Myrsky MY-5's fuselage frame was taken to sandblasting and painting

Keskiviikko 16.9.2020 - Tuesday Club member

The earlier blogs describe how  the Myrsky MY-5’s rusted fuselage frame will be straightened, sandblasted and painted before it can be used for the wing test assembly of Myrsky MY-14.

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The text in the box: Original paint under the bracket.

The MY-5 fuselage frame has been fastened on a sturdy metal frame, the assembly jig, outside the restoration space at the Finnish Aviation Museum. It has been straightened on the jig and the remaining parts and equipment have been dismantled. Most of these are different band-shaped fastening brackets. The fuselage frame was cut behind the cockpit, so that it became easier to handle and it can be brought into the museum’s restoration space for the test assembly of the MY-14 wing. Later the fuselage frame parts will be welded together so that it will be the whole Myrsky MY-5 fuselage frame.

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The fastening brackets, which were still attached on the MY-5 fuselage frame, are important when the original paint and its tint are being investigated. When the brackets were unfastened, some well-preserved original paint of the fuselage frame was revealed. The painted surface has been protected from rusting, hidden under the brackets.

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The original paint surface was cleaned by grinding it lightly, so that the tint of the paint became even more intensified. On both sides of the cleaned painted area a paint test was made, using two different shades of grey Isotrol paint (linseed oil alkyd paint). This was necessary so that the team could choose the appropriate tint of the undercoat paint for the fuselage frame. The tints of the tested grey paint were RAL 7005 ja RAL 7042.

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On Tuesday, September 15th, the shortened MY-5 fuselage frame was loaded on a trailer, using a stacker. The frame will be taken to Auto- ja Teollisuusmaalaamo Oy, a paint workshop in Vantaa. The Tuesday Club team tried also to fit the rusted engine frame on the trailer, but it wasn’t possible. The engine frame will be transported to the paint workshop later.

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At Auto- ja Teollisuusmaalaamo Oy the fuselage frame will be sandblasted and painted with undercoat paint. When the sandblasting has been done, the clean metal surfaces will be covered with clear varnish, which protects the frame from rusting. The grey Isotrol undercoat paint will be applied on top of the varnish. The MY-5 fuselage frame, with its undercoat paint, will return to the Finnish Aviation Museum in a couple of weeks.

Photos: Lassi Karivalo.

Translation: Erja Reinikainen.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoration, VL Myrsky, MY-14, MY-5

About Myrsky MY-14 oil cooler, wing root fairings, landing gear doors and MY-5 fuselage frame

Maanantai 24.8.2020 - Tuesday Club member

When the VL Myrsky II (MY-14) port wing half covering was being finished in the restoration space of the Finnish Aviation Museum, also other Myrsky-project items were under work.

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Before the Corona virus pandemic interrupted the work, the Tuesday Club team had completed most of the engine’s oil cooler supply and exhaust air duct parts. They have been made from 1 mm thick aluminium plate. Now it was time to start building, according to the original drawing, the airflow control device into the supply air duct. The control device consists of a circular frame, inside which there are three flaps, which move on their axles. The air flow into the oil cooler can be controlled continuously with these flaps. The air flow control is done from the cockpit.

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The parts needed for the air flow control device were cut from 1 mm thick aluminium plate, using a laser cutter, at ProLaser Oy. Holes for the rivets, which are needed in the assembly work, were drilled on the semi-finished control flaps. The parts of the air flow control device were also chromated to prevent corrosion.

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The assembly work of the oil cooler control device was started at the circular frame. When the round frame had reached its final shape, the ends of the axles of the three control flaps were riveted on the frame. There is a slot on the end of the axle, into which the edge of the aluminium flap fits. The three flap plates fitted perfectly on the axle slots. The following phase will be to rivet an aluminium profile on the flaps, which locks the flaps on the axles.

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Some metal work has been needed when making the aluminium fairings, which cover the connecting point of the Myrsky’s fuselage and wing. The work was started on the fairing which covers the wing’s leading edge and the fuselage. The complicated fairing shape consists of three pieces of aluminium plate, which are welded together. The preliminary fairing parts were cut from 1 mm thick aluminium plate. A wooden last was made for shaping the aluminium sheets into the desired shape. Two lasts are needed, one for the starboard wing and the other for the port wing. The preliminary fairing parts were shaped into their final shape at Flanco Oy, using the last. The shaped fairing parts were welded together at GA Telesis Engine Services Oy.

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The work on the landing gear enclosure doors of the test wing has also continued, including the door fastened on the wheel hub and the oleo strut door. The doors had been nearly finished already in March. The remaining aluminium profile stiffeners were riveted on the inner surface of the doors. The doors were now ready to be installed. The bulging parts or the “bumps” on the outside of the oleo strut door have also been welded into place. These bumps are needed for the landing gear retraction fork which is fastened on the oleo. These bumps have also been welded on the preliminary oleo door plates of the actual Myrsky wing’s landing gear. However, the actual wing doors have not been chromated yet and their stiffeners have not been fastened.

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The Myrsky MY-5 fuselage frame, which was brought from Tikkakoski, has also been under work. The parts, which were still fastened to the frame, have been unfastened and now the frame is “clean” for sandblasting. The fuselage frame will be sandblasted at Auto- ja Teollisuusmaalaamo Oy, where it will also be painted grey.

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A pile of different kinds of brackets and parts was dismantled from the MY-5 fuselage frame. Some of the parts had to be unfastened with some violence, using an angle grinder for the work, because the badly rusted fastening bolts couldn’t be opened. The rust will be removed, and the parts will be painted. All the parts will be needed when the MY-5 fuselage frame is restored to be the exhibition fuselage, which illustrates the structure of the Myrsky fighter. The 2,5-meter test wing, built during the Myrsky project for testing the wing construction procedure, will eventually be fastened to the MY-5 fuselage.

Before that, the MY-5 fuselage frame will be used for test assembling and fitting the Myrsky MY-14 wings. In the fitting phase the MY-5 fuselage frame will be lowered on the MY-14 wing, built by the Tuesday Club team. The wing will be locked onto the fuselage with the four wing attachment brackets or bolsters. The wing parts will be fastened with steel plates and the whole wing can be test fitted in about a month’s time.

Photos: Lassi Karivalo.

Translation: Erja Reinikainen.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoration, VL Myrsky, MY-14, MY-5

About the fuselage frame of VL Myrsky MY-5

Tiistai 4.8.2020 - Tuesday Club member

When the restoration project of VL Myrsky was launched, three damaged Myrsky fuselage frames were available at the Finnish Air Force Museum in Tikkakoski. The rear section has been violently cut away from all three fuselage frames. The least damaged fuselage frame of MY-14 was chosen for the restoration project. This is how the project became the restoration project of the VL Myrsky MY-14 fighter. The MY-14 fuselage rear section, which has been cut off, has disappeared and therefore the rear section of MY-9 was chosen to be connected to the MY-14 fuselage frame. Also a fourth Myrsky fuselage frame (MY-10) exists, in a private collection, and there have been negotiations about purchasing it for the Myrsky project.

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The MY-14 fuselage with its engine and control equipment is mainly restored at the Finnish Air Force Museum in Tikkakoski. The main task of the Aviation Museum Society’s Tuesday Club is to build in Vantaa in co-operation with the Finnish Aviation Museum the other parts of the fighter, such as the wings with all their equipment, the parts of the tail and to build the parts for the nose, e.g. the front engine cowling, NACA-ring and the engine cowlings on the sides.

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Photo: Jorma Laakkonen.

The restoration project started in 2013 and the development of the project has been followed all the time on homepages of the Aviation Museum Society and Myrsky Project, and also in yearly journals. In Tikkakoski the restoration of MY-14 fuselage is already quite far. In Vantaa the Tuesday Club has prepared the tail parts and the wings to the point where their surfaces can be honed smooth and painted. The aim is that the restored – but static – MY-14 can be placed on display during the year 2021.

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The second best Myrsky fuselage from Tikkakoski, i.e. MY-5, was also taken into the restoration project with its separate rear fuselage and engine mounting. The MY-5 fuselage frame has its own important role in the Myrsky restoration project. Some useful parts have been dismantled from the fuselage frame and repaired in Tikkakoski for the needs of the MY-14 fuselage frame restoration. On the other hand, the fuselage frame of the MY-5 will be used by the Tuesday Club for the fitting of Myrsky’s wings. The wing positioning and fastening will be tested on the fuselage frame by the Tuesday Club before the wings are sent to Tikkakoski to be installed on the fuselage of MY-14.

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Additionally, an even bigger role has been planned for the MY-5 fuselage frame. It will be used to build a demo-fuselage of the Myrsky-fighter to illustrate the metal and wood structure of the aircraft. The 2.5-meter piece of the starboard test wing and the 1-meter piece of the port test wing will be fastened on the fuselage frame. Before building the actual wings, the test wings have been built to test the methods how to build the complicated root of the wing with the landing gear and how to lock the wing halves to each other with steel plates.

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The rear fuselage of MY-5, brought from Tikkakoski to Vantaa to the Finnish Aviation Museum, has already been used in the Myrsky-project. The badly rusted rear fuselage frame was straightened in a jig, specially made for the purpose, and sandblasted and painted, using grey alkyd paint. After this the rear fuselage has been used by the Tuesday Club to fit and support the horizontal and vertical stabilizers when they are being built.

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The fuselage frame and engine mounting of MY-5 were brought from Tikkakoski to the Finnish Aviation Museum in Vantaa on July 21st, 2020. The MY-5 fuselage was transported by the Myrsky-project’s PR-man, on his holiday trip to Ostrobothnia. On Friday 10.7 on his way there he took the trailer and “some Myrsky items” to Tikkakoski. On Tuesday 14.7 a group of Tuesday Club members travelled to Tikkakoski and moved, with some assistance from the Air Force Museum, the MY-5 fuselage frame and engine mounting on the trailer to wait for the transportation. The unusual load travelled successfully to the Finnish Aviation Museum on 21.7. Fortunately, the traffic was rather quiet and it wasn’t raining.

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When the fuselage frame was outside the museum, the cargo straps were unfastened. Then the MY-5 fuselage was lifted from the trailer with a forklift and placed on the ground to wait for cleaning and repair. The badly rusted and partly bent and damaged fuselage frame will be straightened and cleaned by sandblasting, straightened and repaired, and then painted grey. Behind the cockpit some frame pipes have been bent and some are even missing.

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Left photo: Heikki Kaakinen.

The assembly jig, which was made from square steel pipe for the straightening of MY-14’s fuselage frame, was re-assembled and modified for the MY-5 work. The jig was fastened on the four brackets by the cockpit on the MY-5 fuselage. These brackets are used for fastening the wings with four fastening bolsters on the wings.

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Photo: Heikki Kaakinen.

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The MY-5 fuselage frame, now fastened on the assembly jig, will be measured carefully and straightened. The places of some parts or their fastening brackets will be defined and photographed before they are dismantled for cleaning. Also the rusty engine mounting, brought from Tikkakoski, will be cleaned by sandblasting and painted.

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When the fuselage frame has been cleaned and painted, the rear fuselage frame (which has already been restored earlier) will be welded to it. Then the MY-5 fuselage frame will be ready to serve as the fitting frame or assembly jig for the MY-14 wings, and later as the basis of the Myrsky demo fuselage. The MY-5 demo fuselage will be restored so that the structures remain visible in the way they were left visible when building the short test wings. The restoration of this demo fuselage is not the main priority at the moment, the work will be started when the restoration of the MY-14 has been completed.

Photos (except if separately otherwise mentioned): Lassi Karivalo

Translation: Erja Reinikainen.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoration, VL Myrsky, MY-14, MY-5