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

P-47 Thunderbolt 1/18

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#31 JayW

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Posted 14 February 2017 - 01:21 AM

Greetings.  Let me fill you in on my progress with the R-2800.  It is proving to be utterly exhausting.  Take a look:

 

 DSC05565_zpsxdc1h34t.jpg

 

OK, what you see are cylinder parts for the rear row up front, and parts for the front row in the back.  Let's start with the rear row parts.  There are 9 completed cylinder bodies, and 9 completed cylinder heads, except for the valve covers (which are next in line).  I have a strategy here - to advance progress on the rear row first, make my mistakes there, as the rear row is not easily seen, learn and improve on the front row which is much more visible.  So, you might notice that 7 of the 9 cylinder bodies are resin (they are slightly yellow).  The other two are built up with lots and lots of pieces of plastic sheet (53 individual pieces per cylinder), as you have seen already in my previous post.  Recall I intended to make resin molds to decrease the amount of labor - make 6 masters, and then mold them twice each, which makes a total of 18 parts (12 resin castings, and 6 plastic masters).  So why do you only see 7 resin castings?  Because they were just maddenly problematic.  Due mostly to poor resin flow issues, I had to scrap just about half my castings.  What I salvaged is less quality than what I was hoping for, but acceptable for the rear row.  I thought about scrapping them all - but geez it takes forever to do just one cylinder and the work is soul-destroyingingly monotonous.  So I reached a compromise with myself.  Also, the rubber molds can only make so many castings before they begin to fall apart - especially with all the thin cooling fins and the gaps between them.  The cylinder heads, you will notice, are not cast at all.  They just do not lend themselves to casting due to shape mostly.  So I bit the bullet and built each one up piece by piece (part count is 33 per head).  I am very happy with the results.  Next are the valve covers on each lobe (two per cylinder head).  It will also be very laborious because of their complex shape.  Perhaps I can resin cast those.....

 

The front row is incomplete, as you see.  Only 6 of 9 cylinder bodies are done, but the ones you see are the picks of the litter.  They will really look good.  I will build up the other 3 later on (just can't wait to do that!) after I get alot more done with the rear row.  You also see all 9 cylinder heads, but only about half built up.  I'll get to that later too.

 

Here is a close-up of a completed cylinder head build-up:

 

DSC05567_zpsov25ed4o.jpg

 

There are 8 layers, each with a bent-up cooling fin, and a bent up spacer to provide the gap.  And each lobe has its own set of parts.  In addition to the valve cover work which is next, the little triangular holes will need some treatment to accept the spark plug cables.  I will get to that in a later post.  

 

There is another feature of the R-2800 that I am going to try to represent - baffles:

 

DSC05566_zpskl0fgyqs.jpg

 

I took that shot from a page in my 700-page book on the R-2800.  Look closely at any picture of an R-2800 and you will see them.  I don't have a real good plan for this yet - they are not going to be easy, even a simplified version.  And if I fail miserably I will leave them off.   Heck - I don't think I have ever seen them modeled anyway.  Accepting ideas.....

 

OK.  At least you now know I am hammering away at it.  What a huge undertaking...

 

Later.


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#32 harvey

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Posted 14 February 2017 - 01:36 AM

DAM !!.....Harv :popcorn:


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#33 ClumsyDude

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Posted 14 February 2017 - 02:16 AM

Unreal!!

Jim
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#34 Shawn M

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Posted 14 February 2017 - 02:37 AM

sofaking cool man, great work.

This is gonna be stunning when its all done


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I dont suffer from AMS, I revell in it..get it...Revell


#35 brahman104

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Posted 14 February 2017 - 06:18 AM

You have much more patience than me Jay! I tried that once with a little lycoming flat 6.... never again!!!!!

 

The engine's going to look awesome when you're done mate.

 

Craig

 

P.s. I had exactly the same issue casting those cylinders as you did, I wish I could help with a solution, the only thing I can think of is ultra slow curing resin, and maybe coating the inside of the mould with resin first before you pour the rest?


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#36 JayW

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Posted 26 February 2017 - 01:37 AM

All right.  In a frenzy of work the last week or more, I have finally completed the aft row of cylinders.  Part count is around 1000.  I have committed myself to some ambitious projects before, but boy howdy - this one is indeed ambitious.  Recall I decided to incorporated aerodynamic baffles for each cylinder like this:

 

DSC05566_zpskl0fgyqs.jpg

 

Well that added significantly to the work load, not so much due to part count but just due to fit up difficulties.  Here - take a look at what I did:

 

DSC05571_zpsizaqzzbl.jpg

 

DSC05572_zpsd3xrhoxh.jpg

 

I should first state that you are seeing a completed cylinder which is a big milestone.  Previous versions were prototypes.  Note the valve covers, and of course the final paint.  I first painted everything black, and then painted silver over the black but not into the gaps.  My decision, good or bad.  You can judge.  You can see the baffles on either side of the cylinder body - looks sort of but not exactly like the real thing.  They are made out of simple plastic sheet wrapped around a tube to give curvature.  Ya know what?  They are all but invisible for the back row.  But I got lots of practice for the front row to come - and the baffles will be much more visible there.  I am pleased I did this - they really need to be there if the engine is going to look authentic.

 

Well I had to multiply that work by nine - and finally, FINALLY, I get this:

 

DSC05574_zpsn7onaxpv.jpg

 

DSC05575_zpsw7ko1jr7.jpg

 

The first shot is the forward side which will be somewhat visible behind the front row.  The second shot is the aft side and will be entirely unseen.  So why did I put in the valve pushrods?  Honestly?  For you guys.  And to get practice so there are no surprises on teh front row, where the valve pushrods will be in full view.

 

And here I will compare what I have done to what it will replace:

 

 DSC05577_zpsb3dppxs5.jpg

 

Now, I will incorporate the support ring for the "inter-ear deflectors", and the deflector baffles themselves for the back row.  That will be tricky but will not take very long.  I will post when I am done, and then it is going to be the forward row - which at present is only about 50% done.  Spring and summer are approaching and with that I will be doing more other things and less modelling.  Hurry hurry. 


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#37 Shaka HI

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Posted 26 February 2017 - 01:49 AM

Meh..I like the kit part better!

 

:)


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#38 harvey

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Posted 26 February 2017 - 01:54 AM

Your wack Shaka.....Harv


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#39 brahman104

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Posted 26 February 2017 - 07:11 AM

Jay,

 

I must offer my congratulations on your first row. You are certainly a glutton for punishment, but the results speak for themselves. Really outstanding work and looks a million times better than the kit part. You'd better display it with at least part of the cowling removed after all that!

 

Cheers, 

 

Craig


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#40 LSP_Kevin

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Posted 26 February 2017 - 11:19 PM

Amazing engine, Jay! Your skills are, to quote the bard, most impressive.

 

Kev


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#41 JayW

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Posted 28 February 2017 - 03:36 AM

Thanks guys.  Look at this picture and you will see a thin black ring between the cylinder rows:

 

 DSC05457_zps9w2hmbg0.jpg

 

That ring is there to support 18 inter-ear deflectors, part of the air flow scheme for the R-2800, and you can see them between the lobes on either side of each cylinder head.  The ring is attached to flanges on the valve covers, maybe 4 locations, not sure (but not 9).  I added that to my 1/18 reproduction:

 

 DSC05578_zpsvqf7lzeu.jpg

 

Of course only 9 of the 18 deflectors are there.  The unpainted white areas are reserved for the other 9 which will be for the front row of cylinders.

 

And that is what is next - finish the front row cylinders.  They are going to look better than the aft row since i picked the best looking ones for the front row and left the mistakes for the back.

 

Craig - you mentioned leave part of the cowling openable.  Well - the engine aft of the cylinders (the intake manifold, intake pipes, exhaust stacks, carburetor, engine mount, and all the stuff in that part of the engine compartment) will be absent.  Now that would be a project!  No, I think I will button up the cowling and instead will be satisfied with seeing all this stuff with a flashlight.  It will not be the first time I have done alot of work on things that cannot be easily seen.   


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#42 Jim Barry

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Posted 28 February 2017 - 10:52 AM

I think I know about your P-38 from surfing the net a bit ago. This is cool to be see this guy come alive. I still recall seeing a 21st C plane in Walmart years ago and being struck by its impression. Way to go learning about resin cast. I keep meaning to dive into that skill. I even have the stuff for it. 


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#43 airscale

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Posted 28 February 2017 - 01:26 PM

incredible! I had a bad enough time making one cylinder for the same engine in 1/24 for my Tigercat so I could cast copies. The thought of doing all of them is a guaranteed ticket to the funny farm if it were me :)

 

Looks superb and it's great to see the diligence in research come to fruition like this

 

Peter


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#44 Guyman1

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Posted 28 February 2017 - 04:44 PM

Very impressive.
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#45 Joel_W

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Posted 28 February 2017 - 08:50 PM

Jay,

   I just read through your entire scratch engine build, and I'm simply blown away :wow: The level of craftsmanship that you've displayed is just beyond what the everyday plastic modeler could even comprehend. 

 

Joel


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