Heavy Mod - 1/18 21st Century Toys P-47D Razorback

[JayW]

"This is simply amazing. Don't you dare stop!"

 

 

 

Ok Shaka - not stopping.  Slowing down some though.  This was to be a winter project, where I could attack with intensity in winter.  And attack it I did - it almost dominated my life the past few months.  But now Spring has sprung.

 

I just wanted to show y'all some machining work.  First, I redid the reduction gearbox housing (the nose).  The first one just didn't have the right shape.  This one is a little blunter:

 

 

 

That's a busy picture.  It also shows the base of the propeller which is waiting in the wings.  

 

Here is a view of the other side of the stack:

 

 

 

I just finished this machined part - it is the intake manifold.  Compare it to this shot of an actual R-2800:

 

 

That is as far aft as I am going to go with this engine.  Everything further aft is hidden by a firewall, coincident with the aft edge of the cowling flaps.  I will fabricate that sometime in the near future.  And I will not (repeat - will not) be making removable cowling panels aft of that plane.  

 

Now, I had planned for the next task to be fabricating and installing the intake manifold pipes, a very challenging job as you will see.  To do that means the aft and front row cylinders and engine block sections must be bonded together.  But it occurs to me that I might not be able to route and attach the spark plug lines to the back of the front row of cylinders with so much stuff in the way.  The real culprit is the ring between the cylinder rows that supports the inter-ear baffles that I showed a few posts ago (and easily seen in the first two pictures).  A little hard for me to explain, but suffice it to say I think I need to re-sequence this engine build-up.  I believe I now have to fabricate and install the ignition harness just forward of the front row of cylinders (and easily seen in the photo above), and create the wiring for the back side plugs of the front row cylinders.  The lines go from the ignition harness up and over the cylinder heads and through holes in the as-yet-uninstalled front row inter-ear baffles, so those have to be made up too, and loose installed with the spark plug wiring.  All that might mean I have to finish up the reduction gearbox housing, which in real life provides the attach points for the ignition harness.  Dam.....   And that housing is also a big deal - it is machined, sure, but all that clap-trap has to be mounted to it (magneto's, etc).  That finally allows me to final attach those 9 back-side front row spark plug wires.  Then, I think I can bond the two engine block sections together, and proceed with the intake manifold pipes, and then the exhaust manifold and pipes.  And finally the remaining spark plug lines, whose routings are easier.  Clear?

 

OK later - the next post, whenever it is, should be very interesting.      

Edited March 29, 2017 by JayW

[JayW]

Well - I really didn't need to drop everything and tackle the front end of the engine like I said in the last post.  I have been working on the intake manifold pipes (made from .118 inch diameter silver solder).  And in parallel I am making the front row aft spark plug cables, while there is still room to do them.  I am just "coiling and stowing" the cables, which allows me to work the aft end of the engine now.  The work is painstaking and slow on the intake pipes because the silver solder pieces they are made from have to all be bent up and hand worked and ground on.  

 

Here is one set (of nine):

 

 

And the first spark plug cable (the engine gets 36 total, but 9 will be done at this stage):

 

 

Soooo, each outlet of the intake manifold (there are 9) has a pipe that immediately splits, one side slanting up to an aft row cylinder head, and the other side turning forward to splice with another pipe coming from a front row cylinder head.  So there are 3 pieces for each pair of cylinders (actually 4 if you include the splice tube which is not shown here - that comes later):

 

 

Put together, they look like this:

 

 

You see 4 of them, 1 not done.  You will also see the big ugly holes drilled into the backs of each cylinder head - 36 total.  I was oh so pleased that I didn't ruin any of the cylinders I labored so much on.  The unoccupied holes are of course for the exhaust pipes (the occupied ones being taken by the intake pipes).  You think the back part of this engine looks complex now?  Wait until I get the exhaust pipes on it.  

 

As of this moment, I have 5 intake pipes done, 4 to go.  I will probably post again when they are done, and perhaps I will have gotten started on the exhaust pipes.  Take care, hope you are enjoying this tough scratch build.  It's going to take alot of time and effort.

Edited April 9, 2017 by JayW

[Guest]

This just keeps getting better all the time........Harv

[Joel_W]

Jay,

Those intake header pipes are incredible, especially when each pair joins into one port. And they fit perfectly at each end. 

 

Joel

Edited April 9, 2017 by Joel_W

[JayW]

Kind words all.  I have a nice little update for you.  First, the intake header pipes are all done.  And, the exhaust headers for the front row are done as well.  Here, take a look:

 

 

 

 

Beginning to look like a snake's nest.  But that is what it is supposed to look like.

 

At the same time I have been working the nose case.  Recall that part was turned on a lathe.  Then, I milled various cuts into it to accept plastic inserts which serve as mounting surfaces for the various pieces of equipment which attach to it.  That equipment is as follows:  scavenge oil pump, propeller governor, "turtleback" magnetos, and a blanking plate for an unused mounting plane.  Here is the scavenge pump:

 

 

It is made from many very small pieces of plastic stock.  Here it is mounted on the nose case; you can see the plastic insert:

 

 

Here is a shot of the top of the nose case, updated to include the blanking plate, the mounting surface for the prop governor, and the beginnings of the magneto's (the .25 inch tubes):

 

 

Lastly, for this post, a front view of the engine which give you an idea what it will look like when looking into the front of the cowling (oops - upside down!).  

 

 

Next post, I hope to show progress on the turtleback mag's, the ignition wire harness, and possibly the exhaust collector pipes.  Also, I will have received in the mail a set of miniature nuts from Meng (I hope they will do the trick).  Stay with me!  It's getting really interesting.

Edited April 17, 2017 by JayW

[LSP_Kevin]

Fantastic work, Jay!

 

Kev

[Citadelgrad]

Wow. Thats all I've got.

 

Wow.

[Shawn M]

that engine is stunning

[Joel_W]

Jay,

  Detailing at a level that just constantly amazes me.

 

Joel

[Jim Barry]

Excellent Jay. My next (tentative) scratch project has a radial engine but I do not think I have the patience for this. Bravo!

[brahman104]

You know with pieces of art like that little scavenge pump, one might suggest you've been taking a leaf out of Peter's book! Very nice indeed Jay. Those manifold's must have been horrible to make but they sure look the part.

 

This engine is an absolute masterpiece!

 

Craig

[JayW]

"Those manifold's must have been horrible to make but they sure look the part."    

 

Thanks Craig!  Have seen some detailing masterpieces from yourself also.  The intake pipes were indeed on the "horrible side" because of the splits.  Those little parts required time on the grinder, at the ends upstream of the split, which got them hot and tended to burn my fingers during the grinding operation.  Once I began to feel the heat, it was usually too late and by the time I could put the part down on the table, I had already burned my fingers!  For that reason and a couple of others, it wasn't much fun.  

 

The exhaust pipes, although they have a "joggle" in each of them, were not so hard at all.  That is because I used the 1/8 silver solder, which is soft enough to form rather easily.  And once you put a bend or a kink in a piece, it has no appreciable springback, so it keeps its shape. On the actual engine, the exhaust pipes are in halves, with a longitudinal welded split.  I wanted that, because you can see it (with cowlings removed of course).  So I ordered some plastic 1/8 half-round plastic stock intending to joggle two pieces and glue them together with a piece of .005 inch plastic sheet in between to represent the welded joint.  It worked wonderfully except one key thing - the material has so much springback that I could not adequately control the forming.  Dimensionally the parts were all over the place, and couple that with the variation I already have among all the cylinders, I could not control the location of the aft end of each pipe - the ends that will mate with the exhaust manifold still to come.  So, I punted on that idea and went with the silver solder which is much more controllable, but less realistic.

 

The scavenge pump's hardest task was to lay it out!  I could not find much information on the part, so I just went with pictures in the Erection & Maintenance manual and any photo's I could find.  It being integral to the engine itself, P-47 engineering drawings (Republic Aviation) do not show any real detail of the part.  P&W drawings would, but I don't have any of those.  But once I "imagineered" the part, it was fairly easy to make although pretty small.  As you know, patience is the name of the game with small parts.  That and high magnification, and liquid glue!

 

Surprisingly, E-bay helps sometimes.  Amazing how many aircraft parts you can find on E-bay, with great photo's.  I found a "turtleback" mag there, as well as a GE prop governor.  It will help as you will soon see.

 

Jay

Edited April 18, 2017 by JayW

[richdlc]

that engine block is awesome!!

[JayW]

A quick but important update:  The ignition wire harness is complete and ready to accept spark plug lines, as soon as I attach it to the engine block.  It's a big deal to me, as I was stressing out about how in the world I could make a convincing part.  Turns out it wasn't so bad really.  Some pictures:

 

 

As you can see I got some great coaching from P-47 publications such as the erection and maintenance manual.  Also engineering drawings and photos from the web helped.  There are several versions of the harness - the one you see here is specific to the GE system with the turtleback magnetos.

 

A close-up:

 

 

 

It is made from a ring of .063 inch diameter aluminum tube, many little plastic stubs for the wires, and a multi-piece block of plastic for the thicker more robust upper part, whittled on and whittled on.  The thick part has four pedestals on it, that are to mount the aft ends of the magneto's.  You will see that soon (I have to fab the magneto's from scratch - another tough job).

 

A dry fit:

 

 

 

This thing is starting to look like a R-2800.

 

And another shot showing the region the magneto's' will occupy:

 

 

I can hardly contain myself - it's pretty exciting right now because progress is faster and not as monotonous.  Next is joining the two rows of cylinders, attaching the ignition harness, and routing the 36 spark plug wires (now that will be monotonous!).  That also includes making and installing the 9 remaining inter-ear deflectors for the front row (also a bit monotonous).  And then - the magneto's.  Please stay tuned! 

[Guest]

Brilliant !........Harv