OH-XTM Super Chug fuselage ready for repairs

Lauantai 18.10.2025 - Tuesday Club member

Suomeksi

After the Super Chug fuselage had been moved to the Puusepäntie workhop, the preparations to restore the damaged fuselage began. The first task was to detach the engine from the fuselage, because handling the damaged fuselage with the heavy engine in place would be nearly impossible.

Photo: Matti Kainulainen

So we started to detach the Super Chug’s VW 1600 engine from the fuselage together with the engine mounting. In doing so we’ll avoid detaching the wires, tubes and engine equipment within the engine mounting frame.

Photo: Jouni Ripatti

The engine mounting was attached to the fuselage with five bolts. We tried to open the nuts of the bolts that penetrated the firewall. The bolts, however, turned simultaneously when the nuts were turned. Somehow, we had to gain access to the bolt heads behind the firewall. If the nose of the aircraft were intact, gaining access to the bolts would be almost impossible, because the bolts were situated behind the fuel tank between the cockpit and the firewall. Now, however, the nose of the aircraft was torn because of the crash, so we could reach the bolts and unscrew the nuts.

Photo: Ari Aho

Photo: Antti Hietala

At the same time all the wires and cables, connecting the engine through the firewall, were detached. Part of them could be easily detached, but others fought us all the way. When the engine oil had been drained, we were ready to detach the engine.

Photos: Antti Hietala

Photo: Ari Aho

The engine was tied with cargo straps to an engine hoist, and the engine was pulled gingerly out of the nose of the Super Chug, hanging from the straps with the engine mounting. The detached engine was lowered on straps to a solid worktop to wait for further action.

The fuselage without the engine was still resting attached to a support frame made of pieces of four by two. Now the fuselage could be detached from the frame. The straps and other devices were opened, and the fuselage was carefully lifted from the supporting frame on to the table. We were a little apprehensive to lift the fuselage, nearly broken in half, but it held on well.

Because the fuselage of the OH-XTM has been damaged in the lower part between the cockpit and the firewall, it would be the most convenient, if the fuselage were to be on its back. So it was decided to place the fuselage on its back on two trestles, to facilitate the restoration work. One trestle would be by the cockpit opening and the other would support the rear fuselage at the stem of the vertical stabilizer.

We pondered what the suitable working height would be to restore the fuselage. It was decided to be 120 cm from the floor level. We adjusted the legs of the trestle by the cockpit so that the Super Chug’s fuselage top line, or in this case the damaged bottom line, would be at the height of 120 cm. The rear fuselage trestle had to be built.

It was built from the dismantled four by two pieces of wood of the Super Chug’s supporting frame. It resembled a normal wing trestle, only it was narrower. The level of the trestle was adjusted with a piece of fire hose used as strap, so that the whole of the fuselage was level and 120 cm from the floor.

After finishing the rear fuselage support trestle, the fuselage of the Super Chug was lifted upside down on the trestles. Thus the fuselage of the OH-XTM is ready for the restoration work.

Photos: Lassi Karivalo, unless otherwise mentioned

Translation to English: Matti Liuskallio

Restoration of the Bristol Blenheim pilot's seat under way

Maanantai 8.9.2025 - Tuesday Club member

Suomeksi

Last year we finished the restoration of the co-pilot’s stool from a V-series (BL-106) Bristol Blenheim bomber. Our object was a short-nosed Blenheim, assembled after the war from surplus parts in the 1950’s, having dual controls for training purposes. Beside the pilot’s seat there was a stool-like seat for the copilot. The controls in front of the seat were connected with rods to the captain’s controls. Mind you, that this series V-Blenheim aircraft (BL-106), assembled after the war, has in fact nothing in common with the UK-built war horse (BL-106), which was destroyed in a crash landing on 8.6.1944.

After restoring the copilot’s stool we moved our sights on the pilot’s seat. Restoring is all about cleaning the seat frame, basically a steel tube construction, from dirt, grease and rust. For the part of the seat pan, it meant cleaning the surfaces and sanding before painting. Note that the seat had no back armour.

As the first task we detached the leather-covered padding of the seat armrest to be conserved. After that we started the cleaning of the pilot’s seat. Soon we realized that cleaning would be more efficient and easier, if we could separate the aluminium seat pan and the seat frame.

Separating the seat pan and the seat frame necessitated the removing of the steel cross tube, rather like a big split pin, joining them. The cross tube consists of two tubes, joined by a butt joint, and a sleeve around the seam. We finally managed to slide the rusted sleeve from the seam and thus separate the tubes. We stripped the seat frame of all the parts that we could and detached the numerous rusty clips and other fasteners from the frame to be cleaned.

Some of the parts of the pilot’s seat were merely dirty and grimy, so to clean them for instance Fairy Power Spray was used. It removed the grease and dirt reasonably well from the surface of the parts.

The badly rusted tubes of the seat frame were cleaned by using abrasive pads, sanding papers and a steel wire brush attached to a cordless drill. For small parts, like nuts, a steel wire brush attached to a Dremel was used. The small items we detached from the frame were cleaned with an ultrasonic cleaner, which we had obtained.

When rust from the surface of the rusty tubes was removed, in places black paint was revealed. Based on that we concluded that the seat frame of steel tube structure had last been painted black. The cleaning of the tub-like aluminium part of the seat pan, made it apparent that the aluminium surface had been primed with grey primer and finished with greyish green surface coat of paint. The surface paint responds in shade to the greyish green Temalac ML 90 BS 283-shade we had already used in restoring the co-pilot’s seat. As primer we’re going to use Isotrol-lacquer and as surface paint Isoquard Panzer paint. The black paint will be the semigloss Isoquard Panzer paint.

We’ve more or less completed the cleaning the pilot’s seat from rust and grime, so the next phase will be the painting of the seat.

Photos: Lassi Karivalo

Translation to English: Matti Liuskallio

Tuesday Club's autumn season at full swing

Keskiviikko 3.9.2025 - Tuesday Club member

Suomeksi

The autumn season, which started halfway through August for the Tuesday Club, has got on a good start. There’s plenty of work to do. Naturally the Snoopy’s (OH-XEA “Ressu”) restoration will continue with the covering of the fuselage as the main object. The fabric is in place on the fuselage, and the tightening lacquer is being applied. The damaged Continental A 65 engine, which we received to be installed to the Snoopy, is being prepared to be cleaned by glass bead blasting.

With the restoration of the Bristol Blenheim bomber pilot’s seat, we’ll carry on from where we got before the summer break. The seat frame and seat pan surfaces are close to being ready for painting.

The Demo-Myrsky is under construction both at Puusepäntie and at the Finnish Aviation Museum. The Demo-Myrsky consists of the Myrsky MY-14 test wing, built during the restoration project of the MY-14, and the MY-5 fuselage frame. With the aid of the Demo -Myrsky, the inside structure of a mixed construction Finnish fighter will be demonstrated. That’s why, for instance, the fuselage frame won’t be fully covered. At the Puusepäntie workshop the repairs on the horizontal stabilizer, rudder and the damaged original elevator are under way. At the Museum the refurbishing and completion of the MY-5 fuselage frame are being worked on.

We’ve had our work cut out with the two sea containers, bought by Aviation Museum Society Finland, and brought at the yard of the Puusepäntie yard. One of the containers will become a working space for fire work and the other one will serve as a storage container. Both the containers have long since seen their heyday, so they will be refurbished on the outside. Holes in the containers will be patched, and the surfaces will be sanded. The outsides will be painted with the blue colour used by the Aviation Museum Society. One already is of a pretty blue colour.

Photo: Reijo Siirtola

We’ll start with the fuselage the restoration of the PIK 21 Super Chug (OH-XTM), which was donated to Aviation Museum Society. The fuselage was brought from a storage container at the yard of the Finnish Aviation Museum to Puusepäntie. The engine will be detached from the fuselage before we can commence the restoration of the lower part of the badly damaged and plywood-covered fuselage.

The job list for the autumn season also contains the refurbishment and repairs to the ailerons of the DC-3 “the Seagull” (OH-LCD) situated at the yard of the Finnish Aviation Museum. Both the ailerons’ coverings need renewing and the stem of the right-hand aileron is damaged. The Air Veteran lot will detach the ailerons for us to restore.

Photos: Lassi Karivalo, unless otherwise mentioned

Translation to English: Matti Liuskallio

Restoration of the Blenheim navigator?s seat

Keskiviikko 18.6.2025 - Tuesday Club member

Suomeksi

We received the Blenheim V-series or “short-nosed” Blenheim’s navigator and pilot seats for restoration at the Tuesday Club.

Both the seat’s steel tubes were badly rusted, but neither seat had suffered significant damages. The navigator’s seat, or rather stool, was significantly more straightforward to restore because of its simple structure and smaller size. It would greatly help restoring the pilot’s seat, if the seat pan could be separated from the seat frame. The aim of the seat restoration is to clean the rust from the surfaces of the supportive tubes and smaller parts, grinding the aluminium surfaces and finally painting them.

We began the restoration with the navigator’s stool. The padding was detached first and the seatbelt as well. The seatbelt was partly torn and needed to see a cobbler.  The seat cover of leather has worn out and lost its colour. It needs to be conserved. We will not do it.

We examined the round shaped seat plate, bent at the edges, for shades of paint found on the surface. Light green colour was visible, under which darker green could be seen. Thus the surface of the seat plate had lastly been painted with light greenish grey paint and under it there was an older darker green paint.

Paint residue could also be found from the surface of the steel tube stem of the seat. This process was helped when the rusty stems of the seat were treated with Industrial ECO Complex Blue-solution. The solution revealed a green shade of paint on the surfaces of the tubes. In addition, some old pigment or paint chaff was scraped from the surfaces of the rusted tubes of the stem. Some of it was placed under a 600 times magnifying microscope. It turned out that there were three different layers of paint on the tubes of the stem. The lowest was brown, then grey and greenish grey on the surface, in other words the same shade that was found on the surface of the seat plate. In consequence we decided to paint the seat with the similar shade of light greenish grey paint.

To start the restoration proper, we detached the aluminium seat plate from the stem. It was fastened to the stem both with bolts and rivets. The bolts were loosened first. After that the rivets attaching a bracket to the edge of the seat in the upper part of the stem were drilled out, after which the seat plate came off the stem.

Then we started to remove the rust from the stem steel tubes. The rust was removed from the tube surfaces, so that a layer of surface paint became visible. The tubes need not be ground to gleaming metal, because we use Isotrol lacquer and paint for the painting. The Isotrol will stop the rusting from spreading, even though rust would have stayed in the rust crevices of the steel tubes.

Rust was ground off first with a coarse sanding paper, wiping the dust off at times. We then moved to finer sanding papers, feeling at the same time with fingers whether the surface of the tube was clean and smooth enough. After the coarse surfaces had become smooth and the old paint became visible, the sanding of the steel tubes was complete.

We moved on to deal with the seat plate. It was an easier task. The aluminium surfaces of the seat plate were lightly sanded with fine sanding paper. We didn’t indulge in any grinding off of the old paint. The main thing was that loose paint was removed from the seat surface and the aluminium surface became smooth.

After both the steel tube stem and the aluminium seat plate had been ground, they were lacquered with clear Isotrol, which leaves a protecting film on the metal surface. For the surface paint it was necessary to define the shade of the seat colour. We ended up with the grey green Temalac ML 90 BS 283 shade for the seat. With this formula the seat’s Isotrol oil paint was shaded.

Two Comprehensive school students, doing their work experience learning period at the Finnish Aviation Museum, painted the stem and seat plate of the navigator’s seat. Well, at first the quality of the work left something to be desired. However, with careful guidance a good result was achieved. That’s just the purpose of this kind of work experience period, isn’t it?

After the painting it was time to reassemble the seat. The glass bead blasted original assembly bolts were fitted, and the seat stem was riveted to the edge of the seat plate. The rivets were finally painted grey green, to avoid eye sore. We had a cobbler repair the seat belt. The restoration of the navigator seat in the Blenheim bomber was ready.

Photos: Lassi Karivalo

Translation to English: Matti Liuskallio

Puusepäntie workshop got an illuminated sign

Keskiviikko 11.6.2025 - Tuesday Club member

Suomeksi

There was a wrecked illuminated sign of aluminium construction on the outside wall of the Puusepäntie workshop, rented by Aviation Museum Society, left there by a former tenant.
We decided to take it down to see if it could be repaired and transformed to an illuminated sign advertising the workshop of our society. So we took the sign down. The aluminium frame of the sign was, however, badly damaged and would have needed considerable repair work. However, our neck was “saved” when we got hold of an old illuminated aluminium sign of the OP cooperative bank’s real estate, 60 cm x 60 cm in size. It was also intact, so we decided to turn it into an outside advertisement for our Puusepäntie workshop.

We dislocated at first the plexiglass plate of the outer cover. the original sticker emblem could be removed from its surface in pieces with a sharp scraper. Finally, the plexiglass surface of the illuminated sign was wiped clean of the sticker glue with Sinol.

The aluminium surfaces of the frames of the illuminated sign had been oxidized and tarnished. We gently ground the surfaces clean using both an abrasive pad and very fine sanding paper. The old fluorescent lights were removed and after cleaning the inside of the sign the old lamps were replaced with LED-lights.

On the surface of the opaque plexiglass of the illuminated sign we designed a presentation of our workshop. The upper part of the illuminated sign will show a picture of the Focke-Wulf FW 44 Stieglitz (SZ-18), owned by Aviation Museum Society, with clouds in the background, and the lower part will hold the logo of the society and the text Aviation Museum Society Finland.
The abovementioned entity will be printed on the surface of the illuminated sign plex by a printing company. The printing required a vector representation to be made.

We fastened the frame of the outwardly cleaned illuminated sign, equipped with LED-lights, onto the wall of our Puusepäntie workshop, above the opening of the overhead door. We fixed a temporary cardboard plate as the outer cover of the sign to prevent the rain from getting inside.

When the front cover was received from the printing company, with its resplendent picture, the plexiglass was installed, replacing the cardboard one. So the splendid, illuminated sign advertising Aviation Museum Society’s Puusepäntie workhop was ready. The sign is yet be connected to the power supply with a pecu (photo electric control unit, “twilight switch”), so that with the darkening autumn nights it will switch on, advertising the Aviation Museum Society’s workshop.

Photos: Lassi Karivalo

Translation: Matti Liuskallio

Super Sytky OH-XTM to be restored at Tuesday Club

Maanantai 14.4.2025 - Tuesday Club member

Suomeksi

Aviation Museum Society has received PIK-21 OH-XTM Super Sytky (in English unofficially “Super Chug”), a damaged experimental aircraft, as a donation. The OH-XTM was designed, built and owned by M.Sc.Eng. Kai Mellén. The aircraft was completed in 1982 and is a single seat Formula-V-racer of wooden construction, with a VW-1600 powerplant.

Last summer the aircraft was involved in an air accident, serious enough to damage the fuselage beyond repairing to airworthy condition. In consequence the owner of the Super Chug decided - as an alternative to wrecking it - to donate the entire aeroplane to Aviation Museum Society to be restored at the Tuesday Club. The wings of the Super Chug remained relatively undamaged.

The aircraft will not be restored to airworthy status at the Tuesday Club. It will be restored to be a whole, operable display artefact. It’s important that the prototype of the PIK-21 OH-XTM Super Chug, designed and built by Kai Mellén, will remain a display artefact and at the same time an example of the magnificent series of PIK-designed aeroplanes.

On Saturday, 12 April 2025 the delivery of OH-XTM arrived at the yard of the Finnish Aviation Museum. The Super Chug, which had been carefully tied on a trailer, was unloaded. After that the fuselage, supported by a wooden framework, was carried into a sea container for shelter. The wings and other components of the aircraft were also stored in the container.

At the Tuesday Club the restoration of the OH-XTM Super Chug won’t start immediately. We are still in the middle of restoring the OH-XEA Snoopy experimental aircraft at the Puusepäntie workshop. The restoration of OH-XTM Super Chug will commence at some point during this year.

Photos by Lassi Karivalo.

Translation to English by Matti Liuskallio.

Restoration of the Snoopy's fuselage continues

Torstai 10.4.2025 - Tuesday Club member

Suomeksi

The fuselage of the OH-XEA “Snoopy” has been stored at the Finnish Aviation Museum since its restoration was put to hold in December. Now the fuselage has been transferred to the premises rented by the Aviation Museum Society at Puusepäntie in Tuusula, and it is possible to carry on with the restoration work. Although we couldn’t yet fully concentrate on the restoration projects, because the Tuesday Club’s workshop had yet to be fully refurbished. However, we were able to start the restoration work along with finishing the refurbishing of the workshop.

We carried on with restoring the Snoopy with attaching instruments in its empty instrument panel. The lacking instruments have now been installed. The missing instruments could be seen in a photograph of the Snoopy’s instrument panel from 1969. We are grateful to the people at Turku Flying Club, who rustled up most of the instruments in the panel. We also thank the Finnish Aviation Museum for providing us with the rest of the missing instruments.

Kuva: Esko Keskinen

In completing the instrument panel, the one instrument giving us the biggest problems was the Russian air speed indicator, because it lacked the mounting ring fastened on the instrument. Well, we managed to install the instrument with a clamp around it. We were able to fasten the instrument with four angle irons under the clamp.

Because we didn’t want to leave empty the opening at the centre of the lower part of the instrument panel, we stuck temporarily a digital thermometer there. That’s to say, we don’t know which instrument there was originally, because that instrument is lacking from the photo at our disposal. Furthermore we put two switches we bought from Motonet into the two empty holes in the instrument panel. They don’t resemble the earlier ones with longer stems in the Snoopy’s instrument panel, but we’ll let them stay there for the time being. Of course, we’ll be trying to find switches like the original ones to be installed into the instrument panel.

Kuva: Jouni Ripatti

The Snoopy’s metal fuselage frame was completed for covering at the end of 2024. So, we have started covering the fuselage frame with the vertical stabilizer, which is an integral part of the fuselage frame. We made at first a cardboard template of the stabilizer. Cotton fabric was spread over the template and a piece of fabric, a bit larger than the edges of the cardboard template, was cut off.

The fabric was cut to oversize with intention, to leave adjustment allowance, when cutting the fabric to a tight fit.
The cut fabric was laid tentatively on the vertical stabilizer so that the lapels were left outside the trailing edge. We spread NC-Speed nitrocellulose lacquer to the stabilizer’s leading edge and pressed the fabric tightly against it. This way we managed to glue the fabric to the stabilizer’s leading edge, allowing the lapels to be glued with lacquer to the trailing edge of the stabilizer.

All the more, we wanted to check the tightening properties of the fabric we were using. So we attached a piece of fabric with a stapler to a wooden framework and started tightening the fabric with nitrocellulose lacquer. After two layers of 25% lacquer, we spread a layer of 50% nitro lacquer. After applying these layers of lacquer, the fabric began to tighten in a way we’d hoped, i.e. shrink to resemble a drum top. The final tightness will be found out when we’ll get to using the 100% NC Speed nitrocellulose lacquer.

The Snoopy’s fuselage frame came to us without the cockpit plexiglass panes and the windscreen. The new plexiglass panes of the left-hand side of the cockpit and the right-hand side door pane were acquired and cut to form already towards the end of last year. They were made of 3 mm thick polycarbonate plexiglass. A cardboard template was made of the missing cockpit windscreen, and a plexiglass blank will be cut according to the template. The plexiglass sheet will be bent to the right shape by heating, so that both sides of the windscreen nestle tightly to the front sides of the cockpit. So far we haven’t tried this kind of plexiglass shaping by heating, but we are confident of making it a success.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation to English by Matti Liuskallio.

Snoopy's fuselage and engine to Puusepäntie

Torstai 27.3.2025 - Tuesday Club member

Suomeksi

Equipping the Aviation Museum Society’s rented premises at Puusepäntie in Tuusula into the workshop for the Tuesday Club has advanced so well that we decided to move the fuselage and engine of the experimental aircraft Snoopy, stored at the Finnish Aviation Museum, to the new workspace.

This means that restoring the Snoopy will continue from the point where we left it at the end of last year. Bringing the Snoopy to Puusepäntie is a kind of milestone in taking the rented workspace into its proper use. Well, the equipping of the Puusepäntie workspace is still not quite finished, but we’ll get there while working on the Snoopy and other restoration projects.

Let it be reminded that restoration work at the Finnish Aviation Museum’s restoration workshop came to a close at the end of last year, because the restoration workshop was changed into a space supporting the oncoming move of the Finnish Aviation Museum. The Tuesday Club will participate these Museum operations and continue restoring museum worthy aircraft at the Aviation Museum Society’s rented workshop at Puusepäntie.

Kuva: Jouni Ripatti.

Kuvat: Reijo Siirtola.

On Tuesday, 25 March 2025 we gathered at the Museum to transport the Snoopy’s fuselage and engine to our new workshop. The Snoopy’s fuselage and engine, situated in a storage container, were pulled out of the container to the Museum yard. The fuselage was hoisted on to a trailer, where it was carefully fastened with cargo straps. A light tarpaulin was spread on the fuselage to protect it during the trip. The Snoopy’s engine, fastened in its mount could be loaded in a minivan.

Kuva: Jouni Ripatti.

Kuva: Reijo Siirtola.

When the loading was ready, we drove the ten or so km from the Museum to the Puusepäntie workshop. There the fuselage and engine were unloaded and pushed into their new home.

Kuva: Reijo Siirtola.

Kuva: Reino Myllymäki.

The Snoopy’s restoration will commence at the beginning of April, simultaneously with giving the workshop the finishing touches.

Translation to English by Matti Liuskallio.

Equipping Tuesday Club's premises at full swing

Maanantai 10.3.2025 - Tuesday Club member

Suomeksi

Aviation Museum Society Finland rented premises at Puusepäntie (Carpenter Road) in Tuusula to secure the continuity of the Tuesday Club’s work. The Club’s restoration operations drew to a close at the Finnish Aviation Museum’s workshop at the end of 2024, because the restoration space was turned into a workshop serving the Museum’s move.

The premises at Puusepäntie were rented for three years, or for the period of time during which the new Museum building would be completed. Well, if that wouldn’t realize, we could continue at Puusepäntie, until restoration work could be continued in the workshop in the new Museum.

Photos by Jukka Köresaari

Equipment and work machines brought along from the Finnish Aviation Museum have been hauled for the last couple of weeks to the empty hall at Puusepäntie. We obtained a laudable amount of work machines and equipment from there, thanks to the Finnish Aviation Museum. The items include band saws, face grinders, circular grinders, a column drilling machine, a compressor and an industrial vacuum cleaner.

Photo by Jukka Köresaari

Smaller articles have been transported from the Finnish Aviation Museum to Puusepäntie in cars and trailers. To transport big and heavy objects like tables and work machines we luckily had at our disposal a lorry equipped with a rear platform lift. Many of the work machines were manually pushed out of the workshop and on to the lift, but we were assisted in the loading by the Museum’s fork lift.

Simultaneously we have been able to obtain, from a long list of needs, furniture and other equipment to furnish the premises. Fortunately these have been available at a low price or even with no cost. We do still need furniture, such as lockers and shelves, and equipment, e.g. a coffee maker and a medicine cabinet.

The premises rented by the Aviation Museum Society isn’t merely the Tuesday Club’s workshop. It will be at the same time a storage for publications by the Aviation Museum Society and Ketterät Kirjat Oy (a publishing company). A space will be therefore reserved separately for these two storages.

When various pieces of equipment have been brought in through the Puusepäntie door, shelves and lockers are being assembled on the walls for restoration material and tools. So far everything looks quite confusing, but day by day the chaos will turn into organization, and beginning restoration activities will be possible.

It will certainly take some time yet to furnish the Puusepäntie workshop. However, we aim to be able to continue restoration work in the new facility of the Tuesday Club at the beginning of April. Then the members will continue work both on the Myrsky Demo Wing and on the restoration of the Snoopy (OH-XEA). Along with these projects also smaller restorations will be done, such as the refurbishing the pilot’s seat of a Bristol Blenheim bomber.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation to English by Matti Liuskallio.

New premises for the Tuesday Club for continuation of restoration work

Maanantai 17.2.2025 - Tuesday Club member

Suomeksi

As was told in the previous blog, restoring aircraft at the Finnish Aviation Museum took a break. Restoration work at the Museum will continue after the new Museum will be completed in approximately three years’ time. For that purpose all the ongoing projects of the Tuesday Club were halted, i.e. stored in sea containers at the Finnish Aviation Museum’s yard.

The Aviation Museum Society has every intention to secure the continuation of the restoration work without interruption till the new Museum is ready. That’s why the Aviation Museum Society has been looking for a temporary facility in the Helsinki metropolitan area where the restoration work of museum worthy aircraft by the Tuesday Club could be continued. There are plenty of empty storage space for rent, but for instance around Ring road III, or south of it, the rents are too high for the Museum Society’s economic situation.

In looking for temporary premises we aimed at a solution, in which the facility wouldn’t be too far from the Finnish Aviation Museum, because co-operation with the Museum would continue close knit. A few months hard work brought a result at last. The Society decided to rent an empty premise, suitable for our purposes, in Tuusula, not far from the Museum. There’s an open 140 m2 space, suitable to be a workshop. There are two consecutive rooms in addition for storage and social purposes.

The rental contract comes into effect at the beginning of March. Before that the owner will do some maintenance and modifications to enhance the suitability of the space from our point of view. Because the rented property is an empty hall, it must be furnished as a workshop. The last weeks have therefore been spent gathering various equipment and other necessities, to be able to start the restoration work. We have luckily succeeded in obtaining what we need from various sources without cost. We even have succeeded in getting along from the Finnish Aviation Museum necessary equipment, work machines and tools.

After the new Tuesday Club workshop has been furnished and adapted to serve the restoration work, the parts of the Snoopy(OH-XEA) and the Demo Myrsky, currently stored in sea containers at  the yard of the Finnish Aviation Museum, can be brought to the Tuusula workshop. This way the restoration can be continued. It’s possible that later this year the refurbishing of the PIK-21 Super Sytky (OH-XTM) will start. It’s been damaged in a forced landing.

Although the Tuesday Club’s restoration activities will move from the Aviation Museum to the Tuusula workshop, the intense co-operation with the Finnish Aviation Museum will continue. First of all, we’ll continue weekly preparation work for the Museum’s move, under the Museum’s guidance. Secondly, we can nip over to the Museum to use for restoration purposes the fire work container, painting tent or to use machines, like the lathe, which remained in the Museum’s workshop. In this sense it’s excellent that the Tuusula workshop is situated only a ten-minute drive from the Museum.

Photo by Reino Myllymäki.

Translation to English by Matti Liuskallio.

Restoration work took a break at the Finnish Aviation Museum

Torstai 30.1.2025 - Tuesday Club member

Suomeksi

Restoration operations at the Finnish Aviation Museum were discontinued at the end of 2024. The break will last until the work can be restarted in the new Aviation Museum, which is rising near the present Aviation Museum. It may happen approximately at the end of 2027. The reader can wonder, why the break already now?

Moving the Finnish Aviation Museum to new premises is a herculean effort. In principle every artefact in the Museum will be dealt with, assessing whether it will need possible maintenance, repairing, conservation, or restoration measures. If beforementioned measures will be needed, they will be taken and after that it will be decided if the artefact will be placed in the new Museum, or will it be stored in the collection centre?

From the beginning of 2025 onwards the Museum’s restoration workshop will primarily become the maintenance, repair, and restoration space for the aircraft and their equipment from the Museum’s exhibition halls. First to be taken under scrutiny will be minor artefacts in the exhibition halls, for example the aero engines. Maintenance work could then advance from primary gliders and advanced sailplanes to small aircraft. They will be disassembled and brought part by part to the restoration workshop for the necessary repairs or restoration operations. For instance, the primary gliders and advanced sailplanes have been hanging from the ceiling for decades, so at least they should need maintenance.

But before the previously mentioned check-ups and maintenance work can be started, the restoration workshop must be organized and cleaned and the restoration projects, which have continued till the end of last year, have to be stored somewhere else. So the projects, such as the Valmet Tuuli III, OH-XEA Snoopy and Caudron C.50 restorations and building of the so-called Demo-Myrsky, must be packed with all parts and equipment and stored to wait for better times.

We have our work cut out for us in cleaning and organizing the restoration workshop for the new task. Restoration work of aircraft and other museal tasks have really been going on there from the end of the 1980s.

Straight after Epiphany members of the Tuesday Club started, with guidance from the Museum, to clean and organize the restoration workshop and packing restoration projects to be moved to storage. The work has progressed at a good pace. Unnecessary and unusable material for the future projects, such as all kinds of wood and metal debris, have been recycled in large amounts. Part of it has also been disposed of as non-recyclable waste. The premises have also been cleaned and tools and other articles put to their places.

The Tuuli III, Snoopy, Caudron and Demo-Myrsky parts that were in the restoration workshop, have now been wrapped in bubble plastic to be stored. Smaller parts were put in storage boxes. The Tuuli parts were put in a big spacious plywood box.
The Snoopy parts were stored in the container owned by the Museum at the Museum yard and the Demo-Myrsky parts in a container owned by the Aviation Museum Society.

Before storing the Tuuli III fuselage was protected with Tyvek polyethene fabric, which is breathing in such a way that it lets moisture out, but not inside. The fuselages of the Tuuli III and the Snoopy, Snoopy’s engine and the restored Walter Gemma radial engine in the workshop, used by the Finnish Film industry to create wind, were moved from the restoration workshop to the 45 feet long sea container at the Museum yard, owned by the Finnish Aviation Museum. The transportation went on deftly either by a forklift or in a car tow.

Perhaps we’re already getting the upper hand in organizing the restoration workshop. Still there is cleaning and organizing to be done before we can bring the first aero engines from the exhibition halls to the restoration workshop for inspection and maintenance.

Photos by Lassi Karivalo.

Translation to English by Matti Liuskallio.

The Snoopy got its horizontal stabilizer struts

Maanantai 27.1.2025 - Tuesday Club member

Suomeksi

The Snoopy horizontal stabilizer has on both sides a metal strut attached to the fuselage. The struts haven’t survived, so they had to be made. We scrutinized photos of the Snoopy. They showed that the struts have been of round metal tube. We found at the metal store of the Finnish Aviation Museum some 10 mm thick aluminium tube, suitable for making the struts.

Photo by Esko Keskinen.

For making the struts their lengths had to be determined. Therefore the Snoopy’s horizontal stabilizer was fastened to the fuselage. It is fastened to the fuselage with three 8 mm thick bolts. They haven’t survived either. So we bought such ones with nuts and washers. Before fastening the stabilizer, the holes for fastening the stabilizer on the fuselage were cleaned with a round file, after which the stabilizer was fastened to place.

Now the strut length from the bracket in the fuselage to the fastening bolt in the stabilizer could be measured. It turned out to be 60 cm.

Two 60,5 cm long pieces were cut off the aluminium tube. The ends of both the tubes were squeezed flat for drilling holes for the fastening bolts. At first the holes for the fastening bolts were drilled to one end of the strut, after which the struts were fastened to the brackets on the fuselage. The flat top end of the strut was placed in line with the fastening bolts in the stabilizer. We saw that the top end of the strut fitted exactly to the bolt.

We marked the place for the fastening bolt to the flat top ends of the struts with a felt pen and holes were drilled accordingly. After that both struts were fastened in place on the stabilizer. It was noticed that the stabilizer was horizontal and steady at its place. So the horizontal stabilizer had received its new struts.

The struts made of aluminium tube were unfastened to be painted. The struts were painted with blue grey Isotrol oil paint. At the same time the elevator operating rod, made of aluminium tube, was painted. After the paint had dried, the struts were once more put to place, after which the stabilizer was unfastened, waiting for the fuselage restoration to be ready.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation to English by Matti Liuskallio.

Refurbishment of the Hansa and Moth models

Perjantai 24.1.2025 - Tuesday Club member

Suomeksi

The Karelian Aviation Museum in Lappeenranta, has in its collection wooden models of the I.V.L A. 22 “Hansa” 4F35 (later IL-35) and de Havilland D.H.60 (MO-97) aircraft.

Both types of aircraft were licence built at the Aircraft Factory of The Aviation Force (Later the Air Force) in Suomenlinna. The I.V.L. A.22 aircraft were built on the licence from Hansa Brandenburg W.33 aircraft. Many modifications were made in the aircraft built in Suomenlinna so that the aircraft didn’t fully match the original anymore. However, it has always been simply the Hansa in common language, as in this blog, too. The Hansas served as maritime reconnaissance aircraft in the Finnish Air Force, and the Moth as a trainer and a liaison aircraft. The Hansas were struck off charge in mid 1930s and the Moths after the Continuation War.

Because the wooden models of both the aircraft were in poor condition, the Karelian Aviation Museum queried of the Tuesday Club, whether they could repair and refurbish the models. We were pleased to meet the challenge, because we had earlier on restored for them the tail boom stabilizers of the Mil Mi-8T helicopter and the wings of the Link Trainer. On top of that we have, in our Club, an excellent model builder, who took on the job. 

In refurbishing both the models we adhered to the principle of fixing or completing what’s broken but otherwise followed the principles of preservative conservation. The aim is to preserve originality, where the models wouldn’t be repainted, but the original paint surfaces will be maintained with preservation. We will respect the original modellers and earlier restorers by leaving as much of the original patina visible as possible, however, avoiding the models looking ragged.

First we took on the Hansa. The Hansa’s swastika emblems drew our attention. They were of paper and had been glued to the wings and fuselage. We decided to remove the ragged paper emblems. They were soaked with water and removed with a painter’s spatula, and under them painted emblems emerged. This left us thinking, why new emblems made of paper had been glued on. Perhaps the previous restorer had thought that the old ones were worn out and glued new ones out of paper on them.

The painted emblems, discovered under layers of paper, were in surprisingly good condition. They were patch-painted only to an extent that they wouldn’t jump out as too fine, compared to the patinated appearance of the rest of the aircraft.

A quaint detail was that one of the fuselage swastika emblems was a mirror image. We decided to preserve it as it was. It’s common knowledge that so called reversed swastikas had in fact appeared in the surfaces of Finnish Air Force aircraft. Might this have been the case in the 4F35 individual, the example aircraft to this model?

The Hansa model’s engine cowling was rusted. It was meticulously sanded clean. Then the cowling was bordered with narrow masking tape and painted with silver enamel paint. The radiator cells at the front end of the engine were painted dark and the exhaust tubes penetrating the cowling were painted black. The stepping boards at the junction of the wings and fuselage were loose. They were properly fastened and painted silver.

The paint on the wooden surfaces, especially on the upper surfaces, was scaling off. The scaling paint was removed with the masking tape/sticker method, where the loose scales remain on the tape, but the solid paint surface stays untouched. After the tape treatment the surfaces were lightly sanded with fine sanding paper. Finally the surfaces were lacquered with matt acrylic lacquer. It suits this purpose well, because the lacquer won’t change the appearance of the original patinated paint surface but gives it good protection.

Both the pilot’s and observer’s “offices” were tidied by painting them with brown acrylic paint. The painting was brought to the upper rims to emulate the leather paddings.

The model’s propeller was made to resemble a laminated wooden propeller. It was sanded and lacquered with semi matt lacquer. Brass reinforcements were painted to the leading edges of the propellers. Finally, the swastikas that were used in the State Aircraft propellers, were transferred as decals on the propeller blades. The refurbishment of the Hansa was now completed, and it was time for the Moth.

The wooden Moth MO-97 model was refurbished like the Hansa complying the principles of repairing conservation. The Moth had suffered worse than the Hansa with the passing of time. The coupling of the fuselage and the upper and lower wings had failed. The threads emulating the wing stiffeners, or lamellas, were broken off. The Moth’s paper swastika emblems had dried up all crumpled and were unusable.

First, the Moth was dismantled, and the refurbishing was started with the swastika emblems. The wings’ paper emblems were removed by soaking and the swastikas that were painted on the wooden surface, were cleaned with a magic sponge. After that the swastikas that appeared from under them, were carefully completed with blue and white paint. The wing emblems were restored to reasonably good condition in this way. The fuselage emblems were in such sorry state that they were replaced with decal swastikas. Otherwise the fuselage and wing surfaces had kept well, so they were just cleaned and given a protective layer of matt acryl lacquer.

Rigging the Moth was started by joining the lower wings and the fuselage. The coupling of the lower wings and the fuselage were made sturdy by installing metal reinforcements. The struts joining the lower and upper wings were fastened on the lower wings. The middle section of the upper wing, where the fuel tank was situated, was mounted on the fuselage. The upper wings could be joined to the middle wing using their original brackets.

The stiffening threads emulating the struts and lamellas in the Moth model wings had to be replaced with new threads. As thread, twined cotton thread of thickness two was used. The darker, thinner thread was used as wing stiffeners and thicker light thread to reinforce the struts. Attaching the threads was started by drilling holes for them into both the upper and lower wings with a Dremel Mini extremely thin bit. The threads were squeezed through the drilled holes with a needle threader used by dressmakers.

When the end of the thread was passed into its hole, a drop of superglue was applied. When the glue had dried, the other end was passed into the opposite hole (e.g. from the stem of the lower wing to the upper end of the strut). The thread was tightened suitably in its hole and superglue was applied into the hole, keeping the thread tight at the same time. The criterion for the suitable tightness is that when you look from the front, the lower and upper wings stay at the right angle compared to the fuselage.

After the glue had dried, we made certain that the thread stayed tight, and we moved on to the next reinforcement thread. Working like this, all the four pairs of reinforcement threads were glued into place. In fitting the reinforcement threads we had to be careful that the reinforcement threads were at the same tightness on both sides of the fuselage. Otherwise, the lower and upper wings won’t set at the right angle, or one individual tread is left too loose. When the reinforcement treads between the lower and upper wings were in place, grids of reinforcement tread were attached to the struts between the lower and upper wings. They were made of the thicker twined cotton thread.

The missing long exhaust tube on the left-hand side of the fuselage was built to the completed model Moth. The exhaust tube was made to look original. It was made from plastic 1:48 aircraft black model sprue, from which a piece as long as the exhaust tube was cut. The piece was heated, and the softened plastic was bent to form. At the end of the exhaust tube an aperture was drilled. The front end of the exhaust tube was glued with superglue to the existing hole in the cylinder block. The middle part was fastened with a metal clip. The tube was painted with black acryl colour so that the front end shows a silver hue due to engine heating.

When the Moth’s wooden propeller had been lacquered, small swastika decals were attached to the propeller blades. Now the MO-95 wooden model repair and conservation was ready.

Both the wooden models of the 1930s aircraft, the Hansa and the Moth, are owned by the Karelian Aviation Museum. The repaired models were now ready to be delivered to Lappeenranta to be put on display.

Photos by Matti Kainulainen.

Translation to English by Matti Liuskallio.

Installing the control wires in the Snoopy's tail

Torstai 2.1.2025 - Tuesday Club member

Suomeksi

The experimental aircraft Snoopy, under restoration at The Tuesday Club, retains the wires from the rudder pedals to the rudder and tail wheel. Instead, the elevator wires had disappeared.

We examined the Snoopy’s fuselage to find out how the elevator wires had run. It transpired that the upper wire is attached to the top end of a rocking lever in the tail. Accordingly, the lower wire is attached to the lower end of the rocking lever. So, how to move the elevator? From the photos taken of the Snoopy we noticed a bar from the tail to the underside of the elevator. The other end of this metal bar has been attached to the lower end of the rocking lever, where there are holders both for the wire and the bar. As the wires tilt the rocking lever from side to side, the metal bar moves back and forth, making the elevator move up and down.

At the lower end of the control column the lower elevator wire runs through a pulley in the fuselage and on through a tube in the control column lower end winding around a pulley to the lower end of the control column. Accordingly, the elevator upper wire runs from the rocking lever through a pulley in the fuselage, straight to the lower end of the control column. This way the wire forms a connected wire loop that can be operated from the control column.

Before we started to install the elevator wires, we had to lathe the two missing pulleys in the fuselage that guide the movement of the wires. The bolt holes in the pulley holders were drilled clean, after which the pulleys were installed. Now we could start threading the wires to place.

The wires were tentatively fastened with loops with wire locks to the lower end of the control column and the rocking lever. After it was defined how tight the wires should be, the wire ends were equipped with metal rings or thimbles. The wire was tightened around the thimble and the end of the wire was locked at the stem of the thimble with two pressable wire locks made of aluminium. The thimble headed wires were finally threaded to the holder at the lower part of the control column and the locking loops attached to the rocker lever.

After the elevator wires had been fitted, we constructed the metal rod out of 20 mm metal tube, to move the elevator, and fastened it to lower end of the rocker lever. We further checked the working of the rod by attaching the horizontal stabilizer and elevator to the fuselage of the Snoopy. When we fastened the other end of the rod to the bracket on the lower surface of the elevator, it moved as planned, when pulling and pushing the control column.

A wire connects the rudder pedals both to the rudder and the tail wheel. The wire running towards the tail, forks halfway of the fuselage to wires going to the rudder and the tailwheel. The tailwheel turns simultaneously, when the rudder is turned by the pedals.

We fastened first the right- and left-hand side wire ends to the pedals. After that we attached the ends of the rudder wires, which forked halfway of the fuselage, to the brackets on the lower left-hand and right hand-side corners of the rudder. At the same time we noticed that in front of the rudder, there had been pulleys guiding the wires in the fuselage. All that was left was the holder for the pulleys.

The missing pulleys were lathed and attached in place. Thus the rudder wires had been installed.

It was time to install the tailwheel wires. The left-hand side wire had been linked to the tailwheel by a coiled spring. The right-hand side original wire lacked the coiled spring. When we thought about the problem, we found out that both the wires should have the coiled spring for the rudder to function properly.

We studied photos of the Snoopy. It transpired from them that both the rudder wires did have a coiled spring. Why it lacked from the right-hand wire, will remain a mystery.

We carried on pondering. If the tailwheel wires have coiled springs, they must have counter springs in the pedals. This way the wires between the pedals and the rudder could remain tight and the rudder movements transit to the rudder and tailwheel. Small metal rings were found in the fuselage and rudder pedals. So we bought suitable coiled springs and installed them to the rudder pedals.

We also bought coiled springs for both the tailwheel wires.  So we decided to renew the left-hand side tailwheel coiled spring, in order for both springs to be identical. Before installing the tailwheel wires, we had cleaned the pulleys for the tailwheel wires to be fastened to the tailwheel coiled spring.

At first the coiled springs on both sides were fastened to the brackets in the tailwheel. After this both the wires were attached to the coiled spring with a ring made to the end of the wire. The ring was locked with two wire locks that were pressed around the wire. We still installed, as had been in the original, a backup wire between the brackets and the ends of the wires. The backup wire was threaded through the coil spring. The wire ensures the function of the tailwheel if the coiled spring breaks loose or breaks. We added a turnbuckle to the left-hand side wire of the tailwheel to adjust the tightness.

Thus we had installed to working order all the Snoopy’s control wires in the tail section.
A different story will be the fitting of the aileron wires in the wings.

Photos by Lassi Karivalo.

Translation to English by Matti Liuskallio.

Painting the propeller of the Snoopy by its painting scheme

Perjantai 20.12.2024 - Tuesday Club member

Suomeksi

The damaged Hoffmann Rosenheim propeller, received as a donation, was primed after its repair with bluish-grey Isotrol oil paint. This paint suits for both priming and surface painting. After the priming, putty was still re-applied to some uneven spots, after which the propeller surfaces were thoroughly ground smooth with sandpaper. The grinding dust was wiped off with a rag moistened with Sinol / water solution (50% / 50%).

Now we proceeded to painting the propeller by the original painting scheme as in the Snoopy, documented in photographs of it. The tips of the blades were red, with a narrow white stripe in the bottom edge of the red. The front side of the blades was painted with the same bluish-grey paint as the whole aircraft. The back side of the blades had been painted matt black between the red tip of the blade and the propeller hub, to prevent glare.

Painting the propeller as in the Snoopy painting scheme was started, after grinding the primer, by covering it fully with bluish-grey Isotrol paint. The front side of the blades simultaneously received its final bluish-grey coat of paint. The paint job was done with a brush. Spray painting was considered, but Isotrol gives an extremely even, smooth, plastic-like surface even when applied with a brush.

Next were painted the red propeller tips. Red spray paint was bought, and used for it. The length of the red tip was estimated based on photos of the Snoopy. It was about 1/3 of the distance between the propeller hub and the tip. The tip part was separated with tape, and the rest of the propeller was protected with cardboard for the time of painting. At first, the front sides of the propeller blades were sprayed red. After the paint had dried, the back sides of the propeller blades were sprayed equally.

Because spray paint dries quickly, the back sides of the propeller blades could be painted matt black on the same day. That was also done by spraying it. Again, the length of the matt black area was defined by photos of the Snoopy. The matt black area reaches from the red tip to the edge of the propeller hub, where tape was applied for separating it. Now, both the tips of the propeller blades and the hub area were protected, and the back side surface of the blades was sprayed matt black.

What is still missing is the white stripe separating the bottom of the red areas from the bluish-grey and matt black areas of the blades. The paint job did not make it in time before the Christmas pause of the Tuesday Club, so the painting will be delayed until the spring of 2025.

The donated German Hoffmann Rosenheim propeller had thus acquired the external appearance of the propeller used in the Snoopy, except for the white stripe.

Photos by Lassi Karivalo.

Translation to English by Hannu Mononen.

New plexiglass windows for the Snoopy's cockpit

Tiistai 17.12.2024 - Tuesday Club member

Suomeksi

The experimental aircraft Snoopy (OH-XEA), under restoration in the Tuesday Club, has plexiglass windows on the doors of the left- and right-hand sides of the cockpit. They have been preserved, but turned dim, yellow, and scratched. Therefore, they will be replaced. The original ones are of polycarbonate plexiglass, to be used also in the new ones.

Photo by Esko Keskinen.

We decided to test assembling the original dim glasses in place, to find out how they were fastened, thinking about buying and assembling new plexiglasses. For attaching the glasses, there are threaded brackets in the fuselage frame of the cockpit, into which the plexiglasses are fastened with screws.

When the original plexiglasses were fitted in place it was noticed that the holes for attachment screws no longer matched everywhere with the holes in the brackets of the fuselage framework. The plexiglasses had somewhat changed their form and shrunk over time. Thus, in many places, new holes had to be drilled or existing holes had to be enlarged to match the plexiglass holes with those in the brackets of the fuselage framework.

When attaching the plexiglasses with screws into the brackets had started, it was observed that the threads in the brackets no more worked in all of them. Therefore, into all of the bracket holes for the plexiglass on the sides of the cockpit and the doors, new threads were made with a tap for 4 mm screws. These screws were purchased and then the old plexiglasses could be mounted into place. Now, the test-fitted old plexiglasses were detached, and marks matching with their attachment brackets were made onto them with a felt-tip pen, for drilling holes into the new plexiglasses. 

New plexiglasses were bought from an Etra shop, where they were cut ready into the shape of the old ones. The old plexiglasses had the thickness of a good millimeter only, and were thus rather flimsy. Therefore, we decided to buy a little bit stronger material and ended up with the thickness of 2 mm. The sawed edges of the new plexiglasses were ground smooth.

Holes were made into the new plexiglasses for attachment screws, according to the original ones. The old plexiglass was placed on top of the new one, and the spots for holes were marked with felt tip pen onto the new one. With a column drill, 4 mm holes were drilled. When screwing the plexiglasses in place was started, it was noticed that the 4 mm holes were slightly tight, and the plexiglass could not be pressed smoothly against the fuselage framework. The holes were widened, and thereafter the plexiglasses of the cockpit door and the left-hand side wall could well be pressed against the fuselage framework. The new plexiglass windows had been assembled. For the time being, the protective films on the plexiglass surfaces will be left in place.

The cockpit windscreen has also been plexiglass, but is has not been preserved. Thus, it must be made. It is a single pane, the same sheet of plexiglass in the front as well as the parts bent to the sides. The bent plexiglass has been attached to its brackets in the fuselage framework through the screw holes by its edge.

To make a new windscreen, we plan to proceed by first making a cardboard model of it. Accordingly, we will get a sheet of plexiglass that will be bent in shape for attachment. It will also be made of 2 mm polycarbonate, bent into the angular shape of the Snoopy’s windscreen by heating.

A large sheet of cardboard was cut and started to be formed into the place of the windscreen, cutting it smaller piece by piece, until it corresponded with the shape and size of the original windscreen visible in photos of the Snoopy. It was checked that the edges of the cardboard will settle in line with the windscreen attachment brackets of the fuselage. There are still adjustments to be made until, based on the spread-out cardboard template, a sheet of polycarbonate plexiglass of its shape will be purchased and bent into its final shape.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation to English by Hannu Mononen.

Painting the Snoopy's rudder decals and taping them

Perjantai 13.12.2024 - Tuesday Club member

Suomeksi

Unlike the other control surfaces, Snoopy’s rudder is covered with fabric. The other surfaces are covered with plywood. The paint on the rudder fabric was badly crackled and also tatty. That’s why we had to cover the rudder again. The new covering and the tightening with lacquer have been dealt with in the blog of May 6.

After the tightening with lacquer (shrinking dope) the fabric surface of the rudder was painted with the blue greyish Isotrol -oil paint the same shade as the original. The painting was done with a hand brush, because the Isotrol paint leaves a very smooth surface when painted with a hand brush.

Before painting the paint was filtered through a funnel to eliminate any lumps. The surfaces were painted twice over, after which the surface of the covering fabric was even and semi glossy. It was time to paint the speed lines and symbols the rudder once had.

On each side of the rudder there are red speed lines cutting diagonally across the surface. In addition, on the left-hand side of the upper part of the rudder there was number 2, and on the right-hand side a profile of a bird with spread wings. Did Esko and Ari Hietanen have a raven in mind?

Both the bird profile and the number 2 were copied on transparent paper from the old fabric that was detached from the rudder. From the paper they were transferred on to black contact plastic and cut off with scissors. Originally the symbols had been of black contact plastic, i.e. they weren’t painted on the rudder fabric.

First the red speed lines were made on the recently painted rudder. They were made exactly according to the originals, or copied from the covering fabric detached from the rudder. The shape of the speed line was bordered on the surface of the rudder with masking tape. The bordered area was painted with red Isotrol- paint. It’s of the same shade as the original. When the speed line on the left-hand side had dried, a similar line was painted on the right-hand side of the rudder.

Now the previously copied symbols, the bird figure and the number 2 could be fastened into place, number 2 on the left hand-side of the rudder and the bird figure on the right-hand side. The rudder restoration was ready.

Photos by Lassi Karivalo.

Translation to English by Matti Liuskallio.

Painting of the repairs in the plywood cover of the Snoopy

Tiistai 10.12.2024 - Tuesday Club member

Suomeksi

After we had patched the holes in the plywood-covered wings, ailerons, horizontal stabilizer, and elevator, those patched spots were ready for painting.

We do not intend to paint all through the patched parts of the Snoopy, but the patches only. This is because in restoration we strive to preserve the original paint surface whenever it is possible. The painted surfaces of the Snoopy’s wings and tailplane still remain in excellent condition. That became evident when prior to fixing the damaged spots we cleaned the plywood surfaces from the dust and dirt that had accumulated during decades. The washed surfaces, most likely painted with Miranol-paint at the time, looked like newly painted.

The painted and repaired areas were re-painted with Isotrol oil paint that produces a paint surface similar to Miranol. It only required first defining the original blue-grey hue for toning the Isotrol paint. This created us a little problem.

Even though all the plywood-covered parts of the Snoopy had been painted simultaneously with the same blue-grey paint, those paint surfaces had become covered with patina or faded at a different pace during the decades. There were distinct differences of hue between painted parts of the Snoopy. Thus, the hue in the colour chart that matched for example the colour of the left wing, did not match with the elevator. We had to settle for a compromise in defining the hue, by choosing one that in average corresponded with the Snoopy’s patina-covered painted plywood surfaces. The formula for this hue became +CT101 3,2GR/0,5 l KAAVA, and the Isotrol paint was toned accordingly.

The paint job was done with a brush, Isotrol paint being brush friendly. The paint covers extremely well already at the first time, and it smoothens also extremely well when applied with a brush, forming an even, semi-glossy surface. After the paint has dried, the covered surfaces can still be polished with mineral spirits.

The paint job was done inside a painting tent or a tent-like cover beside the restoration workshop of the Finnish Aviation Museum. It can be warmed and has effective ventilation. Thus the patchwork of plywood surfaces on both wings, ailerons, horizontal stabilizer, and elevator received a beautiful blue-gray Isotrol coating in the painting tent.

After the painting, there was still some work to be done on the Snoopy’s left wing, because patching the plywood cover of the wing had destroyed some of the letters in the registration marking OH-XEA. The letters O and H had to be complemented. As the marking had been made on the wing using black contact plastic, we decided to do the same.

Black contact plastic was purchased. The lines were marked with sticky tape on the wing to define the location and size of the missing parts. Thereafter, the missing parts of the letters O and H were drawn on transparent rice paper to make a template for them. Placing the rice paper template on top of the black contact plastic, a carpet knife was used to cut through the rice paper the missing part of each letter. These letter parts were then precisely placed to complete the damaged O and H, which succeeded perfectly. Even by a close scrutiny, the seam between the original letter and its complementary part cannot be detected.

The restoration work of the plywood-covered wings, ailerons, horizontal stabilizer, and elevator has thus been completed.

Photos by Lassi Karivalo.

Translation to English by Hannu Mononen.

Constructing the Demo-Myrsky

Maanantai 2.12.2024 - Tuesday Club member

Suomeksi

When the VL Myrsky ll (MY-14) restoration project had come to an end, at the beginning of autumn, as far as the Tuesday Club Members freed from the restoration were concerned, they chose not to stay put twiddling their thumbs. So the idea of building a Demo-Myrsky was dug out.

Our purpose is to build an entity from the Myrsky test wing, currently on show at the Finnish Aviation Museum exhibition, and the Myrsky MY-5 fuselage frame, to demonstrate coherently the structure and equipment of the mixed construction Myrsky-fighter, designed and built by State Aircraft Factory. The inner construction and technique of the MY-14 fighter that we had restored, are hidden inside the plywood covered fuselage and wings. In the Demo-Myrsky they would be exposed.

The test wing, on display in the Finnish Aviation Museum, was built at the beginning of the Myrsky restoration project. By building the test wing it was found out how the Myrsky wing, particularly the root with all its equipment, was constructed at its time. Our ambiguity was mainly caused by the fact that the blueprints at our disposal were partly contradictory. The main reason for the controversy was the ongoing development during the serial production, causing changes to structural solutions. By building the test wing we managed to get our ambiguity to dissolve.

After the test wing was finished, the building of the actual Myrsky wing began. Already at that stage the idea was born to utilize the test wing later to demonstrate the wing structure and the equipment fitted in it. Therefore the test wing was covered with transparent plexiglass instead of plywood and was placed on display in number l Hall in the Finnish Aviation Museum.

After the Myrsky wing was completed, we utilized the MY-5 fuselage frame in testing how to join the wing to the fuselage, including the assembly of the wing root fairings. This led to the idea of utilizing the MY-5 fuselage frame, together with the test wing, for demonstrating the mixed structure of the Myrsky by joining the test wing and the uncovered fuselage frame.

In this task the rear part of the MY-5 fuselage frame is under work, because the rear section of the fuselage frame needs repairing and refurbishing. The rear fuselage will also get a rudder and elevators of wooden construction.

The rear fuselage has been repaired by welding and the tail wheel mounting, made of steel tubes according to blueprints, has been fastened to it. The Myrsky wooden vertical stabilizer has been under construction in a specially made jig. The vertical stabilizer frame is about to be ready. The left and right-hand horizontal stabilizer ribs and the blanks of the wing spars are ready to be assembled. The vertical and horizontal stabilizers will remain uncovered, at least on one side.

How far the Demo-Myrsky MY-5 fuselage frame will be completed, is still an open question. It could be advanced, even if it were on display for the public. Well, a place to show the Demo-Myrsky won’t be available in the near future, at least not in the Finnish Aviation Museum, which is preparing to move to new premises. That’s why the construction of the Demo-Myrsky at the Finnish Aviation Museum will come to an end by the end of this year, even though it won’t be ready. From the beginning of 2025, the restoration workshop at the Finnish Aviation Museum will be reserved for servicing the museum artefacts before moving them to the new Aviation Museum in a couple of years. The Aviation Museum Society is presently looking for temporary premises where the restoration work could be continued next year.

Photos by Lassi Karivalo.

Translation to English by Matti Liuskallio.

A propeller for the Snoopy's engine

Maanantai 25.11.2024 - Tuesday Club member

Suomeksi

The Aviation Museum Society’s donation, the OH-XEA Snoopy experimental aircraft, was without its Continental A 65 engine and the propeller. As far as we know, the engine and propeller had been given away, after the Snoopy’s flying days were over.

Photo by Esko Keskinen.

The problem of the missing Continental A 65 engine was solved when we were donated a damaged Continental engine of a plane that had crashed. It’s not airworthy, but it needn’t be, because the Snoopy won’t be restored to flying status. We’ll restore the engine looking complete and make the exhaust pipes, looking like those that were in the Snoopy’s Continental engine.

Photo by Juha Veijalainen.

We were also lucky about the missing propeller. We were donated a slightly damaged and struck off propeller, fitting the Continental A 65 engine. The wooden propeller is made by the German Hoffman Rosenheim works in 1986. One propeller tip is damaged. It’s both broken and has a dent in the leading edge.

The division between the six fastening bolts was exactly the same as in the propeller hub of the Continental A 65. The holes were, however, slightly smaller, so we drilled the holes with a column drilling machine to respond the to the fastening bolts of our Continental engine propeller hub. The compatibility was tested by fastening the propeller to the hub.

Because the propeller is mainly white, it doesn’t correspond to the Snoopy’s propeller in appearance. The Snoopy’s propeller tips were red. At the bottom of the red area there was a narrow white stripe. Otherwise the propeller frontside was blueish grey or the same colour as the aircraft itself. The backside of the propeller was, however, painted black between the white stripe and the hub.

We’ll repair and restore the propeller’s outer appearance like it was in the Snoopy. That’s why the markings and tapes were sanded off the surface of the donated propeller and anyway the propeller’s surface was rebuffed for the painting.

The crack in the other propeller tip and the dent in the leading edge had to be fixed before painting. We ended up fixing the tip crack with epoxy glue. So the crack was immersed in epoxy glue, after which it was pressed tight between two plastic plates with clamps. When the clamps were taken off after the glue had dried, the crack was well closed and the propeller tip was sanded smooth.

The dent in the propeller’s brass leading edge was first tried to straighten and then file smoother, but the metal turned out to be too hard to shape. So we decided to spackle the dent full with Lightweight Epoxy Filler. When the filler had been spread over the dent, the dent was covered with a plastic mould, shaped similar to the profile of the propeller leading edge. The mould was pressed with clamps to the leading edge.

After the filler had dried, the mould was taken off. It was noticed then that part of the filler hadn’t adhered properly to the dented area, but had come off with the mould. So we spackled the unsatisfactory part again, after which the leading edge dent became universally smooth. The propeller repairs had been accomplished and the priming of the propeller could be started.

Before starting the priming, the surfaces of the propeller were once more buffed lightly with sanding paper. The buffing dust was first wiped off with a dry cloth and finally with soft cloth immersed in a 50%/50% mixture of Sinol /water. The priming was done with a paint brush. As the paint, we had the same blue greyish Isotrol oil-based paint, that we used in painting the Snoopy’s wings, horizontal stabilizer and elevator plywood patches. The shade is the same blue greyish colour that was used on the Snoopy’s original surfaces. The priming will clearly show if the propeller surface will need any additional spackling. After the paint had dried out it was noticed that no more additional spackling or sanding was needed before the painting of the propeller to the scheme used in the Snoopys propeller.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation to English by Matti Liuskallio.