Juggernut Posted September 22, 2020 Share Posted September 22, 2020 Battery venting is normal but the gasses (Hydrogen) should not be corrosive as they are processed through a sump jar containing sodium bicarbonate (for lead acid batteries) if a little electrolyte makes it through to the sump jar. Gassing is normal during battery charging. Battery electrolyte (sulphuric acid in lead acid batteries) leakage (sans any battle damage) however, is not normal and would not normally leak out the top of the wing in spite of the lower air pressure than is found inside the wing. Battery electrolyte leaking comes from over servicing the water level in the battery and subsequently overflows when the battery is charged. Any overflow should be neutralized in the sump jar. The battery case is designed to handle an overflow and even in extreme cases, I don't think an overflow would fill the sump jar and then get siphoned out the vent discharge tube. It is my considered opinion that those metal wear areas are primarily from foot traffic, servicing and maintaining the aircraft. Having said all that, the entire functionality of the system depends on regular and adequate maintenance. As a related note; battery compartments in aircraft of that time are usually coated with a bituminous paint that withstood electrolyte spillage and would not adversely affect surrounding structure. I have no idea whether this was done on WWII combat aircraft or not but I could not find any reference to such a paint (by name) in the B-17G E&R so it might not be applicable to at least this particular aircraft. Uncarina, LSP_K2, Lee_K and 1 other 2 2 Link to comment Share on other sites More sharing options...
LSP_K2 Posted September 22, 2020 Share Posted September 22, 2020 As I think about this more, many aircraft tended to show more foot wear on the port side than on the starboard side. Lee_K 1 Link to comment Share on other sites More sharing options...
Lee_K Posted September 22, 2020 Author Share Posted September 22, 2020 1 hour ago, LSP_K2 said: As I think about this more, many aircraft tended to show more foot wear on the port side than on the starboard side. That's certainly true on fighter aircraft due to the common approach from the port side (a tradition started with mounting horses), with the P-39 being the exception. On bombers however, it could be just a carryover from fighters as most bombers were accessed via ladders and hatches or through the bomb bay. LSP_K2 1 Link to comment Share on other sites More sharing options...
LSP_K2 Posted September 22, 2020 Share Posted September 22, 2020 27 minutes ago, Lee_K said: That's certainly true on fighter aircraft due to the common approach from the port side (a tradition started with mounting horses), with the P-39 being the exception. On bombers however, it could be just a carryover from fighters as most bombers were accessed via ladders and hatches or through the bomb bay. Well, I was just pointing out that it's seldom, if ever, completely symmetrical. Lee_K 1 Link to comment Share on other sites More sharing options...
justplanecrazy Posted March 11, 2021 Share Posted March 11, 2021 just curios if anyone has a picture of Princess Pat's nose art? I would LOVE to do this a/c Link to comment Share on other sites More sharing options...
LSP_K2 Posted March 11, 2021 Share Posted March 11, 2021 Looking over these images some more today, I have another observation/question. Why does it seem that the port side exhaust streaks more or less flow straight back the wing, toward the trailing edge, while the starboard stains seem to flow across the wing toward the fuselage? I'm guessing this has a lot to do with prop rotation, but don't really know for sure. Derek B 1 Link to comment Share on other sites More sharing options...
justplanecrazy Posted March 11, 2021 Share Posted March 11, 2021 I've been told that it has to do with where the aircraft flew in formation . not sure about this because it does seem to occur on the right side in most photos I've seen LSP_K2 1 Link to comment Share on other sites More sharing options...
LSP_K2 Posted March 11, 2021 Share Posted March 11, 2021 I had assumed something similar must be the cause. I've never in my life seen a Fort model depict this. Until today, I was not aware of it myself. Derek B 1 Link to comment Share on other sites More sharing options...
Juggernut Posted March 11, 2021 Share Posted March 11, 2021 (edited) After thinking about this for a minute or three, it most likely is airflow over the wing in addition to prop wash and something called P-factor. It may be also be a result of the B-17 airfoil/aspect ratio/lateral taper. I don’t recall seeing this particular anomaly on B-24 or B-29 wings. I also haven’t noticed the same effect on Lancaster wings either. I haven’t really studied any of the aforementioned airframes to the same degree as I have the B-17. Maybe someone can take a look at some other four-engine bomber examples and post their findings. I am not able to do that any time soon. If you also look very closely, you'll notice that the black streaks that seem to originate from the air exhaust vents behind each engine in the wing, actually don't. They are a continuation from further forward and pass aft in between the exhaust vents. I think the airflow through the vents disrupts the staining pattern. Edited March 11, 2021 by Juggernut Uncarina and Derek B 2 Link to comment Share on other sites More sharing options...
Iain Posted March 11, 2021 Share Posted March 11, 2021 Note that air over the top of the wing tends to migrate inwards and so on one side it adds to the prop wash effect, and the other side against - which is why it's not the same both sides. It tends to migrate outwards underneath the wing - which is how you get tip vortices, but I digress... https://www.skybrary.aero/index.php/Induced_Drag Iain Jack, D.B. Andrus, Derek B and 1 other 4 Link to comment Share on other sites More sharing options...
LSP_K2 Posted March 11, 2021 Share Posted March 11, 2021 7 minutes ago, Iain said: Note that air over the top of the wing tends to migrate inwards and so on one side it adds to the prop wash effect, and the other side against - which is why it's not the same both sides. It tends to migrate outwards underneath the wing - which is how you get tip vortices, but I digress... https://www.skybrary.aero/index.php/Induced_Drag Iain My same reasoning, and the cause that I guessed above, prop rotation effects behaving differently from side to side, coupled with aerodynamic issues. D.B. Andrus and Iain 2 Link to comment Share on other sites More sharing options...
Juggernut Posted March 11, 2021 Share Posted March 11, 2021 (edited) Since I can’t delete the post itself, sometimes I need to RTFP before replying....LOL. Edited March 11, 2021 by Juggernut Link to comment Share on other sites More sharing options...
thierry laurent Posted March 12, 2021 Share Posted March 12, 2021 17 hours ago, Juggernut said: If you also look very closely, you'll notice that the black streaks that seem to originate from the air exhaust vents behind each engine in the wing, actually don't. They are a continuation from further forward and pass aft in between the exhaust vents. I think the airflow through the vents disrupts the staining pattern. By the way, for whatever reason, it is one of the most common errors seen on weathered models! LSP_K2, edfifer and Derek B 3 Link to comment Share on other sites More sharing options...
tomprobert Posted March 12, 2021 Share Posted March 12, 2021 22 minutes ago, thierry laurent said: By the way, for whatever reason, it is one of the most common errors seen on weathered models! Along with painting the entire interior of a Fortress interior green... Uncarina, thierry laurent, D.B. Andrus and 1 other 4 Link to comment Share on other sites More sharing options...
Uncarina Posted March 14, 2021 Share Posted March 14, 2021 Just finished watching “The Cold Blue”. Very impressive colorized footage filmed from Memphis Belle and other aircraft, with insights from the veterans who flew these missions. Also a good weatheing reference. https://www.imdb.com/title/tt8693770/ Cheers, Tom Derek B 1 Link to comment Share on other sites More sharing options...
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