Spirit of St. Louis - some considerations

[birder]

Leif, do you think possible to leave the rear cabin former out and detail back far enough to be more realistic? I'm seriously considering this one, although have some projects still lined up in the near future

[GreMir]

Glen,
If you are asking about former W8 then Leif already answered that in the previous thread. This former is to be inserted only temporarily to help correctly shape fuselage.

[Leif Ohlsson]

Glen, like Michael points out, I think (without having seen a finished model) that the interior detailing goes far enough back. You won't be able to see farther back through windows or partially open door.

But the issue you raise is pertinent, and I look forward to discussing it in further depth a bit down the road. I take it you have the model, so we can compare notes.

Meanwhile I have mined the "Donald A. Hall Photograph & Document Collection" a bit deeper and added another twenty photos to the Spirit of St. Louis - original construction album. Here's an example (aileron fitting details):



There are also some fascinating and informative photos of the unfinished wing:



Note the ribs hanging on the wall - they are probably not for the Spirit wing (which is already finished, right!).

[Leif Ohlsson]

I'll start a discussion of the intriguing issues when modelling the Spirit of St. Louis with this: What was the colour of the fabric inside the aircraft, as it flew between New York & Paris?

It is not such an easy question as it seems, since the aircraft as it hangs today from the Smithsonian has undergone a number of modifications. The first happened already immediately after the night landing at Le Bourget, where an unruly mass of souvernir hunters literally ripped the Spirit apart.

The French authorities were much embarrassed, and a team of French mechanics worked overtime to repair the aircraft, so that it looked brand new when Lindbergh saw it again, for his flight to Brussels.

According to one expert (see this discussion, a few posts down), the dividing line of the repair can still be seen in modern photos of the Spirit:

[Click on the thumnails to see larger photos posted in the gallery; click on these in turn to see maximum size photos. While you're there, feel free to familiarize yourself with the Spirit of St. Louis galleries - I have tried to cite original source captions, and have added a fairly liberal amount of my own comments and notes of issues still outstanding]:



Look on the left side, and the dividing line between undoped and silverdoped fabric.

The silverdoped section in front can be seen more clearly in this photo:



(Note here the handwritten text on the silverdoped fabric. It must refer to the carburettor heat lever. Carburettor heat was not installed until in New York. The position of the lever for carb heat is an issue in itself, which I will bring up again later on.)

There is only one more (colour) photo of the interior I have found, and it shows all tan, undoped fabric aft of the pilot:



From this evidence, are we supposed to think that the internal colour of the fabric was silver before the French repairs? I don't believe so, and the clinching piece of evidence would be the following photo:



According to the source (Wikipedia) this represents a "Small piece of the fine linen fabric painted silver from the Spirit of St. Louis from a larger piece presented by Charles Lindbergh to the Belgian Ambassador to France in Paris, May, 1927".

The original source is stated as "The Cooper Collections". I have not been able to identify that source, but I will provisionally accept the photo as being of an authoritative sample. If it was indeed presented by Charles Lindbergh in Paris, May 1927, it was likely a piece of the fabric which was removed by the French mechanics who repaired the torn fabric. If so, it is most probably an authoritative example of what the fabric looked like, which, in turn, means that a colour scheme of silver on the outside, and tan fabric on the inside, is the most appropriate.

It may be the case that the silver painted section on the left side of the inside fuselage originally was slightly larger, perhaps to correspond with the silver doped inside of the door. But I do not believe that any major part of the inside very well can have been silverdoped.

Final consideration: Could the outside silverdope have soaked through to the inside? I don't think so. This is demonstrated both by the fabric sample, and by the photos of the interior, even if the fabric shown there should be a result of French repairs. After all, the French mechanics silverdoped the outside just the same as the workmen at Ryan's in San Diego.

What this means, is that the interior of Rafael Ciesielski's Gremir Spirit will have to be recoloured, or that a tan-coloured paper should be used for printing the inside pattern (with the exception of the inside of the door, and just possibly a corresponding section on the left side).

What do you say?

[birder]

Leif and Mike, thank you both, I think this looks like a great model of perhaps the most famous aircraft of all time (except the Wright flyer). If one looks at Lindberg's lack of interest in personal comforts and desire for weight saving I would think the interior fabric would be unpainted, maybe now somewhat faded though, may have been white cotton duck canvas originally? Or sealed with a coat of varnish? I can ask Addison who built the Boeing 40, he knows so much about fabrics of these aircraft, although Shrike has worked personally with these materials. The tubing color unpainted?

[Gil]

Hi Leif,

It was and still is usual to paint the fabric with quite a few coats of sealer before the color coats are applied. In 1927 the sealer used was nitrate dope as was the final color coat which, in the case of the Spirit, was nitrate dope with powdered aluminum. I've tried spraying this combination on cardstock with good success. It requires a rub down with 0000# steel wool between coatings to keep the paper texture from showing through. Applying inkjet ink to it after painting is no problem.
As for the original aircraft I believe that the material was left natural on the interior as applying paint from the inside after covering would be rather difficult and would have added unnecessary weight...,

+Gil

[shrike]

The fabric would have been given a brushed on coat or two of tautening nitrate dope followed by one to three coats of dope , sprayed or brushed, into which aluminium powder would be mixed for heat and sun (UV) resisitance.
The bare cloth is white to off white, either cotton or linen (off white Irish Linen in the case of the Spirit) which darkens and yellows slightly with the dope. Depending on the thickness of application of the initial clear coats, some silver may show in flecks and oozes.

All of the above is true for practically EVERY fabric covered structure from 1920 onwards whether or not any additional colour is used for a final finish. From 1965 on, a newer set of materials may produce a pink interior, but still with the silver coats.

In the specific case of the SoStL, they used Irish linen, and scrimped on the aluminium powder to save weight.

The steel tubes could have been finished in a couple of ways. Certainly primed if not painted. Zinc chromate is a standard by 1931, at least.

[shrike]

Follow up Re: Tubes

Fokker who pioneers steel tube frames used a clear lacquer mixed with lampblack giving a translucent grey finish. It was ineffective, so rust appeared quickly.

Red-oxide primers, oil and lacquer were common followed by, but not replaced by, zinc chromates by the late 1920's. Silver (aluminium) lacquer and bituminous paints were also used where corrosion was likely to be a problem.

[dansls1]

So likely the area on the inside coated with the silver color is incorrect to original 'as flown' condition - possibly due to the hasty repairs and using whatever materials they had on hand?

[Leif Ohlsson]

... or - and here's a completely new theory - it's a piece of silverdoped cardboard, plywood, or similar, installed as protection for the fabric covering when manouevring the levers or something, or perhaps just in order to be able to write the "heat off-on" text? Compare these three photos:

[click on thumbnails for gallery photos]

The first one is from the Smithsonian, today. The second is the inside photo already studied, also from the Smithsonian. The third is undated; it looks old, but I doubt that it is from the construction of the original aircraft in San Diego, even though the fabric isn't there, since the new type of earth inductor compass actuator/regulator (next to the wicker chair) is mounted, and that did not take place until New York.

Since the fabric is gone in the third photo (not done prior to NYP flight), it follows that it must be from some restoration or other (either after landing in Paris, by French mechanics, or on some later occassion, doubtful when). I have no further information about the photo.

Note particularly in the third photo that although the fabric covering is missing from both sides of the fuselage, the piece of cardboard (or whatever) is still there, which seems to prove that it isn't part of the fabric covering.

Since the carb heating wasn't installed until New York, just prior to the NYP flight, it would have made good sense to install a fool-proof sign reminding the pilot (who would not have had ANY chance of trying out this new feature) of the correct maneouvring of the essential carb heat lever.

For modelling purposes, I therefore think we ought to assume that it looked just like that, including text; that it was there for the NYP flight; but that it is not part of the fabric covering. In other words: An extra small part, silver coloured, glued to the inside simulated fabric.

What do you say?