (water/alcohol mixture) injected and whether or not an aftercooler is used. Its a weight/complexity tradeoff. Eliminating the aftercooler reduces empty weight, but you must carry more ADI --- heavier gross takeoff weight. Of course the ADI is a consumable so at some point in the race you are a bit lighter than the guy lugging the aftercooler around.

What does all of this pontification have to do with Amelia Earhart's flight? Well, I still believe measuring fuel flow rates in an R-1340 today using a contemporary fuel might provide relevant information. We are not concerned with high manifold pressure power settings; rather, just the opposite. So I don't see where detonation is a problem at fuel/air mixture ratios down to about 0.072 (13.9 pounds of air per pound of fuel). I freely admit that below that ratio there could be a problem. My uncertainty is due to lack of a mixture ratio versus combustion temperature curve or any experimental data.

Incidentally, one does not need to duplicate Amelia's apparent flight duration or profile. Merely flying different power settings at possibly two or three altitudes long enough to obtain accurate data should suffice as long as the test program is well thought out. What is "long enough?" Perhaps 10 minutes after stabilization at a given test condition as a guess. Most intriguing is what fuel economy could be obtained at mixture ratio = 0.070, 2,400 rpm, 24 inches. Kelly Johnson did not measure this condition, only recommended it as an alternative in case of unexpected headwind.

Reviewing Linda Finch's records would be interesting to me as well. Don't know if that is possible. As for buying her airplane, I am sorry to say I couldn't afford to fill it up!

Once again Ric, if this is too boring feel free not to post it on the Forum. If you do not, perhaps you would be kind enough to pass it along to Mr. Brutlag.

From Ric

It's interesting information, and a re-creation would be fun, but we wouldn't prove anything about Earhart's flight. Even Elgen Long concedes that if Earhart had followed Johnson's recommendations she would have had more endurance than he claims she got. The only way he can make her run out of fuel when he wants her too is to have her depart from those recommendations.

Subject: Re: Long vs. TIGHAR
Date 4/10/00
From: Herman deWulf

Let me try and explain. In the past serious authors reported facts and explained why things happened the way they did or why things went wrong, based on known or proven facts. Like explaining that the Titanic foundered because she was damaged under the waterline by hitting an iceberg. It was a scientific approach.

Today there is a new trend in a new world which has become a market place for the printing industry. If an author wants to make a buck he will not simply tell the story using well known and proven facts. He will convince the market his story is better because he has knowledge of new and hitherto unknown facts. Even if he has to invent them. There is no way selling the Titanic again without a new theory, regardless of historic or scientific facts. That new approach may not make sense in the eyes of educated people but it does wonders for selling a book to an uneducated public. Like suggesting that Titanic steel plates were made of lesser quality than its sister ship's and therefore became brittle in cold Arctic waters...

Forgive my over-simplification. But what we see happening around AE/FN is exactly the same scenario. We all know that AE's Electra disappeared in 1937. We all know AE and FN failed to find Howland. TIGHAR has reason to believe they made it to Gardner island and this forum is still discussing various aspects of this development to see if the theory holds water and proof can be found. Yet wasn't there recently a new book on the old subject that suddenly claimed "the mystery solved" ? It was solved only in the mind of one author who developed a theory that fitted his scenario. It explains all provided you want to believe him. Most of us at this forum will disagree with his theory and his conclusions.

But haven't we all bought the book ?

Some who are better placed than I am to judge call that "good marketing".

LTM (who read the book and put Long's opinion on the shelf, next to the thin skinned Titanic)

From Ric

I've known Elgen Long for about 12 years. I can't say that we're friends, but we've spoken many times and I've been to his home and seen his collection of material on the Earhart disappearance. I believe he is completely sincere in his adherence to his theory and I do not think that his book was a marketing ploy. The title, however, was. As I understand it, the Mystery Solved title was not his idea and he is much embarrassed by it. Those who have never had the pleasure of negotiating a book contract may be surprised to learn it is not uncommon for the publisher to reserve the right to determine what title goes on the finished book. That decision seems to often be based solely on what the publisher thinks will sell.

Subject: Age of Bones
Date: 4/10/00
From: Don Jordan

Tom King wrote in part:

>The doctor who examined the bones and decided they were Polynesian was
> by definition the product of 1930s medical training. . . . He was not "on
> the scene," but in Tarawa; he examined the bones when they arrived there.
>His analysis was subsequently contradicted by the analysis of Dr. Hoodless
>when the bones arrived in Fiji; Hoodless -- also, of course, the product of 1930s
> medical training, and also not a forensic osteologist -- said they were most
> likely the bones of a European or mixed-race male. . Our two forensic
> osteologists replicated his analysis as closely as possible and their analysis
> suggested that the closest match is to a female of northern European origin.
> Certainly it's possible that Isaac or Hoodless were right, and without doubt
> they had more to look at in developing their conclusions, but on balance, until
> we have something better to work with, I think the modern analysis is
> superior.

What amazes me is that when we talk about the bones, we always forget the one thing that all who saw them agree on. It is never discussed. That is the suspected age of the bones when found in 1940. It doesn't matter if the bones were found with a leather flying jacket on. . . if they were older than two and a half years when found . . . they can not be related to the Earhart mystery.

It doesn't take any medical training to somewhat accurately guess the age of bones. Ask any cattle rancher who stumbles across that long lost steer back in the high country somewhere. My limited experience with such things, is that the first six months after death, it is pretty easy. Even after a couple of years, there is still some skin in various places. Especially in the skull. It takes about three years before there is nothing left but plain bone. The Coconut Crab might be a formidable creature, but they can't hold a candle to a hungry Coyote.

I don't mean to be gross here, but as far as I can remember , none of the original examiners said anything about any "matter" (skin or brain material) still inside the skull. I think there was some mention of a ligament attachment point, or something like that.

Perhaps one of our more experienced forensic scientist can comment on how long it would take, under normal circumstances to remove all traces of flesh from bone laying out in the open.

Who was it? Dr. Burns, I think, who helped examine some bones found from a suicide victim on Tarawa a couple of years ago. Maybe she could tell us exactly what was left of the skull after some six months in the open.

I know we have to continue the bone search and discussion, and I know that the modern methods can't determine bone age in 1940. But I also think that is an important clue in trying to analyze the bone story. The one thing they all agreed on should not be dismissed as not important.

Don J.

From Ric

>It doesn't take any medical training to somewhat accurately guess the
>age of bones.

Well, you learn something every day.

Somebody else tell him. I don't have the strength.


Re: Age of Bones

Date: 4/11/00
From: Tom King

Well, I take it Don's talking not about the age of the individual represented by the bones but the time the bones have been lying around. Actually the degree of skeletalization, and the condition of the bones, are highly variable based on a number of factors -- what's around to gnaw on them, exposure, climate, etc. etc. etc. That's based on my own experience exhuming maybe a thousand bodies here, there, and the other place, plus a ghoulish childhood career collecting animal bones on the farms and forests of northern California, plus such of the pertinent literature as I've reviewed.

Kar Burns may want to comment further, but the skeleton she examined (and I did, too) was on Fiji. Its owner had died about four months before it was found in the jungle, an environment not unlike Niku. It was completely skeletonized, and the bones were somewhat scattered; some were missing altogether. Some had been gnawed, probably by dogs or pigs. If I had found it on the ground without associated artifacts, I don't think I could have confidently guessed at how long it had been there, other than to say that it probably wasn't hundreds of years old.

Another recent example is from Saipan, where we have a detailed report of the investigation of a site (inhabited by coconut crabs) where two murder victims were disposed of. Again about 3-4 months had passed since they'd gone missing, and the bodies were completely skeletonized, but in this case the bones had not been scattered.

My conclusion -- understanding that we know nothing about Gallagher's or Isaac's qualifications for judging how long bones had been on the ground -- is that I wouldn't put much faith in their guesstimates. In addition, we have the sextant box. Is it plausible that a wooden box would have lain around for very long in Niku's environment and still be in good enough shape to (a) retain discernible markings, (b) be a suitable container for the artifacts sent to Fiji, and and (c) be something Vaskess would want to keep on display in his office (assuming we accept Foua Tofinga's account of seeing it there)? Maybe, but on balance -- assuming we accept the sextant box as associated with the bones -- I think the condition of the sextant box argues for the bones not having been on the ground too long.

Tom King

Subject: Re: Octane, Performance, Fuel Economy
Date: 4/11/00
From: Alan Caldwell

Ric wrote:

> The only way he can make her run out of fuel when he wants her to is to
> have her depart from those recommendations.

Ric, that little sentence is one that we all need to cut out and paste on our computers in front of us. I could not count how many times I've seen a comment (sometimes mine) that only had validity if there was a departure from known facts. I remember some time ago you posted a brief recap as a nice reminder to help prevent some our little side trips. It was a big help to me even as long as I have been following AE's mysterious trail. It's the little facts that get us in trouble. Perhaps they are easier to ignore.

What escapes some, I believe, is that it is obvious the Longs put the cart before the horse. They made a decision as to what they believed happened and THEN set about to support it. That NEVER works. There is a ton of evidence that has been sorted through and much has been qualified to some extent or another. It is certainly reasonable to play down certain information if it does not meet a reasonable test but it never can be disregarded until it can be PROVEN to be false information. The smoke the Itasca was supposedly laying down is a good example of our attempt to qualify that information. At first blush it seemed to be a fact that the ship was indeed laying an obvious smoke trail that the Electra should have seen. Since it wasn't seen then the Electra could not have been in the vicinity. Well, now we can see the fallacy of that reasoning. This same careful approach is being done on all the evidence -- the bones, plexiglas, fuel consumption, etc. Nothing is being ignored. Nothing taken for granted. Our problem is we tend to forget little tiny facts that oftimes lead us astray. I don't know whether the Longs "forgot" little facts or just decided some didn't fit. Their conclusion might even be right but they have no, nada, zilch support for their theory. If someone can support their idea tell me how.


Subject: Learning to think about the performance of the 10E
Date: 4/11/00
From: Oscar Boswell

There's a saying that if you give a man a fish, you feed him for a day; if you teach a man to fish, he can feed himself for a lifetime. Perhaps some similar motto is appropriate for this forum.

I was delighted to see you quote Learned Hand. Hand it was (I think) who said that he felt sometimes that he had spent his whole life "shoveling smoke." That's how people who must deal with law sometimes feel about it. There's a lot of smoke in connection with AE, too, but - you should be happy to note - there's not much in the area of airplane performance.

It's pretty simple stuff, numbers and seventh grade arithmetic, and you don't even need a calculator, much less a computer. (As a matter of principle, I did all the numbers in this with pen and paper.)

That being said, there's an obvious problem with talking about performance. You asked, for example, what the 150 mph "base speed" (as I think AE called it) was. Was it an average speed at each power setting, the highest speed, the lowest speed, indicated or true, etc.?

The obvious way to answer that is to find out what Kelly Johnson said ! He must have told AE. But if what he said is available, I haven't seen it.

Can we answer the question with the data we have in some other way ?

I think we can, but doing so raises the ugly head of the aircraft performance monster (and the fear that many people seem to have of him). And it puts the person who trys to formulate an answer in a quandry: how much do you say, and how do you say it ? If you give a categorical answer, everyone asks (quite rightly, I suppose) "who are you to say so". If you show a sketch of your work, people roll their eyes and say "I don't understand." If you take it very slowly, some people still don't understand, and others feel that they are being condescended to. Well, life's hard.

Categorical answer: I think Johnson expected that the power settings he provided AE would maintain a minimum true airspeed of 150 mph true at the specified altitudes, and that the air-speed would gradually increase during each segment, until it was reduced by the next scheduled power reduction. More specifically, I believe he planned the final reduction (38 gph) to take place near the point at which aircraft weight would be around 11,000 pounds (500 over normal gross) and the 38 gph setting would produce 150 - 152 mph at 10,000 feet. The rest of this paper shows the major part of the work to produce that limited conclusion, and formulate one or two rules of thumb that might have some relevance in calculating or evaluating other performance of the 10E - if anyone feels a need to do so.

The discussion of aircraft performance is important for two reasons:

(1) the 24 hour anticipated endurance is the sine qua non of the mystery (if the anticipated endurance had been 20+30 no one would have any real question about what happened), and

(2) the fact that many members of the forum have surprisingly little knowledge about aircraft performance leads them to fall again and again into the same mistakes, and generates a great deal of discussion about things that are relatively clear, if one takes the time to think about them, and is willing to do a little reading and a bit of calculation.

I have already expressed my own opinion that we know enough about the 10E's performance to say that Gardner is possible. Why discuss performance further? Because the subject always comes up - and if we talk about a subject, we owe it to ourselves and others to be as accurate as possible.

It disheartens me to see you confuse yourself about the "indicated" and "true" airspeed question, and to refer to fuel consumption as a "black art." And I cringe when you seem uncertain about 20gph. There are well-known rules(and rules of thumb) about all of these things, and people who wish to discuss the subject owe it to themselves to attempt to understand those rules.

For example, true airspeed (by rule of thumb) is 2% per 1000 feet higher than indicated airspeed - this rule of thumb works quite well; it converts 120 indicated at 10,000 to 144; the calculated result (standard conditions)is 142 (on myE-6B, which seems to be harder to read than it used to be). "Standard conditions" means a barometric pressure of 29.92 inches, and a temperature of 59F(15C) at sea level, which gives an OAT at 10,000 of -5C (the "adibiatic lapse rate" being 2 degrees centigrade per 1000 feet). "Standard conditions" is an important statement, because performance changes (to one degree or another) when conditons vary from standard. Anything I say is meant to be at standard condtions and 10,000 feet, unless the contrary is stated.

Fuel consumption calculation is not very difficult to understand. Average modern efficient engines are assumed to burn 0.45 pounds of fuel per hour for each horse-power produced, with normal leaning techniques. (The range of consumption is actually from something like 0.40 to 0.50.) A gallon of aviation fuel weighs 6 pounds. Cruise settings are usually stated as a percentage of rated power. If, for example, the airplane has a rated horsepower of 200, and is flown at a setting that yields 60% of power, it is producing 120 horsepower. In an hour it burns 0.45 pound of fuel for each of the 120 horsepower. Since 0.45 x 120 = 54, it burns 54 pounds of fuel in an hour. Since fuel weighs 6 pounds per gallon, and since 54 divided by 6 = 9, in one hour it burns nine gallons of gas. (Shorthand: the airplane burns 7 1/2 gph for each 100 horsepower being produced.)

Since we can calculate fuel consumption when we know the horsepower being used, we can reverse the equation and calculate the horsepower being produced by a known fuel consumption. Take the previous example: if we know the airplane is burning 9 gallons of gas, we (1) multiply 9 by 6 to get 54 (the pounds of fuel being used per hour). We know that each horsepower requires 0.45 pounds, so we divide 54 by 0.45. We find(as we used to say) that 0.45 "goes into" 54 120 times, so we know that 120 horsepower is being generated. (Shorthand: for each 71/2 gph, the engine is producing 100 hp - if it burns 15 gph, it is producing 200 hp.)

All simple enough, and yet I venture to say that 99% of the aircraft performance arguments on the forum are based upon either misunderstandings or misapplications of these and similar rules. Some of it is understandable (it's easy enough to do the calculations with nice round numbers, easily divisible by 6, but tougher with more complicated figures) but most of the confusion should be avoidable IF WE RESOLVE TO BE CLEAR AND ACCURATE IN DISCUSSING THE MATTER WHEN IT COMES UP.

The "rules" mentioned above apply to the Electra, just as well as they do to any modern airplane - but the fuel consumption rule applies with the caveat that we should give a moment's thought to what the Electra 's actual "specific fuel consumption" was. We don't have to speculate. Lockheed gave the answer in the specifications: 0.52 lbs. per horsepower hour (when using 412 hp per engine) and 0.48 at the lower setting of 350 hp. A bit less efficient than the modern engines. The methodology still works, but we use 0.48 instead of 0.45, and we find that the 10E burns 8 gallons per hour for each 100 horsepower being produced.

Since we know the approximate efficiency of the Electra's engines, we can calculate the horsepower being used at the 38gph setting. Using 0.48 lbs/hp/hour, we calculate as follows:

38 (gallons) x 6(pounds)= 228 pounds per hour.

Divide 228 by 0.48 = 475 horsepower.

Just as a matter of curiosity, what percentage of total horsepower is that? Divide 475 by 1100 to find that 475 is roughly 43.2% of the rated horsepower. Call the setting "about 44% of power". (No mystery there: "During World War II, when the principles of long-distance flying were just being developed, the engineers' figures seemed to indicate that 45 percent power would work the best." Louise Sacchi, Ocean Flying, p.39 (1979).

What about Johnson's other settings? Using a "specific fuel consumption factor" (to give it its proper name) of 0.48, the calculations (which I shall omit, with your permission) give 750 (375 per engine) horsepower at 60 gph (68% power); they give 650 (325 per) horsepower at 51 gph (59% power);and they give 537(268 per) at 43 gph (49%).

The progression of Johnson's settings is roughly 68-59-49-44% of rated power.

But Johnson's telegrams don't tell us the speed! Can we find out anything more about that? I believe we can. Lockheed's specifications give us speeds at three horsepower settings (for a variety of altitudes). None of these settings exactly matches any of Johnson's, but they still give infomation. The factory gives speeds at 450hp (per engine), 412hp per engine, and 350hp per engine. These settings correspond to 82.2% (450), 75% (412) and 63.6% (350) of rated horsepower. The only one of these settings in Johnson's performance range is 350, so let's concentrate on it (though the others may have some significance later).

What does Lockheed tell us about the 350hp(63.6%) setting? Fuel consumption is given as 56gph and this fits neatly between the 51gph Johnson setting (59%) and the 60gph setting (68%), right where it should be. Lockheed gives the following speeds for 63.6% power: 181(mph) at sea level; 188 at 5,000 and 196 at 10,000. (Figures are given for 13,500, but I omit them as outside the scope of this discussion.)

Note that the (true) airspeed increases with altitude, when power remains constant. (This is no surprise, of course, we expect it to do that.) Notice the progression is relatively constant (7 mph in the first 5,000 feet, and 8 mph in the second). This is at a normal, mid-range cruise speed. The increase averages 1.5 mph per 1,000 feet of altitude. This is approximately o.8% of the mid-point (5000 foot) air speed of 188.

We might take a leap of faith, and formulate a rule of thumb for this airplane that a change in altitude (in the normal operating range) will produce something like an 0.8% change in speed per 1000 foot change in altitude, if everything else remains equal.

Let's test that rule against the figures Lockheed gives for speed at maximum continuous power (450 hp). The 5000 foot speed is 204. Using 0.8% per 1000, we would expect a 4% reduction at sea level (5 x 0.8=4). Four per cent of 204 is 8.16mph, and 204 minus 8.16 gives 195.84 mph. Lockheed says the SL (sea level) speed is 195. Close enough.

Calculate an estimate for 10,000 feet. The 5000 foot speed is 204; 4% of that is 8.16; adding 8.16 to 204 gives 212mph (rounded). Lockheed's number is 215 - not quite as close. But look, Lockheed gives this figure for 10,500 instead of 10,000. Using our 0.8% rule of thumb means we multiply the 5000 foot altitude speed (204) by 4.4% to compensate for the 5500 increase in altitude (5.5 x o.8 = 4.4), which gives 8.976 mph. We don't pretend to be that exact and we call it 9. Adding 204 and 9 gives us a 213mph estimate for 10,500; Lockheed's number is 215 mph.

(Our estimate is within one per cent; Lockheed says its numbers are + or - 3%.) We're not precise, but the purpose of the "rule" is not (meaningless) precision, but speed and ease of calculation (and thinking).

Let's make a small digression before we test our newly formulated rule of thumb again. This is a self test for anyone who reads this far. Let's assume that we have an airplane (call it a HYPO-1) which under a certain set of conditions flys 140 at 50% of power and 150 at 60% of power. With no changes in altitude or conditions, how fast will that airplane fly at 55% of power? The answers (with grades) are:

1- "something between 140 and 150" - that's right - Grade: C+

2- "145" - you get a B - we can't be that precise (and see #3)

3- "it's hard to say exactly; somewhere above 145; probably around 146 or 147" - A--- (the why is discussed below)

4- any answer above 150 or below 140 gets an F; if after reflection you don't understand why, perhaps a trip to flight school is appropriate.

Why is number 3 the best answer? It's how airplanes work. In the normal spectrum of cruise speeds (say from 45% to 75%) a reduction in power is accompanied by a reduction in speed that is less (in percentage) than the reduction in power. If you reduce power from 75% to 50%, you have made a one-third (33.33%) reduction in power(anyone who thinks this is a 25% reduction should think again), but airspeed does not decrease by one-third, it decreases by some smaller percentage. (I have a Bonanza chart handy, for example: going from 75% to 50% at 6000 feet reduces TAS from 202mph to 170, a decrease of 32, or about 15.8% - purely as an example.) Pilots know this intuitively after a while. In the HYPO-1, when you make the reduction from 60% to 55%, you have reduced power to the midpoint between 50% and 60% the airspeed will be decreased by a smaller factor and so is most likely to be above the midpoint airspeed of 145.This is why reducing power produces "greater efficiency". If true airspeed and fuel consumption varied by the same percentage, efficiency would remain the same - you wouldn't go any farther at 50% than at 75%, it would just take you longer to fly the same maximum range.

The point of this digression? Numbers relating to aircraft performance do not jump around at random. They progress along curves that can be perceived and drawn based upon reasonable assumptions of the performance of the airplane. The more numbers we know, the easier it is to calculate other numbers defining the performance of the plane.

Back to Lockheed's speed numbers for the 10E. Lockheed gives the speed of the plane using 412hp per engine at 5000 as 197mph. Using our 0.8% factor per 1000 feet of change, we reduce this speed by 4% to calculate sea level speed. Four per cent of 197 is 8 ( I know it's 7.88, but 8 is quite close enough, thank you); subtracting 8 from 197 gives 189 - exactly Lockheed's number. Lockheed doesn't give a 412 hp speed at 10,000, but quotes 205mph at 9600 feet.

We increase the 5000 foot speed (197) by 3.68% (4.6 x o.8%) to calculate the speed increase at 9600. That gives us 7.2496mph (we call it 7+). Adding 7+ to 197 gives us 204+ instead of Lockheed's 205.

Why should we bother to develop a "rule of thumb" to give us an imprecise calculation of data that appear in the specifications? Quite obviously, we shouldn't. We develop the rule not to recalculate the data we know, but in anticipation that the "rule" may someday help us calculate data we don't know from data we do know - either directly or through intermediate steps. (It is also fun. And - one hopes - it helps us to learn that the limited numbers we have can be subjected to disciplined and principled manipulation to yield more information than we might at first think.) In any case, we now have a Rule of Thumb:

"TAS in the 10E changes with increases or decreases in altitude from 5000 at a rate of approximately 0.8% per 1,000 feet (at constant horsepower)." We can put the Rule aside until the need to use it arises.

WE KNOW SOMETHING WE DIDN'T KNOW BEFORE THIS DISCUSSION ABOUT THE EFFECT OF ALTITUDE CHANGE, and if someone tells us (for example) that going from 5000 feet to 10000 feet(at constant horsepower) increased airspeed from 150 to 175, we will suspect that statement, because it indicates a 16 2/3% increase, when our Rule leads us to expect only a 4% change.

I am a firm believer that nothing beats the POH (or other detailed data) on the 10E. I made that point in off-the-forum correspondance with you in which (you may remember) I offered to underwrite a modest portion of the copying cost of such data if it could be found. I said (as I recall) "10 minutes with the POH is worth 6 months of speculation."

But if we can't get the POH we must make do with what we have, and what we can develop by analogy from other airplanes. Where can I turn?

I want to turn for a moment at least to a typical high-performance retractable single. Why? Because the performance curves of the 10E look a lot like those of a Cessna 210. (I flew a 210 for years; if I had flown a Lance, the curves might remind me of a Lance. Without meaning to overstate the case, an airplane is an airplane, and those with similar performance curves are - well - similar.) The match is not exact, by any means, but I think it's close enough to teach us another thing or two about the 10E. I still have the POH on the 210M, and I also have a copy of Larry Ball's book Those Incomparable Bonanzas (1971), which does not contain a POH but does have (page 201) a cruise data chart (in mph! You don't even have to convert from knots) for the Bonanza. The numbers from the cruise charts for the 210 and the Bonanza bracket some of the numbers we have for the 10E in ways that might be informative.

Before going into that, I should address the question of whether the performance of a "light" aircraft has anything in common with that of a 10E. It's not a question to be answered before you examine the data, but remember that Lockheed's specifications show the wing loading of the 10E as 22.91lbs per square foot, and the power loading as 11.67lbs/hp. The figures for the 210M are wing loading 21.7lbs and power loading 12.7lbs/hp (Jane's 1975-1976). (Bonanza figures: wing loading 18.8; power 11.96). (Don't worry, we're going to ignore wing and power loadings from now on.)

Let's look at 75% cruise in the three airplanes(@5000 feet):

C-210: 194 mph 10E: 197 mph V35: 200 mph

And 64% (10E at 63.6%) at 5000:

C-210: 184 mph 10E: 188 mph V35: 190 mph

And 64% (10E at 63.6%) at 10000:

C-210: 191 mph 10E: 196 mph V35: 198 mph

That's as far as we can go in the cruise comparision from documented numbers. (I deliberately omitted 75% @10,000 because neither the C-210 nor the V35 can produce 75% of rated horsepower at 10,000. The 10E can because of supercharging.)

Let's go back to the 10E, at the point in the fllight in which Johnson specified a reduction to 38 gph (about 43.2% power). Johnson expected the 10E to depart for Hawaii with 900 gallons of gas, and he instructed that the change take place after 9 hours, with fuel burns of 3 x 60, 3 x 51 and 3 x 43, for a total of 462 plus the extra fuel burned in the initial climb. Let's estimate that 500 gallons (3000 pounds) total would have been burned by the time of the power reduction to 38 gph. Takeoff weight with 900 gallons would have been about 14,000 pounds or a bit under (save that discussion for another day). That means that at the time of the reduction to 38 gph, Johnson expected the plane to be at no more than 11,000 pounds (and perhaps as low as its normal gross of 10,500).

What cruise speed can we expect at normal gross and 43.2% of power at 10,000 feet?

C-210: 155 (at 44%) 10E: ? V35: 163 (at 45%)

The charts I have for the C-210 and the V35 don't go any lower, but I suppose that anyone who reads this far would be will to make another (small) leap of faith, and adjust the numbers to reflect approximate cruise at "43.2%" to something like:

C-210: 154 10E: ? V35: 160 or 161

Well, I suppose that's it. Since we don't have a chart on the 10E, we have to assume that its cruise at 43.2% (and normal gross) may have been 138, or 193 or maybe 406, right?

Or perhaps if you go back and look at the bracketing of the 10E numbers by those of the C-210 and the V35 at other power settings you are willing to assume (as I confess I do) that the 10E's cruise numbers at 43.2% are likely to fit between those of the C-210 and the V35. Likely, I said.

Pursuing the question a step further, what number do we get from the foregoing ? Is 157 the answer? Good as any. (Remember, as they say, this is not rocket science.)

Is a 43.2% (38 gph) cruise of 157 at normal gross weight (@10,000 feet) a surprise to anyone ? Isn't that "about" what we would have expected?

Let's think about that number for a minute or two more. Notice that we have calculated (or should I say estimated) it for normal gross weight of 10,500 pounds, but we have speculated (not without foundation, I hope) that Johnson called for that power to be employed about 11,000 gross weight (or a bit over 2 hours before fuel burn would reduce gross weight to normal gross of 10,500).

Does that mean that Johnson specified a reduction to 38 gph at about the time when the weight of the airplane (11,000 pounds) would permit it to hold a true airspeed of 150 (or slightly above) at that setting? Doesn't that seem likely too? The difference between 150 (or 151 or 152) at 11,000 pounds and "157" at 10,500 pounds represents the increase in airspeed caused by decreasing weight due to fuel burn. (I say "150 or 151 or 152" not only to show that I take all of this with the proper grain of salt, but also to point out that Johnson was dealing in round numbers when he dealt with AE - and quite properly so. Think of the unnecessary complexity of telling someone to fly at setting "X" for 2 hours and 47 minutes, and setting "Y" for 3 hours and 2 minutes and setting "Z" for 3 hours and 14 minutes (or whatever) - "obviously" you should say "3 hours each at X, Y and Z" .)

(Not to overburden this with parenthetical remarks, but I put quotes around the word obviously in the last paragraph because the people who wrote the long-range cruise charts for the C-47 didn't understand this --- and neither did the man who calculated the heading changes for AE! But those are other stories.)

Back to our calculated 157 mph cruise at normal gross weight (10500 pounds) and 10000 feet, at 43.2% power and 38 gph. What speeds would that same horsepower have given at 5000 feet or at 1000 feet ? Remember the Rule of Thumb we formulated for the 10E: "TAS increases or decreases with increases or decreases in altitude from 5000 feet at a rate of approximately 0.8% per 1,000 feet (at constant horsepower)." How do we calculate the reduction in airspeed when the 10E drops to 5000, but maintains the same horsepower ?

Since I am lazy, I would normally multiply 0.8% by 5 (= 4), take 4% of 157 (= 6.28), round the result (to 6) and subtract 6 from 157 to get 151. And in truth, that probably gets us close enough for the kind of work we're doing now. But if I did it that way I would be making an important error in procedure, which does no harm in this example, but can cause problems. (A similar error in procedure is, I think, at the heart of Mr. Elgen Long's mathematical problems --- of which, perhaps, we will say more on another occasion.)

What was my error in mathematical procedure ? I assumed that because something increases 4 % in going from 5000 to 10000, it decreases 4% in going from 10000 to 5000. It doesn't.

It's easier to demonstrate this than to talk about it. If the speed at 5000 is 100, the same horse-power will produce 104 (4% more) at 10000. But if you reduce the 104 figure by 4% to recalculate speed at 5000 you get 99.84 ! (4% of 104 = 4.16; and 104 - 4.16 = 99.84).

Strictly speaking the reduction from 10000 to 5000 under our rule of thumb is not 4%, but about 3.846 % (4 divided by 104 = 0.03846), which works out (do it for practice) to 6.05822 mph. So 6 mph is the approximate reduction, giving a speed of 151 at 5000 feet.

If 151 is the speed at 5000 and 38 gph, what is the speed at 1000 feet?

Reduce 151 by 3.2% (4 x o.8% = 4.832) (round to 5) (151 - 5 = 146). It's 146.

We can say with some confidence that at 43.2% we expect about 157 @ 10,000 feet, 151 @ 5,000 feet, and 146 @ 1,000 feet, at normal gross weight of 10,500 pounds. (We should add "+ or - 3%" ) One final point, remember that these speeds are for constant horsepower NOT FOR THE SAME POWER SETTING. A setting of "1800 rpm and 22 inches" for example will produce different percentages of rated power at different altitudes. (Should we peek at the C-210 handbook to see what it tells us about 5,000 feet ? We need to interpolate, because the charts are for 4,000 and 6,000 feet. The 4,000 foot number is 128 knots at 43%; the 6,000 foot chart shows 132 knots at 44%. Interpolate for 43.2% at 5,000 and you get approximately 130 knots, which converts to 150 mph. Fancy that !)

What about the speeds at the 43 gph, 51 gph and 60 gph Johnson settings?

By going to the C-210 and V35 charts, we can bracket the speed of the 10E at those fuel consumptions (equal roughly to 49, 59 and 68% of power) and obtain the approximate 10E cruise at normal gross at those consumptions. Once we have that figure, if we assume that Johnson used each of the settings because that setting produced an approximate inital speed of 150 in the overgross condition, we can subtract 150 from the anticipated normal cruise at each setting, which gives us the reduction in speed caused by the overload. If you do all the numbers, you can develop a curve showing the effect of excess weight on speed. Some day (maybe) when I'm feeling energetic, I plan to do that, but I promise not to tell you about it.

I've been reading the forum for a couple of months. I had promised myself faithfully not to get involved in anything like this, not because I don't enjoy it, but because I simply can't afford the kind of time it takes. In retrospect, that was an excellent resolution, and one I will try to abide by in the future. (To think, all I did was suggest that 20 gph was per engine ! It was, you know, and I think I can show that to you, but I have to tend to business.)

I can't close without another brief reference to 20 gph. I see that one member observes that "AE may have had a dual needle fuel flow indicator, though that seems unlikely" ! When's the last time you saw a piston twin without separate indication of fuel flow for each engine (and most often by means of two needles superimposed on a single 3 inch face) ? None of the pictures of AE's panel is clear enough to judge. They might, I suppose have had a single (combined flow) indicator (something could have been rigged up because, I understand, both engines fed from the same tank under the arrangement they had) but hardly at the expense of individual flow indication - which is, after all, engine information that is useful (fuel pressure).

The 20 gph discussion taught me one thing - we all have to watch our prejudices. You saw the episode as being another example of AE covering her mistakes - because you think she often did that. I saw it as another example of her casual attitude toward the technical details. I know that if I were on a final shakedown flight with Paul Mantz trying to teach me how to operate that airplane, I would be looking at the panel, and not at the sunrise. I don't doubt for a moment that AE knew the indication was for both engines, and since she was making notes for herself, there was no reason for her to enter that fact - she would remember. What concerns me is the casual "under 20" rather than "about 19 3/4" or whatever. Perhaps that's unfair - maybe she was just taking a break !

Subject: Re: Learning to think about the performance of the 10E
Date: 4/11/00
From: Greg, Mark Prange, et al

Ric, an outstanding contribution from Oscar Boswell. Thank you.

When I happened into the forum some months ago I assumed that these concepts were well embraced by those in the group. My mistake. The search for evidence needs to include the common knowledge of the art and science. I have always believed that it would be worthwhile here to put together a spreadsheet of the flight using the known performance of the 10E. The spreadsheet would be broken into half hour or hour segments and the pieces in effect joined by the numbers which they produce. This is a piecemeal method of doing integration (calculus) which everybody can see and discuss without any serious mathematics. The finer the time period the better the integration but the limits of knowledge here suggest not to push it below 15 minute segments and that only at the beginning of the flight.

Is this of interest to anyone else?


From Mark Prange

Perhaps the main points of the Boswell posting should be given headings or Roman numerals, so that when part of it is referred to it will be easy to scroll right to the section under discussion.

Mark Prange

From Oscar Boswell

Despite recent evidence to the contrary, I really do know that the adiabatic lapse rate does not refer to the 2 degree C decrease in temperature per 1000 feet. Call it a mental lapse. Oscar

From Ric

Let me be the first to admit that Oscar's Explanation gives me flashbacks to Mr. Squires' algebra class. I can see him now, short, looking like the wrestling coach he really was, standing over me with that exasperated look on his face, his neck bulging above his too-tight collar and one inch wide 1962 necktie. "Mr. Gillespie, there is NOTHING difficult about this......" and about 10 seconds into his clarification my eyes would glaze over and there would be this slight ringing in my ears and the next thing I knew the bell would ring and the ordeal would be over until the next day.

All this is by way of saying that I completely understand if postings like Oscar's make some, perhaps most, forum subscribers feel stupid. Finding myself insufficiently educated to make an intelligent assessment of his treatise I have to fall back on other forum subscribers who are better equipped. Fortunately we have several. I'm confident that if a consensus can be reached among our august Aeronautics Academy (AA) the rest of us dolts can feel pretty confident that Oscar is as right as he says he is.


Subject: Dem Bones
Date: 4/11/00
From: Patrick Gaston

Ric wrote:

>>It doesn't take any medical training to somewhat accurately guess the age
>>of bones.
>Well, you learn something every day.
>Somebody else tell him. I don't have the strength.

Well, I think you're focusing on one comment at the expense of Don's message as a whole. A cattle rancher could, indeed, make an educated guess as to the age of livestock remains found in his pasture, based upon experience alone. But he would be taking into account local weather conditions and the habits of local scavengers, along with such other information as, "Let's see, when's the last time I saw ol' Bossy at the stock tank?" The problem here is that we're dealing with an entirely different ecosystem and an entirely different population of scavengers. Nevertheless, there's still a fairly straightforward (if unpleasant) way to test the deterioration rates of mammalian carcasses in the Niku environment, and I hope that such an experiment is planned for the next expedition. The age of the bones is important.

Pat Gaston

From Ric

We don't have the bones so we can't assess their age even if we had the results of a controlled experiment on Niku. The real question is how competent Gallagher, Isaac and Hoodless were to assess the age of the bones. Gallagher had arrived in the Pacific in 1937. While he had some medical school there is no reason to think that his training as a Cadet Officer in the Colonial Service had included assessing the age of human remains. Isaac had only been in the Pacific since 1938 and in Tarawa since September of 1940 (the same month Gallagher found the bones). It seems safe to assume that his duties as medical officer for the Gilbert & Ellice Islands Colony dealt primarily with the living or, in some cases, the recently deceased. Hoodless had been in the Pacific longer but his duties were chielfy adminstrative and his medical credentials minimal.

One thing that Kenton Spading and I noticed while plowing through the stacks of WPHC files in London was how unique the whole bone discovery issue was. This was the only case of human remains turning up, or anything remotely similar. There is absolutely no indication that Gallagher, Isaac or Hoodless had EVER before come in contact with, let alone had to assess the age of, human remains discovered in a tropical environment. These guys were guessing with virtually no experience or training upon which to base their guess.


Subject: Gallagher's description of skeletal remains
Date: 4/12/00
From: Ron Bright

Since we moved back to a discussion of the difficulties of determining age of the bones (not age of the victim at this point) several other questions seem appropriate.

British cadet officer Gerald B. Gallagher first reports to his boss the discovery of a skull "which is quite possibly that of Amelia Earhart". A second report relates his discovery of additional bones,shoe parts, and a sextant box apparently in the proximity of the original skull, but is not very clear on the location. Then on Oct 17,1937 he reports the bone description in response to a request for further details. He describes:

"a skull, lower jaw, one thoracic vertabra, half pelvis, part scapula, humerus, radius, two femurs, tibia and fibula"

Now I like most lay persons don't know the difference between a fibula and a tibula. Thus how in the world did Gallagher have the medical knowledge to identify the batch of "wretched relics" with correct nomenclature. (Don't tell me he had Gray's anatomy book!). Why I ask is could there have been another doctor at Niku during this time frame or are you satisified that Gallagher had sufficent medical training, etc to properly id those bones. If there was someone else there on Niku with that kind of medical training, there may be some hope of another source.

So Gallagher finds this skull, suspects it is Amelia's right off, and then doesn't make any comment on the condition of the teeth/dental remains! Even after a detailed description of the bones, he makes no further description of the skull. Odd.

Even worse is Dr. Hoodless' examination. He makes detailed measurements of the bones, skull, etc and makes his conclusion of race, sex and height. But here is a doctor faced with an extraordinary discovery that may be Amelia, and he doesn't make a single reference to the dental condition (fillings,missing teeth, etc) which is the most critical source of identification and age of a victim. Although TIGHAR points out other areas he failed to describe, the egregious omission of dental condition is inexplainable. An amalgam filling in the upper left bicuspid that matched Amelia's, now that is "evidence". (If she had one.) Dr. Hoodless had a once in a lifetime to solve one of aviation's greatest mysteries.

Have Amelia's dental records ever been found and available for comparison? Also have any medical records of Amelia ever surfaced that might indicate a fracture, say in one of the bones examined by Dr.,Hoodless, that should have been obvious? I understand she was in a number of airplane crashes so it is conceivable she may have had some injury or perhaps in childhood. Just a thought.

According to TIGHAR's report, Dr Isaac released the "wretched relics" on Feb 14,1941 and the Western Pacific High Commission received them on April 28th,1941. Of note is that Dr. Hoodless examined the bones about three weeks earlier on 4 April 1941. Maybe just careless government accounting or maybe Dr. Isaac mailed the bones direct to Dr. Hoodless. Probably doesn't mean anything but...

The lack of Dr. Hoodless's comments on these vital areas may well be related to his training or lack thereof.

Ron Bright #2342

From Ric

My apologies. You and the rest of the forum need better access to more primary source information. Very soon (this afternoon I hope) we'll put up on the website as a new Document of the Week a complete reproduction of all of the WPHC correspondence and notes to the file relating to the bones found on Gardner. We'll also include a brief rundown on all the people mentioned in the official paperwork and a chronology of events. This should clear up a lot of the confusion. But for now:

  • The skull was found and buried several months before Gallagher arrived on Gardner in early September 1940. He didn't dig it up until much later (possibly November or even December) but he did search the area where it had been found. By the time he sends his first telegram on Sept. 23, he has already found the other bones, lower jaw (which has only five teeth), and most of the artifacts.
  • Gallagher was the son of a prominent physician and had attended St. Bartholomew Medical College in London from January to June 1935 before dropping out. It's hardly surprising that he could call things by their right names. It is also not at all unlikely that he even had a copy of Gray's Anatomy with him on Gardner.
  • You'll see that teeth and dental records were discussed. By the time the skull and lower jaw got to Fiji there were only four teeth (but we don't know which four), apparently all in the lower jaw but none showing signs of dental work.

A date error in the TIGHAR report has caused confusion about the bones' odyssey:

  • On December 27, 1940 Gallagher writes a transmittal letter to accompany the bones and artifacts to Fiji.
  • On January 28, 1941 the bones leave Gardner aboard Nimanoa on January 28, 1941.
  • On February 3, 1941 Nimanoa arrives Tarawa and Isaac kidnaps the bones.
  • On March 11, 1941 Nimanoa leaves Tarawa enroute to Fiji with bones.
  • On March 22, 1941 Nimanoa arrives Fiji.
  • On March 25, 1941 Gallagher's transmital letter is logged in and the Secretary (Vaskess) gives the file to MacDonald for action.
  • On March 31, 1941 Hoodless receives the bones from MacDonald.
  • On April 4, 1941 Hoodless examines the bones and writes his report.

As for Earhart's dental records, we've never been able to find any. There was a dentist in Miami who, as I recall, claimed to have done some work for her before she left on the world flight but he wanted a whole bunch of money for the information he had. We don't do that. I know of no instance where Earhart suffered a broken bone. Her crashes, although fairly numerous, were also quite mild. The only time I recall her being hurt at all was a cut on the head when she flipped her Vega while landing in Norfolk, Virginia in 1930.


Subject: Re: Learning to think about the performance of the 10E
Date: 4/12/00
From: Chris Kennedy

O.K., I do not pretend to know anything about flight dynamics or fuel consumption, but is there any disagreement about the conclusion that utilizing the Johnson figures the Electra could stay aloft for at least 24 hours, perhaps more? Also, is there any disagreement that, so long as Earhart stuck to the Johnson fuel management plan and her planned route, got within 100 miles of Howland (north or south) then flew south along the LOP she could have made Gardner? What I am suggesting here is that I have yet to see any work on the Forum as to other variables, such as wind speed, on the duration of the flight, and that such work badly needs to be done.

Let me ask these basic questions to the technical people, and I will make myself the fall guy for lots of other forum participants who might be wondering the same things but are afraid to ask:

1. As I appreciate it, the goal of the Johnson fuel management program was to give Earhart power settings that would result in maintaining maximum time aloft. True or False?

2. "Maximum time aloft" is purely a time calculation. True or False?

3. At the same power setting, I presume the Electra would fly less of a distance if it were flying into a headwind rather than into still air? Conversely, I would presume it would fly farther at the same power setting if there's a tail wind rather than just still air? True or False?

4. If the answers to the above questions are all TRUE, then where am I wrong when I conclude that the fuel managment program tells us nothing about how far, as opposed to how long, the Electra actually could fly under real world conditions?

5. Of course, Earhart didn't presumably set out for a known destination along a known route before calculating that she had enough fuel to get there. So, what was she relying on to give her comfort that she could get there? Is this the Johnson fuel managment program? If so, then there must be an assumption built in there concerning winds for it to be of any value in computing range of the Electra. True or False?

6. If the answer to #5 is TRUE, what is that assumption? How does it change if you compute variables such as head winds/course deviations (I suggest we start with Elgen Long's variables----I have yet to see an ACTUAL calculation which shows that his variables don't support his theory, as opposed to stated conclusions that they don't). Perhaps this has already been done and I have just missed it (the Monte Carlo analysis), but while Oscar's work might tell you how the fuel consumption of the Electra varies, isn't this sort of meaningless to the ultimate conclusion unless you also have some ideas of the effect of winds upon the Electra's range at these various power settings?

--Chris Kennedy

From Ric

>What I am suggesting here is that I have yet to see any work on the
>Forum as to other variables, such as wind speed, on the duration of the
>flight, and that such work badly needs to be done.

There has been oodles of estimation, speculation and debate about what winds may or may not have been present.

>1. As I appreciate it, the goal of the Johnson fuel management program
>was to give Earhart power settings that would result in maintaining
>maximum time aloft. True or False?

False. If all you want to do is stay up in the air you can loaf along at very low speed and power and burn very little fuel, but you won't get anywhere. Johnson's goal was to give Earhart an easy-to-follow, step-by-step procedure for setting her power which would result in a good (but not the absolute best, which would be lots more complicated) ratio of air miles covered per unit of fuel consumed. That's very different from maximum time aloft.

>2. "Maximum time aloft" is purely a time calculation. True or False?

True, but irrelevant (see above).

>3. At the same power setting, I presume the Electra would fly less of a
>distance if it were flying into a headwind rather than into still air?
>Conversely, I would presume it would fly farther at the same power setting if
>there's a tail wind rather than just still air? True or False?


>4. If the answers to the above questions are all TRUE, then where am I
>wrong when I conclude that the fuel managment program tells us nothing
>about how far, as opposed to how long, the Electra actually could fly under
>real world conditions?

See above.

>5. Of course, Earhart didn't presumably set out for a known destination
>along a known route before calculating that she had enough fuel to get there.
>So, what was she relying on to give her comfort that she could get there? Is
>this the Johnson fuel managment program? If so, then there must be an
>assumption built in there concerning winds for it to be of any value in >computing the range of the Electra. True or False?


>6. If the answer to #5 is TRUE, what is that assumption? How does it change
>if you compute variables such as head winds/course deviations (I suggest we
>start with Elgen Long's variables----I have yet to see an ACTUAL calculation
>which shows that his variables don't support his theory, as opposed to stated
>conclusions that they don't). Perhaps this has already been done and I have
>just missed it (the Monte Carlo analysis), but while Oscar's work might tell
>you how the fuel consumption of the Electra varies, isn't this sort of
>meaningless to the ultimate conclusion unless you also have some ideas
>of the effect of winds upon the Electra's range at these various power settings?

The assumption is that you don't try to make the flight if the headwind is too strong. (duh) Long invents a very strong headwind and makes the assumption that Earhart quite literally committed suicide by continuing the flight anyway.


Subject: Re: Learning to think about the performance of the 10E
Date: 4/12/00
From: Chris Kennedy

I think we would all do well to try and understand and agree with what Oscar is talking about before we defer to it, as at some point we will have to explain it to others---"Oscar says so" doesn't cut it.

--Chris Kennedy

From Ric

That is exactly Oscar's point. He says that it's a simple matter of arithmetic and he then goes through the arithmetic. If his arithmetic is right no one has to defer to anyone.

Subject: Re: Learning to think about the performance of the 10E
Date: 4/12/00
From: Chris Kennedy

Thanks, Ric. Before I got this I read Randy's posting in which he uses Oscar's information to reduce windspeed from 16 knots to 13 knots. I am wondering if he could tell us how he computed 16 knots to begin with, and how he used Oscar's figures to reduce the windspeed to 13 knots? Sorry to be so dense, but re-reading Oscar's information again I don't see how it tells you anything about windspeed to begin with, nor do I see how Randy could have used it to re-compute windspeed actually faced by Earhart on the flight. The most I have been able to figure is that if Earhart used the Johnson figures on the flight, she and Noonan may have been able to compute where they should have been along the flight route at various times. This information, when compared with actual position, would seem to have given Earhart a good indication of how her fuel consumption was going, the relative (if not absolute) strength of winds aloft, and available reserves when she was in the vicinity of Howland.....presumably this would be checked at various times, and, if necessary, Earhart could adjust the flight parameters accordingly, turn back if winds grew too strong (at least up to a point) or gamble that conditions would improve. In theory, if she stayed on course and you assume calm winds, she could have reached Gardner after turning south along the LOP. That seems to be the only statement which can be reliably supported as it is based on the Johnson fuel management plan which is in turn based upon the actual test performance of the Electra. I don't see how Randy computed 16 knots to begin with, nor how he recomputed a 13 knot windspeed faced by the Electra on the flight based on Oscar's numbers, nor do I see how Oscar's numbers can be used to compute how differing windspeeds effect the range of the Electra at given power settings. At some point all this needs to be explained, and not just stated as fact. I guess that's the crux of my problem, and I'll drop the inquiry after this posting.


From Ric

It's really not complicated. (I know, I know, I sound like Oscar.)

I think Randy has his adjustment to his headwind calculation backward.

  • We know that it took Earhart about 19 hours to get from Lae to wherever she was when she said, "We must be on you..".
  • We know it is about 2,550 statute miles from Lae to Howland and we assume that when Earhart says "We must be on you.." she really is on the LOP somewhere fairly close to Howland.
  • It therefore seems that she must have made an average speed of about 134 mph.
  • If we assume that the airplane's speed through the air is 150 mph then it must be true that a headwind averaging 16 mph was encountered (thus slowing her actual progress down to 134 mph).
  • If, however, the airplane's speed through the air was more like 155 mph, then the apparent average headwind was more like 21 mph. This is actually closer to Long's postulated 26.5 mph headwind.

The big question is not so much how much headwind was there, but what Earhart did about it. Long claims that her "speed 140 knots" message early in the flight means that she boosted her power (and her fuel consumption) so that she was making an airspeed of 161 mph (140 kts). Subtract his 26.5 mph headwind and you get 134.5 mph average speed between Lae and "We must be on you..." but you use up the gas he needs to have her use so that she can run out at 20:13.

We claim that the "speed 140 knots" is more likely a ground speed provided by Noonan and that there is no reason to think that she departed from Johnson's power management recommendations.

Subject: Re: Teeth
Date: 4/12/00
From: Tim Smith

Having dental work done on a tooth would not, in my experience, change the likelihood of it falling post-mortem. As Dr. Burns says, the shape of the root is a more important factor. Some, especially molars, stay put quite well until the maxilla or mandible bones begin to deteriorate (don't ask about having my wisdom teeth out!).

As for the question about the likelihood of the 4 teeth having had no dental work if AE had four teeth without dental work --- possibly but we would need the teeth and AE's dental records. My experience in looking at archaeologically recovered skulls from before and after European contact is that people's teeth go to heck as soon as they begin trading for sugar and white flour. I wonder if Tom King has observed the same thing in Pacific populations. In recent times if you look at people's teeth (who have access to regular dental care), its hard to find 4 molars that don't have fillings or crowns.

LTM (who brushes regularly after every meal)
Tim Smith
1142C & an archaeologist who has seen his share of skulls

From Ric

I can't speak for the islanders of 60 years ago but I can tell you that the Gilbertese of today have terrible problems with their teeth.

Subject: Amelia Earhart--- Found?
Date: 4/13/00
From: Ron Bright

This idea will probably blow away the entire forum. But sometimes a brainstorm may produce results. Since we are into some esoteric analysis of evidence, clues etc, let's take another look at the Dr Hoodless measurements.

Looks like some pretty detailed data under the skull measurements, i.e., orbital width, height, index, length, and a "cephalic index". Greek to me.

My question then is to Dr. King. Is there sufficient measurement data of Gallaher's skull, including the lower jaw, and the four teeth, all of which were reexamined by and analysed by Drs Burns and Janatz, to reconstruct a skull, at least pretty well based on those measurements.

If so, we could apply current forensic anthropological techniques to reconstruct the tissue and face of that skull to a reasonable likeness of the person. Add AE's known hair style, compare to AE' s well known features and maybe, just maybe, we have a pretty close match. This is done all the time with unknown skulls in the world of forensic pathology so that an idea of what the person looked like may be distributed to law enforcement for identification of missing persons.

If there is enough data there to reconsstruct, what an article that would make for the Discover Archaeology Magazine that Tom King writes for. Maybe they would underwrite the reconstruction as legit scientific research. Nice cover for the magazine.

So if that skull ends up looking like Amelia I get a free subscription to the forum. If it ends up looking like Tom King, ask him where his relatives were on the night of 2 July 1937!

Anyone interested in learning about skeletal age, remains etc, should contact Dr. Donald Reay, King Co., (Seattle) Medical Examiner. He is considered to be one of the top experts in the field of skull id. He got a lot of work with many of the remains dug up by the Green River Task Force with some 47 victims.

Ron Bright ( who keeps his dental records in a safe deposit box!)

From Ric

Like everybody else, you already have a free subscription to the forum. I'm sure Tom King will want to elaborate but I can tell you that the measurements provided by Hoodless are very cursory. To do the kind of reconstruction you're taking about you pretty much need an actual skull.

Subject: Re: Learning to think about the performance of the 10E
Date: 4/13/00
From: Ross Devitt

We have one advantage over Fred Noonan. Just as he was taking off, the weather forecast came in, along with an actual en route observation which confirms its possible accuracy. (Remember this was prefaced with "accurate forecast difficult".)

"Conditions appear generally average over the route (This is good). No Major Storm (Also Good). Apparently partly cloudy with dangerous local rain squalls about 300 miles East of LAE (If FRED had this info he could have used the weather pattern to "find" a tailwind). Scattered heavy showers remainder of route (Pretty much what I have here outside today - hot and raining)."

NOW the good bits...

"Wind: East South East about 25 knots to Ontario (where the heck is that?) then East to East North East about 20kt to Howland."

QNH: 29.898

TEMP: 83

WIND: Easterly "lots" of Clouds at "all levels" coming from Easterly Direction.

NAURU Observation: Wind East. 14mph @ 2000ft, 12mph@4000ft, 24mph@7500ft.

OK, Let's do an actual flight plan from Lae to Howland.

What Fred didn't have was the weather forecast which arrived just after he left:

QNH: 29.898 (inches - I'll have to convert it)

Temp: 83 (that's easy, 28C)

Distance: 2224 Nautical Miles (somewhere around 2570 statute miles?)

Indicated Altitude: 10,000ft

QNH: 1019hpa (don't ask me inches but this is a year round average)

(+6 over ISA x 30)= Pressure Height: 10180ft

Sea Level Temperature: 28C

(15C- 2 deg per thousand feet) = Corrected ISA Temp for 10,000ft: -5C

(25C - 2 deg per thousand feet) = OAT at 10,000ft: +5C

(Difference between corrected ISA & OAT(+10)x120(feet per degree)=1200 +10180) = Density Height: 11380

IAS: 150mph (130knots) from flight computer

TAS: 180mph (156knots) ditto

If Fred was flight planning today, this is pretty much what he would be looking at ASSUMING he flight planned a TAS of 150mph.

From Ric

The reference to Ontario is probably not the Canadian province or the lake on whose shores I failed to grow up. USS Ontario was the ship positioned half way beteen Lae and Howland (just south of Nauru) which was supposed to provide weather information and broadcast the letter "N" on Earhart's request.

Subject: Re: Amelia Earhart --- Found?
Date: 4/13/00
From: Ron Bright

I'm thinking that even from a "cursory" measurments maybe some kind of reasonable extrapolation could be made to reconstruct a skull, then go on with the clay sculputered face. I've seen it done, but I don't know how much of the skull is absolutely necessary. It would be an interesting research project. Can't you just see Tom King putting on the final touches of Earhart. It may break new ground.


From Ric

The whole point of the paper prepared by Drs. Burns, Jantz and King was to say what reasonably could be said based upon the Hoodless measurements. We try very hard not to push our conclusions beyond what the data support.

Subject: Re: Amelia Earhart --- Found?
Date: 4/13/00
From: Tom King

Yeah, Ron, the simple answer to your question is, no; there aren't enough measurements to do the kind of reconstruction you propose. Sorry.

Subject: Re: Gallagher's description of skeletal remains
Date: 4/13/00
From: Tim Smith

Regarding the question about the pelvis: Yes, it is composed of 2 halves, left and right, which are mirror images of each other. Male and female pelves differ in certain shapes and angles relating to the birth canal. The pelvis measurements are one of several indicators of sex but is probably the most reliable. Even so, there is some overlap between males and females. An anthropologist would look at all the available indicators before making an attribution of sex.

LTM (who is not very comfortable talking about this)
Tim Smith

Subject: Re: Gallagher's description of skeletal remains
Date: 4/13/00
From: Tom King

Yes, generally speaking there's a pretty noticeable difference -- several differences, actually. But nothing's absolute; you get male pelvi that look female, and vice versa. Kar Burns tells a story about taking the bones of a known female into a room full of osteologists and asking them to judge the sex; they all judged wrong, because she (the dead lady, not Kar as far as I know) had real male-looking bones. Like most variables, sex indicators describe a sort of bell curve; way out on the edges it's real obvious, but there's a big area in the middle where reasonable people can disagree, and there's lots of room for error.

We also don't know how much of a pelvis they were looking at. Apparently it was one inominate --that is, one of the wing-shaped parts that make up the hips. These have some pretty good sex indicators on them, notably the sciatic notch (narrower in males than in females, generally), but we don't know what shape this particular inominate was in. Nor do we know what Earhart's sciatic notch looked like; it might have been narrower than average for a female. Unfortunately, Hoodless doesn't give us any data on the inominate.

LTM (whose sciatic notch is broad, as it were)
Tom King

Subject: Re: Learning to think about the performance of the 10E
Date: 4/15/00
From: Oscar Boswell

I respectfully suggest that the basic problem with Mr. Devitt's analysis is the assumption that the 10 E will fly Johnson's settings with a true airspeed of 182 mph at 10,000. It is quite true that an IAS of 150 at 10,000 = about 180. The fallacy is in thinking that one can maintain this IAS on the same fuel consumption at 10,000 as can can at SL. One can't. In the 10E you can maintain a true airspeed at 10,000 about 8% higher than the sea level true airspeed on the same amount of power and fuel consumption. If you can do 150 mph (IAS and true) at sea level, you might get 162 true at 10,000 (which would be about 135 indicated). At the same horsepower IAS would decrease from 150 at SL to 135 at 10,000, while true airspeed inreased from 150 to 162 (in standard conditions, IAS at sea level is the same as True airspeed). In addition, Johnson's settings (at 38gph) probably won't maintain 150 IAS at sea level - at normal gross 143 would be more like it. (Also - to comment on another posting - WIND HAS NO EFFECT ON TRUE AIRSPEED).


Subject: Sex determination and facial reconstruction
Date: 4/15/00
From: Kar Burns

Subject: Re: Gallagher's description of skeletal remains

To Ross Devitt:

Yes, there is a noticeable difference in bone structure between a female and a male pelvis -- even if it is only "half" a pelvis. The "half pelvis" is called an "innominate," and it is the most consistent bone from which to differentiate the adult male and female. With innominate alone, sexual identification in a known population can be better than 9 in 10.

Subject: Facial reconstruction

To Ron Bright:

Nice idea, but the skull measurements left by Dr. Hoodless are insufficient for facial reconstruction. Ric is right, a whole skull is needed. But even with the whole skull, facial reconstruction is useful only for tentative identification, not positive identification or even probable identification.

For the most part, facial reconstructions look very little like the missing person. They are useful, however, in bringing publicity to a case of an unidentified individual. Publicity can result in locating "leads" to tentative identifications. In this case, we already have a tentative identification. Now we need more information.

LTM, may her identification never be questioned.
Kar Burns

From Ric

Interesting. That's a rather different picture of facial reconstruction than is painted by the various TV shows about crime investigation. (surprise, surprise)

Subject: Re: Male/Female Pelvis
Date: 4/15/00
From: Tim Smith

I think Dr. King is out of town now, so I'll take a crack at the question. To my knowledge, the angle and shape of the sciatic notch are genetically determined and do not change with childbirth. The pelvis (and most of the other bones) are pretty much the size and shape they will be by the time a woman reaches childbearing age.

However, the pubis (the part of the pelvis that runs forward from the hip socket to the naughty bits) does change with childbirth. The left and right halves of the pubis pull apart as the baby goes through the birth canal. This leaves a small lip or wrinkle on the area where the bones articulate. I haven't done this personally, but Dr. Burns could look at a pelvis and tell you roughly how many children the owner had.

Could it be possible to be much more off-topic?

Tim Smith 1142C

From Ric

This is probably a good place to announce that Archaeologist Extraordinaire Tim Smith will be helping me teach the Aviation Archaeology and Historic Preservation Course/Expedition this summer in Idaho (Tom King being otherwise obligated).

I'm sure we'll be able to get Tim to demonstrate the procedure described above but we'll need a volunteer from among the female registrants.

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