Super Caravelle tow bar restoration completed

Torstai 12.5.2022 - Tuesday Club member

Owned by the Aviation Museum Society and badly rusted, the Super Caravelle towbar was taken in the Tuesday Club for restoration six months ago. For the restoration the bar was dismantled. By March the parts had been cleaned of rust, so the surface treatment of the tow bar, that’s to say painting, could be started.

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The towbar is to be painted in original colours of the Finnair era. The main colour has been “Finnair Blue”, but the ends have been painted with yellow high visibility colour. The original hues could be determined by a firm called “Pintaväri” from the paint residue still to be seen on the surface of the steel. The blue was found to be NCS S 6030 B and the yellow RAL 1023. For the paint, Tikkurila Oy manufactured Unica Outdoor furniture paint, was chosen. As the primer, a translucent Isotrol-lacquer was chosen, as it protects the parts from rusting.

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Before the surfaces were treated with the primer, they were wiped with Sinol-water solution. After this, the parts of the tow bar received as a primer the translucent Isotrol. After the Isotrol had dried, the surfaces were lightly sanded, vacuum cleaned and wiped again with Sinol-water solution.

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First the ends of the tow bar were painted yellow. The length of the high visibility area at the loop end of the tow bar has been 50 cm, and at the connector end 73 cm. The area to be painted was bordered with painter’s tape. The loop headed towing bar was also painted yellow and the nose gear connector at the other end likewise.

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When painting with the yellow, it was noticed that the yellow paint covers insufficiently, especially when painted on the dark steel surface which has been painted with translucent Isotrol lacquer. The yellow had to be applied up to five layers, before the result was satisfactory. The inability to cover is an annoying feature of yellow paint. The yellow paint would have covered better, if we’d had the good sense to use light grey Isotrol to prime these parts. On the other hand, when we started to paint the parts of the bar with blue Unica paint, we noticed that the paint had an excellent cover from the first layer on. The covering abilities with the same paint differ greatly depending on the difference of the pigment.

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When all the parts of the towing bar had received a new coat of paint, the assembly of the towing bar started. First the wheels were connected to the axle, after which the support arms of the wheels were fixed from the lower ends to the flanges in the wheel axles. The wheels were fastened from their support arms to the two broad flanges.  At the same time with assembling the wheels, handlebars were screwed to both ends of the tow bar, to lift or move the tow bar by hand.

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Now we were ready to attach the halves of the 4,7 m long bar to each other. They were locked into each other with a collar tightened around the attachment point. At the same time the upper ends of the support arms of the wheels were fastened to the collars on the tow bar.

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The camber and caster angles of the wheel support arms were adjusted to make the wheels go straight. A connecting piece was fastened to the aircraft end of the tow bar, from which the bar was connected to the nose gear with a pin. Finally the bolt and nut ends of the support arms of the wheels were painted blue.

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The rust covered towbar of the Super Caravelle had been restored in the Tuesday Club to its original livery. The change compared to the rust covered one was remarkable. The towbar will still get an original white Super Caravelle-like logo on its side. Somehow, it’s fitting to this time, that the towbar is in the Ukrainian colours.

Photos: Lassi Karivalo

Translation: Matti Liuskallio.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoration, Tuesday Club, Caravelle

Tuesday Club started its spring season with full capacity

Tiistai 1.3.2022 - Tuesday Club member

Suomeksi

The Tuesday Club was not able to start its spring season in January because the amount of people allowed to work in the restoration workshop of the Finnish Aviation Museum was still limited due to the Covid-19 pandemic. Only the restoration work on the Myrsky MY-14 could be continued in January. Only half a dozen Tuesday Club members could work at a time, wearing masks. In the beginning of this year the Myrsky project has concentrated on the NACA-ring and the port wing landing gear doors, as well as finishing the Myrsky demo-wing before the Myrsky restoration exhibition will be opened.

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Along with the Myrsky restoration work, a couple of Tuesday Club members have been working to finish the painting of the Mil Mi-8P (HS-6) helicopter tail boom stabilizers and to take the large parts of the Super Caravelle towbar to be sandblasted. The tyres of two 1920s aircraft wheels have also been dismantled so that the wheels can be repaired. These wheels have been received from the Finnish Air Force Museum to be assembled on the Caudron C.50 (CA-50) aircraft.

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As the national Covid-19 restrictions have been lifted due to the decreased health risks caused by the pandemic, it was agreed with the Finnish Aviation Museum that the number of people working in the restoration workshop can be increased. This enables us to launch other Tuesday Club activities in addition to the Myrsky work.

On February 23rd we continued from where we stopped before Christmas, particularly with the Caudron C.59 conservation and the Super Caravelle towbar restoration. We still work in two groups of 10 Club members, one group on Tuesdays and the other on Wednesdays. The Myrsky team, with less than 10 members, is working on Tuesdays, Wednesdays and Thursdays.

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The coming weeks will be spent in cleaning the parts which were dismantled from the Caudron’s fuselage, and after that the parts will be painted. Two landing gear wheels were received from the Finnish Air Force Museum for the Caudron. The wheels and spokes are cleaned from dirt, grease and rust. Mechanical and chemical methods are applied.

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The Caravelle towbar has been dismantled and all dismantled parts have been cleaned of rust, either with phosphoric acid or by sandblasting, and the painting work can be started. Before painting, the sandblasted parts were washed to remove the sand dust, which remained on the surface. Then the parts were carefully dried, using compressed air. Some parts have already been painted with clear Isotrol varnish which will prevent rust.

Photos: Lassi Karivalo

Translation: Erja Reinikainen.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoration, VL Myrsky, MY-14, Caudron C.59, CA-50, Mil Mi-8P, HS-6, Super Caravelle

Super Caravelle's towbar is being repaired at Tuesday Club

Torstai 23.9.2021 - Tuesday Club member

Suomeksi

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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoration, Caravelle