1/18 Scale Blue Box F4U-1A Corsair Modification

[JayW]

18 hours ago, Pete Fleischmann said:

can you tell me your technique for cutting holes for access panels in the aluminum?

 

Hey Pete.  What I did on that particular panel, after first tracing the periphery onto masking tape and applying that tape to a piece of heat treated .005 inch thick aluminum sheet, was to scribe a circle onto the flat pattern.  I then formed the skin to approximately the right contour, and then dremmeled (and then filed/sanded) the material away to match the scribe line.  After the cutout was created, I created the fastener pattern.  

 

For annealed skin, dremmeling doesn't work as well, I have found.  But it cuts easier so I will just cut it out as best I can, and file/sand it to final shape. 

 

lastly, if a cutout is near the periphery of a panel, it is usually best to create the cutout before you trim the periphery -  that way you are working with a more robust piece of material. 

[Pete Fleischmann]

4 hours ago, JayW said:

 

Hey Pete.  What I did on that particular panel, after first tracing the periphery onto masking tape and applying that tape to a piece of heat treated .005 inch thick aluminum sheet, was to scribe a circle onto the flat pattern.  I then formed the skin to approximately the right contour, and then dremmeled (and then filed/sanded) the material away to match the scribe line.  After the cutout was created, I created the fastener pattern.  

 

For annealed skin, dremmeling doesn't work as well, I have found.  But it cuts easier so I will just cut it out as best I can, and file/sand it to final shape. 

 

lastly, if a cutout is near the periphery of a panel, it is usually best to create the cutout before you trim the periphery -  that way you are working with a more robust piece of material. 

Thanks Jay for the kind reply- your explanation makes perfect sense, and is super helpful!

 Thanks!!

 

looking forward to more Corsair awesomeness!!

 

cheers

Pete

[JayW]

Thanks all for the encouraging comments on the wing skinning effort.  Greatly appreciated.

 

Wing skinning continues - it is a very big project.  A 1/18 scale Corsair wing has alot of acreage, even just the center part inside the wing folds.  There is much remaining, but it is time for an interim report out.  It is also a stressful project -  not so much failing on a skin panel, but the risk of breaking something - a fear I had before I began this work.  It is heavy lifting work, requiring vigorous and frequent handling of the big fuselage/wing subassembly I have, moving it into various positions, fitting, cementing, and then burnishing down each panel often with considerable force.  Then cleanup.  And the landing gear and gear doors protruding like they do, they are just begging to be broken off.  Casualties so far:

 

  

 

 

Yup - even the fuel tank hook I just installed a week or so ago was sheared off at its fastening plane by a glancing blow of my hand.  The outboard gear doors had no chance at all.  Both are broken off at the hinge points, and will require repairs with tiny splice plates, or something similar.  And I swear - I am being as careful as I know how.  At this point - all I want to do is finish the skinning project without breaking off a landing gear strut.  This stuff you see - I can fix that.  It won't be very pretty, but I can fix it.  A broken LG strut; I don't know.  It would not go well.  This on features (the LG) I poured my heart and soul into to make them perfect.  So, fingers crossed.

 

So what am I getting for all this angst?  Some pretty cool skin panels.  Some are spectacular, some are merely better than what they cover up.  All are worthwhile.  They are just out of sequence - the root cause of the problems here.

 

Some example panel details:

 

An easy one -

 

 

A very hard one (not done at this point)- 

 

 

Not easy, but not hard -

 

 

That hard one is on the bottom, part of the LE intake box that houses air inlets for the supercharger ducts, and the oil cooler cans.  A shot of the process of burnishing it down to contour:

 

 

 

Believe me - it didn't want to to become a corner like what you see.  Hard work, perilously close to the LG strut.

 

Finished:

 

 

 

What I have done so far on the bottom:

 

 

And the top:

 

 

As readers of this string know - a concern was whether or not the skinning could be flush with the LE inlet panels.  I am proud to say that I have achieved this to my satisfaction.  It was done by scraping off surface material just behind the periphery of the LE panel, as required to make that surface approximately .005 inch underflush, to make room for the aluminum skin.  Take a look:

 

  

 

It may be hard to tell from that pic, but all seven skin panels that butt up to the LE intake panel are pretty darned flush. 

 

Corsair wing skins attach to the fuselage skins via "wing/fuselage angle's".  A thin one for the wing leading edge, and a much more beefy one for the wing structural box.  At this point I was able to fab and install the leading edge angle.  I am very pleased with this:

 

 

 

Covers up that nasty gap between wing and fuselage.  The notch you see - supposed to be there.  Provides clearance to one of the Camloc (or Dzus?) panel fasteners.

 

Next post will be more progress on the wing skinning.  The remainder of the skins forward of the main spar will be done, and hopefully the main box skins, some of which are compound curved.  I really have my hands full! 

 

Stay with me - the engine cowl and cowl flaps are on the radar.  What a challenge they will be!  Thank you for tuning in.  

 

Edited June 15, 2022 by JayW

[geedubelyer]

Utterly excellent work Jay. 

[easixpedro]

That looks amazing Jay!  Soooo much better than the kit plastic. Tis a work of art for certain. Thanks for sharing it with us--the trials and tribulations and the successes!  It's going to be epic once you lay some paint down.

[Oldbaldguy]

I dunno know, bro.  I’m pretty satisfied with the whole thing - even the broken parts.  Small price to pay for what you’re achieving overall.

[chuck540z3]

Jay,

 

I am in such awe of your skinning work and also a bit jealous, because this looks like a LOT of fun!  Picky, exacting and at sometimes frustrating work I'm sure, but fun nonetheless.  With all the other bits you've done in the background so far (that engine!), this beast is coming together splendidly and will look awesome once finished.

 

As mentioned before last December, you must airbrush this masterpiece in order to attain maximum perfection.  You MUST!  What's amazing to me and I'm sure many others, is that your painting so far was not airbrushed, because it still looks terrific, but that was for small areas like the engine and cockpit.  Painting all that beautiful aluminum skin will require a lot of paint and a lot of precision which you just can't do with rattle cans and paint brushes.  Take a few weeks off and hone your airbrush skills on mules and other objects before you paint, and you won't regret it.  To make it easier, make sure you buy and use one of the popular acrylic lacquer paints like MRP or similar.  As a matter of fact, I guarantee you will wonder why you didn't start airbrushing earlier. 

 

Cheers,

Chuck

[brahman104]

You got this Jay! Looking incredible mate!

 

Craig

[JayW]

On 6/15/2022 at 4:36 PM, chuck540z3 said:

As mentioned before last December, you must airbrush this masterpiece in order to attain maximum perfection.  You MUST!  What's amazing to me and I'm sure many others, is that your painting so far was not airbrushed, because it still looks terrific, but that was for small areas like the engine and cockpit.  Painting all that beautiful aluminum skin will require a lot of paint and a lot of precision which you just can't do with rattle cans and paint brushes.  Take a few weeks off and hone your airbrush skills on mules and other objects before you paint, and you won't regret it.  To make it easier, make sure you buy and use one of the popular acrylic lacquer paints like MRP or similar.  As a matter of fact, I guarantee you will wonder why you didn't start airbrushing earlier. 

 

Chuck - I have the same feeling I had when Peter Castle insisted I do the aluminum skinning!  Like "Oh crap - I don't want to do this!"  And then, I was glad I committed to do it, although it is some kind of labor intensive.  He really helped me along too, even sending me some litho from the UK.  I suspect the same thing would happen once I commit to going with the airbrush.  

 

I have always considered myself just a second rate modeler with a first rate ability to make a model more realistic.  I have gotten better, true, but I was happy enough with that.  Now, more and more I have first rate LSP modelers, like yourself and Peter and John Thunnus (and quite a few others too) advising me as to how to take the next steps for improvement.  It is an honor to receive that attention.  So, I will look into the airbrush.  This after purchasing six Tamiya rattle cans for the tri-color scheme (white, light blue, darker blue)!   Wonder if it is advisable to decant them....

 

As soon as I complete the center wing skinning (pretty soon now), painting will begin on the center wing/fuselage combo.  So I will first have to apply self-etching primer on all aluminum surfaces.  I have it on high authority that is a must; otherwise paint will not adhere well to the bare aluminum.  I have a recently purchased big expensive can of Rust-oleum self-etching primer for that purpose.  Do you think that stuff can be decanted and sprayed via an airbrush?  Do I need to?  If so how does one "decant" a spray can?  I was going to spray some paneling on my FW-190 mule to see how it goes on.  

[JayW]

It turns out that my right wrist and middle finger got a little worn out with all that awl pressing for hundreds of fastener heads.  I do not want to risk carpal tunnel or some such thing and/or a blistered finger.  Alot more skinning to do!  So I decided to take a break from skinning for a week or so and do something else while my wrist and finger recover.  Next post, I will report on more skinning.

 

The next project after skinning is the engine cowls and cowl flap linkage.  I don't know about you, but that is exciting to me.  That engine front section has been sitting there for literally years waiting for me to do something with it (the aft section went into the now complete engine accessories compartment, as you know). 

 

Here is a shot from the engine cowl installation drawing from Aircorps Library:

 

 

Note how the nose cowl and cowl flap ring attach to the engine cylinder heads.  Originally I planned to start with the nose cowl.  But I thought better of it and decided to instead start with the cowl flap ring.  As shown, each engine cylinder intake and exhaust lobe has a flange or tab on it specially designed to accept support structure or linkage for cowlings and cowl flaps, regardless of which airplane.   Here is a close-up of a typical attachment of the cowl flap ring to the engine cylinder head lobes for Corsair:

 

 

You see a channel section cowl flap ring, with a cowl flap linkage fixed support fitting bolted to it - it slips into the inside of the channel.  What you see is typical 18 places (two per aft cylinder).  That cowl ring is also the aft support for the all important engine cowl panels, which have the all important skull & crossbones emblem.  So VERY important that it be exactly located.

 

So my challenge was to fit that thing onto the engine with good concentricity to the centerline of the engine, and accuracy fore/aft.  To do that I made a fixture:

 

  

 

The cowl ring was made from .1 inch wide Evergreen plastic channel section.  I used the fixture to assure it is the right diameter.  Then I place the ring on the raised portion of the fixture, and drop the engine down into it (the .75 inch hole in the middle fixes the location of the engine).  Here:

 

 

 

The idea of course is to have the engine and cowl flap ring properly oriented to one another, which the fixture does hopefully well, and then somehow insert and install 18 cowl flap linkage fixed fittings and their 4 each links.  And that's the hard part.

 

Here are some of the little tiny fixed fittings, 3D printed (18 total required):

 

   

 

And here are the (ridiculously) small links (four per support):

 

 

.09 inch long, .04 inch wide (and that is too large really), with cut-off .8 mm Meng nuts.  18 x 4 = 72 required.  

 

After getting three supports done, I was able to extract the assembly from the fixture, and the cowl ring stayed in place, although very flimsy: 

 

 

See the splice?  As each support is built, using the fixture to assure proper location, the ring gets stouter and stouter.  Here is what the supports look like up close and personal (four of them):

 

 

So I have done 12 out of 18 supports so far:

 

 

Tomorrow I will do some more - it is microscopic work with magnification goggles and readers.  With all 18 supports, the ring will be very stout.

 

It's fun to work on the engine again after all this time.  Once I get the cowl flap ring completely secure, I will go back to wing skinning.  Stay tuned! 

 

 

Edited June 22, 2022 by JayW

[chuck540z3]

7 hours ago, JayW said:

This after purchasing six Tamiya rattle cans for the tri-color scheme (white, light blue, darker blue)!   Wonder if it is advisable to decant them....

 

As soon as I complete the center wing skinning (pretty soon now), painting will begin on the center wing/fuselage combo.  So I will first have to apply self-etching primer on all aluminum surfaces.  I have it on high authority that is a must; otherwise paint will not adhere well to the bare aluminum.  I have a recently purchased big expensive can of Rust-oleum self-etching primer for that purpose.  Do you think that stuff can be decanted and sprayed via an airbrush?  Do I need to?  If so how does one "decant" a spray can?  I was going to spray some paneling on my FW-190 mule to see how it goes on.  

 

Atta Boy Jay!  We all need to stretch ourselves as modelers once in awhile, otherwise our hobby becomes routine and boring.  Thankfully one of the best acrylic lacquers out there are Tamiya rattle cans, typically in the "TS" series and decanting them is super simple.  Others have different methods (and I encourage other input), so this is what I do:

 

-  Find a clean tube that's about 3/8" to 1/2" thick and cut it to about 5" long.  I'm not sure where I found mine, but I think it's plastic tubing for micro-irrigation in flower beds, etc.  Any such tubing will do, even metal.

 

-  Find a jar that you want the paint to go into, leaving about 50% for thinner.  I use Tamiya 20 ml jars or similar.

 

-  Find a place to spay the paint where you can make a bit of a mess if things get out of hand, which is now rare for me (it wasn't always so!).  A regular paint booth is perfect, because you also want to vent the fumes.

 

-  Shake the can of paint well, then using rubber gloves, spray the paint through the tube into the jar at about a 45 degree angle, using your other hand to cup the jar and prevent paint spilling and over-spray.  With the pressure drop from can to jar, you will feel the paint get very cold which is normal.

 

-  When the jar is about half full, stop spraying.  You will note that the paint will continue to bubble as gasses escape, so don't put on the lid tightly or it will explode when you open it again.  Just leave the lid on lightly for several hours until it de-gasses.

 

-  Add about 50% Tamiya Lacquer thinner (Item # 87077) and stir.  If you want, adding the thinner early helps with the de-gassing process, so you can decant paint and be ready to use it within an hour.

 

-  Add the paint to your airbrush and spray away.  Like all modellers, we all find a certain viscosity that works best for us, our particular airbrush, the humidity and the pressure that we spray the paint.  This is where you need to practice the most, to find that elusive recipe that works every time.  Once you've found it, further painting sessions are easy.

 

That aluminum skin will need a primer for sure and this is where I can't help you much, because I've never done it myself, so I would seek the help from others who have.

 

Cheers- and Good Luck!

Chuck

 

 

[dodgem37]

Bravo Jaybo!  Great detailin'!

 

Sincerely,

Mark

[KiwiZac]

Utterly inspirational, Jay. 

[Oldbaldguy]

Ha!  In all my years I never knew how cowls were attached to radial engines - the cowls on all my flat motors were attached to the airframe and the motor sort of floated inside.  Another arcane mystery solved.

[JayW]

Things are moving right along.  I am not saying I see the finish line, but I am starting to sense this long project actually will get done one day not too long from now (another 6 months or so?).  Ha - famous last words.

 

The cowl flap ring is now completely fixed to the engine aft cylinder row, supported in 18 places just like the real thing.  I will show it off to you all after completion of more details, and application of yellow ZC and dirt and weathering.  Also wing skinning continues; you will see that too pretty soon.  

 

So in parallel with wing skinning work I am starting to anticipate painting.  Thunnus, in an act of great humanity, used his home mask maker to make me some masks.  Included are the various sized white #7 masks, and the skull & crossbones that adorn the engine cowling panels.  He provided some extras, so I wanted to see how they do - namely the highly detailed skull & crossbones.  Also, I had purchased some self-etching primer some time ago to apply to aluminum skinned surfaces.  I was informed by Airscale and Easixpedro both (if memory serves), that this is required to assure paint doesn't pull off during masking, or just flake off with handling.

 

Here are some skull & crossbones results on the poor FW190 mule:

 

 

The one on the right is a Tamiya kit look-alike that John made for me, at the right scale.  I made some mistakes on it (the biggest one being failing to remove the mask portion that defines the lower jawbone teeth, but it seems promising.  It is supposed to have more prominent black teeth gaps, which did not show up well.  Those details are very small, and we are clearly at or near the limit of what masks can accomplish. 

 

The one on the left is a skull & crossbones of my own making, copying one off the web and making some modifications in PowerPoint.  John made that one for me too.  I made mistakes on it too - I unwittingly pulled off pieces of mask that were supposed to stay on.  So the flag outline is missing, as is the lower jawbone.  If one starts with white, and paints on black, one must think in the negative so to speak.  It's a brain teaser, at least for me.  At any rate, fine detail is a bit disappointing on this one too.

 

I think I can work with the masks.  I prefer the Tamiya look-alike - it looks more like the one you see in the period pics of VF-17 Jolly Rogers Corsairs.  Peter (Airscale) is also working up a set of decals for me - another act of humanitarian kindness - and it will include the skull & crossbones version that I made (the LH one above).  I think my preference is the mask, but if that plan falls flat for some reason, I will use the decal.  Or, maybe the decal will be so spectacular, I will use it instead the mask.

 

So I used the FW mule to test out the self-etching primer too.  The mule already has several practice aluminum skins on it - that is how I discovered the paint stick problems a few months ago.  So I cleaned one off, and applied the primer plus the tri-color Corsair scheme:

 

 

 

That paint isn't going anywhere!  So the self-etching primer worked.  It also sprays on quite well.  A load off my mind.

 

OK, onward and upward.  Thanks for tuning in.  

 

 

Edited June 21, 2022 by JayW