JayW

Craig - didn't know you had a 3DP machine. This one has dual rails and is known for being plenty stiff in the z direction. From what I can gather, my support arrangement (just fine on one edge, too few on the other), might have introduced some breathing of some kind. I hate supports and the acne scars that result, so I have been undersupporting to a fault sometimes. My next try will have much better support arrangement. Also perhaps go to .05 mm layer thickness (currently at .03 mm), perhaps drop down the exposure time a bit, and increase the lift distance (possible that the last layer is not poppiing off the FEP?). There is an Elegoo Saturn FB group I joined where I am getting suggestions. We'll see.

OK - the wing skinning in aluminum is nearly complete, save for the narrow panels adjacent to the wing fold. Those will be one of the last things I do for the wings prior to installation onto the fuselage. This skinning work is going to culminate in the simulated fabric skinning - a real challenge. The other tip light is done (blue/green lamp): It'll have to do..... And the skinned wings: Very soon those ugly dremmel holes will disappear. Recall that is where the rocket mounts were. Some details of panels near the guns: Meanwhile, I got involved in a little side project with the clear 3D print resin: That is a Rhino model I created of a P-51D "California 2" canopy glass. P-51D's had several kinds of canopies; this one was the most common. My next project, should I live so long, is going to be another 1/18 scale P-51, either a -D or a -B with a Malcolm hood. I wanted to see how this thing does in clear 3D print resin, so I created a "prototype canopy" (not a production part but a test part). Here is the Slicer software model with supports: About 16 hours later, I got this: 16 hours print time because of its fairly upright orientation which made for some 3000+ layers of .03mm each, and each layer cooked for about 9 seconds. Double that to account for the lifting and the retracting process, and you get about that. Not a great part. For reasons not yet clear to me, I got some kind of rippling effect. Also some of the details didn't come out very crisp. I did some careful but heavy sanding on those ripples, gave it a coat of Tamiya clear lacquer, and got this: Well, it's a test part. But I think I can get there with this process. More to learn.... I joined a FB page for 3D printer enthusiasts with Elegoo printers. There is lots of expertise there, and I have received pointers on what to do next to improve the part. This is as opposed to creating a buck and having one vac-formed. Anyway, I digressed hugely! No more P-51 stuff until I finish this beast! Next post you should see some of that simulated fabric (.005 inch thick plastic) and all that entails. Take care y-all.

Will be VERY interested in how the transparencies work out Peter. As for the rest - beautiful. You are going to have a truly unique model here.

During my long career at the airplane company, I learned that "clad" aluminum sheet ("alclad") is used on aircraft skins where the intent is to have an unpainted layer of corrosion protection. "Clad" aluminum sheet has a very thin coat of commercially pure aluminum (maybe one thousandth or two of an inch) over the aluminum alloy sheet, included in the milling process. Pure aluminum is less subject to corrosion than alloyed aluminum, but has no significant structural strength like the alloyed stuff does. And a clad skin can be polished whereas a non-clad ("bare") aluminum skin cannot, at least not to a mirror finish like what we see here. So I would bet the house on those skins being "alclad". During the war years, I am pretty sure that largely unpainted aircraft (we quit painting many of them later during WW2)had clad skins, but the factories didn't bother to polish the skin. So no mirror finish. Personally, I would rather the skins of resto's not be polished. It's really fancy, but not authentic.

You can say that again Thomaz.

Model making outside with a glass of wine. That I have not seen. The Stirling is really looking like a Stirling. Wonderful project!

Did not know that. Comparing a torpedo bomber to a dive bomber. One skimming along the surface, another screaming down from above. I have not heard of a fleet action where Dauntless (dive Bomber) losses were that bad, nor Avengers (torpedo bomber). Did all those types have their dark days?

Really interesting project Peter. Ready to learn a little about the Helldiver.

Ah! So I too have been making decals with laserjet printer and teh baremetalfoil decal sheet. But have used Testors decal bonder up to this point. Not impressed. Never have been. Is lacquer clear the secret? BTW - a very interesting project!

Yeah good question. If I use the harder stuff (e.g. heat treated), especially the litho plate that Airscale uses, then it is hard enough so that any underlying detail will generally not show through. But if I use the soft annealed stuff (necessary for compound curvature), then it shows anything under it, including paint strokes of the glue if the glue is too thick. When using annealed material I have to fill in any panel lines that I do not intend to match.

Thomaz - don't look too closely; it has inaccuracies. On the real airplane the periphery screw holes (countersunk for flush-head screws) go right through the plexiglass, and the edges are not covered by a strip as one might expect. I could not duplicate that! But at least the covers are clear now.

Well you have waited this long, what's another few months? I am so antsy about getting it finished. Like mile 11 in a half marathon (have done a few of those although years ago). You just want it done. But I must keep form and not get too impatient. Can't get sloppy now. BTW - once the wings are done, there are still tasks remaining - mostly little stuff except the rigging of the MHF cables which will be challenging.

What a great picture!! I wish I had done better on that housing. But I must be satisfied; what I have is worlds better than what was there originally. As for the Bearcat - if you had a digital definition of the tip light, I could take a shot at producing them for you. Let me know if interested.

Yeah me too! Cool factor is sky high Peter.

If you thought I was slowing down on the wings, you would be right. Life, and summer, have conspired once again to put my hobby on the back burner at least some days. Can be frustrating, but it's OK I keep trying to remind myself... OK - I have some cool progress to show you nevertheless. First, wing skinning continues. There is alot of acreage on the wings, and many of the panels have complexities, so the process takes time. Here are new panels on the upper wings above the guns. Not finished but pretty far along: An individual panel ready for installation: The oblong holes are where latches will be. On the wings: The Corsair aficionado will recognize the ammo box covers (done on the RH wing, not yet on the left), and the large hinged access doors, and some other various assundry panels. Also the leading edge tip panels are on now: Hoorah! Sierra Hotel! Tricky because they required more of that burnishing and sanding and ball-peen hammering. Now what about those tip lights? This is what I really want to tell you about. The toy has tip lights like so: Typical. There are two things wrong here - one, the real light covers are clear; only the bulb itself is colored (red for port, green for starboard). And two - the light does not have a 90 deg square corner; it is 98 deg open. Here are some pictures of the real light, compliments of Thomaz: Now, I am not going to be able to 100% accurately duplicate those. But I can come pretty close. Now it has come to my attention that there are some pretty good clear resins out there in which to 3D print clear parts. WOW - how intriguing is that? So with that in mind I ordered some recommended resin from Amazon, and as I waited for it I got to work making some grey resin test parts, designed in Rhino of course. To one, test how well I approximated the contour, and two, to help carve out that 98 deg corner angle on the wings: Two sets. Note they are hollow - 0.025 inch thick. Man do I love my 3D printer. These came out like perfect. Here is the fit to the wing after fiddling with the cutout: Contour matched up fairly well. Note the 98 deg corner.... Now, to make some clear parts just like the grey ones, and make some stuff for the insides (the bulbs, etc). Here is my first try with the clear resin: Ugh. Compare with the grey resin part on the left. I was warned that the clear stuff needs a longer exposure time for each layer, which I did. But see how the shallow-angled edge is deformed and smeared. Also the wall thickness (should be .025 inch) is increased along the curved periphery. This indicates, I believe, that the shallow-angled overhangs were sagging a bit after each layer was cooked on. I cannot use that part - tried, but it is just too deformed. So I modified the orientation of the part to lessen the overhangs, and redesigned the support stilts and got this: The new part is on the right (deformed part on the left). Not perfect; I have some more to learn about this clear resin. But I can work with that part. Here it is with some sanding and polishing with very fine sand paper, and cloth. Plus a coat of clear gloss lacquer: What you see there is a welcome alternative to a vac-formed part. Am I stoked about that? Am thinking P-51 canopy. Here I show it installed onto the tip using CA: Given my skills, I do not think I can improve on that. Now to do same to the other wing (with a blue/green light). Then more aluminum skinning. For those of you interested in what remains on the wings after the aluminum skinning is done, here is a list: 1. Devise a robust wing attachment scheme (am currently thinking multiple shear pins). 2. The extensive 0.005 inch thick plastic skins that simulate the fabric covered surfaces (like I did for the tail). 3. The remaining lights (two ID lights, two formation lights, and an "upward" tear-drop shaped ID) plus their retainer strips and sub-structure. 4. Install the OB flaps. 5. Install the lower surface flap gap doors. 6. Install the already 3D printed ailerons, plus the tabs and tab control rods. 7. Fabricate the pitot mast. 8. Paint. That ought to take me all summer. But man - what a milestone it will be to attach the wings. Stay tuned for adventures ahead!

Following. And thanks for the book reco - it sounds great! Whatcha going to do about the engine?

Peter - that is indeed a war horse. I read the history of her that you posted on the build thread. Yes - he should be very pleased!

I have made some progress on wing leading edge skinning. Most of it has been straight forward with single curvature, so I can use the more robust heat treated aluminum sheet. But just before the tip is this little tuffy: So out comes the annealed stuff, and the ball peen hammer and popsickle sticks. No problem. It awaits the sticky stuff. Here is the leading edge basically complete on the starboard wing, with fuel tank drain fittings, stall strip, and the forward most identification light (colored): Fuel drain fittings and stall strip: Early Corsairs (the birdcage and -1A's) had a "wet wing" - an integral tank in each outboard wing leading edge. Hence the drain fittings. The -1D's got wing pylons where big jettisonable fuel tanks could be mounted, in addition to centerline mount that was there already. So the wing leading edge tanks were discontinued at that point. Starboard stall strip: That thing, on the real aircraft, is a block of shaped wood, basically glued on and then covered with a layer of doped fabric. It is only on the starboard wing, and is there to counteract a tendency of the port wing to stall more quickly than the starboard wing when speeds are near stall (perhaps with power applied?), causing an uncontrollable spin. This strip makes the starboard wing stall more coincident with the port wing. Today I 3D printed the little tubs for the ID lights and formation lights, which I am replacing totally: "Build it and they will come". Glad I got this 3D printer. Here is the first reworked ID light, where I used one of those 3D printed tubs, an aluminum ring, and a round piece of .005 inch thick clear plastic, painted clear red on the inside: A little rough; needs some clean-up. I am just not in love with annealed sheet for skinning. The rivet marks are exaggerated and hard to burnish out completely. Same thing on other annealed panels on the center wing and fuselage, some will recall. But final painting and weathering hides it quite well. So no worries mate. Aft of the skinned leading edge will be the "fabric covered" area, where I will use .005 inch thick plastic sheet just like I did with the tail feathers. Next post the port wing leading edge will be done, and.....not sure what I will do next. The list is still pretty long. Maybe the fabric areas. Ta ta all! Thanks for looking in.

With airbrush? If so, how much did you thin it down?

Beautiful John - man you are flying through these builds. I must finish mine, and soon. I am losing touch....

Pat - do you know what resin you used to print the forms? I understand many resins do not do well in heat, and I suppose the forming process can get them kinda hot? So you have a vac form?

Yeah we are going to see more of it I think. However it does not lend itself to mass production (yet). Closest I could get to that would be to hit the "duplicate" button and fill up my work space as much as it will hold, then print. Same amount of time, only more resin. And, it's not like this aileron is the first 3DP part on my F4U. It is chalk full of 3DP parts already! The entire landing gear main and tail, including tires and wheels, are 3D printed if you will recall. A bunch of other stuff too. This is just the first 3DP part that I have done myself. It may be the last for the F4U - it is in the final stretch. Hah! Well send me the resin bottle Mike, and let's see what we can do! Seriously - I would love to see a 3D printed windshield, or how about a bubble canopy for a P-51? My next project, should I live so long, is a 100% dimensionally accurate P-51D (or possibly a -B/C with a Malcolm hood). One of the biggest challenges will be the transparencies. My current thinking is to 3D print the molds, and then have some kind soul vac form a set or two for me. But how cool would it be to simply 3D print one. I just don't know how clear it would be - depositing one layer upon another like a sedimentary rock formation. Also, it might need to be thicker than a vac-form part. I would want it to be fairly thin, so it fits up to frames more accurately. It will probably be the year 2050 before I get around to all that - the world will be a mad max hell by then!

Says TAG. Well here it is: This is the Elegoo Saturn 2 resin printer. It is "last years model" - an updated version is here, but sold out. This'll do! It is fairly large as resin 3D printers go, meaning it will print larger things. That brown bottle there is liquid resin - nasty stuff. But subject it to UV light, and it turns solid, the whole idea behind 3D printing. The cover is red - a cover that keeps out UV light - a must. There are many kinds of resins - some more pliable and less brittle, some stiffer, some metal infused, etc etc. There are also different colors, even clear. This is a standard resin, color grey. I will dedicate this post to how my initial experience went, being a total newbie. Apologies to the folks who already know about 3D printing. First order of business was to level the "build plate" - a heavy devise that attaches to the tower of the machine and has a large flat plate in which the model attaches to as it is being built up layer by layer. It will be in evidence below. Next was to tweak the machine settings, like exposure time, lift speeds, a myriad of other variables. I left everything to default, until I know more. Then to print off a test part, the file of which was on the thumb drive included with the machine: "Rooks". They came out just about spot on. Took about 3 hours or so. To produce those, first they must be printed off. This gives you a part (or in this case two parts) stuck to the build plate, partially cured, and wet with dripping resin. Next is to give them a bath in isopropyl alcohol to get the liquid resin off. Then to post-cure under UV light. I purchased a little unit to do those last two steps. Next was to try my hand at doing my own parts, namely the ailerons and tabs. First was to convert Rhino files into ".stl" files, short for "stereolithography". These are basically "dumb solids" that are merely shaped volumes (as I understand it) that are readable by printing machines. Here are the .stl files for printing (you have seen the Rhino files already): Aileron LH - Aileron RH - Balance tab - Trim tab - From there, these files are uploaded into a "slicer" software package. It is this software where the parts are oriented onto a base, and support columns added as necessary to deal with overhangs and severely sloped surfaces - details that pose difficulties for layer printing to take place. Also this is where the "slicing" takes place - where the individual layers are defined for the machine to work with. Here is a screenshot of my project in "Chitubox", the slicing software package provided for free with the machine (it is on the thumb drive): Note the base for each part, and the support columns. There is an automatic feature that produces the support configuration once the user orients the parts as he wishes. There is some science in the orientation of the parts, which I will not get into, as I am not very good at it yet. The auto-feature however is not all that trustworthy, and further working of the supports is usually required. I have watched hours of you-tubes on this, and I will learn more as I do more. Once saved (it saves as a ".ctb" file, short for "chitubox" file) onto the thumb drive, plug it into the machine, select the project file you want to print, and press print. Here is what I got after 9+ hours: About 2400 layers, each taking several seconds to cook, each layer being 0.03 millimeters thick. It is the number of layers, mostly, that dictate how long a job will take. Note the tub of liquid resin - that tub has a clear bottom that UV light from an internal lamp shines through. The machine can shield that light to expose only what a layer cross-section of the parts is. Note also the build plate - the large surface that the parts are attached to, upside down. That build plate varies its height (the "z" axis) via that big screw and the two tall slider columns. The slicer program defines the vertical position of the build plate, layer by layer. It starts out completely buried underneath the resin, moves up a layer at a time, stops to let the exposure take place, moves up again, and nine plus hour later it is at about the height you see. Combine that vertical movement and the UV light exposure for each layer, and you get a 3D printed part. That was a victory of sorts - no fails. A fail is when a part detaches itself from the supports or the build plate, falling into the liquid resin. The machine doesn't know this occurs, and continues on trying to print. This can result in the build plate dropping down and smashing into the detached piece, causing damage to the tub. It's a bad thing and something I wish to avoid always. A big cause of such a fail is insufficient number or size of supports, and/or poor placement of supports. So supports are uber-important. From there it was off to the cleaning/curing station. I have no pics of that. Then, as I have so many times in the past, detaching the part from its supports and trimming and filing as necessary. Here: OK - Mostly good. No fails, and the fidelity is just awesome. No layered effect, lots of fine detail. However, there are lots of pock marks where the supports were attached (you can see some of them in that first pic). Nothing new, but I think I can tweak the Chitubox support settings to make them less ugly (smaller contact area, less deep). More serious though - the RH aileron has a slightly misshapened area at its inboard end. Inspection of the Chitubox model tells me that area was insufficiently supported. So I created a rev "a" with a couple more supports, and a few other aforementioned little tweaks, and I am doing the ailerons over again. The tabs are perfect already. I am going to get better with this 3D printing - this was my initial attempt. It's very exciting. Meanwhile work continues on skinning the wing leading edges. Next post you will see the results of all that, plus the second try at those ailerons. Stay tuned!

Really nice Peter - new territory for sure!

And that is the new bar for P-47 models. Let's see if anyone can top it. I don't see how - this is darn near perfect.