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1/24 Scratchbuilt P-38L A retrospective to the present


KevinCG

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Where to start?

It has been stated that the P-38 lightning was an expensive and complex aircraft to construct. However with a number of scratchbuilt 1/24 scale aircraft under my belt what could possibly be the problem?!

Project started 2012 and was based upon some plans I had acquired a long time ago by Le Roy Weber for Superscale. These are regarded by those who should know as the most accurate drawings around. They seem to be readily available now on the internet under various author names.

Next was obtaining a library of reference photos and copies of the original parts and Erection and Maintenance manuals including one on the supercharger.

Prime Portal, and several walk around sites especially Project XP-38N project walkaround were especially informative.

I also had the opportunity to inspect and photograph details of several preserved P-38s in the US and the one that used to be at the Classic Jets Museum, Parafield, SA to whom I am very grateful.

First step was to construct boom and fuselage patterns using plastic card formers with 2 part epoxy pipe jointing compound (Ferropre) as a filler. Patterns then sanded to shape using formers for reference The patterns were made slightly undersize (1mm) to allow for skinning. Key datum points are marked and drilled out.

These composite patterns are then used to cast epoxy patterns in a plaster of paris mould.

These epoxy patterns were then utilised for vacforming. Why go to this extra trouble of epoxy patterns. My experience is that when vacforming over non-homogeneous substrates this can manifest itself in the vacform due to dissimilar substrates having varying heat expansion coefficients. Thus the resulting vacformed piece has some unwanted surface texture such as from open grained woods with pronounced growth rings etc. This then requires much sanding to produce an acceptable surface.

The pic below shows the stages in this process

 

uThFZuk.jpg

 

Next stage was marking out the vacform shells which i will cover in the next installment. Getting to here has been enough in itself!

Edited by KevinCG
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Welcome Kevin.  Cheering you on.  Recently,  I got caught up drooling over Rikyu Watanbe's P-38 cutaways. It's inspired me to do some 3D models of the plane (see below). I  may one day build it (after my Bearcat). I could not believe it that someone here was into this as 1/24 scratchbuild, too. Way to go!  It's a real beauty and even more beautiful the more you study it. 

 

oNbpvk.png

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Many thanks for the comments guys.

 

Greetings Kevin! Best of luck with your P-38 project, if you get a chance you should post some of your other completions on here too. I do love P-38's, so I'm looking forward to following on your build.

 

Cheers,

 

Craig

Thankyou Craig a Number of the builds were featured in the second edition of Scratchbuilt by John Alcorn. I think there was a Corsair, Tempest, DH Hornet and Spitfire MKXIV if i remember correctly. There have been some since then but most of my photos were done in the pre-digital camera age ( a testament to how quickly I build!).

 

Marking the patterns and vacform shells

Transferring measurements from a 2D plan to a #D model is always a challenge.

This is why a datum line or some other reference on the plan is important so that the correct spatial disposition can be obtained.

In the case of the P-38 booms this was easier than most as the top of the boom is parallel to the datum line. The fuselage pod was a little more problematic.

I use a pin mounted in a dremel drill that is mounted in a drill press that is perpendicular to a flat base (checked with a spirit level).

Place the pattern or vacform shell on the plan and mark where the datum intersects with the edge.

Draw  parallel lines on the flat base corresponding to the distance from the datum for important locations such as wing leading/trailing edge main spar cockpit and wheel well cutouts etc and then using the drill lower to make marks for drilling pin holes. I skin my models so such imperfections are hidden on the final model.

If you have cross-slide vice or lathe then this process is infinitely easier.

The photo below show some key marking points on the fuselage pod for the P-38

CGqy3Wt.jpg?2

 

Key markers here are the location for undercarriage leading edge, main spar and also a line of pin holes along datum line for future reference. I have already cut out cockpit and nose canon openings. I think that covers it but happy to clarify

 

Thanks for following

Kevin

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