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


JayW

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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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  • 2 weeks later...

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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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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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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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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"You'd better display it with at least part of the cowling removed after all that!"  Says Craig.  And Jay thinks that he has a point, yet shudders at the prospect.  Then I find this incredible picture somewhere on the web:

 

Picture1_zps2lcbm7vr.jpg

 

Well, I am considering adding an aft section to the engine - all the stuff forward of the pre-heater, which is sort of like the firewall and just under the aft edges of the cowling flaps.  That includes the intake manifold, intake pipes that go from the manifold to the back side of each cylinder, and the exhaust manifold with its individual pipes that also go to the back side of the cylinders.  If I can do all that, then I can have cowling parts that can detach, and I can show an engine that looks complete.

 

This project is prodigious already.  To add all this work is prodigious times two.  It is also a bit risky.  It involves drill 1/8 inch holes in the back of each cylinder head, and I didn't design them to do that.  So I think I will try one out soon and see if it is reasonable.  The worst that can happen is that it messes up the back of the cylinder head, but it cannot be seen anyway.  If that happens I will abandon the idea.

 

The task involves the following:

 

Drill 1/8 holes in back of cylinder heads

Make intake manifold from lathe-turned acrylic part

Make intake pipes from 1/8 inch solder (very difficult)

Make exhaust manifold from thick plastic hogged out part (very difficult)

Make exhaust pipes from 1/8 inch solder (very difficult)

Make engine mount / preheater from lathe-turned part and thick plastic plate

 

Any comments?  I am pretty excited.  I laid it out 4/1 scale, have some reason to believe I have a workable plan.  

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