Seminars and Workshops
Seminars and Workshops
This internship was part time and fully remote.
Aircraft Recognition Models
WW II soldiers training with recognition models
Image c/o Friend or Foe? Museum www.collectair.com
Recognition Model Project at NASM
Air and Space has over 800 recognition models representing over 220 types of aircraft. Most were mass produced by injection molding cellulose acetate plastic, and came to the Smithsonian directly from the factory at the request of the first head of Air and Space, Paul Garber. They were never used.
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After eighty years, these models are deteriorating spontaneously and catastrophically due to the additives to the plastic. In the most severe cases, the model all but disintegrates.
The degradation mechanism was identified by Dr. Odile Madden and Dr. Molly McGill in 2012 by the MCI. Air and Space has yet to determine next steps for the models.
During my Fall 2020 internship, I researched the history of aircraft recognition, treatment options for the acetate models, preventive conservation, and - since treatment may not be an option - the possibilities of replication.
What is a Recognition Model?
With Japan's attack on Pearl Harbor, the United States was suddenly at war and there was an immediate and urgent need to identify airplanes. Almost overnight, the military needed to train soldiers – and civilians – to distinguish enemy from allied aircraft in a matter of seconds. Aircraft recognition became a major part of the war effort, and models were a critical training component.
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Models were mass produced in cellulose acetate and pot metal, and hand built by civilians from wooden kits.
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Image c/o www.collectair.com
Image c/o NASM archives
Image c/o collectair.com provided by Georges Grod
Image c/o www.collectair.com
Historical photos and ephemera on aircraft recognition
Image c/o Friend or Foe? Museum www.collectair.com
Research into Deterioration and Treatment
The models suffer from common issues in cellulose acetate including plasticizer migration, 'vinegar syndrome', and the subsequent complications.
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In addition, the models contain the additive triphenyl phosphate (TPP), added for the injection molding process. TPP crystalizes at room temperature, disrupting the matrix and essentially shredding the models from the inside out.
I worked with Dr. Molly McGill to fully understand this process, and then brainstormed treatment options that would sufficiently halt, slow, or reverse the mechanism. Ideas range from preventive options that are well known but likely ineffective, to highly experimental or invasive approaches such as removing the TPP entirely.
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More research is needed. Air and Space plans on experimenting with various options using fragments of the deaccessioned models.
Deteriorated cellulose acetate model
Image c/o Getty Preservation of Plastics 2014
Replication
Replication via 3D scanning and printing may be the best way to preserve the models in the long term. Air and Space has 3D scanning capabilities, but did not have the methodology established for objects likes the models.
Additionally, Air and Space was interested in conservation's current thoughts and use of replication.
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To explore this, I conducted a brief literature on replication of art and created a survey on replication ethics, posted to the AIC distlist.
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Unsurprisingly, initial results show that while conservators utilize replication, but are divided on the methodology.
Image c/o NASM
Image c/o NASM
Image c/o NASM
Test 3D scan of a recognition model
Image c/o Lauren Horelick
Analysis of 3D Scanning Spray
It is difficult to get a clear scan on uniformly matte, dark surfaces like the recognition models. The Air and Space mounts department is interested in a commercial product, Aesub 3D Scanning Spray, which is meant to solve this problem by creating a light, fine-grain texture.
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The spray is applied, the object is scanned, and the spray sublimates with no cleaning required or changes to the surface.
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I utilized Fourier Transform Infrared Spectroscopy (FTIR), and visual examination with a stereomicroscope to assess the efficacy of the sublimation and suitability for use on artifacts.
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Initial findings suggest that Aesub 3D Scanning Spray sublimates as advertised, although the efficacy depends on the application technique, and more research is needed before use on cultural heritage.
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Running FTIR on the wing of a deteriorated model
Image c/o Lauren Horelick