Highlights From the Forum
January 2 through 8, 2000
In partial response to interest in engine data as posted by the Forum on 31 December, I offer the following. All of the data pertain to the S3H1 Wasp engine:
Data for Dec '35 and May '41 are from P&W power curves for the S3H1/R-1340-AN-1 engines. The remaining three dates represent information taken from P&W data sheets for the S3H1 engine. With the advent of higher octane fuel, Pratt & Whitney was able to increase rated power from 550 to 600 horsepower (with one temporary excursion to 610 horsepower).
Availability of higher octane fuels allowed engine manufacturers to increase manifold pressure through additional supercharging without encountering destructive detonation. Chemical energy of the various octane-rated fuels (about 19,000 Btu/Lb or 138,000 Btu/Gal) was essentially constant even though additives (primarily tetraeythl lead) decreased the detonation tendency at higher manifold pressures. Cruise fuel economy at a given power setting is essentially unchanged with higher octane fuels.
One way higher octane fuel can increase fuel economy is by changing the engine compression ratio. Efficiency increases somewhat by raising the compression ratio. This change was not employed on Amelia's engines, however. The ratio on her engines was 6:1 and remained at this level because she was using 80 octane fuel. As a matter of historical interest, Pratt & Whitney maintained this compression ratio during subsequent years even though high octane fuels became available.
Cruise economy is gained by keeping the manifold pressure up and the rpm low for a desired engine horsepower output. The piston engine is basically an air pump. For instance, Kelly Johnson recommended that Amelia run a fuel/air mixture ratio of 0.072 for all but one cruise power setting. At this ratio, 13.9 pounds of air were mixed with every pound of fuel consumed by each of Amelia's two Wasp engines.
Thanks Birch. That's an excellent explanation.
So, if all S3H1 engines retained the 6:1 blower ratio, and if higher octane rating only becomes significant at high power settings, then perhaps the fuel economy results obtained on Finch's flight might be more useful than we had at first supposed.
In response to Jerry Hamilton's posting on 31 December:
I did not find Report No. 623. There were a few (perhaps less than 1 or 2 percent) of the Lockheed reports listed in their records I wanted that they could not locate. That these reports are missing could be due to a number of reasons. They could have been misfiled. Kelly may never have turned over the reports to the company archives, or someone removed the report and never returned it for record storage. Noticeably absent were reports on Howard Hughes' Model 14, for example.
Kelly's widow has about four cartons of material involving her late husband at her home. I was never able to review these records, although I tried. Even visited her home one day and got a chance to review the many books in his library, but not the cartons. May try again.
My opportunity to review the Lockheed archives came about when Walter Boyne, author of Beyond the Horizons, asked me to support his research for this Lockheed Martin-sponsored history of Lockheed. Because it had corporate sponsorship, I had just about complete freedom to investigate everything they had in the way of files: corporate, technical, financial, proposals, biographies, correspondence files, board of directors minutes and so forth. I reviewed everything I could think of during a period of about 15 months.
As a part of the Lockheed Martin merger, the corporate archive storage and retrieval function was removed from Lockheed, and the entire operation subcontracted to an outside firm. I don't know the name or location of this firm, but could probably find out if it is important.
I do not have a copy of the Model 10E operating manual as I have told Ric previously. Nor did I find reference to one during my search. The one I have is for the 10A and it was put together for export reasons. All of the technical data are given in metric units.
I do have Report No. 465, "Flight Tests on Lockheed Electra Model 10E." This is about 50+ pages in length (including raw data sheets) and consists of three parts or sections. Part three includes "fuel consumption tests." Amazingly, even the calibration curves for the manifold pressure instruments and tachometers are included. I used this particular test report section to calibrate my own fuel consumption calculations. I also used the four power setting data points Kelly provided Amelia prior to the first flight attempt.
I have seven pages in landscape format listing Lockheed and Vega reports I copied during my research. The period by these reports covers roughly 1932 - 1942. If I can assist you with anything specific, please let me know. You can reach me at firstname.lastname@example.org.
That's extremely generous of you Birch, and I would urge forum subscribers not to ask Birch for copies of this data unless you really know how to read and make use of this kind of technical information.
Where, I wonder, did Elgen Long get the idea that Lockheed recommended an increase in power settings in the event of a headwind? On page 233 of his book he says:
In "Notes" he attributes this to Lockheed Model 10 Flight Manual "Indicated Airspeed for Maximum Range, page 35a."
I can't imagine that there is only one flight manual for all four variants of the Model 10 (A,B,C & E), each of which used a different engine. Elgen doesn't specify that he is referencing the Model 10E flight manual and, so far, nobody seems to have seen such a document. Birch, is there a chart or graph for "Indicated Airspeed for Maximum Range" on page 35a of the Model 10A export manual that you have?
>I'm not disagreeing
that it would be good to have a controlled experiment,
Maybe because it's a primary, written source?????
The fact that Gallagher's opinion appears in a primary written source gives us great confidence that it really was his opinion. It does not make his opinion correct. If he reported seeing crabs trotting off carrying bones, that would be pretty convincing -- but all he reports is that some of the bones weren't there and he attributes that to coconut crabs.
His actual words are ( telegram of 17 October 1940):
But from his cataloging of the bones that are present, it is apparent that it is not only small bones that are missing. Half of the pelvis is gone (how much, I wonder, does half of the pelvis of a typical 5 foot 7 inch female weigh?), plus all of the spine and ribs and several of the long limb bones.
I also wonder about the damage to the ends of the bones. Hoodless talks about this and it's apparent that it's not just a matter of the flesh being cleaned off. These bone ends sound like they've been gnawed. I'd sooner attribute that kind of damage to the rats than the crabs, but no rat is going to run off with a tibia ( or rather, I don't want to meet the rat that could run off with a tibia).
I still smell more than a rat, or a crab, at work here.
While I cannot find the reference book I got the info from, I believe FN used an A-5 model bubble sextant manufactured by Pioneer. Accuracy is good---for a bubble sextant. Generally speaking if you can shoot a 2 or 3 line fix and get within 10 miles you are doing pretty good. Besides the problems of shooting through a moving platform you will get an error imposed on the bubble itself by aircraft movement. Personally I say if you can shoot 10-15 miles with a hand-held bubble sextant you are doing good. Holding the thing steady in your hand is also a challenge---in turbulence, forget it!
I mainly use the A-10 series which was used by the AAF in WWII, but I may be coming into possession of an A-7 Pioneer sometime in the future (late Christmas present). The A-7 was the next model after the A-5-not much difference to the best of my knowledge. It's accuracy is about the same. I'm getting the manual to it soon and then I'll be able to tell what kind of averager it had. Understand it was very reliable---all of them are precision instruments to be cared for. I've never tried using a marine sextant at all. You would need an artificial horizon of some sort. I can't comment on how well it would work. In any case, the real key to successful celestial is PRACTICE-PRACTICE-PRACTICE. I've been practicing for 12 years and I am still learning. Fred had been doing it since he was a teenager when he went off to sail square riggers I believe. Fred and Nathaniel Bowditch were the best that ever sailed & flew.
Happy New Year to all. Am going off to go aviate & navigate again. I'll let everyone know if Y2K shut my airplane down. The A-10 is along just in case.
You may be entirely correct about Noonan using a Pioneer A-5. The instrument Manning borrowed from the Navy was a Pioneer bubble octant (serial number 12-36) and if the A-5 was current in March of 1937, then it was probably an A-5.
But watch out for flat statements in Earhart books. There are no reference books on the Earhart disappearance (at least until the 8th Edition is finished) and folklore abounds.
This became a rather LONG post as I checked a few things (sorry) but it is also relevant to references I made in earlier postings about weather as I still don't think a lot of the forum realize what weather does inthe tropics. (Apologies to everyone who has lived in the tropics for a few complete years).
Cumulous tend to get to about 8000 ft here, but I can't remember exactly what clouds we've flown through at night (didn't take notice as I wasn't the pilot. I am NOT instrument rated and NOT flying very often). Over 8000 ft, they are usually Alto Cumulous or Alto Stratus. Once again I opened my mouth too soon. Now I have to check night propagation! However the July 1 forecast suggests cumulous about 10,000ft and I've never seen cumulous clouds stop dead at a particular altitude. (I don't suggest it can't happen).
As for not seeing that kind of activity on Niku, I wonder what a year on Niku is really like? I know you've seen some rain activity in the area. But it's the early part of the trip, and the equatorial area that would have caused them the greatest problems.
On the other hand, have a good look at the Lambrecht photo. We have been prevented from a VFR flight of 80 miles by a sky like that. Our destination reported sunshine, clear skies and not a cloud in sight. 80 miles..... AE could have caught almost any kind of conditions. However she didn't report cloud to Itasca.
I do know the following is described about the Inter Tropical Convergence Zone:
The ITCZ is a band of low pressure which forms over the regions of the warmest waters and land masses in the tropics. The ITCZ is identified on the satellite image as the band of bright clouds located just north of the equator.
The ITCZ is not a stationary band but tends to migrate to the warmest surface areas throughout the year. In the early part of the calendar year, the high sun occurs in the Southern Hemisphere causing a southward displacement of the ITCZ. As the high sun period travels from the Southern Hemisphere to the Northern Hemisphere, the ITCZ follows by migrating northward attaining its maximum northward displacement during the month of June.
It forms a band of cloud around the equator which could have been still near Howland in early July, but not necessarily as far south as Niku. The satellite photos show it fairly localised along the strip a couple of degrees North & South of the equator.
However it doesn't (from my memories of life further North) seem very seasonal, rather it hangs around all year to some extent. I may be wrong about this --- I often am!
Now, back to the Chater report. On July 1st 7.30am the weather report suggested:
EARHART LAE FORECAST
THURSDAY LAE TO ONTARIO PARTLY CLOUDED RAIN SQUALLS 250 MILES EAST
FLEET AIR BASE PEARL HARBOUR
I know this was the previous day, but tropical weather is interesting in its habits. It was followed the next day at 10am by:
FLEET BASE PEARL HARBOUR
BARO 29.898 THEMO
83 WIND EASTERLY 3 CLOUDY BUT FINE CLOUDS CI CI STR CU
These reports and the fact that I live in the tropics (no --- it's not actually ON the equator, and there ARE variables 20 deg S) have led to a number of my suggestions.
1. In the last takeoff movie at Lae, "look at the clouds!". Have a close look at what she was flying in. Not much blue sky in the background. Of course I can't see the original footage, but if that's one of our typical days....
2. Observe the forecast winds as Amelia went higher. 7500Ft mostly headwind at a little over 12 kts. And this:
AVERAGE OVER ROUTE
This also suggests the "Headwinds" I have brought up often when postings refer to fuel usage and average speed. I know we can't "assume" AE had a headwind all the way to Howland, but local conditions would indicate the likelihood. What it was though can only be taken from AE's radio report of "wind 23kts". The only wind she'd be reporting is head or tail as it has a direct bearing on her ground speed (assumption based on common practice).
3. It's the "dangerous Local rain Squalls" I have brought up a few times with regard to part of the flight. If I remember correctly I said "No pilot in his right mind would fly through one".
This bit jumps out from the previous day:
We can assume that they meant the centres of the towering Cumulous were frequently dangerous. However the following report is extracted from a visit to Lat 6-10S Long 140-130W. Bear in mind that in 9 days they travelled about the distance AE would go in one hour:
May 25, 1997 (Saturday). We were introduced to the ITCZ (Inter-Tropical Convergence Zone) somewhat gradually. On our ninth day we saw our first squall. We still had good winds and moderate seas. Then came squall number two and then number three. We watched as lightning lit up the sky off in the distance. As we heard no thunderclaps, we felt that the storm was far enough away to not begin worrying........
We did get some rain but it was not much to worry about. It was somewhat refreshing as we had been subject to uncomfortable heat for several days at that point......
Well the fun was about to begin. I was down below taking my turn at a nap. Phill was on watch and was studying the sky off in the distance on the port side. He saw one cloud formation that looked somewhat ominous. Pretty soon I was called on board and told to make sure I had on my safety harness and was strapped down. Phill had heard a loud whirring off in the distance and decided to put a reef in the main. He barely got the first reef in the main when this whirring increased. ......
We were down to as little sail as we could get. The wind began to blow furiously. The bambini broke loose and was being held on by only two small tie lines in the corners. We cut the lines and threw everything that was in the cockpit into the salon. At about this time the Autopilot went on vacation. Phill told me to get him a lightweight rain jacket, put in the storm hatch board and get down below. The last thing I saw was true wind speeds of 40 knots. ......
We rode this storm for about an hour and a half. There was a steady sheet of rain making visibility for Phill nearly impossible. He had to just stay on course and be able to see the instruments. The storm eventually turned into a normal squall with just moderate to heavy rain and wind speeds of 20+ knots. .......
We checked the instruments and learned that we had seen true wind speed of 44 knots and apparent wind speeds of 44 knots. This was our first and hopefully our last Force-9 gale. .........As a result of this experience we made a concerted effort to get as many weather reports as possible.
Sorry it's so long. This is the sort of storm we would refer to as a "dangerous rain squall". If they are around, they come up suddenly, are pretty ferocious for a while, then disappear (until you hit the next one). They tend to live in groups.
(We are 9.5 hours into the new year and the Millenium Bug hasn't eaten the bank computers yet!. According to the figures I'm just as poor as I was yesterday...). No apparent emergencies. Everything working...
Earhart's reported comment of "wind 23 knots" is interesting. The fact that she reports in knots strongly suggests that the information comes from Noonan (and she has no way of knowing what the wind is anyway). I can't imagine why Noonan would report a wind other than a wind component that was effecting their progress, one way ot the other. Speculating further, it seems like a 23 knot headwind would be something of a concern and not consistent with her earlier reports of "everything okay." Her earlier report of "speed 140 knots" also suggests a tailwind.
I think I told you I was trying to work the celestial backwards to pin down possible tracks or areas where the Electra could have been for Noonan to get a sun shot azimuth of 67 degrees. I have been working with the Dept. of Aerospace Engineering & Center for Space Research Engineering Mechanics at the University of Texas. I received a reply from that department this morning showing me how to make the computations. The preliminary results are general and as follows:
Using an azimuth of 67 degrees exactly and not a fraction off there was no place south of Howland inbound that Fred could have found a 67 degree azimuth. I recognize a slight deviation from exactly 67 degrees could have occurred but it would not change the general conclusion.
If they were on course due west of Howland inbound he had a 67 degree azimuth all the way.
They could also have been north of course as much as 120 nm but at about 200 miles west.
It was 7:42a when they reported "WE MUST BE ON YOU..." so the above information is accurate if the sun shot was made before that time. If the sun shots were made AFTER that time they could ONLY have been considerably north of Howland -- 240nm to 300nm north and I seriously doubt they flew in close to Howland at 7:42a and managed to get that far north in 8 to 20 minutes which were the only times 67 degrees could have been obtained at that late time.
I will refine the data and supply all the figures this weekend. (Busy week.)
Very interesting. If they were exactly on course they would not be due west of Howland but slightly to the southwest (inbound no wind heading of 77 degrees True).
Does this mean that in order to get a 157/337 sunrise LOP they HAD to be somewhat north of course at that time?
> Does this mean
that in order to get a 157/337 sunrise LOP they HAD to be
I wish I could answer that with a definite yes or no but it DOES appear that the answer must be yes. I checked all the coordinates south of 0 degrees 48 minutes North all the way back to 179W. It is possible but less than likely that 67 degrees could be found. But there are close fractions. The easy one would be 67.2 or 66.8 and if they are rounded off or Fred's sextant was not quite that accurate then he could well have been dead on course. I'll check out 77 degrees and see how it comes out but generally speaking I found little probability they could be south of a due east course.
Is it possible to plot a band on a map which encompasses the locations where the airplane could have been and gotten a 67 degree sunrise (plus or minus a couple of tenths)?
> Is it possible
to plot a band on a map which encompasses the locations
Yes, but I won't have time to work on the 77 degree course thoroughly until this weekend but preliminary checks show that although a 67 degree azimuth could be obtained at 6:20a to 6:30a from 179W to 176W the sun's elevation was extremely low --- averaging only a degree and a half above the horizon with a maximum height of 3.3 at the 176W line at 6:30 and at that time They should have been somewhat west of that longitude, about 60nm or so. ( arbitrarily figuring 133k GS)
What that tells me is that they could have been on course but probably on a course somewhat due west to east or even slightly north of that track. There is a lot of room to maneuver and still find 67 degrees of azimuth but I suspect we will be able to eliminate being well south of Howland or well north. It appears to me from first glance your theory that they were pretty close to track and hit Howland fairly close is supportable. I think it also makes it more likely they missed Howland simply because they couldn't see it visually and not because of any gross navigation error.
From Randy Jacobson
This is kinda silly. FJN doesn't actually measure the 67 degree azimuth to the sun. He assumes a position on the globe, the books tell him when the sunrise is going to be and the azimuth. There will be a good range of latitudes that will give him that azimuth +or- a few tenths of a degree. He then compares the book time of sunrise to what he observes, and that gives him a correction towards/away from the sun along a 67/247 line. What's important is where Noonan THINKS he is, not where he really is, that determines the 67 degree line.
A number of people, including Amelia Earhart and some authors, have quoted the range of her Electra 10E as 4,000 miles. This figure derived from a preliminary estimate developed by Lockheed chief engineer Hall Hibbard before a purchase contract was ever signed. George Putnam and Amelia were still negotiating with Lockheed. More important, it was an estimate made prior to establishing the final number of fuel tanks and resulting total volume. This would not be finalized for about three months after the purchase order was signed. In addition, Hibbard was concerned about the takeoff distance with such an overloaded Model 10E in context with the airfields that Amelia might encounter. More to the point, he advised Bob Gross (Lockheed president) that any estimated range was deeply dependent upon fuel management during a long flight. He had serious reservations about Amelia's ability to monitor and control fuel/air ratio. Whether this feeling was grounded in fact or just an apprehension is not know. Everything else can be documented.
Hibbard used a standardized range estimating formula: Range = 0.98 [ No. of Gallons of Fuel - 10 / Gallons per Hour ] x (Cruising Speed in Mph). The 0.98 factor allowed for fuel consumed during climb to cruising altitude. The "minus 10" was an allowance for engine warm up. Hibbard selected 40 gallons per hour average total fuel consumption for long distance flights. This represents a brake specific fuel consumption rate of 0.48 lb-fuel/horsepower/hour. Cruise speed was estimated at 150 mph with the engines operating at about 45 percent of full power (247.5 horsepower per engine). Using this equation and the numbers cited yields a theoretical range of 4,006 miles.
Unfortunately, no one challenged this figure or tried to understand what it represented. It was a preliminary estimate to begin with. It was also an estimate for still air. It was used as a guide for air line operations. And finally, it was overly general for application to a specific flight profile of an airplane with a 50 percent over gross weight.
Why did Hibbard use this estimating approach? Probably for a number of reasons. A primary reason was that Lockheed was financially undernourished at the time, and did not have the resources to do any elaborate parametric range study for a single customer. There was no market for 4,000 mile Electras. In addition, Lockheed was going to sell the Electra to Putnam for a bargain basement price.
Contrary to what Elgen Long claims, Lockheed did not provide any performance guarantee with the sale of Amelia's airplane. One reason was that they had a prior bad business experience with Putnam and didn't trust him. More important, they were modifying a Model 10 to a point beyond their experience. There were too many variables. To have provided a specific performance guarantee would have been an unacceptable business risk, especially with Putnam. Bob Gross was an astute business man who was willing to take prudent risks in return for potentially rewarding payoffs. This wasn't one of those situations.
In spite of this, the 4,000 mile myth has persisted in the minds and writings of a number of people. In reality, is was significantly less than this number.
Great posting Birch. Thanks.
What, I wonder, was the previous bad experience with Mr. Putnam?
What assumptions about the headwind has TIGHAR made? Both the forecasts from Pearl Harbour mention easterlies, Nauru reported upper easterlies and the average winds for the route have a large easterly component.
Assuming that AE knew the mean upper winds for the route (if such data were available then) and had seen the first Pearl Harbour forecast, she would have expected some sort of an easterly. Her "Wind 23 knots" remark could therefore reasonably be interpreted as referring to a headwind.
How does a 20-25kt easterly affect the ability of the aircraft to reach Niku?
I'd prefer not to make any assumption about headwinds, crosswinds or tailwinds. The distance from Lae to Howland is 2,223 nautical miles, but we know that they didn't end up right at Howland. It seems most reasonable to assume that they reached the LOP near Howland, but not close enough to see the island, at around 07:30 local time (1900 GMT), just a few minutes before Earhart's "We must be on you but cannot see you.." transmission. Because we dont know where on the LOP they were at that time, we have to pick an arbitrary number to work from. Birch Matthews used 2, 246 nautical miles. If they covered that distance in 19 hours, they made an average ground speed of 118 knots. The aircraft's recommended cruising speed was 130 knots. If they followed that recommendation, and figuring that climb and descent balance out, that gives them an average headwind over the entire route of 12 knots. Whether that's a steady wind on the nose of 12 knots (pretty unlikely) or a variety of different winds from different directions at different times, really doesn't matter.
The only questions impacting upon their ability to reach Gardner Island are how much fuel they had remaining once they reached the LOP at (ballpark) 1900 GMT and what were the winds between Howland and Gardner? The available information suggests that those winds were easterly throughout the morning at something like 12 knots. Without getting out my trusty E6B and trying to rmember how to plot a wind triangle, I would guess that a 12 knot wind from 090 (True) gives an airplane on a 157 degree course (True), a headwind component of maybe, oh, 5 knots. So running down the LP at 130 knots indicated at 1,000 feet that morning, the Electra was making (ballpark) 125 knots over the ground (uh, water). The arithmetic is easy. If they have one hour of fuel they can go 125 nautical miles from wherever they started. Two hours -- 250 nm. Three hours -- 375 nm. Gardner is 356 nm from Howland. If they start anywhere south of Howland, and have anything close to three hours of fuel left, and just hold that course -- they should reach land.
Birch Matthews said:
>Trapped fuel on
the P-39 amounted to 3.1
That 3.1 percent unusable seems to be awfully high, but if that is what Bell's calculations/demonstration prove, then I guess that is probably right.
However, I think it would be erroneous to compare the generic fuel systems of fighter aircraft with commercial aircraft and arrive at any meaningful answer.
Fighters are designed for performance, lethality and durability. These factors demand an design that is not conducive to conventional fuel systems and often result in unconventionally shaped cells and plumbing. If the main fuel cells are in the wings, for example, they must conform to the demands of the wings' designers and be fitted around spars, armament, ammo boxes, spent-ammo ejector-chutes etc. all of which limit the cells' size, shape and location. Add to that the weight problems of fuel sloshing around in the wings during high-speed maneuvers and additional problems arrive. Additional fuel cells in fighters are often are located where ever there is room, such as the fuselage or sometimes even in the vertical stabilizer, and consequently end up in really strange shapes.
Commercial aircraft are designed for comfort, profitability and practicality (sometimes). Consequently their fuel systems tend to be more standardized, i.e. squares, rectangles, spheres. etc.
The plumbing of fuel systems in fighters and commercial aircraft are greatly different also, again complicating the comparison of their generic "usable fuel" numbers.
The only validity, I would think, between comparing fighter and commercial aircraft would be that they both carry fuel and that a certain portion of that is unusable.
Now, if you want to compare the fuel systems in BOMBERS and commercial aircraft of that era that is a another issue. Anybody out there have access to Boeing's or Consolidated's data on the unusable fuel in the 4-engine B-17 (or B-29) and B-24, respectively? Or better yet, stick to twins and go for the North American B-25, the Martin B-26, or the Lockheed A-20. I would think the fuel system of the twin-engine bomber would be closer to that of a twin-engine commercial aircraft than would fuel systems of fighters and 4-engine bombers.
LTM, who is Y2K
I can't claim to begin to understand the engineering issues involved in some of the current threads, but the general thrust of the fuel consumption debate is causing me to reconsider one of my preconceptions about the Earhart flight. Namely, that although the mystery surrounding its end has given the story longevity, it was essentially a bit of a stunt which wouldn't really have proved anything had it ended in success.
As a layman it looks increasingly to me like even if it wasn't breaking any dramatic new ground in exploration/pioneering terms, in engineering terms the demands made of the plane if everything was to go well mean it was a venture well worth undertaking. Comments?
It's a fascinating point to ponder. At the time of the World Flight, Pan American had been flying scheduled passenger service across the Pacific for the better part of a year in flying boats (four engined Martin M130s). The DC-3 had also been in service for a year but not, of course, on long over-water routes. Conventional wisdom held that trans-oceanic passenger travel was most appropriately carried out in large flying boats. It wasn't until after World War II that commercial aviation began using land planes (most notably the DC-4) for trans-oceanic flights.
Earhart's (and Putnam's) billing of the Model 10E Special as a "Flying Laboratory" was mostly hype. When queried on the subject, Amelia talked about studying the effect of long distance flight on the human body and trying out different kinds of sun glasses. The one piece of cutting-edge avionics installed aboard the aircraft (the Hooven Radio Compass) was removed prior to the world flight. Even the special long-range fuel tank system of the 10E Special was not unique to NR16020. In May 1937, before Earhart and Noonan had even departed on the second World Flight attempt, another 10E Special (c/n 1065, NR 16059) had made the first trans-Atlantic commercial flight when Dick Merrill and John Lambie carried film of the Hindenburg disaster from New York to London nonstop. They returned with film of the coronation of King George VI and flew nonstop westbound more than 24 hours from London to Boston and still had 170 gallons remaining. In other words, in terms of range and endurance, the 10E Special had already demonstrated more capability than Earhart was attempting.
I think your orignal conclusion was correct.
Just a note on unusable fuel, for those trying to get a little closer to what might have been on board; unusable fuel was generally a figure that meant unusable in normal attitudes within the aircraft's acceptable or approved maneuvers list. Most all aircraft will drain more fuel than it is placarded for, as unusable, for this reason in smooth, straight and level flight.
I am not sure but I believe that the C.A.A. only required an operating limitation sheet for aircraft certified at the time of AE's aircraft. This sheet would have been the equivalent of an operators flight manual. This would have been the minimum documentation on board and a manufacturers flight manual would have been a much expanded version of this with fuel flow charts loading graphs, do's and don'ts for the aircraft, etc. It (the operating limitations) would have possessed weights, empty and loaded, available fuel, oil, number of crew and passengers, and operating speeds. A copy of this sheet was normally placed in the aircraft's file(permanent record) with the C.A.A. Has this record been accessed for AE's aircraft? They would surely be in federal dead storage but then again if somebody has changed title on the aircraft recently as in the last 15 years anybody can access the micro-fiche file in Oklahoma City with the F.A.A. If not, a request to the F.A.A. that these files be retrieved from dead storage can be made. This stuff has already been done I'm sure so I hope I'm not speaking out of turn.
Ty N. Sundstrom
Thanks Ty. Due to the on-going interest in Earhart's airplane, the FAA long ago pulled out everything they have to be copied for the curious. We have all that paperwork but there's no manual of any kind amongst it and there seems to be a lot of other stuff missing that you would expect would be there (like all of the weight and balance for the various modifications). Maybe there's more someplace in dead storage but the FAA says not.
Thanks for the info, Ric. The lamb and the dates were added to the background info here. I thought I was missing much more. And thanks for pointing out Gallagher's lack of reliability as an expert witness in this area of the investigation. His testimony on crab behavior could easily be thrown out of court for lack of credentials.
The factors to consider in decomposition experiments:
We have batted all of these factors around without conclusions simply because there is insufficient data. As I wrote to Tom, I have been relying only on experience from the southeast U.S. and places such as Haiti (very similar because it is hot and somewhat dry).
I can think of two ways to produce data that will help with conclusions:
1. Comparative Information: The first comes from Tom's Saipan info: Time and crab dispersal has already been covered by crime scene investigators in a parts of the world with similar environmental conditions and crabs. Let's identify more of those places and learn of their experience. Perhaps I should continue the communication already begun by the police in Fiji. I could offer to teach the course that they want for expenses only if they help me with decomposition data. What do you think? Are there parts of Fiji which are close enough environmentally?
2. Experimental Information: Haul several pigs or dogs along in the freezer and place them in well-documented sites on Niku. Don't stop there. Do the same in a place (such as Saipan) with ongoing meteorological records (as long as the area can be secured).
Enough for now,
I guess the question is, how important is it to establish whether or not coconut crabs scatter bones? Let's say we littered Niku with dead pigs (with a control on Saipan) and found that no scattering occurred. We might then conclude that whatever scattered the bones of the Gardner Castaway was not Birgus latro. We'd then try to determine when the first dogs and/or pigs arrived at Niku. If they didn't show up until AFTER Gallagher found the bones we'd have an even bigger mystery.
However, the only reason we're interested in how the bones got scattered is to be able to make some judgement about when the castaway died. I submit that we're only really interested in that bit of information if we can be quite certain that the castaway was, indeed, Mrs. Putnam. If it turned out that there was good reason to suppose that she somehow survived until shortly before the first colonists arrived, that would be interesting to know.
So, I guess what I'm getting at is that chasing Birgus latro's eating habits seems like a worthwhile line of investigation but not at the expense of limiting our effort to find out who got eaten.
A nagging question but since everyone agrees AE was close to Howland with her "we're on you..." and her last message at 08:43 -46 of "We are on line 157-337...", presumably flying at about 1000ft. altitude, why no further radio contacts if she decided to turn south and fly on to Niku or the Phoenix Is? Wasn't her signal strength the highest at S-5? Or is that the mystery. Or has this been answered?Her radio was working all right it seems. Unless like recent plane disasters the last 1000 ft was only seconds and no time for a last transmission. Was she using a handheld mike or affixed to her helmet?
Everybody remembers that in her last transmission received by the Itasca, Earhart said she was on the 157/337 line, but they tend to not pay attention to the rest of that same message where she says "Will repeat this on 6210 kcs." Immediately following the 08:43 message, Earhart changed frequencies on her transmitter from 3105 (which Itasca had been hearing at S-5) to 6210, a frequency that was known to be a problem on her transmitter (according to the inspection done in Lae) and a frequency that Itasca had never heard her on. There is also widespread agreement among radio operators that frequencies in that range can be a problem in the morning hours, especially over relatively short distances.
In other words, the most likely explanation for why the Itasca stopped hearing transmissions from Earhart is because of the frequency change she said she was making at that time -- not because the airplane suddenly fell out of the sky.
To answer your other question, Earhart used a hand held mic. "Boom" mics on helmets did not come into use until relatively recently and Earhart did not wear a helmet anyway.
> Assuming that
the 157/337 LOP was based upon a precise 67 degree sunrise
With all the years of experience with his equipment and trade and his reputation I would never say that. He had done just the same probably hundred or thousands of times. None of the variables facing him were anything new.
> [H]e knows he's in the right neighborhood.
As you know just being in the right neighborhood will not get anyone to Howland or even close. Both you and Randy are correct that there are or may be variations in the data. There are many inherent errors such as instrument error, instrument capability, abnormal atmospheric refraction, optical resolution of the human eye, dutch roll of the aircraft, rough air, and so on. We can't account for any of that so we need to go with best information recognizing it is not absolute precision. Just like the fuel exercise we can compute it down to the last teaspoon which will give us a base line but still recognizing all the variables and try to visualize the outer edges.
That is what I'm doing with the celestial. I am looking for a base line, something that will approximate the perfect solution and then look for the outer edges of possibilities. To assume perfect micro accuracy is indeed, as Randy suggested, silly but it is necessary to have a starting point.
Fred was, by all accounts, a superior navigator. Such a person, with his experience can play fine music with less than great equipment. My navigator was such a person. We were a select SAC aircrew winning competitions time after time with a 3nm CEA. (Circular Error Average) Both he and I did the shots and compared for accuracy. This was pure celestial that was graded after the flight by standardization personnel. We both knew the short comings of the equipment and of the many errors we faced.
A good instrument has an error of between .1 and .3 degrees. Not a whole lot. My airplane had dutch roll but we compensated for it through experience. You start to get a sense of the movements and you feel out a correction.
Fred may have not been exactly on course but you can bet he was damned near. On his inbound leg he not only had the sun but the moon was about 30 some degrees off the sun's azimuth. If he saw one he saw both.
I'm not going to use an azimuth of even .1 off 67. I can't assume any errors so I'll use none. We need to know under accurate conditions where he most likely was and THEN start factoring in how far off he could reasonably be.
If we instead assume the DG was a few degrees off and he shot the azimuth a few tenths off and didn't accurately handle refraction and the atmosphere was weird that day he could have been anywhere.
At worst we should be able to arrive at general conclusions as to where he was NOT.
Personally I believe the sun of a gun was on course, knew where he was and they just missed seeing the island because of little clouds, glare, or whatever. As you pointed out Ric, with the generator and other noises, clouds, more sun glare, and whatever else even the folks on the ground would not necessarily have spotted the plane at 1,000' and a few miles off.
Forgive me if this is a question that everyone else but me is aware of --- You mentioned that "one piece of cutting-edge avionics" that Amelia had aboard the Electra was the Hooven Radio Compass. What was the reason for them installing and then removing it? And when was it removed? In Miami? In Los Angeles?
And while I'm asking potentially obvious questions, how common was it to use the particular radio direction finder that they used with the circular antenna? How new on the market was that particular direction finding system?
Thanks - Laurie
We haven't talked about this much and it's a subject that is not touched upon in any of the Earhart books, and yet it's both interesting and indicative of Earhart's approach to the world flight.
When the airplane was delivered in July 1936, it had a garden-variety Western Electric transmitter and receiver, and no DF capability. Sometime in October of 1936, one of five prototype "Radio Compass" automated direction finders invented by Frederick J. Hooven was installed in the airplane at Wright Field, Ohio. The "Radio Compass" system was entirely separate from the aircraft's other radios. It consisted of a receiver which was mounted in the cabin on top of the fuel tank just behind the cockpit bulkhead on the copilot's side. Photos indicate that it may have also had it's own dynamotor installed in that same location. (The Western Electric receiver was under the copilot's seat and the dynamotor was under the pilot's seat.)
The Hooven Radio Compass used an antenna that seems to have been more of a ball (roughly the size of a tether ball) than a conventional open loop. The antenna was housed in a translucent dome on the top of the fuselage just about over the midpoint of the wing.
Exactly why Earhart/Putnam had this piece of equipment installed is not known. We know that the world flight was contemplated, if not yet announced, and it may be that it just fit with the idea of a Flying Laboratory. One of the virtues of the Radio Compass (known later as an Automatic Direction Finder and still in use today as the ADF) over the "old fashioned" manual unit is that it is easier to use in that it requires fewer mental gymnastics. That might also be something that would appeal to Earhart.
The Hooven Radio Compass stayed in the airplane until the first week of March 1937 when, as part of the final preparations for the first World Flight attempt, the dome disappeared and was replaced by the now-familar open loop over the cockpit. Hooven, in later years, wrote about the change. He was incensed that Earhart had removed his invention and replaced it with an "old fashioned" system for the sake of saving 30 pounds. He also made the point that the low drag of the faired dome more than made up for the weight penalty as compared to the high drag of the open loop.
At the same time that this change was made, Bendix came out with a new coupling unit that permitted their open loop to be used with existing receivers. This seems to be what was installed on NR16020 in lieu of the Hooven Radio Compass. In other words, Earhart found a way to eliminate on entire radio (30 pounds) and still have DF capability, albeit not the new easy-to-use variety. Ironically, Hooven had also been bought out by Bendix.
Debate still rages about twhether there were one or two receivers aboard NR16020 during the second world flight attempt, but so far I have seen no contemporaneous evidence that a second receiver was aboard. Right up until his death in 1985, Fred Hooven was convinced that Earhart's decision was the principal cause of the flight's failure to find Howland Island. He may have been right.
Love to mother,
Thanks for the answer but a follow up question on AE's frequency change from 3105 (night) to the supposedly better day frequency 6210. You indicate that radio experts believe the 6210 frequency can be a problem in early morning and over short distances.
But if, as TIGHAR contends, she flew on some 400 miles south taking some 2 1/2 hours towards NIKU,why wouldn't Itasca eventually hear her on 6210 at a much longer range (well within her 50 watt transmitter capacity) later in the morning?
Any truth or validity in Carrington's report that AE's receiver crystals didn't "match" exactly Itasca's crystals, that is she had to mechanically switch vs. "hand tune"?
I believe you and Carrington both believe that AE's radio signals were heard sometime around l0:30 AM (Howland time) from 2 July until 6 July 37. How can we explain her ability to transmit then, but not airborne? I'm certainly not a radio expert, so these are lay questions.
The entire TIGHAR theory rests on the fact she flew on to Niku and so a satisfactory explanation of AE's inability to contact Itasca or anyone (other ships or stations) must be explained. After all her transmitter was working fine from 2:00 am inbound to Howland to at least 8:44am. (Some authors add an 8:55am reception from AE repeating the "are running North and South") Don't know what that means.
I don't know where Earhart was at 08:43 (the time that actually appears in the Itasca radio log) or how long it took her to reach Gardner if that's where she went. Neither do I know how long or how many times she continued to try to call the Itasca after so many failed attempts. I don't think anybody knows those answers.
I don't know where Carrington got the idea that the crystals used by Earhart and Itasca did not match but I do know that Earhart had no way to "hand tune" the transmitter frequency even if she wanted to. I don't think Itasca's transmitters were crystal controlled. I do know that they calibrated their frequencies. Frankly, I don't take anything that Carrington says seriously.
I disagree that TIGHAR must provide a "satisfactory explanation" for why Itasca did not hear anything from Earhart after 08:43. We can suggest reasonable possibilities based upon the available evidence (and there are several) but it's doubtful that anyone will ever know for sure.
With respect to Forum members who have questioned or commented on my "usable fuel" estimate, I would point out that the number and length of fuel lines in the modified Electra were in excess of what will be found in a P-39 or P-51. I venture to say that the total length of fuel lines in the Electra exceeded the DC-3 as well.
I believe the lines were increased in size after the airplane was manufactured, possibly at the request of Paul Mantz. I will check my Lockheed correspondence file, but my memory says the size was increased from 3/8 inch to 1/2 inch diameter tubing. (At my age you are welcome to question my memory.) The change makes sense, however. Someone realized that the trapped fuel fraction was excessive and probably the pressure drop in the system with smaller lines contributed to the problem. I suspect that adding a wobble pump was in part due to this (possible) problem. I will check my file and let you know if my memory is correct.
Certainly the total number of tanks in the Electra exceeded all of the above airplanes with each having an ullage volume to one degree or another. With more lines there would be more fittings with the potential to leak. The pressure drop in the system had to be significant because of the internal surface area of the tubes and the number of bends and turns necessary to complete the system. This might be amenable to some rough analysis. Let me think about that.
I would remind all that my useable fuel estimate (using the Bell test measurements as a baseline reference) includes a variety of factors. I would be happy to learn about actual test measurements on other aircraft if any of the Forum members can provide references.
|Back to Highlights Archive list.|