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1/32 Hasegawa P-47D Sleepy Jean III


petrov27

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I am not sure if you are interested, but knowing the serial number and model of the subject you are doing I think I can determine the engine details you need (distributors, mags, wire harness, etc).   Alot of great Thunderbolt models have the wrong engine stuff.

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Hi Jay W - certainly - I have done some investigations but not 100 percent on what would be correct. The Barracuda-Cals instructions say that "Sleepy Jean III" is P-47D-28-RA serial number 42-28641. I had assumed the R-2800 in this would have the "turtleback" distributer/magnetos on each side so no mag on the center top of the front housing of the engine. Just a prop governor though in between the distributer/mags - on the smaller front plate top of the front housing like in the linked photo. The harness/injection ring I am unsure of. I had thought that earlier engines would typically have the "tubular" ring and later engines would have the "flat" ring like I 3D printed above but not sure. Any input is most appreciated!

 

t3g9ax22gp111.jpg?auto=webp&s=8e40563a43

 

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Patrick - this photo tells all WRT the power plant:

 

8gGnurah.jpg

 

I can tell easily by the propeller, hub, and that skinny dome that this is a Curtiss Electric equipped aircraft - electrically powered prop pitch controls, "turtleback" style mags, where the magneto and distributors are all in the same housing.  The ignition harness is completely different from any of the arrangements meant for the Hamilton Standard props (you have modeled one of them - the pressurized one I believe).  Here is a picture taken from a R-2800 parts catalogue of the GE ignition system:

 

hZBdDzKh.jpg

 

Per my voluminous book on the R-2800 ("R-2800 Pratt & Whitney's Dependable masterpiece" by Graham White), the P-47D-28RE/RA models all got the R-2800-59 engine which is equipped with the GE ignition system.  It is a "B" series, with the single stage turbocharger and down draft Bendix/Stromberg carb.  No P-47 aftermarket kit does the GE ignition system justice.  This is partly because, I believe,  it is not normally seen on today's flying Thunderbolts.  

 

You are correct that this engine has a prop governor on the smaller forward mounting flat on the front gearbox case.  And the larger aft flat is unoccupied except by a cover plate.  But the engine also has a brush assembly and a round housing directly behind the propeller hub, with a visible thick wire harness between the brush box and an electrical box attached to the engine along the RH side sharing fasteners with the forward gearbox casing and the engine block.  I have not seen any R-2800 kit that has these details even though plainly visible. 

 

I spent several years building a 1/18 scale P-47D-30 which has the same engine (or nearly so).  The build is on LSP.  I made all those details and am glad I did.  I think they can be scratch made in 1/32 without much problem if you want to.  I have tons and tons of data on all this, and I also made good use of the "Allied Fighters" Facebook page which chronicles in great detail the restoration of P-47D "Dottie Mae" which I seem to recall is a -28.  Great pics of the GE ignition system, although it has a HS prop with hydraulic prop pitch for some reason.

 

I also subscribe to "Aircorps Library" where drawings and technical manuals can be seen for various airplanes and engines.  The Republic engineering drawings and maintenance manuals of the P-47 show quite clearly all the details of the engine's electrical system.   I can provide pictures for you if you like.

 

Let me know.

 

Edited by JayW
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Just looked over the Vector aftermarket 1/32 kit ("early" version) - it has the turtleback mags but it doesn't have the GE ignition harness or any of the other equipment for the GE ignition system - instead it merely has two versions of the P&W harness associated with the Hamilton Standard props (one an early unpressurized one, and the other the pressurized one).   Both are incompatible with the turtleback mags, although by hook or by crook the kit can still be built up.  Nice going Vector...

 

I don't know if there are better kits out there.  Contact Resine appears to be worse, not better.

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Hi Jay - that is some fantastic information there! I think I will attempt to replicate the ignition system you show there! If you had any more pics of that from the Dotte Mae restoration or their facebook page you mention (sadly I do not Face book) that would be great.

 

Regarding the brush housing and prop gov - I believe this pic I found shows those components?

aNWN0mq.jpg

 

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Great pic Patrick!  Oh yes that is the brush housing in all its glory.  Any more pics (like side views)?   Give me a few days to collect up some pictures for you.  I can PM them, or put them up on this thread, your choice.  It's interesting stuff.

Edited by JayW
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Here is what I could find on the engine electrical stuff on the front (visible) end of the engine.  The P-47 Erection & Maintenance Manual (Document number AN 01-65BC-2) is immensely useful, but of course will not provide dimensions.  You'd benefit from having that document but i don't know how to easily get it without a subscription to Aircorps Library.  Most of the pics come from that document:

 

Hub and brush housing:

 

LYvyRE3h.jpg

 

QDMFOCjh.jpg

 

This view is taken from Republic engineering drawing 93P82225 Elect. Install. - Engine Compartment - you can use it to scale the brush housing (I provided some real-size dimensions that I am aware of):

 

vq0SGJNh.jpg

 

 

Some useful pics of the ignition harness (I dimensioned the engine forward case diameter at the attach flange for scaling purposes), from the same drawing and also the E & M manual:

 

z2YgLx6h.jpg

 

Iv1golKh.jpg

 

zk4VQneh.jpg

 

By my own scaling it appears to me the basic diameter of the harness is about 1.0 inch diameter (or 1/32 inch in 1/32 scale).  The upper portion is much larger than that (where the distributor/mags attach).  That's the challenge - making that upper part).  I  just hogged it out of a chunk of plastic when I did it in 1/18 scale.  Note the turtlebacks are attached via those funny looking chambers on each side of them.

 

You can see there is a junction box that has a wire bundle between it and the the brush box.  This junction box attaches to the engine via a bracket.  Some pics:

 

  YEBhgxfh.jpg

 

 

 

Here is the box detail (some dimensions are provided - scale for any others, divide by 32):

 

O9PKFXMh.jpg

 

And the mounting bracket for what it's worth:

 

YVnIW72h.jpg

 

Note the small box mounting holes (three) that match those on the box detail. 

 

Lastly a shot of the prop governor.  Some of the above pictures show it, and it can be scaled:

 

iukIqm9h.jpg

 

It would be exceedingly difficult to scratch build a 1/32 scale prop governor!   Was hard enough at 1/18. 

 

This will all probably give you as many questions as answers.  Let me know what else you might want; perhaps I can help further.  Good luck with the P-47 build!

Edited by JayW
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Well again not a lot of plastic being touched but I am trying a different kind of model - trying to make the Curtiss Electric prop system as from the drawings/pics - not done a whole lot of 3D modelling at least not in many years - mostly just chopping or slightly modifying models from others. But I guess I will see how it goes!

 

The Brush Housing is started. Not sure how much detail to put on this as the whole thing will be like 10mm wide in 1/32....

y393tDt.jpg

 

Edited by petrov27
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