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747-200 (Flaps down - Hasegawa 1/200)


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I lost a couple parts..  Was going glue on some styrene and sand them to shape for those strips that are a portion of the leading edge, but found it easier to glue back on the leading edges I cut away and work with those since they already have the correct profile/curves.   I think I tossed most of them though and will still have to resort to styrene.

 

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Will need to add some missing ends.

 

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Hi Ray, thanks!  : )   I hope I do her justice.  I'm learning a lot from this build -- it's my first airliner build (save for the abandoned Hobbycraft) so I'm kind of embarrassed you guys are seeing this.   Actually, now that I think of it there was this 747 toy I tried to convert a long time ago, but that's another story.  Anyway, I really want to see what AV O's extended flaps look like built and not in pieces the way they've been for 4 or 5 years, so I hope to see this thing to the finish.   

 

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More leading edge work

 

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That's the last among them.   Hopefully those missing ends would be easy to fix.

 

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Started doing the fairings.

 

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Taking a breather.  Standing back to admire that 747 fuselage shape.   I used Tamiya easy-sanding CA for the seams.  When I was sanding the seams down I would turn the lights off every now and then and shine a torch along the seams to make sure I got them all feathered nice and smooth.  

 

OK back to work:

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I may need to use some putty to patch up a few holes.

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The variable camber flap starts out flat and curves up as it extends.   And it has that curved nose at the bottom that is not visible when the flap retracts.  

 

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I'm going to attempt to get that curvature for a fully-extended mid-wing Krueger flap.   I think this only applies to the mid-wing one?

 

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Whittled one out of styrene.   I need it hollowed out for the linkages, though, so I'll need to vacuform it.

 

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Initially I thought about laying this flat on the vacuformer but then I thought the front curvature won't be captured.

 

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So I propped them up on a jig.  Made two flaps -- for port and starboard.

 

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I'm not sure if this will work at all, but it's driving me crazy -- really need to find out  : )

 

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If it works I can cut it up and extract the portions I need.   Then I can maybe transplant the linkages.

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Thanks, Graham! : )   

 

A little slow-going but getting some stuff done:

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Had to thin down these areas.

 

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Some of the rods kept breaking off so I drilled out some holes for some wires and had to use some styrene strips for the aft flap.  I had to notch the flap a little to connect  the styrene strips.   I may have to use a little filler later.

 

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Really appreciate the help I'm getting from you, guys.  Thanks!   

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Posted (edited)

Had to make some modifications to the way I was attaching the aft flap.  Looking at reference pics there should be 4 links  (so inboard would have 3 links in front and 4 in the back;  outboard has 4 for both front and back).   And there should be more overlap for the aft flap -- the landing pics I see show a single sillhouette for the mid and aft flaps.

 

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For the front I still used wire but for the back I had to use 0.4x0.5mm styrene but sanded down a bit more.  That seemed to be the easiest way to be able to attach the aft flap and depict the overlap and angle.

 

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And it still makes the rear linkages visible at certain angles, too, like I see in some pics. 

 

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I was working on the last trailing edge flap assembly and was trying to straighten out the mid-flap by bending it without heating it first and it snapped in two, so I had to fashion one in styrene.   I think I'm actually becoming good at sanding down styrene strips into an airfoil shape, lol : )

 

I actually have a question -- do straightened-out warped resin parts stay straight?   Or would they actually return to their warped shape later on?   Anyway, this styrene piece should hold its shape well.  

 

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Done with the trailing edge flaps, yipee!   : )    Now I'll have to go back to the Krueger flaps, ulp!  :  (

 

Edited by crackerjazz
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Posted (edited)

I've been mulling over whether to scratchbuild more linkages from stryene strips to depict the spacing in the pics.  Then I thought about printing them.   I'm not sure if they will print at all at this scale.  The linkages look too thin and fragile.  

 

  

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Edited by crackerjazz
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CJ,

 

I have a full flap set for the 1/100 scale 747. I also have the same set in 1/144. Both came out awesome, so hopefully yours work in 1/200.

 

Tracy

Edited by Vidar_710
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Thanks, Tracy!  : )       

 

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I had to close the loop at the top or the "horns" can break off when printing with nothing to hold them down.

 

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Will also be trying out having a strip at the edge that I could saw or break off because I've had issues with rod supports causing tent-like ridges that are harder to sand down and level.  This way the supports can connect to the strip instead of directly to the part.   Not sure if the idea will fly but I'll give it a whirl.     I may have to make that strip a bit more narrow.

 

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I moved the strip to the very edge. 

 

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I imagine this will be a nightmare to print but will see how it goes.   

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Posted (edited)

Hi Dutch, thanks!   : )

 

I'm printing this as I type.  Really not sure if the thin walls will survive the printing process, but if it goes well maybe I can add more details and even add the panel lines.

 

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I figured I can do without the upper strip so I removed it -- we'll see how it goes.

 

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I was going to include the bobtail of the A-4 Skyhawk droptank to make better use of the build plate space but was too excited I just poured the resin and printed away.  I'll do the bobtail later.

 

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Edited by crackerjazz
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Posted (edited)

It worked!  : )  I printed it at 0.01mm layer height.  The walls survived and linkage details were nicely captured. 

 

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Will cure it under UV and see if I can cut off the support rods without damaging the linkages.   

 

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Posted (edited)

I made a mistake on the length and had to cut one end.  Will need to modify the 3d model, but it's great to see what's possible. 

 

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Edited by crackerjazz
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Posted (edited)

Thanks!   This was really only possible through AV-O's help and that doc you sent to understand what's going on so thanks, guys!

 

Experimenting with panel lines on the mid-wing Krueger flaps to find out what the minimum width should be for them to stay visible when printed.

 

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Adjusting hinge spacing on the outboard Krueger flaps:

 

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Re-shaped the bottom strip to make it easier to break off.  Theoretically it should work but in reality I see resin collects at the seam and solidifies.

 

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The cones are Skyhawk fuel tank bobtails.   I wanted to make use of all available space because it takes the same amount of time to print all these as printing just one pair of flaps.

 

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I still haven't found a way to really clean them  other than the IPA bath.   What I really want to do is scrub them with a toothbrush after peeling them off the build plate but the resin is still kind of soft until UV-cured so it's not really possible to do that.

 

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I tried to remove the supports before curing but the thin hinges are still soft and flimsy so I'll have to remove the supports after.  Also, I notice a 6-minute curing time makes them brittle so I set the it to just 4 minutes.  We'll see how the support removal turns out tomorrow.

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And this is 1/200 scale?  Amazing fidelity of detail.  You are using resin, not plastic?  Hmm. my son has a 3D printer and he mostly uses nylon for making parts for his work; but other than storing the spools in a heated drying container, he doesn't have to use a UV light or wait for a cure time.  I would be interested to learn more about the process.

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Posted (edited)

Hi Dutch, yeah, 1/200 - crazy, right?  I printed these with a .01mm (10-micron) layer height on an Elegoo Mars 3.  Your son uses the safe kind of printers called FDM that work like a glue gun to deposit melted plastic in layers but you're at the mercy of nozzle size.  These SLA printers are a little more hazardous (you need to be careful and keep the photo-sensitive resin from touching your skin or getting into your eyes), but they are nozzle-free and use a light source to build up the layers.    They come in different resolutions -- 2K, 4K, 8K.    I don't know much about the details of how they really work but I guess they're analogous to TV screen resolutions : )      I'm using the 4K one.   And there's an even better printer technology coming out called DLP that uses a little projector to work its magic.   It's used in the industry but is soon making its way to homes.   Anycubic has released theirs and I believe Elegoo is following suit.  

 

I don't know if you notice but even the boltheads are visible:

 

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Posted (edited)

Glad I printed extra ones because the supports were a bit of a pain to remove and the linkages break off if you snip off the supports the wrong way.  By the third set I've developed a system of removing them in a sequence where nothing breaks.    The curved edge was still difficult to cut, though.   That area didn't come out as modelled in 3D, maybe because it's on the far side (facing the bed).   I read the side facing the LCD always turns out the smoothest and most detailed. The extra strip that I was hoping would easily break off didn't do it's job and it looks like resin just pooled in that area.    I had to make a cut along that edge very carefully and had to do a fair bit of sanding to bring out the curvature.  

 

Variable camber flaps test-fitted.   I read only the inboard ones are the Krueger flaps.  But I guess they're all loosely referred to as Krueger flaps?

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Posted (edited)

I have a little problem with the resin -- there's some warpage. I'm going to try the gray eco resin and see if I'll have the same issues. Also need to experiment on other printing orientations to eliminate the need for cutting and sanding  along the curved edge.  In the meantime I wanted to see how the landing gear struts would fare 3d-printed.   Not sure if 3d-printed legs can support the model but since this is an in-flight build I might be able to get away with it.  Starting on the nose gear:

 

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Thanks, Dutch!  There's a great software called Fusion 360 that is very capable and is free for hobbyists.   I use Solidworks but I'm still having a hard time with an area called surfacing for doing organic shapes  and complex curves such as car bodies or aircraft fuselage shapes or even curvy boomboxes.  I mean it does have functions to create those shapes but they're not as easy to use as Rhino or Fusion 360 which can pull on surfaces I believe and create complex surface curvatures easily.   You may have the advantage of learning Fusion 360 without the hindrance of knowing functions in other softwares such as Solidworks --  I get confused cause I already know one and I kind of look for those functions in the other.   It's easier to start off with one knowing nothing else.   If you want you can install Fusion 360 and we can learn it together -- I do want to learn it again.    I can send you great study links and we can do it step by step, say an hour a week.  You'll be amazed at what you can do in just a couple of weeks.   

 

And as far as 3D printers, it's the perfect time to scout for an SLA one.   With today's printer resolutions, layer lines are practically a thing of the past.   I can also help you out with modelling or printing parts you need -- I like the practice -- as long as they don't have complex curves : )

 

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Corrected the shape of the face of the box.  Not sure why it's shaped that way -- maybe so that the taxi lights tilt downward slightly?

 

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I don't know if the steering piston rods will print -- crossing my fingers.   They're 0.26mm in diameter.   

 

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The indentations on the torque links should be deeper but I need to be careful not to make the walls too thin and unprintable.   

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