The Ressu (Snoopy) rudder covering preliminary work assignments

Suomeksi

The IMY Tuesday club has continued its work with the Snoopy (Ressu).

Planned and built by the Hietanen Brothers from Turku, the mixed structure experimental aircraft Ressu from the 1960s is next in line for the rudder’s canvas covered steel tube structure to be restored.

For the restoration the rudder was detached from the fuselage. The fabric covering was in a fragile shape, and the paint finish of the canvas badly crackeled. On the left-hand side the covering is fairly intact, but on the right-hand side a large piece of covering is missing on the lower edge. From this unexpected opening it could be seen that the covering canvas had been sewn onto the rudder frame outer tubes only, but not onto the cross tubes. The outer ring metal tubes had been covered with 20 mm wide cotton edging ribbon, by winding it the tightly along the tube.  This was a common way to avoid the covering fabric to be attached to form a direct contact with metal. The fabric, that was sewn to the metal structure, had been tightened drum tight with nitrocellulose lacquer, after which the surface had received a light blue coat of paint. Finally the rudder had been treated with red speed stripes, a black number 2 and a bird figure.

Because the Ressu’s rudder covering fabric was in a bad shape and partly broken, we decided to cover it completely anew, complying the old manner of doing it, however. The old covering fabric had to be detached from the steel frame of the rudder by cutting it off with a knife, because the fabric had glued itself tightly to the edging ribbons around the tubes. After detaching the covering fabric, the edge ribbons around the metal tubes were also removed.

The red stripes of the rudder’s covering fabric and the left-hand side black number two and the right-hand side black bird were copied on transparent rice paper. After that the bird and the number were transferred onto sturdy cardboard to wait for the final transfer of these symbols onto black contact plastic, and their fixing onto the surface of the new covering fabric.

The work with the rudder’s metal structure was continued with doing away with the rust on the tube surfaces. Luckily the tubes weren’t badly rusted or corroded. The rust was sanded off with sanding paper, however, so that the tubes weren’t ground to pure metal. The transparent Isotrol-lacquer can be applied as primer even though the surface is still a bit rusty. The shielding cover of the Isotrol- lacquer will stop the rusting process. During the sanding it had been noticed that the rudder had originally been painted red. The paint had most probably been the red Ferrex, used widely in the 1960s to stop rusting.

The rudder frame structure was primed thinly with the transparent Isotrol -lacquer. Owing to the lacquer, the tube surfaces came out beautifully clear and the red paint applied on the surfaces rose up even more gloriously. After a light buffing, a layer of red Isotol paint was applied on the bright Isotrol lacquer, emulating the original red surface paint.

When the rudder frame had dried, we started to cover the steel tubes by winding 20 mm wide cotton edging ribbon around the steel tubes. Thus we’ll prevent, according to the original concept, the covering fabric being in direct contact with the surface of the steel tubes. By hurrying slowly we managed to wrap the cotton ribbon around the outer tubes of the frame. Ressu’s rudder in now ready to begin the fabric covering proper.

Photos by Lassi Karivalo.

Translation by Matti Liuskallio.