JayW

Good comments all. I have been in the both the basic configuration level design environment (PD - product development), and the detail design environment in aircraft engineering groups. Wing planforms, fold lines, gun locations (IB/OB, fore and aft), flap planforms, flap hinge lines - these items are configuration level design. The first things to nail down when designing an aircraft. These are what the most senior high ranking engineers and aerodynamicists throw over the fence to the detail designers. I do not know if this clash situation between the outboard gun and the outboard flap leading edge was discovered during configuration development, or later on in detail design. I highly suspect it was config development, alot of meetings were no doubt had with heated discussions how to avoid compromising that flap, and in the end we got what we see. They could not have liked it, and I'll bet BuAir didn't either. Oh to be a fly on the wall back then when all this was being hashed out. OBG is right - the leading edge lip of the flap at the compromised area is basically sealed to fixed structure throughout its angular travel. I did a quick layout to see if that was the case, and it is. But, there is a gaping hole on the upper surface that is 6+ inches across, and around 5 inches streamwise. It isn't hard to find pictures of that. I just do not see how upper surface flow near the transition of wing upper surface to flap upper surface, at landing speeds with flaps out, on the verge of separation under the best of circumstances (which is what you have when approaching a carrier deck and the pilot is flirting a bit with stall) - how this compromised area is going to do anything other than separate. I'm confident that a goodly percentage of that flap loses lift there as I showed in the previous post. But in the grand scheme of things, with all the other things that affect landing trim - extended gear, those nasty gun openings, the oil cooler / supercharger duct leading edge openings near the wing root, and that stall strip on the starboard wing - it's just one more thing. I'll bet its worth a couple of knots though.... I believe any aircraft with a distinguished service history has some stories to tell about its development, developments that churned the stomachs of the engineers involved. What a time to be an engineer! Oh yeah - I think on that often. In the big commercial aircraft business, we were up against contractual deadlines and delivery date guarantees. That was stressful enough. Back in the 1940's - where the enemy was destroying our air forces? With the Navy or Army breathing down your throat? Now that is pressure.

No update yet - soon. Instead an item of interest where I invite comments. As I was building the wing trailing edge devises, I noticed right off the F4U has a compromised outboard flap. A large section of its leading edge is missing: A section through the missing area: My flap doesn't have this cutout in it; it is covered up by the wing when the flap is retracted, so completely unseen. When the flap is deployed though, this missing section of flap is in full view and in the airstream. A local loss of lift results as can be seen in this view: Due to the local compromised airfoil shape, flow separation will occur on the upper surface of the deployed flap, and the separation will take on somewhat of a fan shape as I depict in blue. It appears to me that up to 25% of the lift capability of that flap is gone. In my professional employment in the airplane company, I learned much about trailing edge devise aerodynamics, especially flaps. If low speed approach and/or deck length limited takeoffs are critical, you need alot of flap to develop high lift at those low speeds, if you are limited on total wing area. The Corsair has alot of flap. You do not need a lift loss like you see above. No sir. So why is it that way? It is that way because the outboard gun butt end clashes with the flap (if not for the cutout): I circled in red where the clash would be. Note in that last picture how deep inside the wing the guns are. That's why the F4U leading edge has those zombie eyes holes in it three per side. As is typical of just about any aircraft with multiple gun arrangements in the wings, the guns are staggered so as to allow feeding of the ammunition. But what is not typical is that the gun barrels are buried deep inside the wing. The F4U's sister ship the F6F Hellcat has its -50's staggered as well, but the barrel tips are all forward of the leading. That is also true of the P-47 Thunderbolt. The P-51 has its gun tips just barely forward of the wing leading edge but there is practically no stagger. Instead the P-51 ammo chutes (some of them) are designed to run on top of one another after a fashion. None of these other contemporary American aircraft have guns that compromise the trailing edge devises like that. So why again? Why are the Corsair's guns placed so far aft? I don't know but I can postulate. The Corsair is the only aircraft among those I list to have a wing leading edge fuel tank (I show it a couple of pics above in red outline). At least the first versions. The -1D's and subsequent did not have the integral leading edge tank; instead they had the duel wing pylons which could carry large jettisonable tanks. Note the leading edge tank is just outboard of the guns. But fuel lines occupy the same bay as the gun barrels and blast tubes. I'll bet guns placed further forward like the Hellcat were incompatible in some way with that leading edge fuel tank and its system runs. Anybody know for sure? Whatever the case, that is a serious design compromise to cut a section of leading edge away from your precious flap. Lower stall speeds and take-off speeds would be had if that flap had 100% of its lift capability. If it were because of that fuel tank, how ironic it is that it went away with the -1D's..... The -1D's were saddled with a limited lift outboard flap for what amounts to no reason at all! I would remind that with flaps up, the wing is clean - that missing portion is covered. So no issue at high speed. Any Corsair experts out there care to chime in on this rather unfortunate design compromise?

John - what a convincing paint job. You may have told me before - do you sand down any rough paint edges after masking? If you do, what do you use?

Uh - NOT far from perfect. Only to the best model painter in the world (or in the top five!).

I take it you have been producing this stuff on the Saturn 2? Whatever - that is some impressive 3DP.

Moving right along, ticking things off the list - 1. Wing attach concept development, and incorporation (will not install wings until later) 2. Inboard end wing skinning 3. Represent gun camera and approach lights inside the wing, if I can. 4. Improve outboard flaps, skin with aluminum and simulated fabric, install. 5. Fab, install lower surface flap gap doors 5A. Fab and install fixed trailing edge aileron hinge fittings. 6. Paint entire wing minus ailerons (double hairspray method on aluminum leading edge panels and access doors, Navy blue on top, intermediate blue on bottom, including the great big stars and bars insignias). Also decals and weathering. 7. Miscellaneous details (tear drop ID light, fuel tank caps, fab and dry fit pitot mast, etc). 8. Prepare (including paint) and install ailerons oriented at approximately 10 deg up and down. 9. Fab and install and paint currently missing upper surface spanwise skin strips just forward of the ailerons (Too fragile to install earlier). Not all in order as you can see. I moved item 9 up - that skin strip has to be there before the wing gets painted. Lower surface flap gap doors. I think most of you know that Corsairs have flat panels just forward of the flaps on the wing lower surface, on simple hinges. These panels rotate into the wing as the flaps deploy, covering the fixed trailing edge cove and providing a fairly clean gap for airflow up and around the flap nose. I created these parts on the inboard wings; now it was time to do same for the outboard wings: There are two per flap - I added brass hinge pins for them. The other panels are fixed. Also, with those lower panels in place, I could install the last of the flap hinge fairings: That part was Rhino modelled and 3D printed. By yours truly. I like my 3D printer! Next was aileron hinge fittings: Very tedious, not very impressive as you see them - just various chunks of plastic carefully located to match the hinge fittings on the aileron itself. But next post or the one after you will see how they support the ailerons, and I think you will like it. Next was that pesky aluminum gap cover strip on the upper surface just forward of the aileron. You can see it in this full view of the wing upper surface: That view shows a wing ready for paint. Here is the lower surface just for grins: Next time you see the wings they will be in some stage of painting. The aluminum surfaces will get the double hair spray treatment on top of a clear coat (this worked pretty well on the aft fuselage). No etching primer. That way I can chip away at the leading edge like I did for the inboard wing - only not as much. The outboard wings were out of the prop wash. Also, lots of wear around the gun bays, where I will consult various pictures, and the time capsule Corsair book. I am pretty pumped about the wing progress. Stay tuned!

Man - chipping. It makes me nervous too. Your effort although not like you thought it might go, still looks pretty convincing. I have a chipping exercise in my near future as well.

Let me update my task list for the wings (crossed out items are complete): 1. Wing attach concept development, and incorporation (will not install wings until later) 2. Inboard end wing skinning 3. Represent gun camera and approach lights inside the wing, if I can. 4. Improve outboard flaps, skin with aluminum and simulated fabric, install. 5. Fab, install lower surface flap gap doors 5A. Fab and install fixed trailing edge aileron hinge fittings. 6. Paint entire wing minus ailerons (double hairspray method on aluminum leading edge panels and access doors, Navy blue on top, intermediate blue on bottom, including the great big stars and bars insignias). Also decals and weathering. 7. Miscellaneous details (tear drop ID light, fuel tank caps, fab and dry fit pitot mast, etc). 8. Prepare (including paint) and install ailerons oriented at approximately 10 deg up and down. 9. Fab and install and paint currently missing upper surface spanwise skin strips just forward of the ailerons (Too fragile to install earlier). Actually this list helps me keep my mind in the game. Note I added item 5A - "Fab and install fixed trailing edge aileron hinge fittings." OK - the gun camera. Ha!! This is the first model I have ever built where I actually made a gun camera. Why? Because the Corsair has a window in front of it in the wing leading edge, allowing it to be seen. Most other aircraft I have seen just have a small dark hole where the camera can't be seen. Lookie - First, if I did not separate the lower and upper wing halves (recall I just couldn't get them apart), how did I get the gun camera (or the approach light you saw last post) inside? By dremmeling a big hole into the inboard end of the wing: A conveniently located post is in there, where I could crudely attach the camera, and also the approach light, such that they are properly oriented. Here is the gun camera in the wing (upside down): Then the skinning could begin, including the little window: Upside down again.... See the camera in there? Oh yes. Then it was on to the outboard flaps. Here is one of them unmodified except some sanding: This flap is primarily fabric covered in real life (the other flaps are fully covered in aluminum sheet metal). Except the leading edge, and that little access door you see on top at the inboard end just behind the leading edge panel. They are aluminum. That door, no doubt, has to be the access provision for disconnecting the flap, allowing it to hang down to afford improved access to the 50 cal's. We discussed this some in a previous post and TAG provided great pictures. Here, I have treated this device like the outboard wing, rudder, and elevators - skin using .005 inch thick plastic sheet for the fabric areas, and skin the other areas in .005 aluminum. Lower surface (note - more drain holes): And upper surface with the hinged access door: An abbreviated leading edge skin awaits installation after the flap is attached to the wing. Like this: A bit of a milestone - outboard flap attachment to the wing. Again I am very happy with the look of the fabric-covered surfaces. Hope you all like it too. Once the flaps were attached (glued/epoxied) to the wings, it was time to add the outboard flap outboard hinge support: It is important to me, because that fitting provides the attach lug for the aileron balance tab control rod (that little white tab sticking out). Yup - that's actually how it is in real life. You will see what I am talking about before too long. At this location, Vought chose not to cover the dropped hinge point with a fairing, as was done at all the other flap hinge locations (save at the side of body where the flap support is actually inside the fuselage). Instead both the wing side and flap side hinge fittings are somewhat aerodynamically shaped, and left to dangle in the airstream on their own. But then, the Corsair aficionado knows all this! I tried to duplicate that. OK, it is now on to the lower surface flap gap doors, and the outboard flap inboard hinge fairing, which I 3D printed a while back. Then aileron supports. The wings are coming along folks. Stay tuned!

Man - what convincing looking exhaust stacks John. The LG are really nice, as always. About that chipping on the anti-glare panel in front of the windshield - can you tell me some time intervals? How long to let layers dry? When I began chipping on the Corsair, I studied up on it alot, and got the impression that you should not wait too long for paint layers (or the hairspray layers) to dry. What say ye? BTW - the chipping looks perfect!

Yes it is indeed good to see the B-17 back in work! And wing skinning - I can relate!! Townsville. Just Google mapped it. East coast DownUndaland. Is that it? This a beach town? Sure looks like it.

Wow - that finish is just magical. Right in your wheel house.

Last post I released a list of wing tasks to complete the wings. Here is where I am so far: 1. Wing attach concept development, and incorporation (will not install wings until later) 2. Inboard end wing skinning 3. Represent gun camera and approach lights inside the wing, if I can. 4. Improve outboard flaps, skin with aluminum and simulated fabric, install. 5. Fab, install lower surface flap gap doors 6. Paint entire wing minus ailerons (double hairspray method on aluminum leading edge panels and access doors, Navy blue on top, intermediate blue on bottom, including the great big stars and bars insignias). Also decals and weathering. 7. Miscellaneous details (tear drop ID light, fuel tank caps, fab and dry fit pitot mast, etc). 8. Prepare (including paint) and install ailerons oriented at approximately 10 deg up and down. 9. Fab and install and paint currently missing upper surface spanwise skin strips just forward of the ailerons (Too fragile to install earlier). Wing attach concept - The wings as is have little tabs on their inboard ends that engage slots in the wing center section. Great for properly locating the wings; wholly inadequate for gluing them on. I need more things to add structural strength to the join. So I got out the dremmel and butchered the ends to allow for some structure: What a mess! Two "spar" stubs that fit in matching slots I dremmeled. Wish they were longer, but the wheel bay ribs are right there not far from the join. And three pins that engage matching holes I drilled. I use the term "matching" loosely. It was hard to match them up perfectly; it is not perfect. Those features augment the already existing tabs that you should be able to see. All that, plus a heap of glue/epoxy/CA and maybe I will have strong wing joins. Hope so; not much else I can do. Then I took a shot at the approach light and its opening on the LH wing, which is part of the wing skinning. The openings were already there - one of the first things I did for the wings a couple months ago. A tricky aluminum skin was made: A crude light was glued inside the wing, a small piece of .005 inch thick clear plastic sheet added, that aluminum skin, and you get this: Hmmm - in that view you cannot see the light box. It can be seen easily though from other views. I'll take it. The toy had nothing there at all. In order to skin the inboard end of the wing with a minimum of ugly gaps, I needed to first establish the dihedral before trimming the various skin panels. I made some tools to check this angle. First, I needed something to orient the aircraft in a horizontal position: The model is simply resting on its brake drums and the new jack under the tail gear. Then I made a crude locating fixture that bears up against the wing lower surface: The outboard wings are supposed to have a 8.5 degree dihedral angle measured at the wing reference plane. That turns out to be about 10 deg measured along the lower wing surface at the main spar (because of its tapered thickness), and that is what that locating fixture reflects. That looks right to me. Comments? What I found is that the toy has less dihedral than that - probably more like 6 deg. Maybe less - hard to tell it is so floppy. This orientation with correct dihedral results in a tight fit at the join on top of the wing (almost no gap at all), and a substantial gap on the bottom. So what I intend to do is to provide extra material on my lower aluminum panels and trim to minimize or eliminate that gap. It is easier said than done. Here is the LH wing with all of the inboard skinning done. Me likes: Much of this wing fold area is fictional - 21st Century Toys (or Bluebox) did a poor job of replicating it, and I never took the time or effort to try to correct. Few will notice methinks. Those lower panels are oversized and, as I mentioned, must be trimmed to fit - a very laborious task that will involve a whole lot of handling this large unwieldy and fragile model. Already I broke a landing gear door hinge fitting - AGAIN! It would make life easier in some ways if I could just glue the wings on right now. But more must be done, and the painting would be near impossible; I would much rather finish and paint the outboard wings separately, so that is what I am going to do. Now - the RH wing needs to be brought up to snuff, including the gun camera and its opening. Then that lower panel trimming will commence. And then, next on the list is outboard flaps. Stay tuned - adventures ahead.

Effin awesome

Hey - ignoramus here. Can anyone explain how those dots work? And what is their purpose?

Boy John - I have been asleep at the wheel. Now I am caught up - such a very clean and professional job as usual, but on an unlikely subject. I sure like that engine!

I am very very pleased to show off my simulated fabric skin bays for the wings, upper and lower surfaces. They have been fully prepared, using masking and layers of primer to simulate doubler fabric, and the strips that go over the rib caps. Also a few drain hole grommets have been added to the lower panels. Upper surfaces: Lower surfaces: Drain hole grommets (lower surface): Lower ID lights and more drain hole grommets: Upper surface formation light, upper ID light base, and the hand hold plate: Don't look now, but these wings are almost entirely skinned. All that remains are the narrow skins at the wing fold (inboard ends), and the long skin strips just forward of the ailerons (upper surface), which will go on last due to they're being quite fragile. The inboard skins will be tough because they will surround the gun camera opening on one wing and the approach light on the other. But first, it is now time to figure out how I am going to firmly attach these wings to the center section. The toy came with a spindly contraption that allowed the wings to fold and at the same time was a means of attachment, along with some alignment tabs. The wing fold contraptions are long gone, the tabs remain and I will use them. So for years now I have been kicking the can down the road, not bothering to think about it much. Now is the time. I can't just glue them; that isn't robust enough. Stay tuned for the next post - I am formulating a plan for a robust attachment and will show it. For those impatient to see these wings done and installed (I am!!), here is a list of what remains, roughly in order: 1. Wing attach concept development, and incorporation (will not install wings until later) 2. Inboard end wing skinning 3. Represent gun camera and approach lights inside the wing, if I can. 4. Improve outboard flaps, skin with aluminum and simulated fabric, install. 5. Fab, install lower surface flap gap doors 6. Paint entire wing minus ailerons (double hairspray method on aluminum leading edge panels and access doors, Navy blue on top, intermediate blue on bottom, including the great big stars and bars insignias). Also decals and weathering. 7. Miscellaneous details (tear drop ID light, fuel tank caps, fab and dry fit pitot mast, etc). 8. Prepare (including paint) and install ailerons oriented at approximately 10 deg up and down. 9. Fab and install and paint currently missing upper surface spanwise skin strips just forward of the ailerons (Too fragile to install earlier). Then it will be time to attach the wings. Should be a month or six weeks or so.....

OMG Woodie - You done good! I am happy to hear you were able to limit the damages. May I ask what symptom(s) made you take action as quickly as you did?

Hey Peter - great work on the Helldiver. And, that link you provided on the Tokyo raids. It is just stunning to me the air power our carriers had in 1945. Those decks were just packed with aircraft - impressive and powerful modern aircraft! Compare to 1942. As for the B-29's - apples and oranges. How can a fleet of B-29's which take off 1000 miles away, and drop bombs from tens of thousands of feet high sometimes in cloud cover compete with a sh_t ton of Helldivers, Avengers, Corsairs, Hellcats, 50 miles off the coast, all carrying bombs and lotsa .50 rounds all of which can closely home in on targets? Pretty effective I'd say. But I would also say we needed both. Would Iwo have been easier to take if there had been more air support....

Man Thomaz - you have some collection of pics of F4U's! Thanks for the info on the plunger!

Continuing on with the fabric skin bays, I can report good progress on the upper surface. Thought I would show the process for creating a simulated fabric bay. First, masking tape is used to create pencil marks on the panel lines which will define the edges of the fabric bay. Also any features within the panel edges are marked (in this case a handhold cutout near the aft end of the tip, the round cutout for the formation light, and a large hand hole cover at the inboard end of the panel. Then that tape is transferred onto the material I will make the panel out of (.005 inch thick plastic sheet). A while back I did exactly this for the rudder and elevators. Like this: From there, I scribe what I need using the pencil marks, and cut it out with scissors: The tip has a little extra so I can wrap it around. Then I mask off already completed panels, and apply 2-part epoxy to the wing with a paint brush (much like I apply contact adhesive for aluminum panels), and lay the panel down and monkey with it as the epoxy sets up. Here, the hardest part was precisely locating the formation light holes on the skin so that they are concentric with the already drilled holes in the wing. That turned out OK. BTW - why do I use 2-part epoxy? The .005 skins are very susceptible to melting and/or deforming if I use normal styrene glue, liquid or tube, and that is also the case with the contact adhesive I use for the aluminum panels. The epoxy works great! Here are the two wings with upper surface fabric bay panels installed, along with some details: A couple of closeups: A fairly large oval access cover, and just above it a curious button that is part of the outboard flap downlock mechanism. Apparently, the outboard flap can be easily disconnected from the other two flaps inboard of it, and dropped down to gain access to the guns. Hey - I'll bet that is what that oval access opening is for. When the flap is dropped down, a shaft with a button head pops up above the wing contour, I guess to serve as an indicator that the flap is not connected, and to reconnect before prep for flight. That button will be red when the time comes for paint. How 'bout that - a blue formation light. Some will notice the ring is a bit simplified; it's just the best I could do, and way better than what was there originally. Also just forward of it is the upward ID light. It is on the RH wing only, like the three colored lower ID lights. It is a teardrop shape, and as you may have guessed, I 3D printed it with clear resin! It is dry fit; I will final install it after paint. Lastly you see a wing tip hand hold (that rectangular thing). It is spring loaded in real life, and probably aids in man-handling the aircraft on the tarmac. Next is the unenviable task of creating the fabric strips on the periphery and the ribs, just like I did on the rudder and elevators. Only this time I cannot use decal material. The big national insignia will be masked and painted at some point, and will spill onto the fabric bay. The masking process would for sure rip off any decals I would use. So instead I will use masking and spray paint primer where the strips are, and hope they show up OK under the top coat. Also, the lower surface has umpteen little circular fabric patches with little holes (they are drain holes). Next post you should see all that stuff. Take care, enjoy the summer (or, winter in the land of Oz).

BRAIDED Wire? Peter that is so effin' realistic. I mean the whole thing. I think I'd say of your many talents, your cockpit parts might be above all else.

Well by god - the cover will be translucent blue, and the bulb will be shiny white in a silver tub! Pretty cool to be part of LSP BTW. Thanks folks!

That sounds pretty reasonable! Thanks. wonder if TAG has anything to say......

The Corsair has "Formation Lights" on top of the outer wings, both sides. A picture on the drawing (I circled in red): Not to be confused with the three identification lights on the lower surface RH wing, which are the same size but colored. My model had these formation lights as blue. Yet the drawings specify a lunar white per some "NAF" spec that I do not have. That seems to be for both the lamp and the clear cover. Any pictures I can find seem to suggest they are blue. Can anyone shed some "light" on the color of these lights?

The question has come up as to fabric on the wing tip (that is what I have simulated), at least aft of the main spar. Forward of the spar is the metallic leading edge, including that portion of the tip. Here is a shot of the tip structure (minus fabric covering) from the wing "skeleton" drawing: That jagged looking part (VS-14059 wing tip assembly) is a metal former designed for fabric to attach to it. Here is a shot of the tip on the top wing assembly drawing (where the fabric covering is defined): Note the "hand sewn" callout. Cross-sections A-A, and C-C (which I have not shown) both show how fabric is attached to underlying structure. Detail "Y" shows how the fabric is attached to a rectangular cutout for a hand hold on the upper surface. So yes - the aft half of the tip is indeed fabric covered. It surprised me a bit - many aircraft have detachable metallic tips which can be more easily removed and replaced if damaged (tips do get damaged). Not so the Corsair.