Category Archives: Fabric Covering

Parts Manual into Excel

What seemed like a very long but necessary step is now complete, I’ve transcribed the dh.82a Schedule of Spare Parts (1943) from PDF into Excel.  This will allow me to better track the components of my Tiger Moth and also make it easier to search for missing parts by their various identification numbers.

I’m going to share this document here, eventually I will add a Downloads section for future versions of this file and more like it.

You may download v0.8 of the excel file here.

In future revisions I hope to cross-reference each part by drawing number, add the Canadian parts and part numbers, and generally continue to build it out to become more useful.  Eventually it will be ported over to a database where I will keep images of each part from my aircraft, reference images for manufacturing new parts, notes on the condition and origin of each part, etc.

If you have any resources that might be helpful in further expanding this document, please let me know.

Paint from the Past

Entire sample - smThis old fabric sample is slowly revealing its secrets.

Using a digital microscope, I was able to closely example the cracked paint surface and actually see the different layers of paint and dope that have been applied over the years.  It’s surprisingly complex.

Most of the sample as you see it here was not painted at all.  The brown-colored areas are only coated with three semi-transparent layers.  The bottom layer, clearly a transparent dope of some sort, is slightly yellowish.  The next transparent layer looks like glass and is a sort of green/yellow color.  On top, which is giving it most of its color, is a brown layer that is still semi-transparent.  I don’t know which of these are true “dope” or which may be some sort of a clear coat.  It’s also possible that one or more of these layers may once have had some sort of unstable pigment in them, which has since disappeared.  I will have to do some real chemical analysis I think if I want to dig any deeper into their composition.

 

Dope - yellow dope - brown dopeDope - yellow dope - brown dope 2

Along the edge of the sample is a dark stripe, some parts look dark brown/black and others are blue.  I call it the blue stripe, just for ease of reference.  It has two more layers than the main section of the fabric, and these layers are opaque paints.

Sky blue paint - yellow dope - forest green paint - brown dope Sky blue paint - yellow dope - forest green paint - brown dope 2

The lower layer of paint, sandwiched between the bottom-most layer of dope and the glass-like green/yellow layer is sky blue in color.  It may not have been well mixed as I’ve seen some spots that appear white as well, but so small that they must have been irregularities in the paint rather than intentional marks.

The other pigmented layer is a forest green.  It lies between the glass-like green/yellow layer and the top-most brown layer.  Where the brown sits over the green it makes a color that looks like coal or graphite.

Sky blue paint - yellow dope - brown dope 2 Sky blue paint - yellow dope - brown dope

The final irregularity is that I have found some areas where the green paint is absent, although the blue is still there.  I need to map these out at some point in order to determine if it seems to be an intentional pattern or just sloppily-applied paint.

If anyone knows of a way I could tell the age or origin of these paints, or better differentiate between paint and dope, please do let me know.

Mystery Paint

81_1One of my goals is, of course, to document as much of the history of A17-370 as possible.  For each year it would be nice to know where it was, what it was doing, what equipment it had installed, and last but not least, what its paint job looked like.  This final point is key because when the restoration is finished I need to have some historically correct scheme in mind to paint her up in.

Most of this will be discovered through paperwork, but there are also hundreds of minuscule clues on the airplane itself that I will discover during the deconstruction phase.  For the most part, the paperwork gives little or no clue about what paint scheme was applied to the airplane, so all of the tangible and specific evidence I have to work with right now is what’s on the plane itself.

26 Attachments for blind flying hoodDuring her period as a derelict, pretty much all of the fabric has been removed and thrown away.  This is par for the course with an old airplane but it sure makes a restorer’s life more difficult!  There are some little bits and pieces still hanging on where they were sandwiched into the structure or glued directly to it, but most of these are only one or two square inches and only show the rust-red dope that seems to be everywhere.

The fabric that was glued to the fuselage plywood is still intact however.  It shows a dark green over “trainer yellow.”  There may be some other grey/blue layer beneath that also, which I initially thought was silver, but now I will have to make a note to take a second look on my next visit.  But that’s the general theme of what paint survives… rust-red dope, then yellow, and then green on top of that.

Entire sample - smWhich is why the sample of salvaged fabric handed me by the previous owner yesterday was such a surprise.  There is definitely some kind of a blue stripe along one edge.  It’s sort of a dark robin’s egg blue, and seems pretty consistent in color (not streaky as if it were heavily faded).  I really don’t understand the layers I’m looking at here.  It seems that there is none of that rust-red dope.  The blue lies directly on the fabric, and the brown lies over top of everything, either over the blue or directly on the fabric, depending on where you look.  I can’t even tell if the brown color here is really a paint… or just some kind of dope/varnish?  It seems semi-transparent.  I’m wondering if there is some chemical test I could run to determine what each of these layers is… and whether there is some difference between Australian and Indian paints or dopes that might help me identify at least when this paint was likely applied.  That will help give me a better clue as to what design the blue stripe may be a part of.

Cropped sample - 300dpi