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

[Citadelgrad]

15 minutes ago, JayW said:

 

I have now, complements of E-bay.  Now that would be a project!  For my subjects however, I want to have access to alot of real definition (if not drawings, then lost of other publications where I can determine what needs to get fixed).  Don't think I could find alot on the Stuka correct me if I am wrong.

https://history.scale-model-aircraft.com/interwar-aviation/junkers-ju-87-stuka

https://www.the-blueprints.com/blueprints/ww2planes/junkers/78640/view/junkers_ju_87_stuka/

https://shop.keypublishing.com/products/junkers-ju-87-stuka-owners-workshop-manual

[Paulpk]

2 hours ago, JayW said:

 

Is there a specific part you are concerned with?  Or just the whole tail gear mechanism?  

Basically the main pieces that give it strength. The tubings, joints and related supports. Not the other detail pieces that are non bearing. I have no experience with 3D printing and from what I’ve read, I thought these plastics were brittle.

 

I do a lot of brass work and thought this would be a challenging piece to make. At least you would only have to make one.

[dodgem37]

Junkers Ju 87

Kompendium, gesamt5.010 Seiten, bestehend aus:

 

Ju 87 A-1, Betriebsanweisung, 1937

Ju 87 A-1, Bewaffnung und Bordfunkanlage, LDv 577/1, 1938

Ju 87 A-1, Bombenausrüstung,LDv 576/2, 1940

Ju 87 A, Lichtbild-Lehrvortrag,1938

 

Ju 87 B-1, Betriebsanweisung, 1939

Ju 87 B-1, Bedienungsvorschrift-Fl,LDvT 2087 B-1,1942

Ju 87 B-1,Bordfunkanlage,LDv577/2a, 1938

Ju 87 B-1, B-2,Bewaffnung, LDv 577/2, 1939

Ju 87 B-1 mit JUMO 211 A, Kurz-Betriebsanweisung,1939

Ju 87 B-1,Ersatzteilliste, Werksausgabe, 1939

Ju 87 B-2, Betriebsanleitung, 1940

Ju 87 B-2,Kurz-Betriebsanleitung, 1940

Ju 87 B,Schusswaffe,LDv 576/3, 1938

Ju 87 B,Abwurfwaffe,LDv 576/4, 1938

Ju 87 B, Gerät und Sonderwerkzeug, 1940

Ju 87 R-1 Bedienungsvorschrift-Fl, 1942

Ju 87 R-2, Bedienungsvorschrift/Fl, LDvT 2087 R-2/Fl, 1941

Ju 87 B, D und R-Typen Änderungsanweisungen, 1941 – 1944

 

Ju 87 D-1, Flugzeug-Handbuch, D(Luft)T 2087 D-1, 1942 – 1943

Ju 87 D-1 trop, D-3 tropBedienungsvorschrift/Fl, 1942

Ju 87 D-1 bis D-8, G-1, G-2, H-1 bis H-8, Bedienungsvorschrift/Fl, 1944

Ju 87 D-1, Schußwaffenanlage,LDVT 2087 D-1/Wa, 1942

Ju 87 D-1, Abwurfwaffenanlage,LDvT 2087 D-1/Bo, 1942

Ju 87 D-5, Flugzeug-Handbuch, D(Luft)T 2087D-5, 1944

 

Ju 87 G-2, Flugzeug-Handbuch, 1944

 

JUMO 211 A, Betr.-Anweisung u. Wart.-Vorschrift,1938

JUMO 211 B u. D, Betr.-Anweisung und Wart.-Vorschrift, 1940

Junkers-Verstell-Luftschraube VS 5, Handbuch, 1939

 

REVI C/12 A,LDv 108, Beschreibung, 1937

Lichtbild-MG, ESK 2000LDv 138, Ausgabe 1935

MG 15 Waffen-Handbuch, LDv 110, Teil 1, 1939

MG 17 Waffen-Handbuch, LDv 111, Teil1, 1939

 

 

Found here:

https://www.luftfahrt-archiv-hafner.de/

 

Sincerely,

Mark

[JayW]

9 hours ago, Paulpk said:

I have no experience with 3D printing and from what I’ve read, I thought these plastics were brittle.

 

Thanks for your interest.  When I first introduced 3D print parts to this model a couple years ago, I had the very same concern.  I felt I could not make a decent main landing gear lower strut by any other means than some sort of mold, or 3D print.  I chose 3D print, but first ordered a test part.  This part:

 

 

I knew this part would bear the weight and the shock from any mishandling of a pretty heavy model.  Others on this site had similar concerns.  So I put it to the test:

 

 

That test rig has 4 pounds of weight on top of the strut, that after starting with one pound.  The part ultimately supported 5 pounds of dead weight on its own and did not fracture, although it flexed for sure.  I ended the test there rather than go until failure.  It showed its stuff, with capability waaay beyond what it has to do.  I was amazed, as well as my audience.  So, the lesson is this stuff is stronger than you might think.  I will say the resin used by my supplier is a high strength mix, supposedly.

 

Carefully designed and applied, 3D print parts are just fine.  For the tail gear, the carriage, fork, and tire are 3D printed:

 

  

 

Those are stout parts I can tell you.  Also the upper compression link and scissors link are 3D printed, shown in this picture of the Rhino model:

 

 

 

The upper link is nice and stout; the scissors link is so spindly and thin that it will break if you look at it sideways!  However, as I explain in my short treatise on the mechanism, it is basically unloaded.  As long as I can get it in there without breaking it, it's going to be fine.  And I did that successfully.  The shock strut, BTW, has 3D printed ends but the rest is made of aluminum tube. 

 

I am constantly amazed when I accurately scale real structural parts at 1/18 scale, 3D printed, just how efficient and strong these parts are.  The best example I can show, other than the lower strut I already showed you, is this (drag struts on the main landing gear): 

 

 

 

That is a fragile part if you try to bend it.  But in pure compression, it is very strong.  I can tell you, the main landing gear on this model are plenty stout.  So will be the tail gear.  Worry not my friend!

 

 

 

 

 

 

 

 

 

 

Edited February 16, 2023 by JayW

[airscale]

just awesome in every way

 

you have learned so many new skills on this build Jay - skinning, 3D etc it has really shown what a master model maker you are

 

Peter

[JayW]

Continuing on with the build.....

 

For quite a while I have been anticipating (maybe better - dreading) aluminum skinning of the aft fuselage and tail.  It is now time.  First among my concerns was the tail cone.  Second the h/stab and fin fillet fairings.  Other concerns but those are on the top of the list.  The guy who performs magic in this arena is Airscale (Peter Castle).  Others too, but Peter is the best of the best I think we all agree.  So he has provided some guidance to me, which is really just some further explanation of what he has done on his P-40 and P-51 builds, and a couple of videos he has done over the years.  Thanks Peter!

 

So I am starting at the aft tip, and moving forward for the most part.  Here I provide views of the engineering drawings of three panels I have made:

 

Upper tip VS-19500:

 

 

Lower tail cone VS-17619:

 

 

And aft fillet fairing (H/stab) VS-15224 (LH and RH):

 

 

Here is the aft end prior to skinning, for comparison:

 

 

Here we go - lots of trimming, burnishing, and tapping with a ball peen hammer to get a shape that annealed aluminum sheet doesn't want to take:

 

 

Glued on:

 

 

 

 

The fillet fairing was easier (the ones further forward will be much harder):

 

 

Glued on:

 

 

 

 

 

Those four panels were not as hard as I thought they would be.  Some of you might wonder why the fastener marks are so small and numerous on the fillet fairing (should it not be fastened with Cam-locs or Dzus fasteners?).  No, it is fastened with flush head 3/32 rivets.   As are the rest of the fillet fairings.  I was surprised but the drawings don't lie. 

 

OK, so far so good.  Next I must apply some P-38 filler to the areas where the larger and harder fillet fairings go.  But before I can do that, and because the fin leading edge fillet fairing spills onto a large fuselage crown panel, I must first make and install that panel.  That's next.

 

Thanks for looking in; you are watching alot of fun taking place.         

 

 

 

 

 

 

     

Edited February 16, 2023 by JayW

[TheBaron]

Absolutely blown away by the quality of this work in both its virtual and physical form. Just inspiring.

[brahman104]

Spectacular work Jay! You've quickly become one with the metal.... I remember not so long ago you were only toying with the idea of using it!

 

Craig

[JayW]

On 2/16/2023 at 2:50 PM, brahman104 said:

You've quickly become one with the metal.... I remember not so long ago you were only toying with the idea of using it!

 

Hey Craig - a bit of a sore subject.    Well, not really.  I  know perfectly well that this build deserves to have a good convincing skin surface so I had to do something.  It has however lengthened significantly the duration of the build, getting on 4 years now.  And it has introduced the dreaded paint lifting.  Very concerning!  Metallic skins however can be very very convincing.  You should know - you  have done some pretty impressive acreage yourself.  

 

I have very difficult skinning yet to do.  Stay tuned for continuing adventures.

 

 

Edited February 19, 2023 by JayW

[Paulpk]

Jay, looking good. What is the thickness of your litho? .012”, .015” or thinner?
 

Thanks for addressing my concerns about the tail wheel strength. I was reminded of the WWI images testing wing strength 

[Greif8]

Continued Top Shelf work Jay, this is a real masterpiece thus far.

 

Ernest

[Derek B]

Fantastic work Jay (hopefully, I shall get into this litho plate covering malarky at some point in the future!). Your main gear looks utterly convincing - I thought I was looking at a photograph of the full size aircraft at first glance - well done.

 

Regards

 

Derek

[JayW]

12 hours ago, Paulpk said:

What is the thickness of your litho? .012”, .015” or thinner?

 

Thinner!  0.005 inch.

[scvrobeson]

Some of the builders on here are true craftsmen, and you are among them Jay.  Making the rest of us look like mere mortals doodling next to Rembrandt and Monet.

 

 

Matt 

[JayW]

Last post I stated that in order to provide a smooth surface for the empennage fillet fairings, I need to putty over the area where those fairings will lay down.  That is how Airscale does it, and he's right on.  But in order to do that, all the skin panels that are in that area must be present.  And there was one panel missing, which is a crown panel whose aft end is underneath the leading edge of the fin, just barely.    Well don't you know that panel is the largest by area of any panel I have added to the model since I started skinning it!   Here is a picture of it from the fuselage top drawing:

 

 

 

Took more than one frame to show it all (red outline).  Note the aft end is underneath the fin fillet fairing.     So off I went laying it out on paper 2x size, and then on a sheet of litho with tape:

 

 

 

 What do we see there -  The penetration on the left just off the centerline is for the antenna mast we discussed ad nauseum a while back.  Just aft of that in the middle of the panel is another penetration for the "section" light.  Why is it called a section light?  And then the two holes furthest aft, one LH and one RH are for hoisting provisions.  They will get cover plates later.  Many aircraft have this feature.

 

It began to occur to me that I had better do a test panel (good thing I did).  This aft fuselage is not straight.  It is a tad "humpbacked" which makes the panels compound curved if only a little.  But this panel is so large, and it curves so severely over the crown, that fit-up problems might arise.  I already had some of that with the forward fuselage on the larger panels.  Not good.  It was easy to do a test panel:

 

 

Use masking tape and pencil to trace the outline from the model, place the tape on a piece of litho, cut it out and burnish some curvature into it.  

 

Using very stout packing tape, I attempted to get this panel to lay down on contour, and it just refused to do so:

 

 

 

 

You cannot burnish that out.  Tape down the forward end, and that is what you get at the aft end.  Tape down the aft end, and you get something like that on the front end.  Force both ends down, and the sides splay out and wrinkle.  And this after having such an easy time with the tail cone, the part I feared the most.

 

OK what to do.  Switching to annealed material might help some, but I know from experience, it too has problems with that amount of compound curvature over a large panel.  And annealed material just shows so much imperfections....  Didn't want to do that.  So I decided to try cutting the panel in half.  I just hate it, but that is what I did.  First I cut the test part:

 

 

And taped it down:

 

 

Much better - I can work with that.  Did same with the "production" part:

 

 

 

I selected the split location at a bulkhead, where a skin joint could have been anyway if the Vought engineers had chose to do so.  I just added an extra fastener row.  Ready for forming and bonding:

 

 

 

So pretty!  And then the WWF wrestling match began.  Several hours of high intensity burnishing and rubbing, burnishing and rubbing, trimming, sanding, applying CA at the edges that just would not cooperate, cursing, trimming some more, applying more CA.  Finally I got this:

 

 

 

The LH side came out better than the RH side, who knows why....  That dent?  A mystery.  No doubt something left over from the brawl.  So this Corsair has a skin joint that isn't supposed to be there.  OBG is going to chime in and remind us that the dent is just fine - that aircraft skins of the day just were not perfect.  And I will agree!  I have to!  Or, I might apply a touch of P-38 to it - after all that is what it is - body putty.

 

Not a real happy camper right now.  Next post is going to be all about P-38 application and the first of the dreaded fillet fairings.  Wish me luck!   

  

 

 

Edited February 18, 2023 by JayW