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.

Refurbishing the Snoopy pilot's seat

Torstai 7.11.2024 - Tuesday Club member

Suomeksi

The pilot’s seat of the Snoopy experimental aircraft, built by the brothers Hietanen from Turku, at the end of the 1960s, was moulded along the times. In the first version, the seat frame had a curved back support and a back rest of plywood, covered with fabric. Later the back rest became rectangular with an inset for the pilot’s parachute. The material of the back rest was changed at the same time from plywood to aluminium. With the inset in the back rest, the distance between the pilot and the control column could be increased, because the Snoopy’s seat isn’t adjustable. The parachute backpack worked as a padding for the pilot’s back.

Photo by Esko Keskinen.

The seat of the Snoopy, a donation to the Finnish Aviation Museum a few years back, consists of the back plate, side plates the shaped bottom plate and the case at the rear of the back rest. These parts have been riveted with pop-rivets to the steel tubes of the seat frame. A plywood plate, with a canvas-covered padding, attached with screws to the cockpit frame, forms the seat.

After tens of years in storage the Snoopy’s seat steel tube frame was rusty, like the fuselage frame, the aluminium parts of the seat were dirty and oxidized grey. The plywood seat plate with its padding had totally vanished.

To restore the seat, we started by detaching the aluminium parts fastened to the seat frame. They were detached by drilling away the pop-rivets that had fastened the aluminium parts to the frame.

After that we disassembled the seat frame of tubular structure, to be refurbished. We had our work cut out for us in doing that. We had to use a jack and a plastic mallet, before we were able to detach the frame parts from each other, because they were joined together with rust.

After separating the frame tubes, they were cleaned from rust to be painted in their original appearance. We did the cleaning by hand, using sandpaper of various grits and abrasive pads. We also did the same to clean the Snoopy’s fuselage frame tubes.

Because we’ll use Isotrol-lacquer to prime the seat frame, the tubes need not be sanded into clean metal. It suffices that the surface rust has been removed and that the surface of tubes feels smooth to touch. An Isotrol paint of the original shade will be painted on the Isotrol primer.

The dirty aluminium parts of the seat were cleaned with Fairy Power Spray agent. The Power Spray is a very efficient detergent for dirt and grease. You spray the agent on the surface of the part to be cleaned and leave it work for a few minutes.

After that the parts will be dried with a cloth or rinsed with water. In doing so we had the aluminium seat parts looking quite different, compared to when we detached them from the seat frame. The aluminium parts will still be buffed out before fastening them back to the restored and refitted seat frame.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio.

Cleaning the parts of the Snoopy?s Continental engine

Perjantai 1.11.2024 - Tuesday Club member

Suomeksi

As soon as parts had been detached from the Continental A 65 engine that we had received for the Snoopy (OH-XEA), originating from a plane destroyed in an accident, they were cleaned. Besides being physically damaged, the engine had also burnt. Unfortunately, many of its devices had been destroyed useless, so the missing parts also had to be searched for.

Photo by Erkki Rossi.

Small metal parts with little or no damage were cleaned from rust by bathing them 24 hours in 33 % solution of phosphoric acid. For example, the propeller hub, detached from the engine and dismantled into its parts, was all immersed into phosphoric acid.

When the acid starts working, foam will be forming on its surface. After a day and night, those propeller hub parts were taken out and carefully dried with fabric. As a result, the parts are rust-free, with dark grey clean surface. Even as such, the parts are fully usable.

However, we decided to blow the propeller hub parts with glass bead blasting to bright metal, to make them appear as brand new. One might ask, why not blast them straight away as rusty. We chose this approach to avoid contaminating of the glass blast media with rust enriching into it.

For aluminum engine parts with dirty surface, we chose another procedure. Aluminum parts that were dirty or blackened after burning, such as magnetos, were first cleaned of dirt and thereafter their surfaces glass bead blasted. Before the blasting, holes in the magnetos were plugged with wooden plugs to prevent the blast media from penetrating into the magneto. With the blasting, the magnetos got clean surfaces. Finally, the clean surfaces were treated with a solution of Sinol and water to prevent the oxidization of the surface.

Oily and dirty parts were initially washed in a basin dedicated to cleaning engine parts, with a handy brush that feeds washing liquid through a hose.

The washed parts were dried with pressurized air, aluminum parts then possibly treated with glass bead blasting and Sinol-water solution. This method was chosen e.g. for the aluminium distributor head cover.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Hannu Mononen.

Preliminary steps for covering the Ressu (Snoopy) fuselage frame

Sunnuntai 27.10.2024 - Tuesday Club member

Suomeksi

The fuselage of the Snoopy experimental aircraft (OH-XEA) was covered with fabric. When Aviation Museum Society Finland received the Snoopy two years ago, the fuselage was totally stripped of covering fabric. Therefore, the fuselage will be covered at the Tuesday Club as it originally was. Luckily we have some good photographs of the Snoopy at our disposal to guide us with the covering. So to work.

The whole fuselage frame of steel tube has been cleaned of rust during the autumn, given a layer of lacquer and finally painted with red Isotrol- paint. These jobs have been necessary for starting the work on the fuselage frame. These include the installing of the long wooden battens along the sides and upper surfaces of the fuselage frame and the partial covering of the fuselage frame steel tubes with fabric strip.

Metal brackets with 10 mm slots have been welded to the structure of both sides and the upper surface. Thin wooden battens have been fastened to these brackets along the whole of the rear fuselage. The purpose of the battens is to keep the covering canvas separated from the fuselage frame trusswork. Otherwise the metal would start to “eat” into the canvas, especially when rusting.

In order to prevent direct contact between the canvas and the longitudinal steel tubes at the upper and lower corners of the fuselage frame, cloth strip had been tied around the tubes. There were still remains of these strips left in the tail and vertical stabilizer of the Snoopy.

Next we started making the long protecting wooden battens. We found suitable material to make the battens at the restoration workshop’s woodware storage at the Finnish Aviation Museum. The battens were cut to measure and shaped to fit the brackets. At fitting the battens the brackets were squeezed tight to them. The batten was locked into place with small nails. Finally the battens that were fastened to the brackets, were protected with nitrocellulose lacquer.

Along with making the battens, we started covering the steel tubes of the fuselage frame with 20 mm wide cotton strip or tape. We bought that from Eurokangas. When the shop assistant queried what we needed it for, we said that it was used for covering a museum aircraft. The assistant was surprised but interested, so we briefed her in more detail about the purpose of the fabric strip. We must have been the first customer of this sort.

The ribbon was wound around the fuselage tubes to form a solid surface of fabric around the tubes. We wound the fabric strip to overlap the edge by about 5 mm. The stripping thus became solid, without any metal surface being visible. On the lower surface of the fuselage, without the wooden batten, we wound the strip on the lower part trusswork as well.

All the strip-covered surfaces were finally treated with nitrocellulose lacquer, which simultaneously glues the strip onto the tubes and later functions as an adhesive surface for the canvas covering. The covering canvas is tightened with that very same nitrocellulose lacquer.

Photos by Lassi Karivalo.

Translation by Matti Liuskallio.

The surface treatment of Snoopy?s fuselage framework

Perjantai 25.10.2024 - Tuesday Club member

Suomeksi

The fuselage framework of the experimental aircraft OH-XEA “Snoopy”, currently being restored  by the Tuesday Club of Aviation Museum Society Finland, was without its fabric covering when the Society received its ownership. When and why the fabric covering had been stripped off, is not known. Anyway, Snoopy had been stored without its covering for a long time, as its fuselage framework, welded of 13 mm steel tube, was in such thick rust.

The first stage of restoring the fuselage framework was to clean it from rust. Cleaning the steel tubes until clear metal appears is however unnecessary, as removing the superficial rust will suffice. When the tube surface feels very smooth to your fingers, it is clean enough. For the purpose, we used sandpapers of various grades as well as scrubber sponge. The grinding dust was wiped away carefully with rags of fabric and solution mixed of Sinol spirits and water.

Not grinding the fuselage framework until clear metal shows is because for priming the tubes for their surface paint, we use the clear Isotrol lacquer (Klarlack Grund). This lacquer penetrates through possible rust to the surface of the tube, stopping the rusting process. The surface can then be painted directly on the lacquer.

After the whole fuselage framework was cleaned from surface rust, we then treated it by a thin coat of Isotrol, covering fully the steel tubes and other metal parts and giving the tubes a nice shiny surface.

After the lacquer had dried, the fuselage framework was painted with Isoqaurd Panzer, an alkyd oil paint for metal. Originally in the 1960’s, the fuselage framework had been painted with red Ferrex anti-rust paint, still visible as residues in the tubes. Simulating the red Ferrex, the Isoquard paint was tuned to the same tone of red. An exception was the landing gear that was painted with black Isoquard, according to its original black paint.

The fuselage framework surface treatment is now done.  The restoration work of Snoopy’s fuselage will next proceed with the cockpit, as well as measures priming the fabric covering of the fuselage.

Photos by Lassi Karivalo.

Translation by Hannu Mononen.

Making the engine cowlings for the Snoopy started with cardboard templates

Maanantai 30.9.2024 - Tuesday Club member

Suomeksi

OH-XEA Ressu (Snoopy) experimental aircraft from the 1960s that we are restoring, was equipped with a Continental A 65 engine. To replace the Snoopy’s lost engine we received, as a donation, a similar engine. The engine cowlings have vanished during the decades as well. So they’ll have to be made anew.

Photo by Esko Keskinen.

From the photographs we have at our disposal the size and form of the cowlings come out very well. The cowling is two partite. The larger, upper cowling, covers the engine from above and the smaller one covers the front part of the engine. The cowlings have been made of sheet aluminium, so that’s what we’ll be using too, utilizing 1 mm thick aluminium sheet. The fact that the original cowling rack fastened to the engine, has survived, will facilitate the making of the cowlings.

The constructing of the cowlings was started by cleaning the rusty cowling rack and painting it with black Isotrol paint. Black, because the original black paint was still faintly to be seen. The freshly painted rack was fastened to the Continental engine donated to us. The first phase to make the cowlings proper, was to make patterns or templates out of cardboard to fit above the rack. According to the cardboard templates aluminium blanks will be cut to be moulded to their final form.

Making the templates was started with the upper cowling. The template was made out two pieces of cardboard cut from a roll. First the tentatively cut left-hand side was fastened to the pegs in the protective rack. After that the same procedure was repeated with the right-hand piece of the template, after which the left and right-hand halves of the template were taped together. The united template of the cowling was modified by cutting and taping extra pieces to reach the final shape of the Snoopy’s cowling.

At this stage the making of the cowling template, covering the front end of the engine, was commenced. A piece of cardboard cut from the roll was bent against the front of the engine. The piece was gradually cut to form and the cardboard was attached to the pegs in the rack. By cutting suitable extra pieces of cardboard to the front cowling it was united with the upper cowling.

Thus, like a patchwork quilt, the cardboard template was built around the Snoopy’s Continental engine prior to making the aluminium cowling. The next stage will be to transform the shape of the cardboard template into aluminium sheets.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio.