Repairing Caudron C.59 front cockpit's windscreen
Perjantai 6.12.2019 - Member of Tuesday Club
On Friday, October 11th some of the Caudron’s (CA-50) fuselage parts were dismantled in Vesivehmaa and brought to the Tuesday Club’s workspace. These items included the damaged aluminium frame of the front cockpit’s windscreen. The windscreen had been fastened on the plywood covering of the fuselage with seven bolts. The bolt nuts were easy to unfasten, but it was a challenge to unfasten the windscreen frame from the plywood, because the bolts were covered with a heavy layer of rust. A screwdriver was used as a lever between the windscreen frame and the plywood covering and finally the rusty bolts could be manoeuvred through the plywood.
The windscreen frame, originally made from thin aluminium sheet, had been badly bent and partly damaged. However, it can be straightened and repaired, and it can be installed back on the Caudron’s fuselage. There were fragments of the original windscreen still attached to the frame. The Tuesday Club team concluded that the windscreen had been made of celluloid, typically used in 1920’s airplanes. The celluloid window has been fastened with rivets between the windscreen frame and the aluminium profiles around the window.
The repair work was started by unfastening the four aluminium profiles that surrounded the window. All rivets that had connected the windscreen frame and the surrounding profiles were unfastened using a spike. The original windscreen celluloid fragments were also removed. The bent windscreen frame was carefully hammered into its original shape. The aluminium profiles were also straightened. Then the new windscreen could be made.
The original windscreen windows had been made of 1 mm thick celluloid plate. Such material isn’t available anymore, so a modern polycarbonate plate in the corresponding thickness was used.
First a thin flexible piece of plywood was placed on the windscreen frame and the window shape was drawn on it. The pattern was used to cut the new window from the polycarbonate plate. The new window was cut a couple of centimetres larger than the pattern, in order to have enough material to shape the plate into the correct measurements. The polycarbonate plate was fitted into the windscreen frame, shaping it gradually. When the new window fitted properly between the frame and the surrounding profiles, preparations for the riveting were started.
The polycarbonate window was fastened between the frame and the surrounding profiles using strong clamps. Then the holes for the rivets were drilled through the plate, positioning them at the original rivet holes in the windscreen frame. When each hole had been drilled, a cleko-fastener was placed in it, using pliers. The cleko-fasterers were used to ensure that the window stayed in place and the rivet holes were in the correct positions. Hole by hole, the edge of the windscreen was fastened with clekos.
The polycarbonate window was riveted onto the frame, hole by hole, removing each cleko-fastener and putting a 1,5 mm long aluminium rivet into each hole. A compressed air hammer and a traditional hammer were used to hammer the rivets into place. When the riveting was ready, the Caudron C.59’s front cockpit window was ready. A protecting film still covers the window on both sides, the films will be removed when the windscreen has been installed into its place on the Caudron’s fuselage. The paint on the windscreen frame is worn and damaged, but the decisions about the surfacing of the frame will be made later.
The windscreen of the rear cockpit has been lost. At first the Tuesday Club team thought that the rear cockpit’s windscreen could be built using the front cockpit’s windscreen as a model. When the team studied the surface and the marks of the Caudron’s fuselage in Vesivehmaa more closely, it was discovered that obviously the rear windscreen had been significantly different from the one in front. Therefore it was decided that the rear cockpit’s windscreen won’t be made before the Caudron’s fuselage is moved from Vesivehmaa into the restoration space at the Finnish Aviation Museum. This will probably take place in 2021.
Photos: Lassi Karivalo.
Translation: Erja Reinikainen.