The restoration of OH-XEA Ressu has been started

Tiistai 21.11.2023 - Tuesday Club member

Suomeksi

As told in the previous blog, the parts of the OH-XEA, designed and built in the 1960s by the Hietanen brothers from Turku, will be restored by the Tuesday Club. The aircraft was nicknamed Ressu. Its wings, horizontal stabilizer, elevator, rudder, tail wheel assembly, wing struts and fuel tank have been brought to the Finnish Aviation Museum. We will concentrate on the restoration of its fuselage frame later. When the condition assessment and the restoration plan of the Ressu’s parts brought to the Museum had been completed, it was time to set to work.

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The restoration of the wings was started by cleaning the plywood surfaces, painted blue. Both wings were brought to the restoration workshop of the Finnish Aviation Museum. We started the cleaning of the painted wing surfaces with a well-tried method: a magic sponge. Naturally the worst dust was first vacuumed off. The aileron was unfastened to be washed separately. The dust in the joint of the aileron and the wing was brushed off with a paint brush and vacuumed clean.

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When using a magic sponge no cleaning agent is used. The tools you need are the magic sponge, a soft cloth, and half a bucket of water. The painted surface of the wing is cleaned by rubbing the surface of the wing, a small area at a time, with the magic sponge dipped in water and squeezed damp. With the soft cloth in the other hand the rubbed area is wiped at short intervals. The magic sponge removes the dirt from the wing surface, and it is wiped off with the cloth, which is rinsed in the bucket. There were also splashes of red paint on Ressu’s wings. Even they could be removed with the magic sponge. The rubbing with the magic sponge does not damage the painted surface unless excessive force is used.

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The plywood covered horizontal stabilizer and elevator were treated in a similar manner. We managed to get their surfaces very clean too. We were satisfied to see that after the wash the greyish blue surfaces of the wings, horizontal stabilizer and elevator were as if newly painted. We wonder whether they have been painted in the 1960s using durable Miranol enamel paint as the painted surface has been so well preserved.

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For the rudder surfaces no washing was needed, but the covering fabric was removed from the metal frame of the rudder. The covering fabric needs to be completely replaced. A carpet knife was used when removing the fabric. We could see that a strip of fabric had been spun around the outer edges of the frame. This strip protects the fabric which covers the metal rudder frame. On the other hand the covering fabric can be sewn on the fabric strip, but we could not tell whether this had been the case here. The fabric strip covering the edges of the metal frame was removed with a carpet knife. The rudder’s metal frame, stripped of the covering fabric, is now ready for rust removal and the surface treatment after it.

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Photos by Reino Aatsalo.

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Photo by Antti Hietala.

Three of the Ressu’s four wing struts have been preserved. The struts are surprisingly heavy, so they are probably made of ordinary steel tube. The surfaces of the struts have been painted yellow but are now covered in rust. The surfaces were sandblasted clean. Then the struts were treated with Isotrol varnish which prevents rust. Now the wing struts are waiting for their final surface treatment, and they will be painted yellow as in the original paint scheme.

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Photo by Lassi Karivalo.

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Photos by Osmo Väisänen.

The restoration of Ressu’s sprung tail wheel assembly was started by disassembling it. Even the tail wheel had to be disassembled so that we will have access to the wheel bearings, which are totally jammed. When the four bolts on the wheel rim had been unfastened, the rusty wheel halves could be wrenched apart by force. When the bearings were visible, we sprayed a lot of rust removing chemical in them and on the rusted surfaces of the wheel rim and left them “to mature” for a week. When a week had passed, we were able to clean the wheel rim halves quite well from rust and the bearings were preliminarily working. The following task will be to repair the sprung tail assembly.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Erja Reinikainen.

Avainsanat: aviation history, restoration, Tuesday Club, Hietanen HEA-23b, OH-XEA, "Ressu"

The condition and damage assessment of Hietanen OH-XEA Ressu and its restoration plan

Sunnuntai 19.11.2023 - Tuesday Club member

Suomeksi

The Tuesday Club is starting the restoration of the Hietanen OH-XEA Ressu aircraft which has been stored at Lemu in the Turku area. The aircraft was built in the 1960s by Ari and Esko Hietanen from Turku. The first phase of the restoration will include the wings, horizontal stabilizer, elevator, rudder, tail wheel assembly, wing struts and fuel tank, which have been brought to the Finnish Aviation Museum from Lemu. The fuselage has no covering, but it remained at Lemu, and its turn will come later.

The first step in the renovation work is to assess the condition of the aircraft and its possible damage. Therefore we took the Ressu’s parts into the restoration workshop at the Finnish Aviation Museum and went carefully through the condition and damages of each part and made preliminary restoration plans for them.

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We could see that the plywood covered surfaces of the wings, horizontal stabilizer and elevator are very dirty and have stains of red paint. The damages on the plywood covering are mainly small crushes or holes. However, on the underside of the left wing there is a large area around the registration mark where the plywood covering is badly broken. Or should we say has been intentionally broken – it certainly looks that way. The first phase in the restoration will be to clean the surfaces of the wings, horizontal stabilizer, and elevator and then to repair the damages on the plywood covering.

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Ressu's rudder has metal structure and fabric covering, in similar manner as the tubular structure fuselage. The covering fabric is torn on one side of the rudder and a piece is missing.

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The rusty metal frame of the rudder can be seen under the torn fabric. The metal frame will be cleaned and painted as it originally was. It seems that the frame has been painted with red Ferrex, the anti-rust paint which was commonly used in the 1960s. The red colour is visible under the rust. We will paint the frame using modern red Isotrol paint.

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Finally the rudder will be covered with new fabric and painted pale blue, following the original paint scheme. Red stripes will be painted on both sides of the rudder, following the original look. Number 2 will be painted on the left side and a black bird figure on the right.

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Ressu's tail assembly has metal structure and an air-filled tyre. The wheel bearings are completely stuck. We will try to repair the wheel into operating condition. The tail frame will be cleaned of rust and painted yellow, following the original paint scheme.

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Ressu’s wings are supported with two wing struts, made of metal tube. Two of them are sturdier, fastened on the brackets on the wing’s front spar, and the two thinner ones are fastened on the brackets on the rear spar. We have both front struts but only one rear strut. The wing struts had been stored inside Ressu’s fuselage frame. The struts have been painted yellow but are now badly covered in rust. They will be sandblasted clean by a contractor and painted yellow as the original ones. We will make a new rear strut to replace the missing one.

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The fuel tank is located at the root of the left wing, it has been lowered into place from the upper side of the wing. The fuel tank has dents, and they will be straightened. The fuel tank has had some kind of cap with a rubber seal, there are marks of it left on the wing as well as on the tank. The cap has disappeared. If we can find out what the cap has been like, we will make one. And if we can’t find what it has been like, a good alternative is to make a cap from e.g. 1,2 mm thick aircraft plywood.

The Hietanen brothers have obviously been planning to double the size of the 21-litre fuel tank. We can judge this from the fact that the wing rib next to the tank had already been removed and the wing’s plywood covering had been opened between the wing spars up to the following rib. We will, however, restore the wing structure to its original condition where there is only space between the wing root rib and the first rib for the original fuel tank. This means that the missing rib will have to be made and the opened plywood covering repaired.

Photos by Lassi Karivalo.

Translation by Erja Reinikainen.

Avainsanat: aviation history, restoration, Tuesday Club, Hietanen HEA-23b, OH-XEA, "Ressu"

Covering the DO-5 tail openings

Sunnuntai 12.11.2023 - Tuesday Club member

Suomeksi

The rain covers for Aviation Museum Society owned Douglas C-47 (DO-5) tail openings were finished in October. The tail has been without vertical and horizontal stabilizers and the tail cone for donkey’s years. Due to that rainwater and snow have penetrated into the fuselage. The building of the covers out of aluminium plate has been reported already earlier in a Tuesday Club blog.

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A strike force of Tuesday Club members set off from the Finnish Aviation Museum to Turku Airport to fasten the covers to the DO-5 tail at the end of October. The covers and other equipment came along in a trailer. The DO-5 fuselage is on display beside the Caravelle III, restored as Finnair’s “Bluebird” (OH-LEA) in the vicinity of Turku Airport Passenger Terminal. After arriving at the Airport we got the covers made of aluminium plate and other necessary tools and a ladder out of the trailer got on with the job.

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We divided into suitable work groups. One of them fastened the ILS look-alike antenna and the thermometer probe we had brought with us for the DO-5. These were fastened in their original places on the undersurface of the nose cone.

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Another working duo started to fasten the covers for the openings of the right- and the left-hand side horizontal stabilizers. The third pair concentrated on fitting the covering shields for the tail cone. The fourth pair was tasked to fit in place the covering case we had built to cover the vertical stabilizer fastening point and to fasten in place the shaped hood, made of thin aluminium sheet, to protect the front end of the case and the fixed fuselage fin at their seam.

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The fitting advanced rapidly, because the covers made at the Museum’s restoration workshop according to blueprints, settled in place as we had planned. The horizontal stabilizers’ covers were fastened to the edge of the opening at their top edge with stainless steel screws. Holes were drilled through the covers into the fuselage for the screws. After this the cover was fastened to the fuselage also from its lower edge. We used stainless steel screws deliberately, so that they won’t start leaking rusty streaks along the fuselage surface as time goes by. An extra bit had to be cut off from the rear end hem of the left-hand horizontal stabilizer’s cover, to get the cover to press tightly along the edges of the horizontal stabilizer’s opening.

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When thinking about the way to fasten the covers, it occurred to us that we could have utilized the existing holes in the fuselage. However, it would have been extremely difficult to match exactly the fastening holes in the cover with the holes of the horizontal stabilizer fastening screws. That’s why we ended up with the above-mentioned method, which produced a few extra holes in the fuselage. If the DO-5 were to be made airworthy, the method would have certainly been different.

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The tail without the tail cone was protected with two separate aluminium covers. We had to shape the edges of the upper cover a bit before it clicked into place and was fastened with a few screws. We also had to shape with a hand drill the curved opening in the lower cover, so that we could get the protuberant strip in the fuselage to “pop out” through the opening and press the cover tightly against the end of the fuselage. This cover, too, was fastened with a few stainless-steel screws. The edges of the lower cover shielding the rear fuselage were bent at 10 cm width to an angle of 90 degrees. This way the sides of the cover could be pushed under the covering sheet of the horizontal stabilizer’s rear end and linked to it with a couple of screws.

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The vertical stabilizer’s fastening point wasn’t covered with just an aluminium cover, like the other openings, but a nearly three metres long covering case was made for it. The seams of the aluminium sheets were covered with duct tape, after which the case was lifted to place on the low support braces of the fastening point. It was noticed that the case settled in its place as planned. The rear end of the case’s aluminium sheet was bent from its lower edge to form a canopy against rain on the rear end of the fuselage. Despite the case being fairly heavy, it was fastened by its hem with a few screws to the fuselage. Thus not even a strong gust of wind gets to throw it from its place.

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Photo by Mikko Jaakkola

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Photo by Esko Ruohtula

When the protecting case of the vertical stabilizer’s fastening point was in place, we started work on the final shaping of the hood, covering the joint of the case and the fixed fin. The hood had been bent to its preliminary shape from 0,3 mm thick aluminium sheet at the Museum. We had to shorten it quite a bit before it was the right size to protect the joint. The hood was fastened from its lower edge to the fuselage with a few screws and the sharp head of the hood was shaped round.

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Photo by Mikko Jaakkola

The openings for the DO-5 horizontal stabilizers, vertical stabilizer and the fuselage rear end had now been protected against the weather, and we could start the home journey to the Finnish Aviation Museum, satisfied with our work.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio

Avainsanat: aviation history, restoration, Tuesday Club, DC-3, C-47, DO-5

Hietanen OH-XEA "Ressu" to be restored by the Tuesday Club

Perjantai 10.11.2023 - Tuesday Club member

Suomeksi

Last year Aviation Museum Society Finland was donated a single-seat experimental aircraft, designed and built in the 1960s by Esko and Ari Hietanen, two brothers from Turku. The aircraft was inspected and registered in the civil aircraft register on August 13th, 1969, with the registration OH-XEA. The aircraft, nicknamed Ressu (meaning Snoopy), is a high-winged, mixed structure single-seat aircraft. The tubular framed fuselage is fabric-covered. The wings, ailerons, vertical stabilizer and rudder have wooden structure and plywood covering. The rudder is tube-structured and fabric-covered.

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Photo via Aviation Museum Society, Finland.

Ressu is a small aircraft. Its wingspan is 7,4 m and the fuselage is 5,5 m long. The widest part in the fuselage is the landing gear, with 1,4 m from one end of the axle to the other. In its time, Ressu had several registration marks. First it was registered as H-EA (Hietanen Esko and Ari), then OH-HEA and eventually OH-XEA when it was approved in the civil aircraft register. Ressu’s engine was Continental A 65. The aircraft was removed from the civil aircraft register on January 1st, 1973. We don’t know how many hours Ressu has flown.

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Photo via Aviation Museum Society, Finland.

After the flying activity ended, Ressu was stored in several places and its fuselage was badly damaged. Today the fuselage has no traces of the fabric covering and the tubular frame is covered in heavy rust. In the cockpit there is just the pilot’s seat, control stick, pedals, and an empty instrument board. The engine, the instruments from the cockpit panel and the landing gear wheels have all disappeared during the years. Out of four wing struts only three remain. The wings were painted pale blue, the horizontal stabilizer and the elevator have been preserved quite well, there are only some damages on the plywood covering.  The fabric covering of the rudder is broken and the paint on the fabric is badly crackled. The fabric covering on the fuselage has probably been painted pale blue as the wings.

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The aim is to restore Ressu at the Tuesday Club to resemble its appearance in 1969 when it was registered. This means that the plywood covered surfaces of the wings and parts of the tail will have to be cleaned and the damages repaired. After that we can consider restoring the fuselage. There the first step would be to treat the rusty fuselage before covering it with fabric. We will try to find instruments for the cockpit if we are able to find the kind of instruments Ressu had. The engine could well be a discarded and inoperative Continental A 65, if we could find one.

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Photo by Elias Viitanen.

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In autumn 2022 Aviation Museum Society Finland volunteers assembled Ressu in the former shipyard hall in Pansio where the Caravelle III, owned by the Society, was under restoration. Ressu was also on display at the Society’s stand in the Turku Airshow in June.

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After that Ressu has been stored at Lemu, in the Turku area. From there we fetched Ressu’s wings, horizontal stabilizer, elevator, rudder, tail wheel assembly, fuel tank and wing struts, and brought them on a trailer to the Finnish Aviation Museum in Vantaa. In the Museum’s restoration workshop the Tuesday Club members have already started the restoration of Ressu’s parts. The fuselage remained at Lemu, but it will probably be taken under restoration next year. The Tuesday Club has now started Ressu’s restoration project which is estimated to take a couple of years.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Erja Reinikainen.

Avainsanat: aviation history, restoration, Tuesday Club, Hietanen HEA-23b, OH-XEA, "Ressu"

Making the lower sheet metal cowling for the Myrsky engine

Maanantai 6.11.2023 - Tuesday Club member

Suomeksi

The VL Myrsky II (MY-14) engine has a lower and upper cowling, made of sheet metal. The lower cowling was built at the Tuesday Club. The cowling was made of 1 mm thick aluminium sheet. The stiffening formers that were fastened on the inside surface of the cowling were made of the same material. The upper engine cowling will be built at the Finnish Air Force Museum, where the main undertaking will be the restoration of the MY-14 fuselage.

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Before the 1 mm sheet, cut out of aluminium plate, was started to be formed into the U-form of the lower engine cowling, a female forming last was cut out of sturdy plywood. This forming last works as a model, showing that the lower engine cowling needs a curved shape. The shaping of the sheet was done by mangling the sheet in a mangler with three rollers and comparing the sheet to the forming last at intervals. After the mangled sheet had been made to press itself tightly against the forming last, it had reached its correct form. Next the formed sheet could be tried on the Pratt & Whitney engine used in the Myrsky. The engine was moved into the restoration shop in the Finnish Aviation Museum. We managed to fit it snugly on the side of the engine.

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Photo by Heikki Kaakinen.

The lower engine cowling needs several stiffening profile strips to keep it in form. The stiffening strips were cut and bent according to the programming information given at Prolaser Oy. After this we started to fasten the stiffening profiles on the inner surface of the engine cowling. The stiffening strips are fastened by riveting onto the metal casing.

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The Myrsky blueprints gave us the exact position of each profile strip on the inner surface of the engine cowling. So we started fastening the profile strips, but not straight with rivets but at first they were fastened in place with 12x3 mm small bolts. The holes for the bolts were drilled on the rivet spots according to the blueprints, and a small bolt was put in the hole to fasten the stiffening strip to place. When all the profile strips had been fastened, the inside of the engine cowling looked a bit like a porcupine, because the nuts of the small bolts were sticking out of the edges of the profile lists.

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Now the engine cowling with stiffening profiles was fitted on the engine. The casing still settled laudably in place, so we could start fitting the fastening latches in the top part of the engine cowling. The lower and upper engine cowlings are fastened to each other with openable latches because the cowlings have to come off when maintaining the engine or armament.

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Before we started changing the fastening bolts of the stiffening profiles to countersunk aluminium rivets, the outside holes of the bolts were countersunk to suit the flush rivets. The profile strips were riveted, one hole after the other, onto the engine cowling’s inner surface with 8x3 mm aluminium rivets. The riveting was done with a riveting pin and a counter part pressed on the rivet head on the opposite side.

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Finally it was checked that the flush heads of the rivets had been riveted flush with the engine cowling surface. Some rivet heads had to be tapped with a hammer flush with the engine cowling surface, so that the outside surface of the cowling was left absolutely smooth after the riveting. The finished lower engine cowling will still be chromated, the same way as all the Myrsky aluminium parts.

Photos by Lassi Karivalo expect if otherwise mentioned.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, MY-14, VL Myrsky, Tuesday Club

Constructing the weather shields for the stabilizer openings for the DO-5 (Douglas C-47)

Lauantai 4.11.2023 - Tuesday Club member

Suomeksi

The fuselage of the Douglas C-47 (DO-5) owned by Aviation Museum Society is situated in vicinity of the Turku Airport passenger terminal, close to the Caravelle III, magnificently restored as Finnair “Bluebird”. The DO-5 tail has no elevators or rear cone. That’s why rainwater and snow blizzards have penetrated into the fuselage for years, to play havoc inside. Now we can get rid of this problem when the Tuesday Club has made shields to cover the openings. To build them we visited Turku to measure the sizes of the openings and cardboard templates were made. (see the blog from Sep.21st 23)

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Photo by Ismo Matinlauri

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When we were starting to build the covering shields, we contemplated, whether we’d build the shields from plywood, or thin aluminium sheet. We ended up with a compromise, where we would build a plywood case covered with aluminium to shield the vertical stabilizer’s fastening point. The openings of the horizontal stabilizers and the rear openings we would shield with aluminium sheets.

Building the vertical stabilizer covering case

The fastening point of the vertical stabilizer is built in such a way that it can’t be covered with a shield alone. That’s why we’ll be building a covering case from plywood, which can just be pressed into place, supported by the fastening point’s 10 cm high supporting brackets. The top of the case will be built from sturdy plywood plate. The sides will be from thin plywood. Because the plywood we use isn’t weatherproof, we’ll cover the plywood case with thin aluminium offset-press sheet, which goes well with the aluminium fuselage of the DO-5.

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The construction of the covering case of vertical stabilizer fastening point was started from the top, which duplicates as the frame of the case. To make that we used sturdy 12 mm thick plywood plate. We had to build the top from two joined pieces, because the length of the plywood plate at our disposal wasn’t enough to cover the 240 cm length of the vertical stabilizer’s fastening point.

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We cut two pieces of plywood, which were a bit broader than the fastening point of the vertical stabilizer. The pieces were joined with a 30 cm long plywood joint piece. The form of the fastening point was drawn according to the blueprint on the more than 240 cm long case top. After that the extra bits according to the drawing line were sawn off, so that we had the finished piece of plywood for the top of the case.

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The sides of the case were made from 3 mm thick aviation plywood. 15 cm broad ”strips“ were cut, using a cutter, from the plywood plate to form the sides of the covering case. A 15 cm broad plywood side shields well the vertical stabilizer’s fastening point. The plywood strips were fastened from their upper side to the side of the roof plywood with 20 mm nails. They were joined to one another with a lap joint, so that the ends of the plywood overlapped 10 cm.

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When the vertical stabilizer’s covering case was structurally ready, it was covered with 0,3 mm thick offset printing sheets. From 100x70 cm aluminium sheets at our disposal, we cut off strips that were 1 cm broader than the sides of the case. That way the covering strip reaches a bit past the plywood side forming a “dripping edge”, preventing rainwater from rising into the plywood under the aluminium sheets. The aluminium strips were nailed with 20 cm nails to the edge of the 12 mm thick top plywood edge. The strips were joined with lap joints overlapping about 5 cm. The lap joint will be covered with aluminium tape when the covering case is fitted into place.

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After the sides of the case had been covered, the case roof was covered. Three one-metre-long pieces were cut from the offset sheets. The sheets were cut about 5 cm broader than the case roof. This is because the edges of the aluminium sheets will be bent over the roof edge to cover the roof/side plywood joint. As the roof covering sheet had been fastened in place, its edges were bent with gentle beating with a hammer onto the top edge of the side sheets. The overlapping edge of the offset sheet was fastened to the roof edge with a few sheet metal screws. The case covering the vertical stabilizer joint was finished.

To shield the front end of the covering case, there will be a tapered “hood”, which will be formed from aluminium sheet. This hood will cover the joint of the vertical stabilizer’s front part (fin) and the covering case. The hood was made from 0,3 mm thick offset sheet and it was bent into form with a bending machine. The so far oversized hood will be formed to its final shape when fitting the vertical stabilizer covering case to the DO-5.

Making the horizontal stabilizer opening covers

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The covers for the DO-5 horizontal stabilizer openings were made from 0,7 mm aluminium sheet. A piece was cut, big enough for both the openings of the horizontal stabilizers. The cardboard template of the openings was fastened on the aluminium sheet with adhesive tape. The outline of the template was drawn on the sheet with a felt pen, along which a billet to cover the opening was cut with a cutter and tin snips. Because the cutter and tin snips left the edges of the aluminium piece jagged and sharp, the edges were smoothed with a file. In a similar way the other cover was also cut using the cardboard template. We presume that the covering pieces we cut, are mirror images and will fit either of the two openings.

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At the leading-edge head of the stabilizer opening there’s a fixed pipe for the stabilizer’s anti-ice rubbers’ pressure hosepipe. A hole was cut in the covering shield for the hosepipe. Now we were ready to remove the protective plastic sheets on the covering piece. Any traces of the plastic were washed off with white spirit.

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The horizontal stabilizers’ opening covers, cut from 0,7 mm aluminium sheet, are very flexible, so it was decided to stiffen them with strips of plywood. From 3 mm plywood panel about 10 cm wide plywood strips were cut with a cutter. They were glued on the inside of the horizontal stabilizers’ covers using the Sikaflex 221.This way the covers gained suitable stiffness, which facilitates their fitting in place to shield the openings of the horizontal stabilizers of the DO-5.

The tail end covering plates

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The DO-5 tail is without the tail cone, so the rear end of the fuselage is prone to rain. The rear end will be covered with two aluminium plates, of which the upper is small compared with the lower one. A template from cardboard we had made was placed on the 0,7 mm aluminium plate and the outlines of the templates were drawn on the plate with a felt pen. Covers for both of the rear fuselage openings were cut from the plate. The edges were smoothed with a file. A curved slit a few mm wide had to be made to the lower shield, through which a solid protuberance on the fuselage “peeps” out. That slit was made by drilling a hole to the end of the slit and then drilling the slit open with a keyhole saw.

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The covers for the vertical and horizontal stabilizer openings, as well as the rear fuselage, were ready to be fitted to the fuselage of the DO-5. The fittings will be completed yet before the winter sets in.

Photos by Lassi Karivalo except if otherwise mentioned.

Translated by Matti Liuskallio.

Avainsanat: aviation history, restoration, Tuesday Club, C-47, DC-3, DO-5

How to Fence a Caravelle

Keskiviikko 1.11.2023 - Ismo Matinlauri

Suomeksi

Since the beginning of June, the restored Caravelle has been protected at Turku airport by temporary rented fencing – providing only rather moral security. On Tuesday October 24th the permanent fence around the aircraft was completed. Fortunately during these months before the real fence was built there were no damages or accidents caused by the lack of proper fencing.

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Photo by Ismo Matinlauri

When the Caravelle’s location was planned in the Turku airport area, it was already obvious that a fence must be built around the aircraft. The main worry were vandals, graffiti sprayers and odd curious visitors. Secondly the fencing helps to control visitors and in other times protects the curious passers-by from accidents in the vicinity of the aircraft.

Naturally the fence will not stop the most persistent trespassers, but it will, however, provide sufficient security.

The purchase of the fence material started already before the Caravelle arrived in Turku. In spring 2022 Aviation Museum Society Finland bought the material for the fence and the gates. First the construction of the fence was scheduled to take place before the aircraft is moved to the site in spring 2023. Soon it was discovered that the fence will hamper the crane operations on site during the assembly and also make the actual assembly work more difficult. Therefore it was decided that the Caravelle is assembled first, and the fence is erected after that.

The construction of the fence was left to a professional – that means that a contractor was hired to erect the fence. For cost saving reasons some of the work was done by the Aviation Museum Society Finland volunteers. In this case this meant assisting in setting the fence poles into concrete and in spreading the net wiring between the poles. This reduced the total cost nicely.

Building the fence was an efficient procedure, completed in five workdays:

• Day 1: marking and levelling the fence line, digging the holes for the concrete foundations,
• Day 2: setting the posts into concrete, 50 – 200 litres of concrete was poured into each hole,
• Day 3: drilling the bases for the fence posts on the rock slope behind the aircraft and landscaping the concrete foundations,
• Day 4: fastening the wire net on the gate halves (two 5 m wide gates) and making preparations for fastening the wire net,
• Day 5: unrolling the wire net and fastening on the posts, installing the gates and checking their operation.

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Photo by Janne Salonen

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Photo by Janne Salonen

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Photo by Ismo Matinlauri

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Photo by Jouko Tarponen

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Photo by Jouko Tarponen

Building the fence in late October was eventually a good thing. The weather is getting cold and there is quite a limited amount of work which can be done inside and outside the Caravelle due to the cold and wet weather, so we had plenty of time to assist in erecting the fence.

Avainsanat: aviation history, restoration, Caravelle, OH-LEA, Sinilintu, Bluebird

Mil Mi-8T (HS-4) helicopter tail boom stabilizers' covering with thin aluminium sheet

Sunnuntai 29.10.2023 - Tuesday Club member

Suomeksi

The tail boom stabilizers’ covering of the Mil Mi-8T helicopter, situated in the Karelian Aviation Museum, has started briskly. As was told in an earlier blog about the HS-4, the stabilizers will be covered with a thin aluminium sheet, instead of covering fabric. This is because the aluminium sheet stands much better to weather. And we must remember that HS-4 stands outdoor at the Museum yard most of the time and it’s not airworthy anymore.

The covering of the stabilizers got really started after they had been stripped off tattered and rotten fabric and the faded aluminium surfaces were ground and waiting for painting after covering.

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We decided to start the covering from the underside of the right-hand stabilizer. The covering will be done with 0,3 mm thick aluminium offset-printing sheets that were donated to us. Because one printing sheet isn’t enough to cover the whole area, both sides of the elevator will be covered with two aluminium sheets, joined to each other with edge joints.

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We drew the area to be covered from the stabilizer stem and tip onto cardboard and cut the cardboard with a cutter to serve as models for the stem and tip aluminium covering sheets. Then we put the cardboard models on the aluminium sheets and attached them to the sheet with tape. This way the cardboard models stuck to the sheet when the aluminium sheets were cut to form with a cutter.

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The edge joint of the stem and tip sheets is made on the centre rib of the stabilizer. Therefore a 5 cm wide aluminium support strip was riveted on the rib. The edge joint of the aluminium sheets will be placed in the middle of the support strip and the sheets will be riveted into the strip at the edges. Now the covering sheets could be placed on the stabilizer to their final form. The edges were formed, however, in such a way that the sheets are equally wide at the joint and their top edge joins tightly with the edge of the steel reinforcement on the surface of the stabilizer.

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When the underside sheets had been shaped into place, the riveting was commenced from the tip sheet. The sheets will be riveted to the stabilizer at their outer edges with 3,2 x 6,0 mm blind rivets or pop rivets. First the places of the rivets were marked with a pen at three cm intervals at the edges of the sheets. Then the marks for drilling the rivet holes were snapped with a spike. The drilling took place with a 3,2 mm bit.

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After the holes on one side were done, the pop rivets were riveted in place one after the other. The rivet was tightened with rivet pliers through the covering sheet into the structure of the stabilizer. After the stabilizer tip sheet had been riveted at its edges to the stabilizer underside, the stabilizer stem covering sheet was riveted to its place.

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Because the aluminium sheets were only riveted at their outer sides, the contact surface of the rib and aluminium sheet was seamed with silicone. That way the aluminium sheet glues itself to the rib and won’t resonate in strong winds.

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After the undersurface of the right-hand stabilizer was covered, the upper surface covering could be continued in similar manner. The procedure will be the same, when covering the left-hand stabilizer of the HS-4 tail boom with thin 0,3 mm thick aluminium sheet. When both stabilizers have been covered with aluminium sheets, it’ll be time to move on to the painting phase of the stabilizers, and that, as Kipling put it, is a different story.

Photos by Lassi Karivalo.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, Mil Mi-8, HS-4, Tuesday Club

MY-14 rear fuselage covering

Sunnuntai 29.10.2023 - Reino Myllymäki

Suomeksi

The rear fuselage plywood covering of the three fuselages (MY-5, -9 and -14), which were at the disposal of the VL Myrsky II restoration project, has completely disappeared, so the MY-14 received a completely new covering.

The MY-14 belonged to the so-called main series (Myrsky II) and the blueprints for its rear fuselage have disappeared. The early blueprint of the prototype (Myrsky), the test series (Myrsky I), and the early main series, used for the MY-5 and MY-6, has been preserved. According to it, the rear fuselage has been covered with 1,2 mm shreds of diagonal plywood joined with scarf joints.

By examining photographs a means of covering used in later main series aircraft was found. There seven diagonal plywood sheets were used, with grading in the horizontal seams.

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Because diagonal plywood isn’t available, we made it by joining together plywood sheets sawn into triangular shape and glued with scarf joints. The sheets obtained in this way were roughly sawed into shape and then fitting them to final measurements. Gluing was done with Gorilla Glue and the necessary pressure was obtained by using stretch film, clamps at the edges and staples in other places. Originally the staples were used at 20 mm partition.

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For the first plywood sheets the inner painting was done after the gluing, but the last ones had to be painted before gluing. In the latter case the patches to be glued were drawn on the plywood and only the areas between the lines were painted beforehand. After the gluing the remaining areas were painted, if possible. The used paint was Temalac by Tikkurila and the shade was RAL 7005.

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External priming was done according to the original advice with alkyd primer, where about 50% aluminium powder was added to the first layer. After this the fuselage was painted twice over with the same paint but without the aluminium powder. Between the coats of paint the surfaces were given primary sanding and puttied where necessary, using Spakkeli which is the Tikkurila wood putty. As a primer Futura 3-solvent thinned primer, shade RAL 7005 was used.

The blog is based on the report and photographs produced by the Finnish Air Force Museum restoration group.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, MY-14, VL Myrsky

The MY-14 sliding canopy

Tiistai 10.10.2023 - Reino Myllymäki

Suomeksi

The original sliding canopy of VL Myrsky II MY-14 has disappeared. However, we had at our disposal two original but badly corroded sliding canopies with all their parts remaining. The plexiglass parts were, however, destroyed.

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The sliding canopy which had been chosen to be restored was taken apart and we noticed that total corrosion hadn’t taken place. So the canopy frames were sandblasted and painted grey. The bearings of the sliding mechanism were replaced with bearings of original quality. For some reason the sliding mechanism didn’t work with the new bearings before the outer rim of the bearings was honed slightly narrower.

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The locking peg, which moved inside the canopy frame, was rusted solid and the wire moving the peg was cut off. The old locking peg was removed and replaced with a new one, lathed according to the blueprint. A reinforced peg was made, according to modification amendment C 301, because the original peg in the frame was of that model and the locking slots in the runner were measured for the reinforced peg.

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The wire inlet/guide piece was in a poor shape and was replaced with a new one, made of parkesine according to the blueprint. A new wire was soldered to the locking peg and an end piece was made to the wire according to the blueprint, and a piece of rubber hose, which worked as the handle was attached with brass string. The original lever for the opening mechanism, cast in brass and the aluminium press button at the end of the lever were cleaned, and the lever was painted grey, the press button black. The “PRESS”-text engraved at the end of the press button was nearly vanished. The engravement was repaired where needed and the text was painted white.

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The new bent canopy plexiglass panes were sawn into measure and the necessary rabbets were milled and ground, so that the panes settled flush with the canopy frame strips. The original inner plexiglass aluminium holder strips were cleaned with oxalic acid and painted grey. The plexiglass panes were fastened with new 3 mm screws and nyloc nuts. A suitable hole was made into the canopy’s top plexiglass pane to give access the opening press-button.

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The original aluminium strip at the rearmost end of the canopy was badly corroded and broken, so a new strip of 0,7 mm aluminium plate was made according to the blueprint. According to the blueprint there should be a seal made of felt at the front end of the canopy, but according to photographs it seems that it has never been fitted there, so we left it out, too.

The blog has been edited from the report by the Finnish Air Force Museum’s restoration group. Photos by the Finnish Air Force Museum.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, MY-14, VL Myrsky

The Finnish DC-Association's DC-3 visited Turku

Sunnuntai 8.10.2023 - Ismo Matinlauri

Suomeksi

On Wednesday, October 4th, the Caravelle restoration work was interrupted in a very positive way: The DC-Association’s Douglas DC-3 OH-LCH landed in Turku and taxied to the airport terminal.

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We can say that “the flying eternally youthful visited the new senior”. The DC-3 was in Turku on a training flight and the crew came to see how the Caravelle’s restoration work is progressing.

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The crew members who visited the Caravelle: pilot Mikka Rautakoura, maintenance director Jussi Pakarinen, mechanic Reino Ahola and chief pilot Petri Munukka.

There was a lively conversation in the cabin and on the flight deck about the technology used in the Caravelle. The visitors were particularly interested in how the acquisition of the flight instruments for the instrument panel is progressing.

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Photos by Ismo Matinlauri

A brief update on the restoration work: This week we installed the last new plywood boards into the floor and now the necessary areas have been replaced. Four boards of 12 mm thick waterproof plywood were needed, but now the critical areas of the floor are in good condition.

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We installed a sheet of thick plexiglass in the cabin floor area above the wing-fuselage joint. In the future the visitors are able to see the details of the wing-fuselage joint.

Outside the aircraft the polishing work on the fuselage has also progressed. The polishing of the front section will be completed before the autumn rain and cold weather settle in. During the following two weeks a permanent fence will be built around the aircraft. That will be the topic in the blog at the end of this month.

Photos by Jouko Tarponen except if otherwise mentioned.

Translation by Erja Reinikainen. 

Avainsanat: aviation history, restoration, Caravelle, OH-LEA, Sinilintu, Bluebird

Making a look-alike ILS-antenna on the DO-5 nose

Sunnuntai 8.10.2023 - Tuesday Club member


Suomeksi

Last spring the missing lower part of the nose cone was made of glass fibre to the C-47 (DO-5), owned by Aviation Museum Society Finland. To make the nose appear real, it should include an Instrument Landing System glidepath antenna. It consists of the antenna arch, made of 10 mm thick aluminium tube, a vertical support in the middle of the arch, the antenna stem shields, a base plate, a wedgelike form plate and a rubber seal. With the aid of the form plate it’s possible to fasten the antenna tightly and at the right angle on the curved surface of the nose cone. Both ends of the antenna arch penetrate the stem shields, reaching the underside of the base plate, where at both ends of the antenna tube there’s a connector for the antenna’s electric wire.

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We don’t have this antenna to fit on the DO-5. So we decided to make a look-alike copy of the antenna, because the DO-5 will not be made airworthy. We were lucky to get an original antenna for making the look-alike copy, although it is without the form plate made of cork and the rubber seal belonging to the antenna. At the same time, however, we got a broken base of the antenna to be used as model, on which to make the look-alike copy. The base still had the form plate and the rubber seal in place. We are obliged to return the form plate, so it, too, has to be done.

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Picture by Reijo Siirtola.

To make a look-alike copy we made a model drawing, which is on the outside looks like the original antenna. The difference from the original antenna is that we replace the original antenna made of aluminium tube with a solid 10 mm thick aluminium bar. The fastening of the antenna arch to the base plate also differs. Because our antenna will not be functional, we’ll fasten the antenna arch to the base plate with nuts. For that purpose the ends of the antenna arch will be pushed with their shields 10 mm past the underside of the base plate and the ends will be threaded for the nuts. We’ll have to make a new form plate, too. We’ll make it out of mass plate that can be reshaped, instead of cork.

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Photo by Reijo Siirtola.

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We started making the look-alike antenna by dismantling the antenna base we had. The antenna end shields, made of hard plastic, which were attached to the base plate with small screws, were broken. They were mended with epoxy putty. After the putty had dried, the shields were formed to their original shape and painted black. At the same time holes were opened through the shields, to enable the ends of the aluminium rods, modelling the antenna arch, to be pushed through the shields.

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Photo by Juha Veijalainen.

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To make the antenna arch, we cut an overlong piece of 10 mm thick round aluminium rod.  To bend the antenna to its original form, we built a bending device. With it we bent the aluminium rod to the exact arched form of the original antenna. We pushed the overlong ends of the antenna arch through the antenna shields to cut them to exact length. For that purpose we measured from the original antenna the distance from the top of the arch to the surface of the base plate and added the necessary 10 mm, the distance that the antenna ends reached below the base plate. We cut off the extra bits from the antenna arch ends, after which the ends were threaded for the fastening nuts.

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To make the vertical support in the middle of the antenna arch, we cut off from 10 mm aluminium rod an also overlong piece for the centre support. We shaped the top end of the rod as concave, for it to press tightly against the top of the antenna arch. We measured the necessary length for the centre support and marked the lower end of the rod accordingly and cut off the extra. The centre support is fastened at the top with a small bolt through the antenna arch and at the bottom end with a small bolt through the base plate.

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Then we marked the attachment point for the centre support on the antenna arch and drilled a hole for the top fastening bolt. There’s already a hole in the original base plate for the bottom end bolt. After the holes have been drilled in the top and bottom ends of the vertical support, inside threads were made with a threaded pin, and the vertical support for the antenna arch was ready for fitting in.

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A new form plate to replace the original one made of cork had to be made. We made this form plate out of easily workable mass plate. The mass plate was ground wedgelike from the sides. The side against the base plate was left straight, but the side against the nose cone was worked as concave, according to the original model. Finally holes were drilled in the new form plate for the antenna arch nuts.

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It was time to assemble the antenna. We pushed the ends of the antenna arch in their shields in such a manner that the vertical support in the middle of the arch settled nicely between the antenna arch and the base plate. We turned into place the bolts to the ends of the vertical support. Then we fastened the antenna shields to the base plate with four small screws through the base plate. That done we tightened the antenna arch into place with the nuts at the arch ends. The vertical support worked as a stiffener when fitting the antenna arch into place. When the form plate with its rubber seal was fitted, the glidepath antenna look-alike copy of the DO-5 instrument landing system (ILS) was finished.

The next thing to do will be to go to Turku and install the antenna look-alike copy onto the upper edge of the DO-5 nose cone’s lower part made of glass fibre. The DO-5 is situated by the Turku Airport Terminal, beside the Caravelle “Bluebird”. We can measure the exact position of the antenna from the original “DAK” nose cone, so according to that we’ll drill the necessary holes into the upper edge of the lower half of the DO-5 nose cone made of glass fibre and install there the ILS-antenna look-alike copy we made. We’ll go and install the antenna still before the winter sets in.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, Tuesday Club, DC-3, C-47, DO-5

The MY-14 canopy rear panes

Sunnuntai 8.10.2023

Suomeksi

The VL Myrsky II MY-14 canopy’s rear pane frames with their fastening strips have been preserved but are badly corroded. The frames of the opening hatch have remained as separate parts. The plexiglass panes have all been destroyed.

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The rear pane frames were sandblasted from rust. The front and rear fastening points were thoroughly corroded, so replacement parts were welded from new tube.

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After repairs the frames were painted and fitted back to place. Some of the plexiglass fastening steel strips were badly corroded and they were replaced with new strips. The axles of the opening hatch locking bars, made of piano wire, were broken off so they were removed, and new axles were welded to replace them. The aluminium strips inside the hatch were bent and cracked, so they had to be straightened and repaired by welding. All the strips and the opening hatch frames were cleaned of rust and painted grey.

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The plexiglass panes were cut to measurements and fitted into place. Rabbets were milled and ground in the plexiglass panes, so that the fastening strips settled flush with the plexiglass panes. The plexiglass panes were fastened with new 4 mm screws and nyloc nuts.

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The original aluminium locking clasp for the openable hatch was in good condition, so it was only cleaned with oxalic acid and refitted to place. A hole for the antenna wire was made in the right-hand side rear pane.

Photos by Finnish Air Force Museum.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, MY-14, VL Myrsky

Fitting the front parts of the Myrsky wing root fairings

Sunnuntai 1.10.2023 - Tuesday Club member

Suomeksi

The wing and fuselage seam is covered in the VL Myrsky II blueprints by sheets called the wing root fairings. The Myrsky wing root fairings are made of thin aluminium sheet.

The Myrsky wing root fairing consists of two parts. The rear part covers the seam from the main spar to the trailing edge of the wing. The front part of the fairing in turn covers the area from the main spar over the leading edge of the wing to the lower surface of the wing and fuselage, reaching the main spar. The edges of the right-hand and left-hand wing root fairings meet under the fuselage in the centre line. The front parts of the wing root fairings are attached from their front edge to the tubular structure the heat shield’s fastening ring. To this same ring are also fastened the aluminium covering plates (engine cowlings) on the front fuselage, which can be opened.

The fitting of the wing root fairing front parts, made during the restoration process of the Myrsky II MY-14), is underway at the Tuesday Club. This phase was made possible when the Myrsky MY-14 wing and the MY-5 fuselage frame were joined, to test the fitting of the wing to the fuselage frame.

To fit the front ends of wing root fairings in place, we didn’t have the abovementioned fastening ring of the heat shield at our disposal. The MY-14 heat shield with its original fastening ring has already been assembled to the MY-14 fuselage under restoration at the Finnish Air Force Museum. We solved the problem of the lacking fastening ring by building a ring of sturdy plywood to the measurements of the original one.

The plywood fastening ring we made must be assembled to the MY-5 fuselage frame we used for the test fitting of the wing, at exactly the spot corresponding the fastening ring of the heat shield. The reason for this is that the front parts of the wing root fairings could be fastened to the plywood ring the same way they will in their time be fastened to the actual heat shield fastening ring, which is presently at the Air Force Museum.

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To measure the exact situation of the plywood fastening ring, which emulates the actual heat shield ring, we used the fuselage centre points marked in the Myrsky blueprints. The important one being point 51 of the fuselage centre, which is the centre point at the end of the transverse tube, located on the lower part of the front fuselage frame. From that point the three measuring points of the plywood ring were defined. They are the reference line in the fuselage centre line, formed by the metal tube, and the centre of the two bolts, which lock the wing to the fuselage frame.

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First the aluminium tube, which acts as the reference line was aligned to place. The top of the fastening ring was attached to the end of this tube. The plywood heat shield fastening ring was locked to the front bolts of the wing/fuselage joint with adjustable threaded rods from both sides. With the aid of these three fastening points the position of the plywood heat shield attachment ring could be defined to the millimetre in relation to the Myrsky fuselage frame. The top of the plywood attachment ring was propped to the fuselage frame with four metal supports, of which two are adjustable threaded rods. In addition the lower part of the attachment ring was propped to the floor.

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After the plywood ring was locked into place to the fuselage frame, the fitting of the front parts of the wing root fairings was started. The wing root fairing front parts were fitted to place in turns. They were attached first to the wing surface with cargo straps to keep the fairing tentatively in place during the fitting.

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In the fitting, the wing root fairings were attached from their front part to the plywood attachment ring with clamps. It was noticed with pleasure that the aluminium sheet wing root fairings settled very well into place in relation with both the wing surface and the attachment ring.

The front parts of the wing root fairings will finally be fastened to the fastening ring brackets with Dzuz-locks. In the test fitting of the wing root fairings the Dzuz-locks were replaced with plywood brackets, which were fastened to the plywood attachment ring. Because of the Dzuz-locks, a reinforcement ring will be made of aluminium sheet to the front edge of the wing root fairing. It has already been tentatively placed between the front part of the wing root fairing and the plywood brackets in the temporary fastening ring.

Photos by Lassi Karivalo.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, MY-14, VL Myrsky, Tuesday Club

Mil MI-8T HS-4 tail boom stabilizer covering began

Keskiviikko 27.9.2023 - Tuesday Club member

Suomeksi

An example of a Mil MI-8T helicopter, used by the Defence Forces and registered as HS-4, is situated in the Karelian Aviation Museum. The tail boom stabilizers’ covering fabric is rotten and partly lacking altogether. Two thirds of the area of the stabilizers is covered with fabric and one third with sheets of aluminium. The aluminium surfaces are still in good condition, apart from a worn-out coat of paint.

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Photo by Kimmo Marttinen

In the spring the Karelian Aviation Museum offered the covering work of the stabilizers to Aviation Museum Society’s Tuesday Club. We agreed, because we had earlier covered the tail boom stabilizers of HS-6, which stands at the yard of the Tuulonen shopping centre. We promised to start the work in the autumn.

For the covering a permission from The Finnish Defence Forces Logistics Command (FDFLOGCOM) was needed, because the helicopter is still in their possession. Permission was granted and in such a form, that we could cover the stabilizers with fabric as they originally were, or alternatively with thin aluminium sheet.

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We agreed with the Karelian Aviation Museum that the stabilizers would be covered with a weatherwise better thin aluminium sheet, instead of fabric, as we had done with the HS-6 stabilizers last year. At the same time it was decided that after the covering the stabilizers would be painted all round, ergo the upper surfaces greyish green and the undersurfaces light grey, according to HS-4.

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The Museum detached the HS-4 tail boom stabilizers in April, after which they were delivered to the Finnish Aviation Museum in Vantaa. At the beginning of the Tuesday Club’s autumn season the removal of the remaining rotten pieces of fabric was started. The last bits were removed with the tip of a knife. In the same manner we scratched off the thick layer of paint on the stabilizer’s steel reinforcements.

Before the grinding of the HS-4 tail boom stabilizers’ faded and dirty aluminium surfaces could be started, the tone of the colour of the stabilizers’ upper and under surfaces was defined. At the Vantaa branch of Pintaväri the light greyish green of the upper surfaces was defined as the Defence Forces camouflage light green paint, code AN 22. With an electronic tone gauge the stabilizer’s faded green coat of paint was defined to be the greenish tone SG010-G9OY. The light grey of the undersurface was defined as S2500-N. We also defined the tones of the stabilizers’ aluminium surface, using the colour maps at the Finnish Aviation Museum. According to them the upper surface green was RAL 6013 Reed Gray. The undersurface light grey is closest to RAL Effect 830-1. According to the camouflage scheme of the Defence Forces for Mi-8 helicopters, the tone of the stabilizer upper surface is Light bronze green, and the undersurface is Light aircraft gray. We’ll take a closer look at this tone-of-paint-puzzle before the actual painting phase of the stabilizers.

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The grinding of the faded paint surfaces was done by a random orbital grinding machine, using P180 and P240 grit sanding discs. Our aim wasn’t to grind the faded coats of paint to pure aluminium. It’s sufficient when dirt and loose paint have been removed from the surfaces and the stabilizer steel reinforcements cleaned of rust. When grinding the stabilizer surfaces, darker green adhesive primer appeared. On some uneven parts pure aluminium surface appeared.

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There are roundhead rivets on the stabilizer and the stabilizer’s tip, made of glass-fibre reinforced plastic, has been attached with roundhead screws with grooves. When working on the rows of rivets and screws, the random orbital grinding machine wasn’t the best tool. So we used a grinding brush fixed to a power drilling machine to clean the rivet and screw stubs, which was very suitable for the purpose. Both the HS-4 tail boom stabilizers are ready now for the actual covering.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, Mil Mi-8, HS-4, Tuesday Club

Covering the DO-5 openings for the stabilizers

Torstai 21.9.2023 - Tuesday Club member

Suomeksi

When in June we were preparing the C-47 (DO-5) fuselage, owned by Aviation Museum Society Finland, for display at the Turku Airshow, the working list included covering the DO-5 tail openings for the stabilizers with aluminium plates. The reason for the covering being to prevent rainwater from getting inside the fuselage. At the time we didn’t have time to make the covers to shield the openings. At the beginning of the Tuesday Club’s autumn season we included the covering of the stabilizer openings on our work list.

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Photo by Janne Salonen.

At the moment, the DO-5 fuselage is situated by the Turku Airport, next to the Caravelle III or OH-LEA “Bluebird, which is the object of restoration and owned by Aviation Museum Society Finland. That’s why we had to go to Turku to measure the covers for the stabilizer openings. On Monday, September 4th, we headed for Turku.

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Photo by Jouko Tarponen.

Measuring the sizes of the openings on the DO-5 and making cardboard templates of them took quite a few hours. Our work was facilitated by the fact that we had at our disposal a high enough worktop, given to us by the Caravelle restoration project, on which we could reach to measure the vertical stabilizer’s opening, which was highest up. Or as a matter of fact, the vertical stabilizer’s attachment point isn’t an opening at all, like the horizontal stabilizers’, but the vertical stabilizer is attached from its lower part to aluminium attachment brackets rising from the fuselage.

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We started with the right-hand side horizontal stabilizer opening in the tail. A cardboard template was made by shaping and attaching to the stabilizer opening several numbered cardboard panels, one after the other. Finally we shaped a cardboard template of the curved leading edge of the stabilizer opening. Because we assume that the right- and left-hand side openings are symmetrical, we only made a cardboard template of the right-hand side stabilizer opening.

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A cardboard template of the vertical stabilizer’s attachment point wasn’t made, because it isn’t an opening in the fuselage like those of the horizontal stabilizers. At the vertical stabilizer’s attachment point, from the top of the “cut off” tail, seven rectangular 10 cm high solid attachment brackets, made of aluminium, are sticking up stretching 240 cm in distance. The vertical stabilizer is attached to these brackets with screws, and from its hem to the side of the fuselage.

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Photo by Reijo Siirtola.

We ended up sheltering the vertical stabilizer’s attachment point with a rainproof case. The case would be pressed on the 10 cm high attachment brackets. The top of the case would be of sturdy plywood, covered with a sheet of aluminium. The sides of the case will be made of sheets of aluminium. They will be attached from their top rim to the edge of the plywood cover, so that the top rim remains under the downward bent edge of the aluminium sheet on top of the case. This will guarantee that the joint becomes watertight. The bottom sides of the case overlap the top of the fuselage by 4 cm. Thus the rainwater running along the case’s sides can’t get inside the fuselage.

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To build the case covering the attachment point of the vertical stabilizer, a sketch was made, where all the relevant details to build the case were measured.

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Photos by Ismo Matinlauri.

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Because the DO-5 tail cone isn’t fixed to the fuselage, the tail cone opening must also be protected from the rain. The opening will be protected with two aluminium sheets, because of the structure of the tail’s cross-section. So we made individual cardboard templates of the top-and lower halves of the fuselage of the DO-5 without the tail cone.

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The covering of the DO-5 tail stabilizer openings was started with the case protecting the vertical stabilizer. First the plywood top will be built. It will act as the frame for the case. There was suitable, sturdy plywood in the material storage of the Finnish Aviation Museum. We will have to make the top plate out of two halves, though, because the length of the plate at our disposal isn’t enough to cover the whole 240 cm length. The measures for the vertical stabilizer taken in Turku, were transposed to the plywood plate, which became the case’s top. Next the top plate will be sawn into measure.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, Tuesday Club, C-47, DC-3, DO-5

Caravelle's autumn season started in the beginning of September

Keskiviikko 6.9.2023 - Ismo Matinlauri

Suomeksi

The restoration work of the Caravelle OH-LEA at Turku airport started efficiently on Monday, September 4th, when there were nine volunteers at work. In the Turku area it rained a lot in August, and it wasn’t possible to do any of the remaining restoration work outside the aircraft. During the summer weekends the Caravelle was open to visitors, and this led to some restrictions to starting the work inside the aircraft.

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On the last weekend we had the summer season’s last open doors event and after this it was possible to continue the restoration work from where we had left it in June. The half cloudy weather was ideal for sanding, polishing, and painting the last identification markings.

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On the underside of the fuselage there is a small area which needs to be sanded and painted with aluminium colour paint. The last identification markings will be painted on the wings and fuselage. The largest of these is the registration OH-LEA missing on the underside of the wing.

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Photos by Lassi Karivalo.

A lot of polishing work is still needed, this is the main item to be completed on the outer surface. Polishing will be continued as long as the weather allows. However, there is so much to be polished that the work will continue next spring.

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The work inside the aircraft has also started. The repairs and painting of the flight deck and the toilet area will be the first work items. The floor and the ceiling area in the cabin will follow in the coming weeks.

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It was a pleasure to have visitors from the Tuesday Club at Vantaa. Three club members came to Turku to measure the openings on the tail of the DO-5, which is temporarily parked next to the Caravelle. Protecting covers will be made at the Tuesday Club to cover the holes before the autumn storms arrive.

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The busy afternoon was spent at work, but there was a moment for lively discussion when the Turku team and the Tuesday Club members had a coffee break together inside the aircraft at “Café Caravelle”. The Tuesday Club is a valuable support and aid for the Turku team when the details of the restoration work are pondered. We are looking forward to making good progress during the autumn.

Photos by Jouko Tarponen except if otherwise mentioned.

Translation by Erja Reinikainen.

Avainsanat: aviation history, restoration, Caravelle, OH-LEA, Sinilintu, Bluebird, Tuesday Club

Tuesday Club's autumn season 2023 under way

Keskiviikko 30.8.2023 - Tuesday Club member

Suomeksi

Tuesday Club members returned from their summer break “back to the lathe” on August 22nd. However, once again it must be noticed that the group working on the VL Myrsky II (MY-14) had the stamina to work with the Myrsky through the summer. As a result of their effort the Myrsky wing is now united with the MY-5 fuselage frame, which we have as a testing fuselage. Thanks to this the wing/fuselage joint covering fairings could be test-fitted.

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Along with the Myrsky restoration project, the main project of autumn 2023 is to continue the restoration of Valmet Tuuli III (TL-1), which has been on hold for a number of years. In this project, led by the Finnish Aviation Museum, we’ll be concentrating on the aircraft’s fuselage, whose outer exterior surface we had started to polish clean and shiny already in the autumn season of 2022.

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In 2015 and 2016 nearly all parts of the Tuuli II had been dismantled for restoration purposes, including the cockpit instruments and gadgets. For the most part they had also been cleaned. In 2018 these parts were packed in case the Finnish Aviation Museum would have moved at that time to a cargo terminal freed by Finnair. However, that didn’t happen and now we continue in a way from where we were left then.

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First we’ll concentrate on the thorough cleaning of the Tuuli cockpit, which was nearly emptied. The cockpit’s inner surfaces and structures will be washed clean, possibly partly with a pressure washer. Simultaneously we’ll start to go through the parts packed in 2018 and cleaning them where cleaning will be necessary. The long-term aim of our work is to assemble the Tuuli for display. It will, however, take a few years before that will happen.

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The horizontal stabilizer of the 1920’s Caudron C.59 advanced trainer was refurbished and was fully ready to be covered with fabric already a couple of years ago. Now we’ll start to cover the stabilizer with cotton fabric. However, first we’ll test its tightening properties. For that reason we built a wooden frame, onto which we attached a piece of the acquired fabric. We already made a water tightening test on the fabric by spraying it with water. We will test with lacquer by starting with thinned nitro cellulose lacquer ending up with pure lacquer. The patched lower wings of the Caudron took too much space, so they were moved from the restoration workshop to the I-hall of the Finnish Aviation Museum, to wait for the next work phase.

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Photo by Janne Salonen.

We will carry on with work on the C-47 (DO-5) fuselage, Caravelle III (OH-LEA “Bluebird”) and MiG 21 BIS (MG-111) cockpit. Aviation Museum Society’s owned DO-5 and OH-LEA are presently on show in the vicinity of the Turku Airport Terminal, but the cockpit of the MG-111, which will be turned into a cockpit simulator, is at the Finnish Aviation Museum. On top of that, we ‘ll cover the derelict tail boom stabilizers of the Mil Mi-8 (HS-4), situated at the Karelian Aviation Museum.

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Of the jobs assigned to the Tuesday Club to refurbish the Caravelle, the repairing of the right-hand wing tip, including the making of the navigation light frames, is still unfinished. There’s also been talk about refurbishing the pilots’ seats into functioning condition at the Tuesday Club. This would necessitate bringing the seats from Turku to Vantaa. Also the making of protective sheaths of fabric or leather for the pitot tubes beneath the nose would be on offer for us.

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Photo by Ismo Matinlauri.

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During the spring season we worked hard to get the C-47 (DO-5) fuselage, which had been used for training paratroopers for the Defence Forces, ready to be on show at the Turku airshow. Time ran out for us then to do all we planned, and we are going to catch up now with the work, even though the fuselage is in Turku. The most important item on the list will be the making of protective covers for the openings for the horizontal-and vertical stabilizers, to prevent rain water getting into the fuselage. The stabilizers naturally aren’t attached to the fuselage now.

We are also making a lookalike copy of the glide path antenna, which is a part of the ILS (instrument landing system) in the nose of the DO-5. For that we have an original antenna as a model and the stem of a broken antenna.

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During last year’s autumn season and the spring season we managed empty the MiG 21 BIS cockpit for it to be transformed into a MiG 21 BIS cockpit simulator. This cockpit section was received by Aviation Museum Society when the aircraft was scrapped by
breaking it to pieces at the Aviation Museum’s yard. A few BIS- jobs were left undone from the spring, like the opening in the rear bulkhead of the cockpit for a fresh air blower, removing a few brackets from the front part of the cockpit and making of the floorboard in the front part. The jobs have already been commenced.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, Tuesday Club

Time to test-fit the Myrsky oil cooler

Lauantai 19.8.2023 - Tuesday Club member

In Finnish

Parallel with the fitting of the wing root fairings, the test-fitting of the barrel-shaped oil cooler was commenced. The Myrsky oil cooler is situated in the fuselage centre line, attached to the main spar “forehead”. Air comes to the oil cooler through an air duct from the left-hand wing’s leading edge. Respectively, after going through the oil cooler the air exits from the underside of the right-hand wing.

For the MY-14 fighter restoration we have at our disposal an original Pratt & Whitney R-1830 Twin Wasp engine’s oil cooler, the very engine that powered the Myrsky. We received it from Airveteran Oy. Instead we have had to manufacture all the accessories for the oil cooler, including the ducts for the supply and exhaust air and the dampers adjusting airflow.

The air ducts were made of 1mm thick, easily workable aluminium sheet. The pieces cut off the sheet were shaped in wooden shaping lasts, after which the seams were welded. We also made the dampers or gills that adjust the amount of air going through the oil cooler. The dampers adjusting the amount of supply air are controlled mechanically from the cockpit.

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Photos by Heikki Kaakinen.

Normally the oil cooler is permanently attached to the main spar. Because the MY-14 wing is made of two halves and the oil cooler is situated at the junction, the oil cooler must always come off, when and if the Myrsky will be dismantled for transportation to another museum or some other place to be placed on display. That’s why a handy rack with attachment straps was constructed. The oil cooler will be strapped on it and the rack is easily detachable from the wing spar and can also easily be reattached.

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Photos by Heikki Kaakinen

The test-fitting of the oil cooler was started by attaching the oil cooler attachment rack on the junction of the wing halves. The oil cooler was tightened to the straps. After that the cooler’s right-hand cooling air exhaust duct was fitted into place. The duct opens to the underside of the right-hand wing’s leading edge.

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Photo by Heikki Kaakinen

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The gills adjusting the incoming airflow were attached to the other end of the oil cooler. The gills are situated between the oil cooler and the supply air duct. The duct for incoming air is twofold. One end of the duct’s straight part is attached to the supply air damper and the other end to the front end of the L-shaped supply air duct. The opening of the incoming air duct is situated in the right-hand wing’s leading edge. There’s still work to do in fitting the oil cooler parts before every part is settled in its place as planned. A veritable “collection of gadgets” this Myrsky oil cooler system has proved to be.

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The pitot-tube, which measures the airspeed of the aircraft and is situated on the left-hand wing, was also test-fitted. The pitot-tube rack has been in place for long in the left-hand wing’s leading edge. We noticed, to our chagrin, that the 300 mm pitot-tube at our disposal was of a wrong length. It should be of the 500 mm long type. This can be seen in the Myrsky blueprints and photos taken of the Myrsky. Might there be a pitot-tube of the right length for us in the collections of the Finnish Air Force Museum?

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Along with all other tasks numerous inspection hatches on the wings are being fitted into place. We had to grind the collars of the hatches a bit deeper, so that the hatches would become flush with the wing surface.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio.

Avainsanat: aviation history, restoration, MY-14, VL Myrsky, Tuesday Club

Caravelle visitors are welcome

Tiistai 4.7.2023 - Ismo Matinlauri

Suomeksi

The Caravelle restoration team went on a well-earned summer holiday after the Turku Airshow. The restoration work is not finished outside or inside, and the team will continue its work in August. However, the unfinished appearance isn’t an obstacle for presenting the aircraft to the interested audience. The nearly 1300 visitors during the Airshow days proved this to be true.

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Last week I had the pleasure of presenting the Caravelle to a group of motor bikers consisting of Hornet-men mainly from the Defence Forces, Insta, Finnair and Patria. This was a group of experts and the first hour or so was spent outside the aircraft discussing the wing construction and engines. The Caravelle’s history and similarities to the Comet, especially in the flight deck, were discussed, too.

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The visit to the cabin and flight deck was brief, mainly due to the temperature resembling a sauna. There the visitors concentrated on the differences in the passenger cabins of modern and 1960s aircraft. The seat frames in the rear cabin caught the visitors’ attention as they are not from a Caravelle III.

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I thank the visitors for their interest in our project – and take the opportunity to welcome more visitors to come and see the Caravelle. English-speaking vistors are welcome, too! At the moment we don’t have regular visiting times, but we try to be flexible in arranging someone to come and give a tour. Feel free to contact me about a visit, preferably well in advance, so that we can arrange a tour for you.

Contact berfore visiting: Ismo Matinlauri, +358405013495, matinlaurii(at)gmail.com

Photos by Ismo Matinlauri.

Translation by Erja Reinikainen.

Avainsanat: aviation history, restoration, Caravelle, OH-LEA, Sinilintu, Bluebird

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