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

[JayW]

Perhaps some of you can offer some advise - Very soon I will be working on the firewall for this beast.  And in order to design it, I have to decide how to deal with the removable fuselage panels that will cover the engine accessory bay.  The firewall will have flanges that serve as the aft edge attach surfaces for those panels.   I think magnets and steel strips might be the best way forward.   I remember my Tamiya Mustang had this - a model that I got rid of unfortunately.  Does anyone know where I can go to get very small magnets and magnetic strips?  

Edited December 13, 2021 by JayW

[Citadelgrad]

1 minute ago, JayW said:

Perhaps some of you can offer some advise - Very soon I will be working on the firewall for this beast.  And in order to design it, I have to decide how to deal with the removable fuselage panels that will cover the engine accessory bay.  I think magnets and steel strips might be the best way forward.   I remember my Tamiya Mustang had this - a model that I got rid of unfortunately.  Does anyone know where I can go to get very small magnets and magnetic strips?  

Certainly, Jay, they are readily available on ebay:

https://www.ebay.com/itm/183034264227?_trkparms=ispr%3D1&hash=item2a9db13aa3:g:1fMAAOSwBgZdI2ZO&amdata=enc%3AAQAGAAACkPYe5NmHp%2B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsS7UXID%2BRPOSNsnm8kYPghtHhD4X0gpV59z9lrNcOJZ10rbomMpsvWvuQUVtFRmdsqPk0AD3Ff0jCsOmEVD5T0i27GJ%2BaJeuLcaPPNnmr7ea8NJzMHnZ3PIx%2BXaAOqvKOGYMpfevQl%2BRncUXqoVYQt%2FJa7ypTcZB7AV46fF2x0JsWRtYHgDivg%2FQeOx0v3JfvCW5TdCLkmDXJfBjgFWZ4sGA7BG6qCvU%2FVRQqmBVV85Z3GqKtnNEA4UKVGBuvTXueMauSFH3jXOO%2FDYprRdQTQDdRGg9MiNmUgJIoZJTfWg6y0GtrlkWG%2BHjV9CEq0I%2BeQM%2BDLoeKxzoFs%2F9HXsqKge4%2BANVXlWdJ5SA00qw7pJae01ulLVWq4CEj9tVElnxavhTEa6n7%2BRKYXIUnfDzDuNd%2F7xZfc6u6lpMPwMdhST%2BTGbEQAnmtoYJUvgng8i3zgDBX822u1R7858UvHORKMc5NVNKZ1%2BHKAem6ia3b0xi6Hze47YbUh2Pz%2FpQh%2BpWpeqjRBoNUWyfpLiG5CE6OCLv6kcitC5kD68ahl0oPPsUil5FKjofSa6Weyp4%2F%2BOwwdJwqoefzh%2B%2F81kJZXQZCk5dcuNN9kk7JCGFXXlNUvMCG9u5tL8SNfMXAp8pIonEMNHRxy7hQjmk78Z9fgM4uZK5JL9LSw2k3JP2vc2CNxWHZRlveZaAI8zjXD%2BtIbnSioZ3aur8DXflg1peuotjcgxTKOdjuhoikHLxn07Smn3%2F%2BOpkyI5xm9P0oSHHFxYAfNtPqLVC%2Bae5QCOZ7JU%2B1d7heTWJvggZTDzBQEhXR770fdEbhgHf5yk5%2FE1HQnUwPp|clp%3A2334524|tkp%3ABFBM5M761LZf

 

Wow, that's a LONG link, sorry about that.

 

I think magnets on each part will give you a better bond than steel strips, I got a set and they are probably the size of a capital O.  They came in a large stack of 100 or so, but I haven't used them on anything yet. 

 

 

[TAG]

[JayW]

19 hours ago, Citadelgrad said:

I think magnets on each part will give you a better bond than steel strips,

 

Thank you for that!  Well if they are very thin, that would be OK.  The panels are going to be .02 inch think though.  I can use the little "capital O's" inside on the attach flanges.  But I need something very thin on the panels.  Doesn't Tamiya (and others?) use magnet plus steel strip for their removable panels?  

Edited December 14, 2021 by JayW

[Rocat]

Stunning work

[Citadelgrad]

On 12/14/2021 at 7:39 AM, JayW said:

 

Thank you for that!  Well if they are very thin, that would be OK.  The panels are going to be .02 inch think though.  I can use the little "capital O's" inside on the attach flanges.  But I need something very thin on the panels.  Doesn't Tamiya (and others?) use magnet plus steel strip for their removable panels?  

Ive yet to build a new tamiya kit, so i dont know exactly how they use the magnets.   They are very thin, though.  
 

I went back and looked at my purchase, i bought these ones, they are 1/16” x 1/32”, pretty darned thin

https://www.ebay.com/itm/263051543634

[dodgem37]

If you buy wafer magnets they will break.

 

Sincerely,

Mark

[JayW]

7 hours ago, Citadelgrad said:

I went back and looked at my purchase, i bought these ones, they are 1/16” x 1/32”, pretty darned thin

 

6 hours ago, dodgem37 said:

If you buy wafer magnets they will break.

 

And I thank you for your input.  I settled on the same magnets - 1/32 thick by 1/16 diameter.  I suspect I will be using many.  I also obtained some tin plated steel .013 thick strip, which attracts well to magnets.  As thin as the magnets are, I might have the option of just using a back-to-back approach rather than using the steel strip.  That work is pretty far down the road, and will be a big challenge to get right.

[JayW]

On 12/11/2021 at 8:56 PM, JayW said:

The belly door awaits, then some dremmel work to make way for carb air and supercharger ducts.  And then - wing/fuselage join and back into the cockpit!!!  

 

So said I last time I posted progress.  Well a little change of plans.  I got some more 3DP parts in the mail, and that drove me to re-sequence a bit, as follows.

 

First, I indeed did some good preliminary layout work on the belly door for the engine accessories compartment; you will see that next post probably, or the post after that.  But then, I felt like I was really pressing my luck without a good stand to mount this partially completed center section.  Here it is:

 

 

 

And with the model placed on it:

 

 

MUCH needed; this does a decent job of protecting those fragile landing gear doors, and the struts too.  That last pic also shows that the integral stiffening elements on the bottom of the fuselage just forward of the wing have been dremmeled away, in preparation of the very exciting work in the engine accessories compartment.  That work is going to happen sometime this winter after the cockpit is finally finished.

 

So those new 3DP parts - yahoo!!!:

 

  

 

What you see there is the following:

 

1 - forward LG doors (one set with support sprues in the inside, one with the support sprues on the outside).  I will use the ones with the sprues on the inside, because the outside is cleaner looking.

2 - Various "shoulder" parts for the engine compartment "diaphragm".  These parts lie underneath the cowl flaps, which on this model will be wide open, which then exposes these parts to view.  You will see these parts later this winter, I hope.

 

Those shoulder parts in Rhino 7:

 

    

 

So, it's a little premature to order up those shoulder parts, but I really needed those LG doors, and I get them from Tim in the UK, and postage is a bit pricey.  So I combined orders.  As usual, I am trying to limit 3D printing to those parts that I cannot do a good job of fabricating myself.

 

The forward LG doors:

 

 

In real life, these doors doubled as dive brakes!  Yes.  Corsair pilots, when doing dive bombing runs, were to run out the landing gear to help keep speed under control.  There is a special position of the landing gear controls in the cockpit for this function plus a speed limitation placard. 

 

Attaching these details to the landing gear struts is my very next project.  The reason?  They will go a long way towards protecting the delicate "shrink link" mechanism on the gear struts.  You look at those mechanisms cross-eyed, and they break. 

 

I have modelled these details in Rhino - very important that they are right, and hang the doors properly:

 

  

 

 

 

 

All that clap trap will be scratch build stuff - pretty small, and finicky, and probably not alot of fun.  But I think it will turn out awesome.

 

And in parallel with that Rhino work, I actually jumped back into the cockpit after literally months.  Preparations for joining the fuselage halves together, and then joining to the center wing section.  I am so afraid that I will not be able to complete some of the remaining cockpit tasks due to inadequate accessibility once those big parts are joined.  We will see won't we....

 

Latest from the cockpit:

 

 

That "defuel" line is dry fitted.  It must wait for final install until after the fuselage and wing center section is joined.  It is a good example of a part where I must reach down into a deep hole with long tweezers to final install it.  And it really is deep!  The white (unpainted) foot trough is another great example.  It also is dry fitted, and must wait.  The rudder cables are yet another example.  Oh man - adventures await.

 

But first, let me finish up the forward LG doors, and then probably the belly door.  Merry Christmas all!  Watch this space.

Edited December 19, 2021 by JayW

[LSP_Kevin]

I haven't commented much lately, Jay - but this build continues to amaze and delight. I really don't know how you do it!

 

Kev

[Out2gtcha]

Amazing honestly

[Citadelgrad]

Holy COW that is an amazing amount of detail, so lifelike.  This hard work is paying massive dividends.  
 

Jay, this is breathtaking. 

Edited December 29, 2021 by Citadelgrad

[JayW]

5 hours ago, LSP_Kevin said:

I really don't know how you do it!

 

Kevin - this was a brief topic of discussion on the big Hellcat page (Chuck).  I need to better explain how I do it.  That is, unless you mean how do I have the patience to do all this.  To that - I don't know.  I am retired, and aircraft engineering was my profession and my passion.  This is just a kind of continuation!  And my patience is wearing thin - I have to occasionally keep reminding myself this is fun.  

[JayW]

Last post I said that the forward landing gear doors were next, and so they were.  I modelled the support bracketry in Rhino, and I am glad I did:

 

 

But first, let me describe a minor feature of the F4U forward LG door that many are not aware of.  On the upper (or forward) edge of the door there is attached a fabric cover:

 

 

That picture is from Dana Bell volume 7.  What we often see on landing gear doors is some sort of auxiliary door or flap that covers up what the main door cannot - an unavoidable eventuality when the gear strut hinge point is well inside the wing contour.  The F4U is no exception - the door itself is unable to cover up the most forward part of the lower wing skin opening; otherwise it would jam into the wing skin when the gear extends.  I modelled this a while back in Rhino when I was modifying the gear door cutouts:

 

 

Note how the forward edge of the red LG door stops short of covering where the strut penetrates.   So the fine engineers at Vought decided to cover it with a square of fabric - with one edge attached to the door, and the opposite edge attached to the lower wing skin. 

 

In addition to the door support structure, I also represented this fabric square.  Here are some pictures of the now final installed forward landing gear doors:

 

 

 

May not look like it, but that was hard!!  Just scratch built little bracket parts mostly, and a large diameter tube clamp.  But tiny and hard to handle.  The computer model was indispensable - everything fit pretty well.  Perhaps you see the back of the fabric square (painted brown).

 

The fabric is better seen here from the front:

 

 

I made the square from plain white paper, with .005 inch thick plastic attaching strips, all bonded with CA glue.  Amazing how large these details look in that picture - they are actually very small.

 

Some more shots:

 

 

 

 

 

This thing is starting to look like a Corsair.  This step was a victory mostly because I didn't break anything.  Next is the belly door with it's piano hinge "pleats".  Merry Christmas you all!  And stay tuned! 

 

[Uncarina]

Jay, it is starting to look like the most comprehensive Corsair build I’ve ever seen! Happy Holidays to you as well.

 

Cheers,  Tom