The Caravelle III towbar restoration began

Suomeksi

In the restoration project of the Caravelle III (ex SE-DAF Sven Viking) owned by the Museum Society, which was brought from Arlanda to Turku, there is a small side line – like the proverbial gnat in the soup – of restoring the Caravelle’s derelict towbar. This tow bar is produced by the SUD AVIATION factory and is of the same production type, although of an earlier version, as the Super Caravelle towbar, used by Finnair, restored by the Tuesday Club into the colours of Finnair during the spring of 2022.

Photo: Pekka Simula.

The towbar, brought along with the Caravelle III from Arlanda to Turku, is in much worse condition than the Super Caravelle towbar, which we restored. The rod of the towbar, wheel racks and the wheel rims are covered in thick rust. One of the rims is partly rusted through. The tires are shredded and thus unusable. It is also strange that the rims are quite different from one another. The rim halves of one wheel have been welded to form a solid rim. The halves of the other wheel rims have bolted together. The separate bearing hub is also attached to the rim with bolts.

Both ends of the tow bar lack the rectangular handle bars made of metal rods. Only the places of the handle bars with their cut-off fastening screws are visible. A supporting flange has been welded to the rod, which tells us that the rod has been broken at some stage. Perhaps it’s been run over. We really have lots of work cut out for us in the future to restore the rod.

The Caravelle III towbar will not be restored in the SAS livery. It will be made to look like the towbar used by Finnair. Thus the livery of the towbar will be in harmony with the ex-SAS Caravelle III, which will be painted in Finnair colours and is to be put on display near the terminal of Turku Airport. The first Finnair jet airliners were of the Caravelle III type.

During the restoration the towbar will be dismantled. The rusty parts will be cleaned either by sand blasting or bathing in 30% phosphoric acid. The towbar will be painted “Finnair Blue “, apart from the ends. They’ll be painted with yellow high visibility colour.

Before we started to unfasten the parts of the rusty towbar, the rusted bolts and nuts were sprayed with rust dissolving WD or CRC multi-purpose spray several times.

The dismantling began with loosening the manufacturer’s plaque, which was attached to the body of the towbar, in order to prevent it from getting damaged in the sand blasting of the body. To loosen the plaque the rusted and jammed screws in the corners were bored out.

At the same time the dismantling of the towbar’s two wheel racks was started. The nuts of the wheel rack attachment flange bolts were surprisingly easy to open and the rack unfasten from the tow bar. The unfastening of the wheels from the axles followed after this.

One of the wheels departed fairly easily from its axle. Also the bolts uniting the rim halves could be detached, ditto the bearing hub bolts. However, taking the tyre off the rim proved problematic. The tyre was as if glued to the rim from its one side. In the end the only way was to cut the tyre along the strengthening wire on the side of the tyre with a keyhole saw and yank loose the wire, that was glued to the rim. We found out that the wire in the side of the tyre had simply rusted solid to the rim.

If the problem with one wheel was detaching the tyre from the rim, the other one was difficult to detach from its axle. Finally by using brute force we managed to dislocate the wheel, but at this effort the wheel bearings broke. The tyre was easy to take off from this wheel. The wheel racks with their rims are now ready for rust removal.

Because the rim of one wheel is partly rusted through, and the bearings of the other were destroyed when dislocating the wheel, we have to consider acquiring new wheels for the Caravelle III tow bar. Decision-making time will come, when we see what the rims look like after sandblasting.

Photos: Lassi Karivalo except if otherwise mentioned.

Translation: Matti Liuskallio.