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.
Cockpit nacelle of the aircraft, prior to acquisition. Note the steering wheel, which controlled the wing-warping wires of the aircraft.
Port and starboard wings in storage, prior to acquisition. Note the significant tears in the fabric covering.
Interior of the aircraft, prior to acquisition, viewed through the port access panel. The rudder control for the aircraft is visible on the floor.
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.
Disassembled aircraft in a carbon dioxide bubble, undergoing fumigation for a possible insect infestation.
- Top left: port wheel of main gear, before treatment.
- Top right: starboard wheel of main gear, before treatment.
- Bottom left: port wheel of main gear, after treatment.
- Bottom right: starboard wheel of main gear, after treatment.
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.
Realignment and consolidation of damaged belt threads on the main gear tire.
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.
Conservator reassembling wire rigging located on the aircraft fuselage.
Brass turn barrel (reproduction). This component was missing from the aircraft when it was acquired.
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.
Close-up of the fabric wing surface coated with cellulose nitrate dope. Note the generally poor condition of the fabric and coating.
Fabric tears in the top surface of the starboard wing at the leading edge. The white material visible through tears is backing material from a repair on the bottom surface.
Conservator repairing fabric damage on the bottom surface of the starboard wing tip.
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.
Left: fabric tear on the bottom surface of the port wing tip, before treatment.
Right: repaired surface, after 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.
Top: cockpit coaming, before treatment. Coaming surface is made from leather with a filling of kapok: note the large area of loss.
Bottom: Cockpit coaming, after treatment. Large area of loss has been filled in, using similar leather backed with polyethylene foam.
Top: propeller, before treatment. Note the large area of loss and deformation of the surface.
Bottom: propeller, after restoration treatment.
Borel-Morane monoplane on display at the Canada Aviation and Space Museum.
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.Back to top