Torstai 23.9.2021 - Tuesday Club member
The Aviation Museum Society has an original towbar for Sud Aviation SE 210 Super Caravelle, which has been used by Finnair, but is now in poor condition. The towbar still has a Sud Aviation manufacturing plate on it. The towbar was donated by Swissport, where it has been stored outdoors since the Caravelles were removed from operation in the 1980s. The towbar will be restored into its original Finnair appearance as a part of the Caravelle-project, which aims to place the Caravelle SE-DAF (Caravelle III version) from Arlanda on display in Finland.
The restoration of the towbar will involve a lot of work: the five-meter-long towbar is covered in a heavy layer of rust, due to the long storage outdoors. The original layers of paint have almost completely been destroyed by rust.
The towbar has been painted light blue with bright yellow signal colour at both ends. Fortunately there is some original blue paint visible on the lower side of the towbar and under the brackets and some yellow at the ends. In the middle there is the text Super Caravelle, painted in white and barely visible.
At the tow-vehicle end of the towbar there is a shaft with a spring, which is pushed into the towbar. The spring of the shaft is located inside the towbar. There is a pull-eyelet at the end of the shaft to fasten the towbar on the hook of the pulling or pushing vehicle. The shaft has rusted and doesn’t move. The aim is to restore it into an operating condition.
At the other end of the towbar there is a tow-fitting for fastening the landing gear heads, which are aircraft type specific. The Caravelle nose landing gear head is fork-shaped and has six metal pins to lock it on the tow-fitting. The pins are secured with fokker pins at their lower end. The towbar is fastened on adapter on the aircraft’s nose wheel with the landing gear head, which has a shear pin. The tow-fitting, the landing gear head, and the shear pin will be restored into operating condition.
In the middle of the towbar there is a pair of wheels for moving the towbar. The wheels are located slightly off the towbar’s longitudinal centre of mass. Therefore the end with the pull-eyelet tilts towards the ground. Under the towbar there is a metal leg which balances the towbar and prevents the pull-eyelet from touching the ground. The shear pin of the towbar is kept on the wheel arm, which has brackets with holes for holding the shear pin.
The wheel rims and the wheel arms have rusted, and they will be cleaned and painted. The outer tyre on the starboard side has broken and so has probably also the inner tyre. New outer and inner tyres will be installed. The outer tyre on the port side is still intact and in good condition. There is still air inside the tyre, it is probably “old air” from the 1980s.
At both ends of the towbar there is a rectangular metal hoop. These hoops were used when the towbar was moved, or its end was lifted when it was fastened on the pushing/pulling vehicle or on the aircraft’s nose wheel. One of the hoops has disappeared but its holder holes can be seen on the towbar surface. A new lifting hoop will be made.
The restoration of the Caravelle towbar will begin by dismantling it into pieces as far as possible. That won’t be easy because the towbar and its parts with their fastening bolts and nuts have rusted badly. For disassembling the parts rust removing chemical has been applied. If necessary, the parts will be disassembled by heating.
The larger rusted parts of the towbar will be cleaned by sandblasting, this will be done by a contractor. The smaller parts, such as bolts, pins, locking pins and nuts can be sandblasted using the sandblaster at the Finnish Aviation Museum.
When all the parts of the towbar have been cleaned from rust, the parts will be painted with undercoat paint which will prevent rusting. On top of that a finishing layer of light blue and bright yellow paint will be applied. Before sandblasting the hue of the blue and the yellow will be defined from the original painted surfaces which are still visible.
The text Super Caravelle in the middle of the towbar has almost faded away, but it can still be copied on transparent paper or plastic. The text will be repainted on the restored towbar.
Photos: Lassi Karivalo
Translation: Erja Reinikainen.