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

[Gazzas]

Top work, Jay!

[JayW]

3 hours ago, MARU5137 said:

Just think ,your impressive build and your engineering  drawings , and techniques etc immortalised in a book.

 

Great complement MARU - I am humbled.  However the war is not won yet.  Only some key battles.  The engine compartments were like the Battle of Midway - a great victory, but by no means the finish.  The tail is going to be immensely difficult to do well, with compound curvature skinning, and a wheel well that is chalk full of systems with small parts that do not yet exist.  And the aft-to-fwd fuselage join is going to be a big test of skinning and painting skills.  The tail feathers - I don't even have a plan yet for how to depict fabric-covered structure although there are good examples in LSP.  And the outboard wings?  Huge project.  It just boggles the mind how much remains.

 

As for a book -  interesting proposition, but you will have to settle for a multi-part LSP article.  

Edited October 3, 2022 by JayW

[Citadelgrad]

Keep marching, Jay.  Your list of things to do is far eclipsed by your ingenuity, attention to detail, and sheer determination.  

 

If this were a mountain, and you were holding a spoon, I have no doubt you'd eventually outlast the mountain and we'd have a nice plain in its place.  

 

Watching , marveling, and wondering.  

[Oldbaldguy]

1 hour ago, Citadelgrad said:

Keep marching, Jay.  Your list of things to do is far eclipsed by your ingenuity, attention to detail, and sheer determination.  

 

If this were a mountain, and you were holding a spoon, I have no doubt you'd eventually outlast the mountain and we'd have a nice plain in its place.  

 

Watching , marveling, and wondering.  

Indeed.  And every time I see those first photos of the original Corsair at the top of Jay’s post, I laugh out loud.

[Maybach_man]

On 10/1/2022 at 2:27 AM, JayW said:

 

I don't think so.  I don't grip the model there.  Maybe though.  We'll never know.  I tell ya - even with steel wool sanding (to try to sand down the edges of the paint), the new paint is still pretty fragile.   Can't wait to join the aft fuselage to the forward, and mask for paint!  

Try some Bilt Hamber etchweld primer....

[JayW]

5 hours ago, Maybach_man said:

Try some Bilt Hamber etchweld primer....

 

Checked on this stuff - It appears I cannot get it from a USA supplier; would be shipped from the UK.  Which is OK I suppose - it's only money.  Do you know of a USA supplier?

 

So far I have used two self-etching primers on this model.  Rustoleum and Duplicolor.  Afraid I cannot recall which failed me on either side of the fuselage.  The area was local thankfully.  Other areas seem to be more robust.  If I were to somehow learn that the Bilt Hamber stuff was more effective and more reliable, I'd go for it.  Have you had good experience with it?  BTW - I had great expectations with the Duplicolor stuff, but it went on very rough almost like a frosting rather than a smooth coat.  Hated that; quit using it.  So unless I can find something better, it's the Rustoleum.  I suppose I could try decanting the Duplicolor and airbrushing it.....

 

Also, I have used four different aluminum materials for the skins:  Litho plate supplied to me by Peter Castle (Airscale), "Shop-Aid Shim in a Can" from McMaster & Carr, Wieland annealed sheet from McMaster & Carr, and a coke can (yes, a coke can).  I have lost track of the alloy types.  The lifting occurred on a panel made from the annealed stuff, and also one made from the "shim in a can".  But not all the panels have been subjected to masking.  So short story would be I don't know if the underlying material made much of a difference.  I suspect Peter's litho is best, but I cannot use it everywhere - must use annealed stuff in some places with compound curvature.

 

I think I am going to do another round of test panels.     

Edited October 7, 2022 by JayW

[Sasha As]

Great building site ! I love it!

[JayW]

Just thought I'd let you know what I have been up to on this project (besides loafing).  All work has been solid modeling in Rhino 7:

 

 

It isn't complete, but I have accomplished alot.  And similar to my other big layouts, the thick gages have introduced problems that I have to design my way out of, in such a way as to eliminate the issues (almost always a clash of some sort) without completely ruining accuracy.  The secret to this digital layout is to accurately model the fuselage especially its contour.  A whole lot of stuff is going to be attached to the inside of it, and quarters are cramped.  This is what I have had to approximate to the best of my abilities:

 

 

Some of what you see there is going to be dremmeled away.  Some other things will get covered up.  Anyway, lots of frames and bulkheads and other fixed structure will show up in there, as well as the tail gear mechanism (which I have finished modeling and can be seen in the first picture above).  Also, not Rhino modelled yet are the arresting hook mechanism, the tail gear doors (very difficult to model), and the tail gear door operating mechanism.  It has, among other various cranks and links, a pair of bicycle chains with length adjusting turnbarrels, and sprockets:

 

 

Next post I hope to have that all Rhino modelled.  A good many 3D printed parts are going to come from this Rhino modelling, including the doors.  But also alot of good old fashioned scratch building.  You perhaps recall that I have already had some of those parts 3D printed:

 

 

So that chain.  I don't know if I can pull that off, it's so tiny.  I'll try.  Tamiya didn't even bother!  Any ideas?

 

OK next post I suppose I will show more Rhino modeling.  By then I will have eliminated any clashes and assured that everything will integrate.  At that point I will select the parts I want to 3D print and send off the order.  And while I wait for the parts, I will begin scratch building stuff.

 

 

Edited October 11, 2022 by JayW

[Oldbaldguy]

Is that “chains and sprockets” per side or just one set?  I swear those Vought guys were on drugs.  You ought to be able to source something close to the right size turnbuckles on line.  Maybe the segments of chain as well because there are large scale motorcycles and even bicycle models out there if I’m not mistaken.  Just a thought and maybe not worth the time and expense, but there is going to be only one of these ever built, so….

[JayW]

On 10/10/2022 at 5:47 PM, Oldbaldguy said:

Is that “chains and sprockets” per side or just one set?  I swear those Vought guys were on drugs.  You ought to be able to source something close to the right size turnbuckles on line.  Maybe the segments of chain as well because there are large scale motorcycles and even bicycle models out there if I’m not mistaken.  Just a thought and maybe not worth the time and expense, but there is going to be only one of these ever built, so….

 

Per side OBG.  Would love to have been a fly on the wall in their engineering department.  Actually - that chain mechanism gives you a 25 teeth to 9 teeth gear ratio = 2.78/1.  So if one shaft turns about 30 deg, the other shaft turns 83.4 deg.  Those doors rotate on their hinges through an angle something like that.   It's kinda cool.  But uber complicated.  Mustangs and Thunderbolts just have swivel links that connect the doors to the tail gear carriages directly.  Makes you go "Hmmmm." 

 

I believe the motorcycle chains you speak of are 1/6 scale, so would be much too big.  In full scale, a motorcycle chain would have an individual link length somewhere near the same as the chain you see in the picture (0.5 inch pitch).  At 1/18 scale that becomes 0.028 inch between pins.  The link lugs are approximately .015 radius (.03 diameter).  So an individual outer plate would be .028 + .03 = .058 inch long (call it .06) by 03 inch wide by .005 inch thick, with rounded ends.  Not that hard to make from .005 thick plastic sheet.  Then I could make the inner links out of .02 x .03 x .06 long plastic strip - they would space the outer plates apart by .02 inch to allow for the sprocket (which I think would be toothless).  Then start gluing them together along a flat pattern....  That is my thought at the moment - I am sure it is easier said than done.  Super small parts.

 

Edited October 18, 2022 by JayW

[SwissFighters]

5 hours ago, JayW said:

 

Per side OBG.  Would love to have been a fly on the wall in their engineering department.  Actually - that chain mechanism gives you a 25 teeth to 9 teeth gear ratio = 2.78/1.  So if one shaft turns about 30 deg, the other shaft turns 83.4 deg.  Those doors rotate on their hinges through an angle something like that.   It's kinda cool.  But uber complicated.  Mustangs and Thunderbolts just have swivel links that connect the doors to the tail gear carriages directly.  Makes you go "Hmmmm." 

 

I believe the motorcycle chains you speak of are 1/6 scale, so would be much too big.  In full scale, a motorcycle chain would have an individual link length somewhere near the same as the chain you see in the picture (0.5 inch pitch).  At 1/18 scale that becomes 0.028 inch between pins.  The link lugs are approximately .015 radius (.03 diameter).  So an individual outer plate would be .028 + .03 = .058 inch long (call it .06) by 03 inch wide by .005 inch thick, with rounded ends.  Not that hard to make from .005 thick plastic sheet.  Then I could make the inner links out of .02 x .03 x .06 long plastic strip - they would space the outer plates apart by .02 inch to allow for the sprocket (which I think would be toothless).  Then start gluing them together along a flap pattern....  That is my thought at the moment - I am sure it is easier said than done.  Super small parts.

 

 

The motorcycle idea came to my mind as well...not sure how different scales would work but here is a pic of a Tamiya product (1/12 Scale Honda RC166 Metal Chain Set
Item No: 12633) to show that such chains are available (comprising all the individual linked parts). Quite amazing.

 

[JayW]

8 hours ago, SwissFighters said:

here is a pic of a Tamiya product (1/12 Scale Honda RC166 Metal Chain Set
Item No: 12633) to show that such chains are available (comprising all the individual linked parts). Quite amazing.

 

 

That is really something!  Basically a chain made from photoetch plates and tiny pins. 

 

I am getting deja vu here.  A few years ago I travelled this road while building the sliding canopy operating mechanism for the P-47 Thunderbolt in 1/18 scale.  It too uses a bicycle chain in real life.  And try as I might I could not find anything small enough and resorted to a tiny black jewelry link chain, hoping that viewing eyes would not be able to focus in that closely! 

 

I looked in several places and could not get any technical data on this product - like what is the pitch.  So I tried to scale a picture of it draped over a finger.  From that shot the pitch looks to be about 0.05 to 0.06 inch, which is twice the size of what I would need.  It is also much wider than I need. 

 

All to say that I may be looking at mission impossible here.  We shall see.....thanks for that suggestion!  

[JayW]

Digital Integration of the tail wheel compartment has been a slow and difficult process, but I have been hammering away at it.  Many clashes and many tweaks to fix.  I have gotten it to the point where I am almost ready to create more detailed 3D models of all the parts I wish to have printed (and there will be many), and to start scratch building parts, and dremmeling out features I don't want. 

 

First a picture of the latest development of the layout I am doing in Rhino 7:

 

 

 

Hmmm - forgot to "unhide" a couple of things - the rudder shaft, and some door operating mechanism stuff....anyway I have a few things to finish up, the most important of which is the doors themselves with their internal structure as well as skins.

 

So what do you suppose is the first first part I made for this area?  Well, the bicycle chain for the door operating mechanism.  It is the only feature in the tail wheel bay where I was stressing about how to make it.  And the last couple of posts there has been discussion about it.  Tamiya appears to have completely ignored this feature in the 1/32 Corsair, understandably.  However, at the risk of completely violating the "sometimes less is more" axiom, I felt the chain ought to be present in my 1/18 Corsair, as it is not at all invisible:

 

 

Here - you have seen this picture before but I show it again as a reminder:

 

 

My solution?  Do it the hard way - link by link.  The turn barrels will not be a problem.  I determined that the chain can be done fairly to scale using .01 x .03 inch Evergreen strip for the outer plates, and .02 x .03 inch strip for the center link.  Each link or plate should be about .06 inch in length.  All these dimensions are smaller than what you get with the smallest roller link chain I can find (the Tamiya 1/12 scale chain we have already discussed).

 

So I set off a couple days ago doing a "POC" project (POC = "proof of concept").  Here:

 

Incredibly small chain link details.  My magnification goggles were required along with my reader glasses!  I used the "Mega Tool" punch to simulate the exposed ends of the pins.  These parts have a remarkable ability to disappear into another dimension at the smallest provocation, causing a fruitless search, and then a redo.  Not as maddening as in the past though, because each piece is fairly easy to make as long as the x-acto knife is sharp.  Gluing them together (with Tamiya extra thin), was done on a little fixture to get the right shape:

 

 

Much care is required to minimize how much glue to use.  These parts are soooo small.  The painted chain you see is really the POC chain, and I will not use it.  The white chain is the "lessons learned" chain, and I will use it.  Here it is painted:

 

 

Under the electron-scanning microscope that is the Imgur "huge thumbnail" it looks a bit rough.  But in the world of normal human vision, it looks pretty good.  I have three chains to go, and they are not as difficult to build up as you might think.  A couple days and they will be done.  I am stoked!!  I cannot declare victory just yet - when the time comes to install the chains, the turn-barrels must be accurately fabricated from very small tube, and then somehow connected to the chain ends and installed onto the sprockets included on the middle and lower shafts of the door operating mechanism.   You will not see that for a while; alot of other structure must be added to the bay before that is attempted. 

 

Stay tuned, and be patient.  I think the tail wheel bay effort is going to extend into the winter (or summer for you down unda folks).  A big deal.

 

 

 

 

 

Edited October 23, 2022 by JayW

[monthebiff]

On 10/11/2022 at 6:30 AM, SwissFighters said:

 

The motorcycle idea came to my mind as well...not sure how different scales would work but here is a pic of a Tamiya product (1/12 Scale Honda RC166 Metal Chain Set
Item No: 12633) to show that such chains are available (comprising all the individual linked parts). Quite amazing.

 

Also check out Studio 27 and Top Studio as they make excellent chain sets which you build yourself so you can get the correct length you require!

 

Regards. Andy 

[LSP_Kevin]

That chain is an amazing feat of miniature modelling, Jay!

 

Kev