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

[easixpedro]

Oh my, that's looking wonderful!  Excited to see everything mated together!  You're presenting a master class on how to turn a toy into a master piece!  I keep finding myself scrolling for these kits on the ol' FB marketplace...

[JayW]

3 hours ago, easixpedro said:

You're presenting a master class on how to turn a toy into a master piece!  I keep finding myself scrolling for these kits on the ol' FB marketplace...

 

You no doubt noticed how they bring quite a price!  I can still recall that idea quite a few years ago.  First time I saw a 1/18 scale Mustang by 21st Century Toys.  Was too alluring to ignore - a toy that was fairly close to realistic,  and doing what one can to make it much more realistic taking advantage of the large scale, just for fun.  What turned out was this (at the time) knock-em dead P-51 "Miss Velma" that looked better than I had dreamed, and in many ways rivalling any P-51 build at any scale at the time, at least in my opinion.  Since then of course Tamiya came in, in 1/32, and kind of blew it out of the water.   And also since then I have become so much more involved in LSP, and have seen some of the miracles that are chronicled here every day it seems.   So now, each time I do one of these things, the ante is upped, the expectations grow.  To the point where a 100% scratch build like Airscale does routinely is the end game, instead of reworking some existing platform.  It still makes me chuckle that he purchased a 1/18 scale P-40 and ended up not using any of it on his current build!   Too much error to fix.  Alas - I have done the same thing.  I laid down about $300 nearly a year ago for a replacement 21CT P-51 to replace the obsolete Miss Velma, only to realize that I probably won't be satisfied with it, and instead will attempt a 100% scratch build.   Should I live so long. 

 

Miss Velma:

 

Edited February 24, 2023 by JayW

[easixpedro]

It's a struggle to stop those thoughts.  I keep imagining a 1/24th SB2C or perhaps an A-4. Mostly because I'm a glutton for punishment. It's a case of my eyes are bigger than my stomach and my brain is in overdrive at times. And then I look at my miniscule stash of like 5 kits and think I'd better get building so I can get after these dream projects!

[JayW]

Some more blow-by-blow coverage of skinning of the tail, aft fuselage, and fillet fairings - last post I had the fillet fairings licked except the RH side.  So relieved!    Well that's done now, without incident.   Next is skinning the h/stab planks.  They have a long leading edge panel, a long upper and lower main panel, and a tip panel.  The tip panel is going to wait a good long time, as it will be subject to damage.  But the leading edge and main panels are front and center now.  

 

The leading edge - man what a PITA!!  I tried bending a piece of heat treated litho around the tight radiused leading edge, and it was immediately apparent that the soft annealed stuff was going to be required.  Here is a finished panel ready to be glued on:

 

 

Bonding it in place was a chore for some reason, but I won the wrestling match and got it down.  There are a few dents and imperfections - but I have to say these leading edges took a terrible beating in real life, and those imperfections will fit right in with the weathering down the road. 

 

I won't describe the main panel (lower LH side) because it was straight forward, and made of heat treated litho - much easier to work with and no forming required.  I will say it took half the day to make it though - lots of fine trimming to get it to match the already installed leading edge panel, and the already installed fillet fairing.  And many many fasteners.  

 

Take a look at both panels:

 

 

 

 

That last pic shows the rather complicated inboard aft end of the panel, where a slot is provided for access to the inboard elevator hinge.  Now it is evident what that strange tab is for on the fillet fairing.... The main panel overhangs the models trailing edge a bit - it fixes an inaccuracy.  But it is fragile (it can bend) and I will have to protect it somehow.

 

OK - the leading edge panels are both there (LH and RH).  And you just saw the first of four main panels.  Two have the round access doors (five each).  So next step is making those three panels.  Gonna take a while.  Take care and I will post again ASAP. 

Edited February 25, 2023 by JayW

[brahman104]

Jay,

 

This is just an absolute pleasure to watch! I'm so impressed with everything you're doing here, especially the myriad of access panels you've fitted. The uniformity of gap around each panel is difficult to achieve on 1:1 scale, let alone what you're doing here! 

 

Bravo Sir. I'm still very much living vicariously off your updates while the B-17 plods its way across the Tasman (hopefully) in one piece!

 

Craig

[JayW]

14 hours ago, brahman104 said:

I'm still very much living vicariously off your updates while the B-17 plods its way across the Tasman (hopefully) in one piece!

I miss your updates!  You are one of the aluminum skinning maestro's!  

[Greif8]

Watching your build is better than watching TV Jay.  Not only is it a real pleasure to follow it is educational as well.

 

Ernest

[airscale]

fantasic work Jay!

 

what has been as enjoyable as watching this build, has been watching you conquer what you percieved as a skills gap. I know for months you were fretting about skinning this area and you have done an amazing job on it as I always knew you would

 

stunning build

 

Peter

[JayW]

3 hours ago, airscale said:

I know for months you were fretting about skinning this area

 

Sure was!  And it did go better than feared.  The aft crown panel on the turtledeck was a disappointment though.  Was wondering what you thought of that (excessive compound curvature).  How do you think you would have tackled it?    

[JayW]

So my hand and wrist and forearm are getting sore again.  From pressing hundreds of fastener head marks into skin panels.  Last this occurred was on the forward fuselage and center wing panels many moons ago, and I had to do another project in parallel (where skinning was not involved).  Will have to do same now, and I think it should be the pilot's seat and support structure.  After all - it's on the horizon!!  It gets installed along with the forward/mid fuselage join, also on the horizon!   I could also do further work on the sliding canopy, which really needs it.  

 

Meanwhile, skinning - I finished up the horizontal stab main skin panels.  The piece de resistance are the panels with the five round access doors.  Here is a little aluminum wafer that is one of the ten access doors I fabricated from litho:

 

    

 

Yes, there are count em' five access doors per h/stab, shown here on the far side of the end item unit:

 

 

 

The door assembly drawing:

 

 

Comes on or off with one fastener.  The Corsair tail is full of these 4 1/2 inch diameter doors.  In some cases they actually provide access to something, like a tab mechanism.  On other cases, like here, there appears to be nothing in which to access.  So, I am guessing they provide a way to close out a rivetted bay without having to use blind fasteners.  

 

Anyway - the finished panel detail, ready for installation, sitting on the saw horses in my 1/18 scale shop:

 

 

Hee-hee!  Sorry, I just love my saw horses.  The holes were a bit of a challenge.  They are .25 inch diameter - you just don't go firing up the high speed drill and drill those holes in 0.005 inch thick aluminum.  A good way to mangle a panel in an instant.  Instead I punched 4.5 mm holes using the RP Toolz large punch & die set which I spent lotsa money on, and that is the largest punch I have.  That got me to .175 inch diameter.  From there I used reamer tools to gradually and carefully bring the holes up to .25 inch dia.  Worked great!     

 

Installed:

 

 

 

All that remains for the h/stab planks is the tip skinning, which is not going to be a problem, and will not happen for a while - at least not until I finish skinning the mid fuselage.  I have declared victory on the h/stabs.  Was fun.

 

Then it was on to continuation of skinning the mid fuselage proper (mid fuselage being the section between the forward end of the tail wheel bay and the aft end of the cockpit).   Just a couple of days ago, look what comes across my FB feed, from Vulture's Row Aviation: 

 

 

 

 

That panel outlined in red is the very one I am posting on in this post.  How 'bout that....

 

I was hoping this panel would lay down well (Vulture's Row mechanics had to wrestle with it apparently).  Well, so did I!  Fabricating it (from heat treated litho) was easy enough.  It's just large, and has hundreds of fasteners.  Thank goodness most fastening on this panel is spot welding which I am not trying to depict.  Otherwise the fastener count would absolutely soar.   Here is the LH panel:

 

 

Typical of a large panel with a slight compound curvature, it lays down except the last corner or edge, which doesn't want to lay down, and when you force it, it wrinkles or pooches.  Here:

 

 

Recognize that?  There are several locations on this Corsair where this has occurred.  And it's getting old.  When I dry fitted the panel it looked like it would lay down.  But it didn't in the end.  So no warning really.  I think I might use annealed sheet for the RH panel and see if it does better.  I am getting deja vue though - I went through exactly this on the forward fuselage panels directly underneath the cockpit, and the annealed panel didn't do  much better than the heat treated one.  Gonna try anyway I think....  

 

Take care!

 

 

 

 

 

Edited March 1, 2023 by JayW

[Oldbaldguy]

Are you making patterns from masking tape for these panels?  If so, are the masking tape patterns showing the same issues?

[LSP_Kevin]

Exacting work, Jay - and it seems, frustrating work also. What's the difference between 'heat treating' and annealing? I thought they were the same thing!

 

Kev

[JayW]

3 hours ago, Oldbaldguy said:

Are you making patterns from masking tape for these panels?  If so, are the masking tape patterns showing the same issues?

Yes, and yes.  I have a couple things I am going to try before I resort to annealed sheet.  This particular panel has so little amount of double curvature, I thought I'd get away with it.  Next post I'll describe.  

 

 

2 hours ago, LSP_Kevin said:

Exacting work, Jay - and it seems, frustrating work also. What's the difference between 'heat treating' and annealing? I thought they were the same thing!

 

 

Kevin - annealed material is soft and without any real strength.  That is probably the basic condition of any aluminum alloy.  It must be heat treated to give it the kind of strength required for aircraft structure.  I do not know of a way to take annealed material and heat treat it to a stronger condition in a home environment.  I believe it is a complicated process and done at foundries or metallurgical facilities of some kind or another.  However, heat treated aluminum can be annealed by simply heating it, believe it or not.  Don't ask me how.  Peter C does it all the time with his heat treated litho, just by putting it to a gas stove flame.  Maybe that is what you are thinking of?

 

I have a big roll of annealed aluminum sheet .005 inch thick.  I also have two kinds of strong heat treated aluminum sheet.  One is the same litho Peter uses (he sent me a batch a while ago); the other similar.   The heat treated stuff cannot be used for complex curved stuff like wing tips or fillet fairings - that is for the annealed stuff.  But annealed material picks up every little blemish when worked - a dust mote, a hair, a small sliver, etc.  It also show the adhesive used to bond it, if the adhesive is thick at all.  And punching fastener head marks in it often results in holes, or at least the marks being too deep.  So it's best used only if you must.

 

I know from my past profession that all aluminum has basically the same stiffness.  Heat treated, or annealed - same stiffness.  The reason why annealed material bends and conforms is not stiffness related, but strength related.  To bend or deform either one - you just take the material beyond its ability to react a load until it begins to deform and not spring back.  That load is much higher for a heat treated material.  Plus, heat treated material is more brittle, and will fracture if deformed too much.  Annealed material - much more pliable, less prone to fracturing. 

 

So - these slightly compound curvature sheets - the heat treated stuff is about as pliable as paper (like not at all).  So it wants to wrinkle or buckle or pooch.  But so does the annealed stuff, if you are not taking it beyond its yield strength.  And trying to stretch it over a slightly compound curved surface doesn't take it beyond that stress.  So the problem  persists.  I am still going to get wrinkles or pooches.  But with annealed material, it locally responds better to burnishing and bashing.  So the wrinkles can hopefully be more effectively burnished out.  The penalty is a more messy looking panel with more blemishes. 

 

I don't know what I'm going to do yet.            

[chuck540z3]

4 hours ago, JayW said:

 

Recognize that?  There are several locations on this Corsair where this has occurred.  And it's getting old.  When I dry fitted the panel it looked like it would lay down.  But it didn't in the end.  So no warning really.  I think I might use annealed sheet for the RH panel and see if it does better.  I am getting deja vue though - I went through exactly this on the forward fuselage panels directly underneath the cockpit, and the annealed panel didn't do  much better than the heat treated one.  Gonna try anyway I think....  

 

Really nice metal work Jay and as we always point out to others, we modelers are our own worst critics, because we are more focused on the flaws of our work than the accomplishments.  The other thing to keep in mind, which you already pointed out with the leading edges of the wings above, is that the real deals are far from perfect, even from the factory.  These were killing machines manufactured as fast as possible during the war and cosmetics always came second to performance and safety, so a few panel line flaws here and there were a non-issue.  Your photography is super close as well, which is great for us to see your work, but it also magnifies things we might not notice as flaws from a foot away.  No model is perfect anyway and your many great accomplishments so far, will overwhelmingly overshadow a few blemishes here and there.  Conclusion:  "Fuhgeddaboudit"!

 

Cheers,

Chuck

 

[Greif8]

Following your build is like looking at a reproduction shop in 1:1 scale Jay!  Mind blowing work man!

 

Ernest