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

[brahman104]

Massive congratulations to you Jay!!!!

 

I know just how pivotal moments like this are, and they're very hard to convey to anyone else, because photos don't show all the effort and mental energy that goes into what you can see in the photos.

 

From where I'm sitting though it looks pretty darn epic! It's great to see moments like this.

 

Craig

[Citadelgrad]

Im not even sure what is happening here, other than you created a jig to ensure gear geometry is correct, but its amazing to watch.   Master class next level stuff here, Jay.  

[Rainer Hoffmann]

Good grief, how did I miss this? Just read thru the whole thread. That is sooo impressive. Absolutely amazing work, Jay 

 

Cheers

Rainer

[Kaeone57]

Jay,

 

Thankfully, I hope, You get/got what I was saying/typing earlier!?

 

AMAZING! Nothing I can type/say to do this work any Justice!!! This is just More THAN AMAZING!  AMAZINGLY BEYOND GOODER than GOOD!!!

 

WOW, duuuhhh, duuuh, Fu..ing Duhhh!!!

Sh...tttt. it's that Good! I can't wait, though I will. Can't wait to see how you replicate the "canvas/hemp" zippered covers in the inner wheel bay's side walls on this. Oh no, more canvas/hemp covers, to cover.. LoL

 

Hate/Love You for this!!! LoL

 

Alfonso

 

 

[dodgem37]

You killer elite!

 

Sincerely,

Mark

[JayW]

7 hours ago, Kaeone57 said:

Can't wait to see how you replicate the "canvas/hemp" zippered covers in the inner wheel bay's side walls on this.

 

Alfonso - I was just thinking on this a little yesterday.  I continue to be at a loss how to do it.  And I don't even know what color to make it (gray like the rest of the bay?).  Calling all master modelers!  How can I simulate a canvas cover with a zipper?  

Here is the drawing:  

 

 

Edited September 8, 2021 by JayW

[Ironwing]

1 hour ago, JayW said:

 

Alfonso - I was just thinking on this a little yesterday.  I continue to be at a loss how to do it.  And I don't even know what color to make it (gray like the rest of the bay?).  Calling all master modelers!  How can I simulate a canvas cover with a zipper?  

Here is the drawing:  

 

 

Tissue dipped in water and white glue or lead foil maybe?

 

Whatever you do will be good. I hope you see the art in what you've created...rock on brother

 

Geoff

[JayW]

15 hours ago, Citadelgrad said:

Im not even sure what is happening here, other than you created a jig to ensure gear geometry is correct,

 

In a nutshell, the 21CT toy had its own retractable landing gear, and as is typical it looked just awful.  Here is one to the left of the improvements that I made:

 

 

And this taken eons ago before I started on this journey:

 

 

The toy's gear leg rotates directly backwards on trunnions situated parallel with the ground plane when you look fore/aft, and parallel with the wing leading edge when you look down on the wing.  Also, the gear leg is a tube within a tube, so the lower portion (with the wheel on it) can spin.  That allows the wheel to fit into the wheel well much like the real thing.  In order to allow the gear to retract/extend, the manufacturer ignored the folding drag links that the real aircraft has, entirely.

 

So of course we try to make things as realistic as possible, and this toy's arrangement is not realistic at all.  I dremmeled away every feature inside the wing used to attach that gear leg, tossed the landing gear struts themselves, and was left with a blank slate.  The actual gear leg has a direct attachment to the wing in the wing leading edge via a "knuckle fitting", and a swiveling strut pivot fitting that fits inside the knuckle fitting.  Not a trunnion.  Orientation is 45 deg looking fore/aft, and 45 deg looking inboard/outboard.  I tried to describe that in some earlier posts.  Further, to control the gear struts orientation, it is supported by a set of folding drag links.  These drag links attach to the struts about midway up their height, and to heavy fittings on the wing spar.

 

So that was my challenge - to duplicate that more realistic arrangement.  Along with new gear struts, I had to create drag links, leading edge knuckle fittings in which to attach the struts, and new wheel well main spar segments with drag link fittings:

 

 

 

The drag link (it doesn't fold nor does it need to):

 

 

 

To do all this, I first CAD modelled the local wing around the wheel well area to the best of my abilities.  The wheel well is smack dab in the middle of the reverse gull wing kink in the wing, so the contour is tough to duplicate on the computer.   Turns out I did a barely adequate job, but good enough to do what I wanted.  It allowed me to digitally model the knuckle fitting and pivot fitting, and the drag link.  It also allowed me to fabricate spar segments that almost fit!  It will also allow me to fabricate the four wing ribs that form the wheel well. 

 

Then - to install these things into the wing accurately with little to go on.  The lower wing cutout for the gear doors helped alot of course.  That plus lots and lots of "measuring twice and gluing once".  Once I had the knuckle fittings and spar segments installed, it was time make the drag link fittings on the forward face of the spar segments.  This was the most critical step of the process - where the rubber meets the road so to speak.  These along with the drag links themselves were going to control the orientation of the gear struts.  So I needed a jig that would force the correct orientation of the gear struts.  Then I could trail-and-error the shape of the drag link attach fittings.  That jig is shown in previous posts.  I had digitally modeled the drag link attach fittings, so I had something to start with.  But so many little errors had accumulated with this process, that the shapes were not quite right.  However once the imperfect parts were dry installed, it was pretty easy to determine what changes in shape were necessary.  It was easy - merely cutting fairly simply shaped little lugs from .04 thick plastic sheet.  A little trial and error, and I was able to fab and install the fittings, correctly shaped to mate with the spar, and not force any preload into the drag links (important).  All that was done with the wing and gear struts constrained by the jig.  So in theory now, I can final install the gear struts and drag links, without the jig, and the gear will be properly oriented.  In reality, when the time comes, I will reuse the jig to glue the struts and drag links into the wing, just to make sure.   

 

Hope that helps.  

 

 

Edited September 8, 2021 by JayW

[N.H.71]

4 hours ago, JayW said:

 

Alfonso - I was just thinking on this a little yesterday.  I continue to be at a loss how to do it.  And I don't even know what color to make it (gray like the rest of the bay?).  Calling all master modelers!  How can I simulate a canvas cover with a zipper?  

Here is the drawing:  

 

 

Self-adhesive aluminium tape.

zipper: make a strip with two offset riveting lines. 
That‘s what I did to my 1/24 scale Bf 109 F-4/Trop conversion.

Color: is there no indication on the drawing for Color or material??

 

Regards 

Nuls

[JayW]

5 hours ago, N.H.71 said:

Color: is there no indication on the drawing for Color or material??

 

Good question.  The material is "Navy Spec V-T-276 type "1B".  I'll bet that spec has a color requirement; maybe I will try to look it up.  The wheel well however is supposedly painted gray per Vought requirements.  Does that include the fabric cover....  I have not found that gray paint requirement; therefore I know not what kind of masking would have been required.  For instance, it would have been a mistake to paint gray over the zipper!!   Or the actuator rods!!  Or the door hinges!

[N.H.71]

I‘ m not familiar to US Navy or Vought standards. But I‘m sure someone in this forum is an can help you with required information.

For recreation of zipper shape you can also try a gear wheel rolling over the stripe of self-adhesive aluminium tape but only half of the width of the stripe. Treat the other side same manner but with an offset. 
Hope my explanation is understandable somehow.

 

Regards

Nils

 

[JayW]

2 hours ago, N.H.71 said:

Hope my explanation is understandable somehow.

It is!  And thank you.  It's a very good idea.

 

[Kaeone57]

On 9/8/2021 at 11:05 AM, JayW said:

 

Alfonso - I was just thinking on this a little yesterday.  I continue to be at a loss how to do it.  And I don't even know what color to make it (gray like the rest of the bay?).  Calling all master modelers!  How can I simulate a canvas cover with a zipper?  

Here is the drawing:  

 

 

Well...

 

1st- you mentioned for color on these covers, "gray like the rest of the wheel bay". That was the topcoat, SOMETIMES(Non Spec Insignia White on Counter Shaded/3(4)tone aircraft) over the "salmon" primer on early "Birdcage" F4U-1's. You're building an F4U-1"A", so your wheel bay's would be white topcoat on whatever primer at the time of your F4U-1"A" delivery.

 

2nd- It would either be a tannish, or whitish cover for the later airframes I would imagine. Difficult to ascertain as pic data is "VERY, Very" scarce. I'd paint it in a way to at least show that it's canvas/hemp and not an aluminum panel. Hopefully you get what I'm saying... Maybe??

 

3rd- The zipper! Tough one without an assisted item, 3D printed maybe, or some aftermarket flexible car addition bits!? Not sure. Also, not sure if the zipper had a flap/over lip covering the break on the zipper, hmmm?

 

I know that KD431, THE TIME CAPSULE FIGHTER, the Yeovaltin museums example has these covers still and you can see the overspray on them which makes me lean towards unpainted material!?

 

Hope that helps, if not, my apologies, Great re-work regardless!!

[Kaeone57]

Also, keep in mind that they appear to be very "tight covers" so no need to "drama" them up with folds/wrinkles and such!

 

Alfonso

[Citadelgrad]

On 9/8/2021 at 10:34 AM, JayW said:

 

In a nutshell, the 21CT toy had its own retractable landing gear, and as is typical it looked just awful.  Here is one to the left of the improvements that I made:

 

 

And this taken eons ago before I started on this journey:

 

 

The toy's gear leg rotates directly backwards on trunnions situated parallel with the ground plane when you look fore/aft, and parallel with the wing leading edge when you look down on the wing.  Also, the gear leg is a tube within a tube, so the lower portion (with the wheel on it) can spin.  That allows the wheel to fit into the wheel well much like the real thing.  In order to allow the gear to retract/extend, the manufacturer ignored the folding drag links that the real aircraft has, entirely.

 

So of course we try to make things as realistic as possible, and this toy's arrangement is not realistic at all.  I dremmeled away every feature inside the wing used to attach that gear leg, tossed the landing gear struts themselves, and was left with a blank slate.  The actual gear leg has a direct attachment to the wing in the wing leading edge via a "knuckle fitting", and a swiveling strut pivot fitting that fits inside the knuckle fitting.  Not a trunnion.  Orientation is 45 deg looking fore/aft, and 45 deg looking inboard/outboard.  I tried to describe that in some earlier posts.  Further, to control the gear struts orientation, it is supported by a set of folding drag links.  These drag links attach to the struts about midway up their height, and to heavy fittings on the wing spar.

 

So that was my challenge - to duplicate that more realistic arrangement.  Along with new gear struts, I had to create drag links, leading edge knuckle fittings in which to attach the struts, and new wheel well main spar segments with drag link fittings:

 

 

 

The drag link (it doesn't fold nor does it need to):

 

 

 

To do all this, I first CAD modelled the local wing around the wheel well area to the best of my abilities.  The wheel well is smack dab in the middle of the reverse gull wing kink in the wing, so the contour is tough to duplicate on the computer.   Turns out I did a barely adequate job, but good enough to do what I wanted.  It allowed me to digitally model the knuckle fitting and pivot fitting, and the drag link.  It also allowed me to fabricate spar segments that almost fit!  It will also allow me to fabricate the four wing ribs that form the wheel well. 

 

Then - to install these things into the wing accurately with little to go on.  The lower wing cutout for the gear doors helped alot of course.  That plus lots and lots of "measuring twice and gluing once".  Once I had the knuckle fittings and spar segments installed, it was time make the drag link fittings on the forward face of the spar segments.  This was the most critical step of the process - where the rubber meets the road so to speak.  These along with the drag links themselves were going to control the orientation of the gear struts.  So I needed a jig that would force the correct orientation of the gear struts.  Then I could trail-and-error the shape of the drag link attach fittings.  That jig is shown in previous posts.  I had digitally modeled the drag link attach fittings, so I had something to start with.  But so many little errors had accumulated with this process, that the shapes were not quite right.  However once the imperfect parts were dry installed, it was pretty easy to determine what changes in shape were necessary.  It was easy - merely cutting fairly simply shaped little lugs from .04 thick plastic sheet.  A little trial and error, and I was able to fab and install the fittings, correctly shaped to mate with the spar, and not force any preload into the drag links (important).  All that was done with the wing and gear struts constrained by the jig.  So in theory now, I can final install the gear struts and drag links, without the jig, and the gear will be properly oriented.  In reality, when the time comes, I will reuse the jig to glue the struts and drag links into the wing, just to make sure.   

 

Hope that helps.  

 

 

It does, concise and clear as usual.  Amazing miniaturization of the real thing.  Keep going!!! It's amazing.