Borel-Morane Monoplane
The Borel-Morane monoplane arrived at the Canada Aviation
Museum in need of cleaning and repair. The fabric parts of the
aircraft, although largely intact, had many tears, and the fabric
coating, or “dope,” was in poor condition, with
several areas actively flaking. Given the aircraft’s
historical significance, the Museum decided to preserve all
components and finishes in as close to original condition as
possible.
An initial examination of the aircraft revealed a possible
insect infestation within the hollow areas of the wings and
empennage. The Borel-Morane was subsequently placed inside the carbon dioxide bubble as a precautionary step. It was
kept in this fumigation chamber for a period of three weeks, to
cover all stages of the insects’ life cycle. The aircraft
was then removed from the chamber for a full condition report and
treatment.
Before treatment is begun, an artifact’s condition must
be fully documented and photographed. In some instances, the
artifact may also be partially or completely disassembled, so
that all surfaces can be thoroughly examined. Next, the
conservator and curator draw up a written treatment proposal,
specifying the procedures and treatment methodology that they
have agreed should be followed.
In the case of the Borel-Morane, treatment began with a
general cleaning of all surfaces to remove loose dust, dirt, and
insect debris. Treatment of the fuselage involved several steps.
The wooden plywood panels located on either side of the cockpit
were removed to allow for the gluing of delaminating layers.
Corrosion on fasteners and rigging hardware was mechanically
removed and stabilized. Before reattaching the wire rigging,
reproduction turnbuckles were fabricated to replace components
that were missing or had deteriorated. The two parts of the
fuselage were then reassembled.
The main gear wheels were in poor condition. The rubber was
embrittled and flattened (deformed) due to age and storage
conditions. Unfortunately, little can be done to stop rubber
components deteriorating. Providing suitable storage conditions
and the proper environment can, however, slow down the process of
degradation. The fabric belts that help to strengthen and
reinforce the rubber outer surfaces had to be realigned and
consolidated to prevent any further deterioration.
The padded coaming of the Borel-Morane is located on the top
surface of the cockpit opening, in front of the pilot. The
original materials, leather with kapok stuffing, were in poor
condition with large areas of loss. These were infilled, using a
foundation of polyethylene foam with polyester padding placed on
top. The fill material was then enveloped in black leather
similar to the original material, and fastened into place. Small
areas of loss were infilled using a tinted adhesive.
The Borel-Morane had been involved in several crashes during
its lifetime, and so the propeller acquired with the aircraft was
in poor condition, with one of its blades broken and deformed
with a significant loss of material. The propeller was
straightened and consolidated with an appropriate adhesive. A
wooden infill, to replace the area of loss, was glued to the
blade and formed to the same shape as the other blade. A wood
stain and protective coating were applied to give the new surface
an appearance similar to that of the original. As the aircraft
was acquired without an engine, a metal stand was fabricated so
the propeller could be put on display.
Next to be addressed was the cotton fabric used to cover both
the empennage (elevators, horizontal stabilizer, and vertical
stabilizer) and the wings of the aircraft. The bottom surface of
the wings appeared in generally good condition, allowing for an
aqueous cleaning method, whereas the deteriorated state of the
top surfaces permitted no more than careful cleaning with a soft
bristle brush. Materials and techniques were then developed and
tested for repairing the many fabric tears. Adhesives and
application techniques were borrowed from the field of paintings
conservation. First, Grade A cotton aircraft fabric was coloured,
using a wash of acrylic paint in deionized water. Once dry, the
fabric was mounted onto acid-free card stock and then, using a
heat-sensitive adhesive film, attached to the back of the
existing fabric. The film was heat set using a tacking iron. In
some cases, the only access to the back of the tear was through
the tear or area of damage. These conditions limited both the
size of the repair patch and the techniques that could be used.
An effective solution was found by fashioning loops in the repair
material, using a needle and thread, and applying gentle pressure
from the back of the repair. After the adhesive was heat set, the
thread was simply cut and removed through the front of the repair
patch. The last step in repairing the fabric surfaces was the
application of a resin coating, which consolidated the “dope” and
will permit cleaning of the aircraft in future. The vast majority
of treatment time and resources was spent on repairs to the wing
fabric.
The aircraft’s rudder had been repaired previously and
covered with a modern material, Dacron® (also known as
“Ceconite”). The Museum decided not to remove this material in
favour of a more historically accurate fabric.
After all treatments had been completed, the Borel-Morane was
carefully reassembled in the conservation lab. The wings and
wing-warping cables were attached last—and not without some
apprehension, considering the aircraft’s age and condition.
Once completely reassembled, however, it was found to be
physically stable. An adjustable stand was fabricated to support
any warping of the fuselage that might occur due to the weight of
the machine.
The aircraft was then disassembled and placed in several
vehicles for transportation to the Canada Aviation Museum. Upon
arrival, it was reassembled and placed on display in the
Conservation/Restoration exhibition as an example of an aircraft
that has undergone conservation treatment.
There are several advantages to having applied conservation
treatment methods rather than restoration methods to this
particular aircraft. First and foremost is the preservation of
historical materials and coatings that may otherwise have been
removed. Another advantage is the smaller expenditure of time and
materials needed for a conservation treatment as opposed to a
restoration treatment. One disadvantage might be the lack of
opportunity that the procedures gave for examining the interior
surfaces of the wings, elevators and rudder for damage and
deterioration. Although the numerous tears and areas of damaged
fabric did allow at least some glimpse of the interior components
and their general condition.
Conservation of the Borel-Morane called for a significant
investment of time and resources. Several hundred hours were
needed to clean, stabilize, and treat the various components of
the aircraft. The Museum is hopeful that, with these repairs, the
Borel-Morane will remain stable for many years to come.
