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Sikorsky S-39 "Spirit of Africa" - Scratchbuilt


Hubert Boillot

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That's disappointing Hubert. I have similar problems with my Anson, I'm pondering how to get the more pronounced angles along the fuselage and how to improve the canopy moulding. I'm with you 100% in the need for female vacuform moulding, is it a more complicated and demanding process?

Max

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Female molding requires that you pour a mold (with holes for the vacuum in the cavity) around the master. Not as simple as plugging a master on a board and pulling some heated plastic over it. BUT the results are so much better (see my Nieuport Sesquiplan or some high quality vacs like Heritage or Dynavector) : the details are where they should be, i.e. on the surface of the part, they are crisp, separating the part from the backing sheet is easier because the separation line is more clearly defined, etc. I dare say that female vac-forming would make the vacforms far more accessible and encourage the modellers to have a go at it, because of the greater quality.

 

As for the S-39, I have decided on a mixed approach, but may change my mind in the end.

The problem with the canopy height is two-fold: 1) the shape of the nose on the fuselage part is wrong, being too rounded, and therefore compounding the height issue if you try to align the clear part with the top of the fuselage nose, and 2) the fuselage sides at cabin level are not high enough. Adding a wedge, 3 mm high at the windscreen level, and 0 at the tail end, would correct the issue.

At this time, I think I will keep the fuselage as a base, correct the mistakes, and add the strakes, filling-in the gaps created by the rounded angles. Not 100 % sure though, as I need to cut bulkheads to have the right shape, so when I have all of them, I may be just as well off gluing plastic sheet on the created frame.

 

For the clear part, the final conclusion, after double-checking with Paul Matt's drawings, is that it is accurate in height, but the profile shape at the rear is dubious, and the key problem is that it is not very clear, grainy on the inside, and I can see it now, yellowing somewhat. So on this one the call is made: I will make a new master for the cabin turtle deck, pour a resin female mold, and vacform the new part both in standard white plastic and clear acrylic. This way, I can either use the full-clear part, or cut the windows on the plastic part and insert the clear ones. This will also solve the issue of the raised side windows at pilot/copilot's level, missing on the kit molding : in fact they were sliding up or down with a simple starp system (see Paul's video).

 

Without the kit as a trigger, I may never have started the project. But it may well be that I will totally scratchbuild the S-39 in the end ;) ...

 

Hubert

Edited by MostlyRacers
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I seem to recall a FSM article that showed how to scratch a S-39, in 1/72... Should be scalable.

 

 

 

 

Edit- Here it is... http://www.ebay.com/itm/Fine-Scale-Modeler-June-88-M-26-Pershing-Ferrari-Testa-Roadster-Sikorsky-S-39B-/360319044742?hash=item53e4b04c86:g:UXgAAOSw9mFWHoT6

Edited by Lee White
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Hi Hubert,

 

Here is another suggestion, and please do as you wish in the end!

It seems nearly all the clear panels are basically flat, so why not use clear sheet styrene (or another clear material).

The clarity would be perfect. 

There are 2 windows on top that have a curve from what I can tell, but those you could save from the kit maybe, or make a small

form to crash-form on.

 

Regards!

Alain

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This is exactly the state of my thinking Alain :). I am just mulling around on how to have as scale-like as possible frames in the cabin area.

 

My thinking for the time being is to use some aluminium sheet around the windows and for skinning the fuselage ...

 

In the meantime, I am redrawing the frames to 1/32 scale from the Matt's drawings, to transfer them to the Silhouette, to at least cut some accurate templates, if not plastic sheet directly.

 

Hubert

Edited by MostlyRacers
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I have this kit. 😠😂. I will be watching closely. Thanks so far for the "tweek" list. I chose to do the Anson first. No sure if I avoided much pain.

 

I plan to do S-39 in the "Varney" airline livery. Avoid the animal rug camouflage you mentioned. I have collected many photos from the web. I have not been able to locate views of the inside. I would appreciate a pointer to a source. I bet one could take much artistic license with the African travel airplane. Two seats with supplies stored all over maybe.

 

I redo the combative models clear parts as a matter of fact for all my kits. Some are clear enough but are starting to yellow. Some have unwanted clumsy ribbing. Jeff made me a set of clear fuselage halves for my Anson so that I can paint the windows add frames etc. He has also re-popped new clear parts for my oldest kits.

 

I do all my shape shifting create sharper edges etc. using Apoxi-sculpt. Drill holes under the area of modification so that the stuff has place to grip. One can shape and smooth the stuff with the thinner right up to the set for good state. Works well from the inside too.

 

Finally I noticed that the turnbuckles and other anchors for the rigging are quite prominent on the real ac. Another challenge probably.

 

Wish you as much luck as you can take in,

 

Rick

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Thank you Rick, I will need all this luck, definitely :)

 

The pics of the restored "Spirit of Igor" are a great source for the inside, and then there is Paul Matt's Historical Aviation Album Vol. XIV. If you can't locate it, I can always send you a scan of the relevant pages.

 

The more I think about it, the more I am headed into a metal skinning of the cabin area, to keep the scale thickness.

 

Having a 5-days break in Lisbon right now (hey Stephen, do you hear me, you can have a stash and keep your wife happy wiwth travels ;) ! ), so I will resume this one next week-end

 

Hubert

Edited by MostlyRacers
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  • 2 weeks later...

Made some progress, although I am not too sure what you will see in the pic below ... :(

 

Anyway, I finished drawing the frames and the keel for the main  fuselage, based on Paul Matt's drawings scaled to 1/32. The drawings have been transferred to the Silhouette cutter, with which, for the time being, I have cut the frames out of aTamiya masking tape sheet, and transfered them to a sheet of plastic. This will give the guide to cut the frames and glue them to the keel.

 

My idea is use 1mm thick plastic card for the keel and non visible frames, and brass for the hollow cabin frames. This will give me more mechanical strength when cut in close-to-scale thickness. My only issue so far is that the 1mm thick card is closer to 1.05 to 1.12 mm :BANGHEAD2: and this promises to make adjustements necessary ...

 

The drawn frames :

 

S-39_couples_V4_zpsm3uwya3n.jpg

 

Masking tape cut on the Silhouette :

 

IMG_1058_zpstkforimr.jpg

 

... and transferred to plastic card ...

 

IMG_1027_zpshmjdu5pv.jpg

 

More hopefully soon.

 

Hubert

Edited by MostlyRacers
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Indeed it will be, Shaka :) ...

 

Now comes the fun part, or how to trust the electrons and waste a perfectly good sheet of masking paper.

 

I imported the frames drawn on another software as a .dxf file in the Silhouette one. Somehow, it resized all my work. I remember saying to myself "strange, this was a really tight fit on my design sfotware - the size of the masking sheet is 240x180 mm - and now I have space all around". But I sent the file to the plotter anyway. And the result was too small by some 15 % :(. I realised it when I wanted to compare the bulkhead I had done for the vac-kit and the one I had cut out :doh:

 

Anyway, the file has now been exported to .pdf format, and the Silhouette software is now plotting the cutting trajectory on 1/32 scaled frames ...

 

Hubert

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I have a feeling that one of these features in the film The Aviator.  Leo DiCaprio (Howard Hughes) takes Cate Blanchett (Catherine Hepburn) flying, and there are some nice interior and exterior shots.  OK, I have no idea whether the interior shots were actually done in one of these aircraft, I have no idea how authentic they are if they weren't,  and I'm not even 100% sure the a/c in question was one of these.  Quite probably all CGI. But it may be worth a look in any case as it's a cracking good film.

 

I'll be watching the film again soon, and I'll be watching this build with interest. 

Edited by MikeC
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