Apr 04, 2025
By Lauren Anne Horelick, Janelle Batkin-Hall
Over the past 12 years the Conservation Unit at the Museum has received grant funding from the National Collections Program to help care for our most vulnerable artifacts as they are transferred from off-site storage to the Steven F. Udvar Hazy Center in Chantilly, Virginia.
Some very unusual artifacts have come through the lab during this time. Many of the materials and construction methods are familiar to most conservators, however, the interaction between materials compounded by their age, previous repairs, and their inherent fragility poses unique treatment challenges. They also provide the opportunity for us to develop new stabilization methods.
In this blog we share some highlights from working with the collection of historic aircraft models. These models showcase artistry and engineering innovations that offer a unique perspective on the evolution of aviation.
Langley Triangle Kite
Samuel Langley was a leading scientific figure in the United States in the 19th century and is well known as the third Secretary of the Smithsonian Institution. Part of his career included aerodynamic research, and he developed flying machines fabricated in both large and small model-scale form. One of these models is called the Triangular Kite, made from cotton, wood, and metal.
When the kite arrived in the Emil Buehler Conservation lab for stabilization, it did not resemble a kite. Several joints on the wood frame were loose and four wood rods had snapped. Two of the rods were missing large sections, causing the degraded cotton fabric to hang loosely over the frame, rendering a non- aerodynamic shape. The fabric covering the frame consists of two sections that, when secured to the frame, forms the three sides. Each of the three sides had incurred long tears and small losses and was no longer supported by the frame and tensioning wires.
In order to stabilize the object, disassembly was required. The fabric was removed, surface soiling was reduced, and the cotton was lined with a stabilizing fabric utilizing a synthetic adhesive. The wooden structure was repaired by stabilizing breaks and compensating for losses with wood dowels reinforced with carbon fiber rods. The type of wood used for the dowels was different from the original wood, making original and non-original materials easily distinguishable.
The wood structure required aligning to resemble an isosceles triangle with a central axis. The tensioning wires not only help stabilize the wood frame by keeping its shape, but they also support the top and bottom edges of the textile when attached to the frame. After treatment, the kite resembles an isosceles triangle once again and the textile is fully supported on the frame.
Umbrella Plane Model
This Umbrella Plane model, dates to around 1910 and is attributed to American aviation pioneer and engineer Chauncey Milton “Chance” Vought as a prototype. The model was given to Princeton University in 1965 and hung in the university library Aviation Room until it was donated to the Smithsonian Institution in 2016.
The model is constructed from wood, metal wires, rubber bands, and thin sheets of Goldbeater's skin, which are tensioned across the wooden frame. Rubber bands were used here to power the propeller by twisted them in one direction, and then when released this generates airflow over the Goldbeater's skin, thereby propelling the model. Goldbeater’s skin is more commonly found in the tool kit of guilders as it was used to literally beat gold into a thin sheet. Historically, this was also used for the internal bags that hold the gas in rigid airships. Its use as a covering material for models was not as popular as Japanese tissue or silk, and it is made from the outer membrane of bovine intestine. It is valued for strength, durability, uniform thickness, lightness, and resistance to puncture.
Prior to the Museum’s acquisition, the Goldbeater’s skin panels had torn in multiple places and were repaired with strips of clear tape. The clear tape had degraded, turned yellow, and lost its adhesive properties, causing the already torn Goldbeater's skin to droop from the frame. The loss of tension led to slack in the wire, and the rubber bands had become stiff and cracked. At some point the propellor became detached. Past practices included writing accession numbers directly onto artifacts, which can be seen on the right on the image below. Museum professionals have long abandoned directly labeling artifacts in this manner.
Unlike the Langley Kite, the wooden frame was in good condition with no breaks. Our treatment focused on conserving the Goldbeater’s skin that form the flight panels. This was done by carefully removing the aged tape followed by fully supporting each section of the panels with a new and compatible archival lining material.
Given the model's three-dimensional nature and the delicacy of the Goldbeater's skin, each panel was numbered to ensure it returned to its original position. The panels were carefully removed and laid flat for lining. A support lining was essential to address gaps and prevent further damage, as the edges no longer aligned perfectly. Japanese tissue paper, reinforced with a conservation-grade heat-activated adhesive, was used for lining, facilitating handling and reattachment to the frame.
Lastly, the wood propeller was attached, and the rubber bands were consolidated with adhesive to prevent breakage in the future. As an additional step the rubber bands were wrapped in a protective Mylar sleeve. The plane now closely resembles its original design from the early 1900s and its maker’s intentions.
Both artifacts posed unique challenges that required innovative stabilization techniques and careful attention to detail. These conservation projects not only protect the artifacts for future generations, but also provide a deeper understanding of the construction materials and engineering methods used in early flight experimentation. These conservation treatments not only highlight the challenges conservators face when working with fragile materials and complex constructions, but also demonstrate the role that conservation plays in preserving history.
We rely on the generous support of donors, sponsors, members, and other benefactors to share the history and impact of aviation and spaceflight, educate the public, and inspire future generations. With your help, we can continue to preserve and safeguard the world’s most comprehensive collection of artifacts representing the great achievements of flight and space exploration.
We rely on the generous support of donors, sponsors, members, and other benefactors to share the history and impact of aviation and spaceflight, educate the public, and inspire future generations. With your help, we can continue to preserve and safeguard the world’s most comprehensive collection of artifacts representing the great achievements of flight and space exploration.
