The Caravelle right-hand wingtip leading edge is completed

Suomeksi

Owned by Aviation Museum Society Finland and now on display at Turku Airport, the Caravelle lll (OH-LEA Sinilintu, Bluebird) has had its damaged right-hand wingtip leading edge restoration completed. The wingtip in the Caravelle is a separate entity, which can be detached from the wing. For the sake of simplicity, I’ll use the term wingtip for this structure in the future.

The last task in building the new leading edge for the wingtip was to rivet the edges of the upper and lower covering sheets to the centre line of the leading edge. The edges of the covering sheets meet at the centreline of the leading edge. Otherwise the covering sheets of the new wingtip had already been riveted in the wingtip structure.

To be able to rivet the covering sheet edges on the leading edge centreline, the sheet edges were tightened against the leading edge using a cargo strap, tied around the wingtip. After this, rivet holes were drilled at both ends of the sheets and the edges were riveted on the centre line with pop rivets.

It was noticed that a gap of 1-4 mm was left between the edges. The edges of the sheets therefore didn’t reach each other to form a butt joint. It was decided to cover the gap with an aluminium covering strip, running along the leading edge centre line.

To make the covering strip, an 8 cm wide and 40 cm long aluminium strip was cut out of 1 mm thick aluminium sheet to conceal the seam between the covering sheets. The aluminium strip was shaped to the curved form of the leading edge by shaping it against a suitable size iron tube. The concealing strip was arduous to shape because the wingtip leading edge slopes to various directions. The strip was, therefore, moulded phase by phase, fitting it to place at times. Thus the concealing strip was made to press tightly against the leading edge ridge.

Now the blue plastic films protecting the aluminium sheet could be removed and start the riveting of the covering strip. For the riveting the covering strip was tightened to place at both ends with a cargo strap. Masking tape was applied to both ends of the covering strip to mark the places of the pop rivets. The places were marked on the surface of the tape at even spaces with a compass and pencil, and the holes for the rivets were drilled accordingly.

We discussed what would be the best order to rivet the covering strip, so that it would best confirm to the shape of the wingtip leading edge. We ended up in starting the riveting from the rear end of the covering strip, proceeding rivet by rivet towards the wingtip. In doing so, the covering strip riveted itself tightly to the wingtip leading edge. Finally, the edges of the covering strip were tapped with a hammer and a piece of wood to press it still more tightly to the underlying surface of the covering material.

The demanding task of rebuilding the destroyed wingtip leading edge of the Caravelle III was now ready. Let’s not forget the fitting of the 3D-printed navigation lamp cover to its place in the leading edge tip.

Photos by Lassi Karivalo.

Translation by Matti Liuskallio.