TIGHAR
Amelia Earhart Search Forum => Join the search => Topic started by: Ric Gillespie on January 05, 2013, 09:11:32 AM
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If we're looking for airplane parts in underwater photographs we need to know what airplanes parts look like when they have been underwater for a protracted period of time in a similar underwater environment. Such models are hard to find but the recent discovery of an F2A Brewster Buffalo that landed short of the runway at Midway atoll in 1941 or '42 may qualify. What do you see? What questions does the photo raise?
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Yes, slightly dfferent environment but it does beg the question on the Rope/Wire video - If the rope/wire is part of the wreck and there are other items that have been identified, why is the rope/wire more visble than some of the other 'larger' peices?
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Yes, slightly dfferent environment but it does beg the question on the Rope/Wire video - If the rope/wire is part of the wreck and there are other items that have been identified, why is the rope/wire more visble than some of the other 'larger' peices?
That is a great question, Chris. I think that the cable is under some tension, as it seems to have eaten channels into the coral below it from place to place. If it moves, even infrequently, it could sluff off whatever plankton has settled on it in the meantime, wheras other more stable parts might tend to stay at rest. Just a guess, of course.
I might add that this plankton/snow stuff might make a major difference in the appearance of objects after a period of 75 years. You won't find in in as great abundance at the depths where the divers are examining the three-bladed propeller, I don't think.
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It is odd to me how many times I've seen propellers separated from engines like this, but with the shaft / splines appearing intact. How?
I'd be interested to see other examples of props separating from shafts but leaving the splines/shaft intact. I've seen lots of crashes on land but I don't recall ever seeing a prop come off the shaft.
An abandoned latter-day salvage attempt or by natural forces during the accident? Always a bit strange. Same for missing jugs when impact damage isn't so clear.
This is reported as a new discovery so an abandoned salvage attempt seems unlikely. The accident was apparently just an inadvertent ditching and the pilot swam to shore so the forces generated during the accident couldn't have been enough to account for the damage we see in the photo. The depth is only ten feet. I suspect that we're seeing the effects of many years of the wreck being tumbled about by the surf.
ADDED: It is probably fair to note that what we are seeing here lies in a somewhat less complex environment than is the case at Niku so far: shallow, sandy and less-than precipitous, whereas Niku has a more severe and somewhat shifting 'landscape' due to the reef slope, etc. By this I can realize by graphic contrast what we've long realized - that we could well have buried / semi-covered items lying about in those waters that are difficult to see. None-the-less, form is form, and we can see here the sort body that might be found yet.
The prop appears to be partially buried but other pieces of debris are not. Note the lack of coral growth on the metal except for the two large clumps - one on the prop hub and one on the engine case. We see the same phenomena on the shallow (50 ft) TBD in Jaluit lagoon.
I'd love to know more about the balance of the airframes remains, but there is not yet much being released. I looked this find up and found that the Marine Corps has closed the area around Midway while more archeology is being done. Fascinating.
This is a NOAA Marine Heritage survey. We know those guys well. We should be able to get more details and possibly photos.
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If the engine was running during the ditiching, would it be possible that the damage to the cylinders be due to the intake of water and the resultant hydrostatic lock? Considerable rotating mass would be involved, with the propeller acting as a flywheel. This could possibly also result in shearing the crankshaft and the resulting liberation of the propeller.
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If the engine was running during the ditiching, would it be possible that the damage to the cylinders be due to the intake of water and the resultant hydrostatic lock? Considerable rotating mass would be involved, with the propeller acting as a flywheel. This could possibly also result in shearing the crankshaft and the resulting liberation of the propeller.
Sounds like that might be theoretically possible but I've never known it to happen.
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My guess so far is that what I took to be a 'clean' departure of the prop from the splines is really at least partly an illusion, and that some direct force is responsible for a failure in some manner that we cannot discern from the picture.
Not likely a "hydrolock" in this scenario but more likely as you say Jeff, a direct force as in the prop impacting the water at high speed shearing it off from the shaft, imo, which could possibly explain it's close proximity to the rest of the engine. What say our former aircraft accident investigator?
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Hi All
Just a quick question, If the Electra was in deepish water on reef and Amelia an Fred wanted to run engines would they have been able to remove the propellers tools permitting ?
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Hi All
Just a quick question, If the Electra was in deepish water on reef and Amelia an Fred wanted to run engines would they have been able to remove the propellers tools permitting ?
Not in their wildest dreams Richie could they have removed the props much less having the tools and the hydraulic lift to take one off.
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Hi All
Just a quick question, If the Electra was in deepish water on reef and Amelia an Fred wanted to run engines would they have been able to remove the propellers tools permitting ?
Ah, THAT'S why...
No - you can't run the engine without the prop, Richie. The 'flywheel' effect (mass) is needed to damp out the power pulses, etc. in a recip.
If they got to that point of need, they would have been in deep... ah, well, worse than water.
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Not likely a "hydrolock" in this scenario but more likely as you say Jeff, a direct force as in the prop impacting the water at high speed shearing it off from the shaft, imo, which could possibly explain it's close proximity to the rest of the engine. What say our former aircraft accident investigator?
When turning props impact water or land they bend. At idle or low power the blades been back. Under high power the blades bend forward. At least one of the Buffalo's props is bent back, which is consistent with the supposed ditching. I've never heard of an impact with the water, or ground for that matter, causing the prop to separate from the shaft.
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Not likely a "hydrolock" in this scenario but more likely as you say Jeff, a direct force as in the prop impacting the water at high speed shearing it off from the shaft, imo, which could possibly explain it's close proximity to the rest of the engine. What say our former aircraft accident investigator?
When turning props impact water or land they bend. At idle or low power the blades been back. Under high power the blades bend forward. At least one of the Buffalo's props is bent back, which is consistent with the supposed ditching. I've never heard of an impact with the water, or ground for that matter, causing the prop to separate from the shaft.
Ric, of course you are right. I should have thought further than I did before making that comment.
Bad Bob, who never was spanked with a fly swatter. ;)
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Not being an airplane mechanic and confining my skills to engines that remain on terra firma, or sometimes water, I am not overly familiar with how the propellor is mounted to the shaft. It appears that it fits onto a splined shaft. I would presume that it is then held in place with a nut of some type, similar to a crankshaft pulley on a car engine. If that is the case, would there possibly be a dissimilarity in the metals used which would allow the nut to corrode away? I dive alot and I know that in shallow waters the wave action can really move stuff about. My thought is that the nut holding the prop to the shaft may have corroded away, allowing the prop to come off when the entire assembly was rolled about by the surf. After separating, there isn't alot of surface area for the surf to act on with the prop, allowing it to drop to the ocean floor. The engine itself now has a lot less surface area compared to mass and would require heavier surf action in order to move it. I think this would help explain the current condition of the parts. Prop attached, the whole assembly is rocked back and forth and rolled about, dislodging cylinders, etc. Prop detached, the prop lays flat and the engine moves much less, if at all, allowing the two parts to remain close to each other. Separation took place a fair time ago judging by the coral build-up on the prop hub. I'm curious as to how far the engine assembly made it from the airframe. My $.02 for the day. LTM- John
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Not being an airplane mechanic and confining my skills to engines that remain on terra firma, or sometimes water, I am not overly familiar with how the propellor is mounted to the shaft. It appears that it fits onto a splined shaft. I would presume that it is then held in place with a nut of some type, similar to a crankshaft pulley on a car engine. If that is the case, would there possibly be a dissimilarity in the metals used which would allow the nut to corrode away? I dive alot and I know that in shallow waters the wave action can really move stuff about. My thought is that the nut holding the prop to the shaft may have corroded away, allowing the prop to come off when the entire assembly was rolled about by the surf. After separating, there isn't alot of surface area for the surf to act on with the prop, allowing it to drop to the ocean floor. The engine itself now has a lot less surface area compared to mass and would require heavier surf action in order to move it. I think this would help explain the current condition of the parts. Prop attached, the whole assembly is rocked back and forth and rolled about, dislodging cylinders, etc. Prop detached, the prop lays flat and the engine moves much less, if at all, allowing the two parts to remain close to each other. Separation took place a fair time ago judging by the coral build-up on the prop hub. I'm curious as to how far the engine assembly made it from the airframe. My $.02 for the day. LTM- John
John, here is a picture of an R985 Wasp Radial engine. The prop shaft is steel and the nut that holds the prop hub on is also steel. There are no dissimilar metals I am aware of in the assembly of a prop hub to the shaft. That would be a recipe for disaster even on dry land. Aircraft components are inspected for corrosion during every annual inspection of an aircraft.
Edit: This is very similar to the Pratt and Whitney R1340's were on Amelia's Electra L-10E.
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However it happened, if Earhart's prop came off the shaft that entire hub assembly had to slide off - and for that to happen the nut on the end had to somehow go away.
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The Brewster Buffalo had a different engine/prop (Wright R-1820 and 3-blade prop) than the Electra but the general method of affixing the hub assembly to the shaft was probably similar.
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However it happened, if Earhart's prop came off the shaft that entire hub assembly had to slide off - and for that to happen the nut on the end had to somehow go away.
Ric, not saying that a steel nut wouldn't corrode away in that environment whether there were dissimilar metals or not. Since the engines nor the props have been found in one condition or another, all this is pure conjecture anyway IMO. No telling what happened down there now since all that stuff is so corroded. BTW Ric, have you gotten any more pictures of the Buffalo that might show more of the remnants of the plane and where they are in proximity to the engine.
Bad Bob, who was never spanked with a fly swatter. ;)
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Since the engines nor the props have been found in one condition or another, all this is pure conjecture anyway IMO.
"There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy."
BTW Ric, have you gotten any more pictures of the Buffalo that might show more of the remnants of the plane and where they are in proximity to the engine.
Not yet. Workin' on it.
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Since the engines nor the props have been found in one condition or another, all this is pure conjecture anyway IMO.
"There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy."
Touché Shakespeare,
"Hamlet and Horatio are friends from university. They are both educated men, and Horatio has a hard time believing in things like ghosts. However, once they are visited by the ghost of Hamlet's father, they get spooked. Hamlet makes Horatio and the guards promise not to tell anyone what they have seen, and then he says this quote to Horatio. Hamlet is telling Horatio that earthly education and philosophy can't explain everything. Now that they've seen the ghost, their previous beliefs are turned upside down."
Bad Bob, who was never spanked with a fly swatter. ;)
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This reminds me of an airplane I found online looking at sunken ship wreck sites. I was surprised to see how much had deteriorated just not that much was left. Which is what this looks like not much to see.
http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html (http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html)
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This reminds me of an airplane I found online looking at sunken ship wreck sites. I was surprised to see how much had deteriorated just not that much was left. Which is what this looks like not much to see.
http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html (http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html)
Excellent data point Mr. Sain. Thank you. The amount of deterioration is similar to what we've seen in other aircraft near the California coast. The rubber tire seems to have held up pretty much intact.
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This reminds me of an airplane I found online looking at sunken ship wreck sites. I was surprised to see how much had deteriorated just not that much was left. Which is what this looks like not much to see.
http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html (http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html)
On the other hand, here is the write up, on the same web site, for the crash of a Navy TBM Avenger (http://www.ub88.org/researchprojects/tbmavenger/tbm-avenger.html), again off the California coast. According to the information provided, this aircraft hit the water at 110 kts but both crew members survived the impact. The pictures attached to the article show that the engine apparently separated from the aircraft but no pictures of the engine are provide. However, large sections of the aircraft are shown as relatively intact even after all those years (1952-2007).
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The Brewster Buffalo had a different engine/prop (Wright R-1820 and 3-blade prop) than the Electra but the general method of affixing the hub assembly to the shaft was probably similar.
In either case the pitch-change device has to be removed; the gland nut is buried well down inside the prop hub itself and is not easy to reach except with the right tool.
If memory serves, the splined surfaces are typically case-hardened on those shafts on probably all makes of engine - it is a fairly common design feature. There can be something of a natural stress riser zone in the transition area between splines and threads too - not so much to fail easily, but perhaps the right impact forces could have caused the nut/threaded area of the shaft to yield and fail, after which the same forces might have caused the prop to continue forward and off the shaft. Props are not interference-fit onto splines like that, only close-tolerance.
The 'scenario' is pure posit on my part, of course, but it is hard to imagine that anyone went down there with the right wrenches to do what we see, and it would not have been done casually with a pipe wrench...
Below is a picture of the special tool/wrench used to remove/tighten the gland nut holding the Electra's propeller to the engine crank shaft. I remember reading somewhere, and I have not been able to find the reference right now, that AE and FN carried a tool like this with them on the flight. I don't know if that would include the "breaker bar" too or only the "socket" but IMO, probably both.
Here is a link to the picture of the propeller tool (http://earchives.lib.purdue.edu/u?/earhart,229) and a copy of the picture. This is also a good picture of AE's shoe.
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The Brewster Buffalo had a different engine/prop (Wright R-1820 and 3-blade prop) than the Electra but the general method of affixing the hub assembly to the shaft was probably similar.
In either case the pitch-change device has to be removed; the gland nut is buried well down inside the prop hub itself and is not easy to reach except with the right tool.
If memory serves, the splined surfaces are typically case-hardened on those shafts on probably all makes of engine - it is a fairly common design feature. There can be something of a natural stress riser zone in the transition area between splines and threads too - not so much to fail easily, but perhaps the right impact forces could have caused the nut/threaded area of the shaft to yield and fail, after which the same forces might have caused the prop to continue forward and off the shaft. Props are not interference-fit onto splines like that, only close-tolerance.
The 'scenario' is pure posit on my part, of course, but it is hard to imagine that anyone went down there with the right wrenches to do what we see, and it would not have been done casually with a pipe wrench...
Below is a picture of the special tool/wrench used to remove/tighten the gland nut holding the Electra's propeller to the engine crank shaft. I remember reading somewhere, and I have not been able to find the reference right now, that AE and FN carried a tool like this with them on the flight. I don't know if that would include the "breaker bar" too or only the "socket" but IMO, probably both.
Here is a link to the picture of the propeller tool (http://earchives.lib.purdue.edu/u?/earhart,229) and a copy of the picture. This is also a good picture of AE's shoe.
Yup, can you imagine Amelia and Fred taking off that gland nut? Who'd hold the prop still without getting lifted off the ground?
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Hi Bob
Clearly in image you see Amelia holding propeller blade whilst it is being tightened.
C.W. Herndon
The reason Gallagher was able to identify the shoe, As being that of a woman's shoe, was because woman's walking shoe's of late 1930's The toe area was rounded not pointed.
http://www.fashion-era.com/flapper_fashion_1920s.htm scroll down to 1920 - 1930 shoes
You only have to look at images of Amelia an George Putnam for example to see his are pointy shoes were as her's are rounded
Thanks Richie
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Hi Bob
Clearly in image you see Amelia holding propeller blade whilst it is being tightened.
To me it just looks like she is holding on to it, rather than holding it for the mechanic. I'd be cautious with that photo because it is a posed photo which Earhart seems to have done a lot as part of the pre-flight publicity hype.
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To me it just looks like she is holding on to it, rather than holding it for the mechanic. I'd be cautious with that photo because it is a posed photo which Earhart seems to have done a lot as part of the pre-flight publicity hype.
I agree. I've never seen any indication that AE participated in, or was much interested in, aircraft maintenance except as a photo-op.
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To me it just looks like she is holding on to it, rather than holding it for the mechanic. I'd be cautious with that photo because it is a posed photo which Earhart seems to have done a lot as part of the pre-flight publicity hype.
I agree. I've never seen any indication that AE participated in, or was much interested in, aircraft maintenance except as a photo-op.
I agree. I only posted the picture to show what the tool looked like. I feel sure, if they indeed carried the tools with them, it was to ensure that the mechanics would have the correct items with which to work on the propeller, if necessary, which had to be done on the first flight. If you look closely at Bob Lanz's photo, attached below, you will see that the tip of the propeller, probably well padded, is resting on top of a maintenance stand while the mechanic torques the gland nut.
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Hi All
My Apologies for last post.
I was lead to believe, Not by anyone at Tighar. That a locking nut was designed to thread opposite the object it was securing.
I.E if the propeller rotates clock wise the locking nut would have anti-clockwise thread ::) My Bad
I also read that Lockheed in the 1930's designed some twin engines to operate, Right engine clockwise and Left engine anti-clockwise to steady ship better :-[
Dangers of the web aye
Thanks Richie
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I also read that Lockheed in the 1930's designed some twin engines to operate, Right engine clockwise and Left engine anti-clockwise to steady ship better :-[
The XP-38 Lightning had inward rotating propellers. Production versions had outward rotating propellers.
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This reminds me of an airplane I found online looking at sunken ship wreck sites. I was surprised to see how much had deteriorated just not that much was left. Which is what this looks like not much to see.
http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html (http://www.ub88.org/researchprojects/f4ucorsair/f4u-corsair.html)
On the other hand, here is the write up, on the same web site, for the crash of a Navy TBM Avenger (http://www.ub88.org/researchprojects/tbmavenger/tbm-avenger.html), again off the California coast. According to the information provided, this aircraft hit the water at 110 kts but both crew members survived the impact. The pictures attached to the article show that the engine apparently separated from the aircraft but no pictures of the engine are provide. However, large sections of the aircraft are shown as relatively intact even after all those years (1952-2007).
I am not an authority since many WWII era planes are in the water and in pretty good condition. Others like the Buffalo and this one have nearly disappeared. Does anyone know why some rust away so much faster than others? Personally I would expect the shallower air frames to suffer the worst but that does not appear to be the case. Tighar has two WWII planes both in shallow water in much better condition. The P38 I thought was covered in sand.
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Does anyone know why some rust away so much faster than others?
Not really. There are dozens of factors and combinations of factors that come into play.
The P38 I thought was covered in sand.
It is. The anaerobic (no oxygen) environment is a big factor in its preservation.
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Gland Nut Popoff theory
Ok -- Have you ever seen a model rc airplane prop strike a hard object like the ground on a bad approach landing ? or a rock , or I guess non compressible water?
The idea is similar to a concrete post that gets an impact from a car in an accident at the bottom. The top of the post splinters from the force of the accident below but the post is ok down there at point of contact. The force magnified by a kind of standing wave thru the post appiles pressure to the top circumfrence of the post and throws any nut off and causes splintering..
Ie the model airplane hub nut is thrown off by the imapct force magified by bounding thru the shaft. Once the nut flies off the prop follows it quickly , ask an RC model flyer ,
yes the prop and shaft are ruined bent and possibley broken lying in front of the plane ...
just my theory from observations .....