Oldbaldguy Posted February 1, 2022 Share Posted February 1, 2022 By Jove, I think you did it! Very convincing oil system. Thankfully, you did not paint them orange. The orange lines seen in the photo of a restored Hellcat are semi flexible silicon impregnated high pressure fire sleeved hoses, a fairly recent technology that makes fuel and oil systems safer and more durable. Contemporaneous of WW2, your airplane’s oil system was made up of a number of preformed aluminum pipes that were joined by fabric reinforced black rubber couplings held in place with typical AN hardware screw clamps. These couplings not only connected the segments of pipe, they also provided vibration isolation and the ability for the whole system of hard lines to flex a bit, an absolutely essential characteristic for just about anything that flies. Air cooled engines heat up pretty quickly, relying on air flow, oil and in some cases fuel to help dissipate the heat. As the oil makes its way around the inside of the engine doing its job, it picks up heat which is why it needs to go through a radiator like oil cooler once it comes out to shed all those unwanted BTUs. Radial engines use/need lots of oil, which is why the oil lines are so big and the oil capacity is measured in gallons rather than quarts. All this has nothing to do with your wonderful build, but hopefully sheds a little light on a specific system most of us never think much about when building a kit. John Stambaugh, JayW, LSP_Kevin and 1 other 2 2 Link to comment Share on other sites More sharing options...
chuck540z3 Posted February 1, 2022 Author Share Posted February 1, 2022 29 minutes ago, Oldbaldguy said: By Jove, I think you did it! Very convincing oil system. Thankfully, you did not paint them orange. The orange lines seen in the photo of a restored Hellcat are semi flexible silicon impregnated high pressure fire sleeved hoses, a fairly recent technology that makes fuel and oil systems safer and more durable. Contemporaneous of WW2, your airplane’s oil system was made up of a number of preformed aluminum pipes that were joined by fabric reinforced black rubber couplings held in place with typical AN hardware screw clamps. These couplings not only connected the segments of pipe, they also provided vibration isolation and the ability for the whole system of hard lines to flex a bit, an absolutely essential characteristic for just about anything that flies. Air cooled engines heat up pretty quickly, relying on air flow, oil and in some cases fuel to help dissipate the heat. As the oil makes its way around the inside of the engine doing its job, it picks up heat which is why it needs to go through a radiator like oil cooler once it comes out to shed all those unwanted BTUs. Radial engines use/need lots of oil, which is why the oil lines are so big and the oil capacity is measured in gallons rather than quarts. All this has nothing to do with your wonderful build, but hopefully sheds a little light on a specific system most of us never think much about when building a kit. Thanks for that- and now a few more questions. Is the oil going behind the firewall somewhere to get cooled? Since it's right next to that big air pipe, it would seem reasonable that this is all related. Thanks in advance, Chuck Link to comment Share on other sites More sharing options...
JayW Posted February 1, 2022 Share Posted February 1, 2022 Oh man Chuck - what an inspiration! Wasn't it you who depricated yourself about being unable to create scratch built parts? No sir. Dropping the engine - OMG. I know the felling! I did not drop my 1/18 R-2800 (or not yet anyway), but I can guarantee you things would come off, and irreparable damage would probably occur. Such an event would relegate my several year effort to the SOD for sure. So that cannot happen. Unfortunately I have a whole lot of engine handling ahead of me - I will be doing the engine accessories compartment as well. Am so proud of you with the oil systems runs! Great that you decided to tackle it! I am struck by the similarities between F4U and F6F - clearly they were designed to perhaps the same specification. And with the same engine, well that makes for alot of similarities. Example - the armor plate in front of the oil tank. F4U had one too! But oddly, it was deleted sometime during production. I can only surmise that it was not seeing alot of "action" in service, and constituted a good weight savings to get rid of it. That being the case, why didn't it get deleted on the -5 Hellcat as well, if not the -3? Maybe it was! I ought to check Aircorps Library....nah. Leave it there Chuck! chuck540z3 1 Link to comment Share on other sites More sharing options...
theseeker Posted February 1, 2022 Share Posted February 1, 2022 An absolutely amazing build all around! chuck540z3 1 Link to comment Share on other sites More sharing options...
williamj Posted February 1, 2022 Share Posted February 1, 2022 Absolutely spectacular work going into this Hellcat Chuck. very special. chuck540z3 1 Link to comment Share on other sites More sharing options...
JayW Posted February 1, 2022 Share Posted February 1, 2022 11 hours ago, chuck540z3 said: The only pic or diagram I have of the rear of the engine is this one which is low resolution, but it’s good enough to locate and identify where these hoses should probably go, as #12 Oil Outlet and #15 Oil Inlet. You are absolutely correct (good thing - it's done!). I did an eye-watering amount of research on the back of this engine (well the -8 which is same except for carburetor location), as you know, for my 1/18 R-2800. There are more than just oil lines that go back there in that morass. Electrical (starter), fuel lines, and hydraulic. Depending on what else you want to put in there, just say the word and any help needed is on the way. chuck540z3 1 Link to comment Share on other sites More sharing options...
chuck540z3 Posted February 1, 2022 Author Share Posted February 1, 2022 (edited) 25 minutes ago, JayW said: You are absolutely correct (good thing - it's done!). I did an eye-watering amount of research on the back of this engine (well the -8 which is same except for carburetor location), as you know, for my 1/18 R-2800. There are more than just oil lines that go back there in that morass. Electrical (starter), fuel lines, and hydraulic. Depending on what else you want to put in there, just say the word and any help needed is on the way. Thanks Jay- whew! Going by exploded parts diagrams is kind of like feeling around in the dark, so you're never sure if you are doing things "correctly", even though nothing is truly correct when modeling an engine. As for more detail, I'm always open to just about everything, but I have my limits. Those big-ass oil hoses were a must, and there are some linkages and other lines I plan to add later that are obvious, but every tiny line here and there isn't going to happen. I plan to do most of this when the engine is finally glued to the firewall near the end of the build, so that something is holding the sucker so that I don't remove any more paint with my hands- or drop it again! One little feature I'm thinking of doing is this "Accumulator" which has a line that appears to go all the way to the front behind the prop, attaching to Part J24 on the top of the bell housing. If I can pry off the tank without breaking it, it seems like a nice small addition that could be fun to do. Thanks to "spartacus2000", I have some diagrams like this to work with. Unfortunately, this little tank appears to have been deleted from all the restored Hellcats I can find, no doubt because something better was created since the war. Cheers, Chuck Edited February 1, 2022 by chuck540z3 Link to comment Share on other sites More sharing options...
Oldbaldguy Posted February 1, 2022 Share Posted February 1, 2022 2 hours ago, chuck540z3 said: Thanks for that- and now a few more questions. Is the oil going behind the firewall somewhere to get cooled? Since it's right next to that big air pipe, it would seem reasonable that this is all related. Thanks in advance, Chuck Behind the firewall as in inside the fuselage behind the firewall? Not likely. The only oil behind the firewall and therefore inside the cockpit (which is immediately behind the firewall) would be the small line going to the required oil pressure gauge. Oil temp gauge was probably electric via a sending unit somewhere in the system. Oil doesn’t move around by itself; needs a mechanical pump to keep it moving and the pressure up and in a closed system doesn’t cool itself. The oil cooler requires air being rammed through it to pull the built up heat away the same as the radiator on your car. Ambient air like you have in the cockpit or fuselage isn’t sufficient, so the system needs either the pressurized air inside the cowling to force air through the cooler fins or a scoop if the cooler is remotely located for whatever reason - see Corsairs, Bearcats, some Spits, etc. The Hellcat was designed in a hurry to be built as quickly and cheaply as possible because it was desperately needed in the Pacific to counter the A6M and other Japanese planes. Strong, easy to build, minimal complicated systems, easy to work on and cheap enough that the government would buy a bazillion of them, so technology and elegance weren’t high on the list of must haves. Everything needed to keep the prop turning (save fuel) was compartmentalised in one place under the cowl ahead of the firewall because that was the easy solution and there was plenty of room. All that hot oil stays on the engine side of the firewall, the hot air venting out through a door at the bottom of the cowling or maybe under (but not inside) the forward part of the fuselage, the whole idea of a firewall being to keep things that burn separated from things you don’t want burned. Sorry. Was that even close to what you were asking? Link to comment Share on other sites More sharing options...
chuck540z3 Posted February 1, 2022 Author Share Posted February 1, 2022 Thank you sir for that well thought out description. What I'm really getting to is whether or not any of that oil moved through an actual radiator, like maybe that circular one beside it and if not, what is that for? All I see is oil coming out of the engine and getting looped around the oil tank and "Oil cooler shutter" before it goes back into the engine, which doesn't look like much in the way of cooling to me. What am I missing? Thanks, Chuck Link to comment Share on other sites More sharing options...
Oldbaldguy Posted February 1, 2022 Share Posted February 1, 2022 Sorry, I got carried away above and missed what you were asking. You know that big fat silver thing at the bottom of your motor? Fed by and connected to the chin scoop on cowling? That’s where the cooler lives. Inside there. The drawing doesn’t show it, but that’s where it is. Fresh, cold air is rammed into the scoop, down the big duct, through the cooler and then out the door in the back. The door is adjustable from the cockpit so the pilot can control the oil temp. Pretty simple once you get it figured out. Is this going to be one of those forehead slapping moments? Link to comment Share on other sites More sharing options...
JayW Posted February 1, 2022 Share Posted February 1, 2022 5 hours ago, chuck540z3 said: One little feature I'm thinking of doing is this "Accumulator" which has a line that appears to go all the way to the front behind the prop, attaching to Part J24 on the top of the bell housing. Yes that is the propeller accumulator - a "gizmo" that is pressurized with air (hence the shape), and through magic supplies the right amount of engine oil to the prop governor on the nose of the engine. I took a look at some F6F drawings, and found that the part is Hamilton Standard part number 58198, and is a government issued part (installed by Grumman). It doesn't have a Grumman part number or drawing number. The bracket assembly holding it to the engine mount does however, and it has a 3.17 inch radius mating surface to the accumulator. That tells me the accumulator is about 6.34 inch diameter, if it is to perfectly match the bracket. It also has spherical ends, except with a cap of some sorts where the line attaches. Divide for your scale, and perhaps knowing the diameter, you can guesstimate the length and any other dimensions. chuck540z3 1 Link to comment Share on other sites More sharing options...
chuck540z3 Posted February 1, 2022 Author Share Posted February 1, 2022 2 hours ago, Oldbaldguy said: Is this going to be one of those forehead slapping moments? Thank you sir and no, not at all. That's why I mentioned that it seemed beyond coincidence that the cooler canister and the big air duct would be next to each other, which is why I wondered if there was something going on behind the firewall. Well, "firewall" is inaccurate because it's well below the true firewall to the cockpit above, so I should have said "lower fuselage wall", or something like that. Hey, you're dealing with a guy who calls everything a "gizmo", because he knows squat about radial engines! Thanks to you and the info provided by others above, I have learned a lot and am also very happy I added those oil lines, because they are so prominent- and important. Cheers, Chuck williamj 1 Link to comment Share on other sites More sharing options...
scvrobeson Posted February 2, 2022 Share Posted February 2, 2022 He drops painted and assembled parts, just like us mortals! In all seriousness, excellent progress Chuck. The detailing does take it up to the next level. Matt chuck540z3 1 Link to comment Share on other sites More sharing options...
LSP_Ray Posted February 2, 2022 Share Posted February 2, 2022 Beautiful work, Chuck! chuck540z3 1 Link to comment Share on other sites More sharing options...
spartacus2000 Posted February 2, 2022 Share Posted February 2, 2022 Great work Chuck chuck540z3 1 Link to comment Share on other sites More sharing options...
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