Jump to content

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


Recommended Posts

Hello fellow modelers.  I now embark on my 4th and final 1/18 scale mod project - an F4U Corsair.  My past efforts have been a P-51D (Miss Velma), a P-38J (Lucky Lady), and a P-47D (Glen Eagleston's Eagle).  You can find articles on the P-51 and P-38, and WIP and RFI posts on the P-47 on this site, if interested.  All three took more than two years each, and I expect the Corsair will too.  At least.


Here are the customary "before" shots:








Cool huh?  I obtained this toy/model a few years ago along with the P-38 at a local hobby shop where a whole bunch of these large toys were donated by an estate.  As you all probably know, these things are no longer manufactured.  The manufacturer is Blue Box (probably originally 21st Century Toys).  The date on this one is 2005.  To my eye at the time, it looked realistic enough to be a good mod project.


My plan is to greatly improve the following items:


Engine (all new scratch build, including back section)

Engine compartment including engine mount


Landing gear 

Gear bays 

Wing fold mechanisms






And there will be smaller projects as well too numerous to list, similar to what I did with the other aircraft, except even more ambitious.  I hope my eyes are not bigger than my stomach here - it is entirely possible I run out of steam somewhere along the way, or not get up to speed at all.  After all, I just finished the P-47.  But I think not.  I'll take my time and try not to put any pressure on myself (yeah right!).


So when I sat down and really inspected this toy, I saw things I like, and things I don't like.  As usual there are lots and lots of inaccuracies that are fixable - I expect that.  Here is what I did not expect - I was very disappointed to see that the engine cowling is not correctly shaped.  I mean it is deal breaker to me unless I can fix it.  Here is what I mean:


The engine cowling has a round cross-section just like it should.  But it should also have a slight taper as shown in this side profile (drawing VS-33001):




Can you see it?  The taper is slight but noticeable (at least to my eye).  Now look at the toy model:




From the cowl flaps forward, this cowling has a constant cross-section.  No taper at all until you get to the front end.  This sticks out like a sore thumb, makes the nose look bulbous.  


So what to do.  Well, this model is going to get a complete engine anyway, with removable cowl panels.  So the cowl flaps and panels over the engine will be replaced anyway.  The nose cowl must be salvaged (I know not how to make one).  The fuselage aft of the cowl flaps is just fine shape-wise.  The typical gage of the plastic is .08 inch - robust.  After some research it turns out that if the nose cowl could be decreased in diameter by about .08 inch (.04 inch on the radius), and reshaped to blend out the shape, I would still have about .04 inch gage to work with on the nose cowl, and I would get the slight taper I want. 


Some of you know I own a small desktop lathe (a Unimat).  So I decided to try to turn the cowling on the lathe.  To do this, I had to lop off the cowling:




I was thinking at this point if this blows up in my face, I will just not do this project at all.  Here is the cowling on the lathe chuck:




Ha!  My lathe is intended to work with raw material no larger than about 2 inch diameter.  This cowling is a bit over 3 inches diameter!  I had to put a large spacer under the head stock mount (see it - its that silver spacer).  I had to mount the cowling very carefully - no wobble allowed.  Then I rotated the head stock about 2 deg and proceeded to turn material off the nose:




Then I removed the nose cowl:




Success - that worked way better than I thought.  So I am off to the races.


I guess the engine is going to be first on the list.  The Corsair was powered by the Pratt & Whitney R-2800 double wasp, as was the P-47 Thunderbolt.  For the P-47, I dedicated about 6 months of my life scratch building a R-2800.  And it didn't include the aft section.   This time, I intend to make use of 3D printing in some way.  At the very least, the cylinders will be 3D printed.  So perhaps it will not take so long and not be as tedious.  


Hope you can look in from time to time!  See ya!  



Edited by JayW
Link to comment
Share on other sites

Here is a shot in the dark - I think I can put a perfectly scaled 1/18 R-2800 into this cowling.  No need to alter it to account for really thick cowl panels or other scale errors, like I had to do for my P-47 engine.  So I would love to get my hands on some R-2800 drawings or scaleable figures.  So far I can find nothing other than poor outlines on the power plant install drawings for the P-47, F4U, and F6F (drawings provided by Aircorps Library).   Anybody know?

Link to comment
Share on other sites

Am in a struggle right now trying to develop critical dimensions for the R2800.  It is so jam packed with stuff, if I get something wrong, it will result in something not fitting.  So, cylinder outer diameters, engine block cylinder base plane distance from centerline, location of intake and exhaust ports on the cylinder heads, distance between rocker arm covers, etc, etc, etc.  You may wonder why I do not just duplicate my P-47 engine, but believe it or not it was chalk full of inaccuracies, all of which I intend to correct.


The best thing to do here is model it digitally, but I am seriously hesitant to one, pay for the program software, and two, learn it.  I can manual draft pretty well....


Stay tuned!

Edited by JayW
Link to comment
Share on other sites

  • 3 months later...

Wow!  The summer is just about gone!  I have been doing alot - just not modelling.  Not much anyway.  


So the first major Corsair project is going to be the R-2800.  It will be a massive scratch build project, even larger than the one I did for the P-47 a couple years ago that some of you are aware of.  That engine turned out pretty good, but it had some errors that I intend to address this time around.  I intend for this Corsair to have a fully displayed engine right from the start so it has to be good, with corrected errors.   Some of the errors centered around the cylinder heads and rocker arm covers, which are very visible with cowlings off.  So I did alot of picture studying, learned some things, and went to work developing a front row cylinder head with improvements over the P-47 effort.


First a typical R-2800 picture:




If you look closely you will see that the intake side of the cylinder head doesn't look quite like the exhaust side.  It's different on the back side too.


Here is the first of 9 front row cylinder heads, basically complete:








There are so many parts here - it's just remarkable.  So daunting to think I have 8 more to go, but I will do it on and off again.  The back row cylinders are a little different - there will be 9 of them also.  Of note - the spark plug depressions on each side, the bolt-on rocker arm covers, the rocker arm shaft hardware, and the intake/exhaust openings on the aft side.  The basic cylinder head is made mostly from 0.01 thick plastic sheet.


Of course, these cylinder heads mount on top of the basic cylinders - which are build-ups of 0.005 inch thick plastic round sheet.  


I know what many of you will say!  3D print!  But I have to purchase and learn a CAD program, and frankly I am not sure if this shape will do well 3D printed.  Will the fin edges do OK?  


I'd love to tell you another update comes soon.  We'll see.  Happy modelling!  And thanks for looking in. 

Link to comment
Share on other sites

I want to establish the baseline for this R-2800 build - which is the R-2800 build I did for my P-47D.  So I include some pics of the finished product:










The Corsair R-2800 will also have the aft part of the engine including the carburetor.  The exhaust stacks will look completely different from the P-47's, and the ignition system will be completely different, making the front end look different.  The rest will be identical except with corrected errors.  The original was a huge adventure, this one will be "huger" still! 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...