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

[TAG]

Gob fully smacked, you are a scratch-building deity, Jay!

[CZPetrP]

Great looking engine

[Shawn M]

wow.....

[brahman104]

absolutely incredible!

 

Craig

[JayW]

The R-2800, like all radials, has intake pipes for all the cylinders.  The R-2800's looks like this:

 

 

The finger-like pipes with the 90 deg elbow bends, just aft of the cylinder rows,  are the parts in question.  Note two pipes emanate from a single hole in the engine blower unit, splitting off like tree branches.  One branch goes directly to an aft row cylinder head port.  The other connects to an "s" shaped pipe between aft row cylinders, and that pipe goes to a front row cylinder.  And there are nine of these pairs.

 

My intake pipes, as mentioned in a previous post, are made from .125 inch thick solder - fairly easily bent and formed and ground to the right shape.  Here is a simple tool I used to form the 90 deg bend, and trim the ends of each piece:

 

  

 

That gives me a consistent .125 inch radius (bending it around a .25 inch tube).  It takes a goodly amount of force to make that bend.

 

After forming and trimming, these parts can be made into a pair and mated up back-to-back and inserted into a thin tube on the blower section:

 

 

The black short tubes on the table on the right are the connectors for the forward row "s" shaped pipe.

 

Finished up it looks like this:

 

 

 

 

 

With that milestone passed, the next step is inter-ear deflectors and the deflector ring.  This job will be more complicated than the intake pipes, which were actually quite straight forward.  I'll post when I can show good progress.  Thanks for looking in!

 

 

Edited May 13, 2020 by JayW

[brahman104]

Beautiful work Jay! You've done really well with those seamless intakes. You make it look easy! I know you have a love of engines but man, after working with the brassin set for the B-17, I'll be happy not to touch another radial for a while!

 

Amazing stuff,

 

Craig

[JayW]

20 hours ago, brahman104 said:

.....I'll be happy not to touch another radial for a while!

 

Well Craig - I do not know what got into me.  You also followed the P-47 engine work a few years ago, where you may recall I expressed on many occasions that I was ready to lose my mind.  Now I am repeating it only with even more ambitious plans which involve even more parts.  And I have rejected any mass production techniques like resin molding or 3D printing for fear of losing quality (the molding didn't go well on the P-47 engine).  But somehow, I am more comfortable with this build.  I feel like I have all the time in the world, and if I get stressed out, I just stop for a while.  You know - the Covid quarantine has played a part giving me alot of free time where I don't feel alot of pressure to do other things.  Had it not been for that, I'd still be toiling away on those cylinders!  The quarantine won't last in its present form (sure hope not!), so all that free time will probably dwindle away.  Also, the Corsair will in all likelihood be my last 1/18 project, and I am trying to pull out all the stops so to speak.  So I am very motivated to give it a great engine, and to make it very visible with removable panels for both cowling and engine compartment aft of the cowling.  Bold words; now to put them to action.

[brahman104]

3 hours ago, JayW said:

 

So I am very motivated to give it a great engine

 

And that Sir, you indeed have! I have to agree with you, the arrival of unexpected modelling time has been a huge bonus for a lot of us, achieving things in a few weeks that would literally take months or years in other circumstances, or not at all!

 

Always impressive!

 

Craig

[JayW]

At present I am working on a very delicate task - the inter-ear deflectors.  Has to be done at this stage (the aft ones at least).  Makes me nervous, as I am drilling holes into the tops of my cylinder heads to create little bosses for the deflector plates to attach to.  Also, the parts are fragile and easy to make mistakes on.  I will show you how I am doing this.  

 

First, P & W (maybe other engine manufacturers too) struggled with cooling of the cylinders of radial air cooled engines.  So along with the cooling fins, various air deflectors were added to manage airflow around the cylinders, some of which you saw already attached to the sides of the cylinders.  There were also deflectors on top of the cylinder heads that look like this:

 

   

 

They are sheet metal and heavily formed in real life.  All 18 of them (well actually 17 of them) attach to a thin round ring that surrounds the engine midway between cylinder rows.  Notice the aft deflectors look very different from the forward deflectors.  And note the deflectors have 4 attachment fasteners each, which match little bosses on the cylinder heads.

 

So how to fabricate these deflectors - out of thin sheet plastic of course!  Here:

 

 

 

That's the best I can do.  Now to accurately locate these pesky little details, I created another fixture:

 

 

Pretty simple, but it assures the ring keeps a good circular shape, allows for attachment of each deflector detail, allows the aft half of the engine to be placed onto it to help locate the individual deflectors, and also assures the ring is located midway between the cylinder rows.  Like this:

 

 

 

That last pictures shows several deflectors located radially and glued to the ring, but not yet glued to the cylinder heads.  

 

I actually kind of dreaded this task; it was a PITA on the P-47's engine, and it's proving the same now.  But unfortunately with cowling off, these details are bared for all to see.  So a good effort must be made to make them as convincing as possible.  These will be much better than the P-47.  Next post I hope to show you the finished set of aft inter-ear deflectors and the ring, installed onto the engine.  Stay tuned. 

 

 

 

 

Edited May 20, 2020 by JayW

[Shawn M]

holy carp....

[brahman104]

The jump from the second-to-last to the last photo made it look easy, but I know the reality is much much different!

 

Looking fantastic Jay!

 

Cheers,

 

Craig

[Wolf Buddee]

Holy crap Jay!!!!!!!
 

 

Just WOW! 

Cheers,

Wolf

[JayW]

3 hours ago, Wolf Buddee said:

Holy crap Jay!!!!!!!

So Wolf - you of all people know what I am trying to do here.  I am NEVER going to be able to duplicate the quality that Tamiya provides on these details.  Your engine, which is as fine an engine as I have ever seen, has great inter-ear deflectors!

Edited May 20, 2020 by JayW

[JayW]

3 hours ago, brahman104 said:

The jump from the second-to-last to the last photo made it look easy, but I know the reality is much much different!

 

Craig - you are actually right.  Once I got the hang of it, and made a bunch of mistakes, it got a good bit easier.  I am not out of the woods yet.  Stay tuned.  

[JayW]

OK - I am very pleased that the aft inter-ear deflectors and the support ring are done.  My fixture did a great job ensuring proper location.  Here is what it looks like:

 

 

The gaps between deflectors (where the unpainted white ring is visible) of course will be occupied later by the forward inter-ear deflectors.

 

Next on the docket is the reduction gear case for the front of the engine, which starts out as a tricky lathe turning, and then gets treated badly cutting big grooves and drilling big holes for all the mounting bosses for accessories - prop governor, Magneto, distributors, and oil sump pump.  My layout:

 

 

I have had to do alot of research to develop the right shape of this very visible part.  I made two of them for the P-47 engine and still didn't get it quite right.  Anyway you will see it next post.  Take care.