A carpenter always comes handy...

Sunnuntai 9.4.2017 - Member of Tuesday Club

The Tuesday Club is known for its conservation and restoration work of museum aircraft. But when needed, its members are also active doing other things. Lately, one such “other thing” has been the Hawk Experience Centre of the Aviation Museum Society.  This movable “mini-museum”, including the cockpit section of a BAe Hawk Mk.51 has been a frequent crowd-raiser at numerous air-shows and exhibitions. In a short time thousands of boys, girls, women and men have experienced their first “cold type” flight in an aircraft still in wide use in air-forces around the world.

But the Hawk Experience Centre is much more than just taking a “flight” in a cockpit-section. At the centre information about the Aviation Museum Society (Finland) and about the activities of all Finnish Aviation Museums is given to a waste number of individuals who might not otherwise get this information. At the Hawk Experience Centre the visitors can also buy article put on sale by the Aviation Museum Society and the different aviation museums. The more the public knows about what the Finnish Aviation Museums are doing and keeping available for their visitors the more likely they are to pay them a visit. Increasing the number of visitors is an important enabler for the continuous development of the activities of the aviation museums.

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The available activities and the equipment of the Hawk Experience Centre are continually refined to provide the visitors a still better experience. This is where the Tuesday Club enters the picture. Its most recent work was the making of the “safe storage/transportation” boxes for the centres three big displays to replace the original cardboard-boxes that were falling apparat.

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Based on measurements of the old cardboard-boxes plans for improved wooden ones were made and drawn. The new boxes are made of two main parts, the bottom one and the top on that can be slid over the bottom one. In this way putting the display into the box and removing it from there was made much easier as you do not have to reach so deeply into the boxes to move the displays. The boxes were made of 6 mm softwood-plywood and pine-laths with the bottom made of 18 mm weatherproofed plywood. The boxes were dimensioned to allow using the original EPS shock-absorbing units in the new boxes.

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So, off we went to get the plywood and laths. Once we had them in the workshop it was time to cut them to measure and assemble the parts into boxes gluing together the plywood parts and pine-laths. To be safe and not sorry, the joints were strengthened by stapling using a pneumatic stapler.

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Wooden handles were fitted to the ends of the boxes. Support-laths, that also function as fenders when the boxes are stored close together were fitted to the top-and bottom of the long sides of bottom part of the boxes.

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With the carpentry done it was time for some finishing touches including painting the boxes. The decision was made to paint the boxes in neutral grey. The grounding was done using white Ferrex-paint and the finishing was done using semi-gloss Futura furnishing-paint. When the paint had dried latches were put in place to keep the top and bottom parts connected.

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Even though the boxes were made as “series production” we applied the pre-WWII Rolls Royce quality principles. Thus the top and bottom part of each box ended up not being interchangeable but being pair-specific. To ensure smooth use of the boxes the individual pairs (top/bottom) were marked with paired, one, two and three, dots.

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This done, we could insert the EPS shock absorbing material from the old cardboard-boxes into our new wooden ones and then take the new boxes from the restauration shop to the Hawk Experience Centre in the yard of the Finnish Aviation Museum.

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There the displays were put into the new boxes, one after another to await their next use at the Hawk Experience Centre at some yet to be held fair or aviation show.

But the experience-centre is much more than just taking a “flight” in a cockpit-section. At the centre information about the Aviation Museum Society (Finland) and about the activities of all Finnish Aviation Museums is given to a waste number of individuals who might not otherwise get this information. At the Hawk experience-centre the visitors can also buy article put on sale by the Aviation Museum Society and the different aviation museums. The more the public knows about what the Finnish Aviation Museums are doing and keeping available for their visitors the more likely they are to pay them a visit. Increasing the number of visitors is an important enabler for the continuous development of the activities of the aviation museums.

Kommentoi kirjoitusta. Avainsanat: Hawk Experience Centre, info monitor, storage box, the Tuesday Club

Wheel-bay cover fastening ring for VL Myrsky II

Lauantai 18.3.2017 - Member of Tuesday Club

The landing-gear of the Myrsky retracts towards the fuselage with the struts and wheels retracting into bays between the main spars in the roots of the single, continuous wing.

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On the top-side of the wing the wheel-bays are covered with slightly domed covers made of aluminium-plate. The covers are fastened with screws to a plywood ring forming the wheel-bay. Most of the wheel-bays, including their aluminium cover-plates remain hidden under the mid-fuselage covering the centre-part of the single wing, but a part of them are covered by streamlining-plates at the wing/fuselage joints.

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The aluminium-plate wheel-bay covers have already been made and now the making of the three needed cover-fastening rings are underway. One is needed for the test-assembly wing and two for the final wing that will be made for the MY-14.

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The making of the fastening-rings begun by making a mould. As on the drawings, a circle with a diameter of 750 mm was drawn onto a strong wooden board. Then sturdy nail were nailed along the drawn line with a spacing of ca. 2 inches. The fastening-rings will now be made by laminating eight layers of 3 mm thick 30 mm high, long plywood strips against the nailed circle, thus forming a 25 mm thick fastening-ring.

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The first plywood-layer was tightened against the nails and onto it three more layers were glued using Erikeeper plus adhesive intended for outdoors use. The four layers were pressed tightly together using clamps. When the adhesive had dried properly, the clamps were released and the next four layer were added using the same procedure.

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When the adhesive had dried the fastening-ring was removed from the mould and finished. It was then planed into a triangular cross-section with a top width of 25 mm. The other two rings will be made in the same way.

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As the test-wing had been fitted into the assembly-jig and the part between the wing-spars had been assembled the test-fitting of the fastening-ring could be made. And it was a good fit. Also the aluminium cover-plate went into place nicely. The next step will be making and fitting the plywood landing-gear well walls in the wing.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

More than just building wing for VL Myrsky II

Lauantai 4.3.2017 - Member of Tuesday Club

In the restauration of the VL Myrsky II (MY-14) the majority of the work done during the past couple of years has been on the wing. This might lead one to believe that the Tuesday Clubs part the whole project is only doing woodwork to make the wing. However, a lot of other types of work has also been done, as I have told you in earlier blog entries. This time I will cover some of the work on the following sub-assemblies; bomb-racks, the propeller-blade openings in the spinner and the landing-gear.

Originally the Myrsky-fighter was not equipped with bomb-racks, but in 1944 a bomb-rack for a 50-100 kg bomb was fitted under each wing. These racks were also suitable for drop-tanks. For these there was a connector to connect the drop-tank to the planes fuel-system.

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Fortunately parts for many racks have survived in the collections of various museums, so with some reconditioning done, we can fit the MY-14 with original racks. However, the racks found were partly disassembled, had broken parts, partly corroded or otherwise in need of reconditioning. So a selection of the best rack-parts were inspected, reconditioned and combined into complete racks to be fitted to the Myrsky´s wing in the Tuesday Club.

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The spinner for the Myrsky has cut-outs for each propeller-blade and its regulator mechanism. At the base of the spinner the cut-outs are open so that the spinner can be fitted over the propeller hub and around the propeller-blades and fastened to the spinner’s back-plate.

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On the spinner’s back-plate there is a protective sleeve made of aluminium that closes the back-part of the cut-out, thus creating a round cut-out hole and a closed back-edge on the spinner. No original sleeve has survived, so new ones have to be made. The missing spinner back-plate has already been made earlier in the Tuesday Club.

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The making of the sleeves begun by cutting blanks out of aluminium sheet, according to the drawings. Then they were test-fitted to the openings. A wooden mould was made for the making of the profiled, bent edge of the cover-plate, and then the blank was fastened to the mould and beaten into shape. We still have to drill the holes needed for fastening the cover-plates to back-plate and then the cover-plates can be fit into position. The finishing work on the cover-plates is now ongoing.

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No complete Myrsky landing-gear has survived to be fitted to the MY-14. Thus most of the landing –gear has to be made. Fortunately original wheels have survived and can in due time be fitted to our Myrsky. The reconditioning of their hubs and brakes has been covered in earlier Myrsky blog-entries.

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The Tuesday Club has neither the tools nor the skills necessary to make the needed new landing-gear oleo-struts. Patria, who is the major sponsor of the Myrsky restoration-project has taken the responsibility for getting them done. However, some landing-gear parts can be made by the Tuesday Club. Work on the landing-gear retraction-fork that connects to the oleo-strut is ongoing in the Tuesday Club. The hollow forks (one for each strut) consist of steel-ribs that are covered with steel-plates.

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The work on the fork was started by making a full-size model to plans. In addition to this a metal jig was made for the assembly of the final forks. The wooden model makes interpreting the drawings easier and without a jig, the necessary dimensional precision of the retraction-fork cannot be achieved.

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Work on the fork itself begun by cutting steel-plate blanks to measure to form the parts that will become the sides of the forks. Holes were drilled at both ends of the blanks after which they were bent to form and measure. Assembling the forks in the jig is ongoing.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

Repairing old and building new wing-struts for Kurki

Maanantai 27.2.2017 - Member of Tuesday Club

Two of the total of six wing-struts for the I.V.L. K.1 Kurki were found at the Päijänne-Tavastia Aviation Museum at Vesivehmaa. The found struts were the front- and the (diagonal) mid-struts. The struts were damaged, but repairable.

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However, a total of six struts are needed for the Kurki, three on each side, so four more have to be made. The existing struts will be used as templates for the new ones. As we have no models and no drawings of the Kurki have survived, we have assumed that they are similar in construction to the front-struts.

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The two found wing-struts were damaged. Their plywood coverings had holes in them and they were partly rotted. The rotted parts must be replaced, and the holes must be mended. The rotted parts will be removed all the way to good plywood and new plywood will be put in in its place. Fixing the holes is underway in the well-proved Tuesday-Club manner – a square or rectangle is drawn around the hole and the cut is made in the plywood along the lines, the cut-out faulty piece is removed and replaced with a new piece of fresh plywood.

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Having to remove the rotten wing-strut covering plywood was actually a blessing in disguise. Doing this, revealed the inner construction of the wing-strut. Thus we got the knowledge on how to make the missing struts. Removing the rotten covering plywood revealed that the main load-carrying part of the strut was a steel tube with an outer diameter of 52 mm. Attached to this was the solid-wood leading edge of the strut and the plywood-covered wooden ribs and the wooden trailing edge giving the strut its aerodynamic form. At both ends of the struts there were wooden support structures and a metal lug at each end for fastening the strut to the fuselage and the wing.

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With the existing struts as models plans for the making of the four missing struts and a list of materials needed were made. As we were unable to source any steel-tube with the right diameter we had to settle for a 50.5 mm one. This was considered close enough for the purpose. Finding the necessary wood-materials for the making of the leading- and trailing edges was a piece of cake.

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We started making the new wing-struts from the 3 m long steel tubes. The tubes were cleaned of their protecting grease and cut to measure. The tube for the front- and rear struts is 262 cm long and that for the mid-strut 273 cm. After being cut to measure the tubes were painted using black Isotrol varnish.

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We decided to start by making the other middle strut. First the tube was firmly fastened to the purpose-built work-foundation. For the making of the wooden leading-edge we first cut 0.5 cm thick strips out of a piece of wood the length of the tube. These were glued together pushed against the tube, giving the back part roughly the shape of the tube and a rough leading-edge that was then planed and sanded to shape of the original leading edge.

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The finished leading-edge was then fastened to the tube using four countersunk screws, with their heads sunk deeply into the leading-edge, after which the holes were plugged using wooden plugs. Thus the leading-edge was finished and it was time to tackle the trailing-edge.

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From the original wing-struts we got the models for the trailing-edge ribs, of which we made some dozens to start with, and then we varnished the sides of the ribs. A strut will take 14-16 ribs. The needed ribs were fitted into place and glued to the tube using epoxy-adhesive – yes, we know epoxy was not used in the 1920’ies but… Then we made the wooden trailing-edge and glued it into place using epoxy-adhesive. Now the main parts of the wing-strut were done.

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It was still lacking the solid-wood support-structures at each end as well as the metal fastening lugs. These are now being made in our workshop.

We decided to make all the missing wing-struts up to this stage, before continuing with the finishing work and covering of them all. Work on the missing front wing-strut is already ongoing.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, I.V.L. K.1 Kurki

MY-14 got original medicine box

Torstai 16.2.2017 - Reino Myllymäki

The medicine box of the VL Myrsky II fighter located outside of the cockpit in the rear fuselage. The box was behind a access panel in the left side of the fuselage.

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The access panel of the medicine box located below the cockipt rear windows. The location was shown by red cross sign. It was not in exactly right place since the access panel was located under the national insignia. Between the access panel of the medicine box and a entry foothold of the cockpit there was one bigger access panel.

The stand of the medicine box was manufactured from the metal plate by shop welding. The sides of the stand was lightened by holes. The box was fixed by leather straps. The straps were fixed to the stand by riveting.

An original stand was found. It was restored by cleaning and painting. The medicine box is a aircraft part standardised by the State Aircraft Factory. VL Pyry and VL Myrsky had same box. MY-14 got the medicine box from Pyry.

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The medicine box was complete except medicines. According to the index of the box, the box consisted of boracic ointment, morphine and aspirin and two bottles of camphor. None wartime pep pills were found and according to the index, pep pills did not belong to the content of the medicine box.

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When MY-14 will be ready the medicine box will be in hiding behind the access panel. Several other interesting details will be in hiding, too. However, a "Demo-Myrsky" is planned to be assembled from a test wing, the fuselage of MY-5 as well as from the extra original parts and newly produced parts. The demo will be covered partly by plywood and partly by perspex. How it will implemented and how the inside structures and detalis will be seen is not clear yet.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

Assembling VL Myrsky (MY-14) test-wing in jig started.

Tiistai 14.2.2017 - Member of Tuesday Club

The MY-14 project group decided to build a test-wing of ca. 2.5 m length, measured from the wing-root. This will be done to ensure that the fitting of equipment and fittings that are fastened to the wing spars, including drilling holes for necessary fasteners can be done properly and also to pinpoint possible flaws in the building of the wing.

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During the early weeks of this year we were able to finish the front- and rear spars of the test-wing as well as the drilled holes for the metal parts lead-throughs. Also all the wing-ribs have been finished. Thus, the test-assembling could be started. The assembly work of the test-wing, as well as that of the final wing, will be done in a precision jig. A separate jig was made for the assembly of the test-wing. Using this, we can make sure that the placement and alignment of the spars related to each other will be spot-on. This is a must for us to be able to assemble the wing in strict accordance to shape and measures of the drawings.

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The assembly of the test-wing was begun by fastening the front- and rear spars in the jig. After this some parts of the landing-gear actuating mechanism were fitted to the drilled-through. The next steps was to start fitting the enclosed wing-ribs in-between the spars.

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At this point the benefit of the test-assembling became evident, as problems showed that the drawings were partly insufficient. Not an earthquake of challenges, but some additional head-scratching was needed before work could continue on the test-wing.

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Now the wing-ribs between the spars are glued into their correct positions and the metal parts that attach to the wing-spars are fitted. Covering the top-side of the wing between the spars is ongoing. Assembling the leading- and trailing edges of the wing will start only after all internal structures between the spars have been made and installed.

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The test-wing will not be disassembled after the tests, but instead it will become a museum exhibit. It will be used to show the visitors the construction of the WW II Myrsky-fighters wooden wing. For this purpose the top-side of the test-wing will be partly plywood-covered and partly covered with a clear polycarbonate sheet. The inter-spar wing-ribs will be plywood-covered on one side with the other side covered with clear polycarbonate sheet to show their construction.

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Parallel to the work on the wing-spars for the test-wing, work on the spars for the final wing has moved forward. The front and rear parts of both wing-spars will soon be ready to be glued together so that they both form box-spars. As this wing will be made as a left and a right wing that will be bolted together with the joint strengthened with steel-plates, instead of the one-piece wing of the original Myrsky –fighter, holes for the assembly bolts must be drilled in the spars. Assembly work on the final wing will take place only after the test wing has been finished and properly tested.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

Luggage compartment of Valmet Vihuri VH-25 completed

Sunnuntai 12.2.2017 - Member of Tuesday Club

The tandem two-seat cockpit section (front and mid-section of the fuselage)  of the Valmet Vihuri II (VH-25) has been undergoing restoration by the Tuesday Club, with a number of breaks in the work, since the 1980ies.

Now the work has come to a point where the cockpit area including its equipment has been all but completed and the luggage-compartment has been installed behind the rear part of the cockpit. Still on the “to do”-list are installing the through-the-floor tube for the light-pistol flares and the sight fixture. Finally the sides of the fuselage section are to be covered with plexiglass and then the section is ready to be admired by the museum-visitors.

Of course we could still continue and build the missing NACA cowling and if someone would give us free or for change sell us a Bristol Mercury VIII engine, wouldn´t it be nice to fit it in place. But of course, we have to stop at some point, we are not aiming at creating a complete aeroplane.

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The luggage-compartment is made up of a canvas bag with an aluminium bottom-plate. The blank for the bottom-plate was cut according to the original drawings. The edges of the blank were bent and the outside bottom stiffeners were cut and fastened to it using pop-rivets. The outside of the bottom-plate was painted grey. This also nicely covered everything that had earlier been painted on the plate.

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The bottom-plate is fastened to the fuselage-frame tubes with metal lugs. The lugs cut from sheet-metal and bent to shape. They were then worked to final shape and measure, attached to the vertical frame tubes and painted grey.

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At the same time work on the canvas-bag was going on. First we were going through draper´s looking for a thick brown cloth that would be as like the original one as possible. Finally a suitable cloth was found and purchased. It was cut to measure and sawn to shape with doubled cloth to achieve the necessary stiffness. The bags opening was covered by a lid sawn from the same cloth. The top of the lid was sawn to the bag and the rest of the lid fastened to the edges of the bag using original like latches.

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The flexible canvas-bag is fastened to the fuselages tube-structure using leather straps with buckles. Suitable straps were readily available in a shop. The straps were run through leather fasteners riveted to the corners of the bag.

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Now the luggage-compartment canvas bag could be fastened to the aluminium bottom-plate. This was done by riveting the bottom edges of the canvas bag to the bended sides of the bottom-plate.

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The finished luggage-compartment was installed into the fuselage-frame behind the cock-pit. First the bottom-plate was to the vertical frame tubes using the fabricated lugs and then the canvas-bag was tied to the frame using the leather belts. Now the brand new luggage-compartment was ready to be used by the pilots – made by the Tuesday Club. But I think it want be flying anywhere!

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When needed for our restoration projects, we have received aluminium plate, both new and used from Finnair technical department. They have also given us written off tools– that have proven themselves most useful for our purposes. We bow deeply and thank Finnair for its valuable support of our efforts to preserve the Finnish Aviation Heritage.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, Valmet Vihuri, VH-25

MY-14's tail repairs, part eight

Perjantai 10.2.2017 - Reino Myllymäki

Suomeksi

The chains and cables for rudder, elevator and aileron trims of MY-14 were lacking except some very rusty chain pieces. So, the chains and cabled had to be manufactured acoording to the designs and original parts.

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The used chain proved original material since the stamp was same than in orginal parts. The wire clips were original material used in the State Aircraft Factory but not exactly same.

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The feed-throughs were existed but abrasion covers were lacking. They were made from "lusto" according to the designs. "Lusto" is an old polymere, nitrocellulose, called also to Parkesine.

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The bearing bracket of the rudder trim and the traction wheel of the elevator trim were in the restorable condition. They were disassembled and repaired. The aluminium wire coils were lacking and the new ones were made by lathing.

All parts were assemled and the entity was tested. It is working!

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

Wing of Kurki to Tuesday Club

Lauantai 4.2.2017 - Member of Tuesday Club

Suomeksi

Since the spring 2016 the Tuesday-Club has been doing conservation work on Kurki Fuselage. Until now it has not been possible to start work on its wings, stored at the Päijät-Tavastia Aviation Museum in Vesivehmaa, because the other ongoing projects have taken up so much space in the workshop at the Finnish Aviation Museum.

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However, now that the Kurki fuselage has been moved to the museums hall for changing exhibitions, there is enough space in the workshop for the Kurki wing. Well, not for the whole wing, but for one of the halves. Compared to the size of the Kurki, the wing is rather big – with a total span of 12.3 m (including the width of the fuselage) each wing is 5.75 m long and 2.32 m wide – quite a kite!

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On January 24th, the Kurki fuselage was moved to the changing exhibitions hall, were conservation/restoration work on it is continuing. At the moment work on the aluminium engine installation cover-plates is ongoing. The top one is fixed but the side-covers can be opened to allow access to the engine mount area. The covers are made of 1,2 mm thick aluminium-plate.

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On Monday January 30th, a Defence Forces interchangeable-platform lorry performed a conscript driver’s special-transport training mission. Coming from Tikkakoski it arrived at the Vesivehmaa airfield where it unloaded its enclosed platform to the ground in front of the back doors of the museum hangar at Vesivehmaa. The right wing of the Kurki was loaded and securely tied-down into the enclosed platform. It was a close fit. The enclosed platform was lifted back onto the lorry and the trip to Vantaa could begin.

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After a couple of hours the precious cargo was at the door of the restoration workshop at the Finnish Aviation Museum at Vantaa and the wing was moved into the workshop. Mission completed – with benefits for all parties – the War Museum (owner of the Kurki), the aviation museums and the Defence Forces. Many thanks to all parties taking part in this operation.

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Both halves of the wing have been damaged, both mechanically and by rot during their 90 years in storage. The Kurki was stricken off the books and put into storage in 1927. There are about 30 holes of different sizes in the plywood surfaces of the right wing. In places the plywood has rotted to a degree requiring its replacement.

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However, the wing is in better condition than the upper wings of the I.V.L. D. 26 Haukka I. But plenty of hard work and elbow-grease will be needed before the work is done. We can begin the actual work after finishing the “current condition check” and the thorough cleaning of the surfaces. The cleaning has already begun.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, IVL K.1 Kurki

Work on the exhausts of MY-14 ongoing

Sunnuntai 29.1.2017 - Member of Tuesday Club

The original engine planned to be used on the VL Myrsky was the British Bristol Taurus. Because of WW II this did not happen. Instead, the American Pratt & Whitney R-1830 two-row radial engine was selected, almost the same version as on the Douglas DC-3.

Myrskyn MY-14 - entisöintiprojektia varten on käytössämme DC-3 koneessa ollut Twin Wasp -moottori. Koska moottori on ollut DC-3 koneessa, se ei ilman muutoksia sovi Myrskyyn asennetavaksi. Yksi merkittävä muutoksen kohde koskee moottorin pakoputkia.

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The Twin Wasp with the exhaust collector of DC-3 in left picture and the Twin Wasp of VL Myrsky II with oval pipes in right picture.

On the DC-3´s Twin Wasp the exhausts from each cylinder is connected to a single exhaust gas collector from which there is a single exit pipe. On the Myrsky a different solution was implemented – The exhaust from each cylinder was gathered to be expelled through five oval exhaust pipes on top of each other on both sides of the engine under the NACA cowling ending at the back-part of the cowling.

At the end of each 10 round exhaust pipes 200 mm long, tapered nozzles were welded. At the weld the nozzles had a diameter of 60 mm but they were tapered towards their end, ending as a 28mm X 60 mm rectangles. A smaller final cross-section was used to increase the speed of the exhaust gases and thus creating some added thrust.

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The exhaust system that is to be built during the restauration will be a copy of the original one. At the moment the single pipes from each cylinder, forming a veritable “snake-pit” are being formed into shape by a partner contractor at Samet Oy. The nozzles are being made by the Tuesday-Club.

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They are being made from 28 rectangular parts cut out from sheet-metal. To form them into the requires shape the club made the necessary male and female mould parts used to shape the flat sheet-metal parts In a hydraulic press.

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After being pressed the edges to be welded were cleaned and chamfered for welding. The assembly, welding and fitting of the exhaust-system to the Twin-Wasp engine will be done by Patria Oyj.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

Oxygen system for MY-14

Perjantai 27.1.2017 - Reino Myllymäki

The oxygen bottles, controls, taps and meters of MY-9 and MY-14 were disappeared but the brackets, adapters, the remains of the oxygen pipes as well as the plate of the pressure and flow meters and controls were remaining. The original oxygen pipes were broken off and therefore they were useless.

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The oxygen bottles were found from the Hallinportti Aviation Museum and they have been in VL Myrsky fighter according to the imprints of fastening bands. The other parts of the oxygen system were found from the storages of the museums. Therefore it was possible to assemble the proper oxygen system of VL Myrsky fighter for MY-14 from original parts. Only the oxygen pipes had to be renewed.

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The best brackets were chosen in order to be restored. The steel and aluminium bands were blasted by glass balls and the bolts were renewed. The abrasion covers of the fastening bands were renewed. According to the design documents they should be made from leather. However, the imprints on the bottles showed that they were made from canvas fabric. Therefore canvas was used in the restoration.

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The bottles and the parts of the oxygen system were cleanded and covered by Renaissance wax. The pipes were made from new copper pipe and the fastening screws were renewed. Othewise the system was assembled from original parts. The normal solder paste was used in the solder joints instead of a hard solder.

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The fastening band of the rubber oxygen tube was taken from the MY-9. It was straightened, basted by glass balls, painted by Isotrol stripping laquer and paint finish. A padding made from leather was fastened inside of the band.

Photos: Finnish Air Force Museum.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

MY-14 got voltage regulator

Keskiviikko 25.1.2017 - Reino Myllymäki

Suomeksi

VL Myrsky II had a Russian voltage regulator located at the right corner in the front of the cockipit. However, the regulator of the MY-14 has disappeared. The brackets remained but they were corroded and bent. The sprung rubbers were destroyed and the filling sleeves were disappeared.

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A proper voltage regulator (RKK GS 1000) was fortunately found from the storages of the Finnis Air Force Museum. It was cleanded outside and inside and covered by Renaissance vax.

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The brackets were fixed, blasted by glass balls and painted. The bolts and sprung rubbers were renewed and the used rubbers were probably from MiG fighters. They seems to be copied from Britishs ones. Needed filling sleeves have been made from duraluminium by lathe work.

Photos: Finnish Air Force Museum.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

The "Kurki" got it's spur

Torstai 29.12.2016 - Member of Tuesday Club

Suomeksi

The I.V.L. K.1 Kurki fuselage brought for restauration/conservation by the Tuesday Club at Vantaa from the Päijänne-Tavastia Aviation Museum at Vesivehmaa was without its spur. And even more interesting was the fact that no sign of a spur having been installed could be found on the fuselage. This fact was strange, as a spoon-type spur can be seen on all historical photographs of the Kurki. Why was it now missing? Probably no final answer on this issue can be given, but we think we can provide an educated guess to this question.

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Surviving photographs show, that the Kurki had a spur when it was flown using both a wheels and skies equipped undercarriage. But documents about the Kurki also tell us that it was finally also flown using floats. We presume that the spur and thereto related items inside the fuselage, useless on the float-version, were removed and the fuselage then partly re-covered.

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In the end the Finnish Air Force was not interested in ordering the Kurki as a liaison-plane, and this led to an end of the development of the plane and to putting it in storage. And thus, it did not regain it’s removed spur. At some stage during it’s storage the floats were removed and replaced with skis, and like this it has been stored at Vesivehmaa since the late 1940ies. The skis are probably not the original ones belonging to the Kurki, but still typical 1920ies skis as produced by the Air Force Aircraft Factory.

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As the Kurki is now on skis, it was decided to refit the missing spur. No drawings of the Kurki have survived, so to remake the spur we had a good look-see at available photographs of the Kurki. Based on them, we assumed that the shaft of the spur was wooden and the rest of it of metal construction. The wooden shaft was supported by a metal-tube support from behind and it was presumably fastened to the fuselage using a metal-plate. The shape of the metal spoon-part of the spur can be seen in the pictures. Based on this we could make the necessary work-drawings for the spur and start making it.

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We started by making the wooden shaft of the spur. Then we fabricated the sheet-metal part with associated sleeve for fitting the wooden shaft and to fasten the assembly to the fuselage.  For the spoon side of the shaft we made another metal-sleeve with which the shaft and the spoon are fastened to each other. Finally we welded the spoon from purpose cut metal parts. The spur-spoon and supporting metal tube assembly was painted using black Isotrol-varnish and the wooden shaft and metal fastening plate at the fuselage were painted silver.

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The Kurki fuselage did not show any signs of how the spur had been originally fitted to the under-surface of the fuselage. We ended up bolting both sides of the upper metal plate of the spur assembly through the wooden bottom longerons running each side of the fuselage using inside metal supports to which the bolts had been welded atop the longerons.

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Luckily, the fabric-covering on the bottom fuselage had been put in place using string-fastening, so it could be easily opened to install the needed metal-parts inside the fuselage. When the plates with associated bolts had been installed, whit the bolts going out through the holes in the longerons and the outside metal sleeve it was time to torque the nuts and the job was done. The result looks very much like the spur on the photographs of the original Kurki.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, IVL Kurki

Windshields for the Kurki cockpit and cabin

Sunnuntai 11.12.2016 - Member of Tuesday Club

Suomeksi.

The aluminium-framed windshields of the I.V.L.K.1 Kurki cockpit and passenger-cabin can be folded down forward to make covering the open cockpit and passenger-cabin with a tarpaulin against rain easier.  The vertical frames are at the edges and in the middle of the wind-shields, which are each additionally supported by three triangular support frames. In 1920ies manner the windshields themselves are made of celluloid. The bottom frames of the windshields which also acts as hinges have been formed with a groove into which the 2 mm thick celluloid has been riveted.

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Many decades of storage has led to almost total destruction of the celluloid sheets, leaving only minor parts in the grooves of the frames. Only three of the triangular support-frames, two middle and one edge-support, have survived and of the frames along the edges of the windshields only a short piece remains. Thus the windshields have to be almost completely rebuilt.

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The work was begun by removing the windshields from the frame. The cockpit windshield hinged frame was fastened to the fuselage with screws and was easily removed but the windshield of the passenger-cabin had been fastened with small bolts through the fuselage cover-plywood. Removing the corroded bolts was an arduous undertaking. The rivets holding the remains of the celluloid windows to the bottom parts of the windshield-frame were drilled out so that the small parts of celluloid still remaining could be removed. The frame-parts were thoroughly cleaned and then painted using silver-coloured Isotrol. As the original type of celluloid-plate is no longer available the new windshields will be made out of 2 mm thick polycarbonate plate.

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The three missing triangular windscreen support-frames were made using the remaining triangular end-support frame as a template. The frames were cut out of 1.5 mm thick aluminium-plate then bended and finally lightening holes were drilled into them.

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Templates for making the windshield “glazing” were made of plywood and these templates will also be used when installing the triangular windscreen-support frames and when trying out the installation of the “gazing” in the hinged bottom-frames.

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The templates will also be useful when making the bent aluminium edge-frames for the windscreens and in making sure they will fit correctly to the “glazing”.

First photo: The foto archive of the Finnish Aviation Museum, others: Lassi Karivalo.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, IVL Kurki

The conservation of the Kurki fuselage reaching its final leg

Torstai 1.12.2016 - Member of Tuesday Club

The conservation of the fuselage of the I.V.L K.1. Kurki fuselage is soon on final. A lot of work has been done on cleaning the corroded steel part, on refurbishing the landing gear, mending damages of the fuselage surfaces and painting them, repairing the stabilizer and elevators, refurbishing the cockpit and passenger cabin and equipping the engine-mount.

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The ski-equipped steel-tube landing gear was taken apart so that the corroded parts could be more easily cleaned. The cleaning was done both using different polishing-grinders as well as using elbow-grease and different grades of abrasives. The cleaned parts were first varnished using clear Isotrol-varnish and then re-varnished using Isotrol that had been tinted black. The landing-gear skies are wooden whit sheet-metal covered bottoms and sides. The sheet-metal parts were given the same treatment as the other metal-parts of the landing-gear whereas the wooden parts were treated with a mixture consisting of 1/3 pit-tar, 1/3 turpentine and 1/3 boiled line-seed oil. The landing –gear is ready to be fitted to the front fuselage.

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The damages to the fabric- and plywood surfaces of the fuselage have been repaired and painted. The painting was done using the original painting procedures. The paint was prepared using nitrocellulose varnish into which colour pigments were mixed. For the silver colour of the fuselage aluminium-bronze pigment was used and for the national insignia ultramarine blue pigment was use for the swastika and a mixture of titanium-white and zinc-white pigmentfor the white background roundel. For a good result the painting was repeated a number of times with rub-downs in between.

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The decayed wooden tip-parts of the elevators had to be totally re-built and in addition to this some holes elsewhere in the plywood covering had to be repaired. One third of the covering of the upper surface and more than half of that of the lower surface of the left elevator had to be renewed. On the right elevator the complete upper surface covering had to be renewed. On the stabilizer a couple of largish decayed areas of the plywood-surface as well as some minor holes had to be mended. Before putting the new surface plywood parts in place their future inner surfaces were properly varnished. Eri-Keeper Plus adhesive for wood was used to glue the plywood pieces in place in addition to which the repairs were strengthened in the original way by using brass screws and nails.

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The areas of the elevators and stabilizer repaired using plywood were first varnished a number of times using clear Le Tonkinois varnish with rub-downs before the application of the next varnish-layer. After this a mixture clear Le Tonkinois varnish mixed with aluminium-bronze pigment in a ratio of 9 parts of aluminium-bronze to 36 parts  of varnish. To finish off the new bright surface and to protect it against moisture, it was given a protective top-layer of clear Le Tonkinois varnish giving it a slightly greenish hue of silver.

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Work has also been done on the cockpit. The cockpits plywood surfaces have been cleaned of grit and mould using a solution of denatured alcohol (Sinol) and water. During late summer the control-column and ancillary devices were removed, cleaned and painted using black Isotrol –varnish. The pedals were treated in the same way. The removed and reconditioned parts have now been re-installed. The control wires have been cleaned.

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The engine-mounts still lack the end plate for attaching the engine as well as its aluminium side and top cover-plates. Their fabrication is ongoing.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, IVL Kurki

Where can we get wing-struts for the Kurki?

Sunnuntai 27.11.2016 - Member of Tuesday Club

Suomeksi.

Even though the fitting of the wings to the I.V.L.K.1. Kurki is still months away the issue of the wing-struts has already popped up. Without them, fitting the wings will not happen.

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In the late 1940ies the I.V.L.K.1. Kurki, like many other planes de-commissioned in the 1920ies and -30ies ended up being stored in an old war-time hangar at Vesivehmaa airfield. Later this hangar became the Päijänne-Tavastia Aviation Museum. When taking the Kurki for conservation we got the fuselage and the wings but only two out of six wing-struts, that presumable were from the Kurki. Presumably, because we’ll really know if, when we start fitting the wing to the fuselage.

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No drawings of the Kurki wing-struts are available, but based on comparison of dimensions of the struts in pictures taken of the plane and those of the available wing-struts, the Tuesday-Club members have concluded that one is the front strut of the right wing and the other the mid strut of the left wing.

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When considering the issue of the wing-struts and taking a close look at photographs of the I.V.L. C 24 and I.V.L. C 25 fighters designed and built at the Air Force Aircraft Factory at Suomenlinna we concluded that their wing-strut arrangement was similar to that on the Kurki. This was especially true for that on the I.V.L. C 25. Thus it is possible, that the wing-struts of these planes, that only reached the prototype stage and were taken out of use already in 1925, could well have been used on the Kurki built a couple of years later.

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It also came to our minds, that when the I.V.K C 24 was restored “around” the rather damaged fuselage, could it be possible that wing-struts fit for the Kurki had been used in this project? To check this, personnel of the Finnish Air Force Museum took a close look at the disassembled I.V.L. C 24 stored at Tikkakoski, However, its wing-struts turned out to be carved out of “common 2 by 4rs”, so no answer there.

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So at the moment we have but two damaged wing-struts that we presume belong to the Kurki. Our next steps will be to repair the damage on the plywood cover parts of the struts and to clean the corroded metal parts and finish of the work by varnishing the repaired plywood surfaces and cleaned metal parts using aluminium-bronze varnish. We will also make drawings to enable us to re-create the missing wing-struts and build them. Inspecting the damaged parts has shown us, that the load-carrying part of the strut is a steel tube of 2” diameter, with a leading edge shaped from solid wood and a trailing part built using wooden wing-ribs and a trailing rib. The whole wing-strut has then been covered using plywood.

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We assume, that the wing-struts on both sides are mirror images of each other, but otherwise similar. Thus we can use the two existing struts as reliable models when building their pairs. Building the missing rear struts though, is a bit of a problem, because the only source we have for their design are the photographs taken of the Kurki. We can start designing and making them using the existing struts as basic models, but they can only be finished once the wings of the Kurki have been conserved and the wing has been fitted to the fuselage supported by the front- and centre wing-struts.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, IVL Kurki

SZ-25 unveiled in Kauhava

Lauantai 1.10.2016 - Member of Tuesday Club

The on June 2015 started Focke-Wulf Fw 44 Stieglitz (SZ-25) renovation project at Tuesday Club got a worthy ending on 29th of September. On that day happened the ceremonial inauguration of the newest showcase at Kauhava Aircraft Park. SZ-25 was placed in this showcase together with VL Pyry (PY-1). The third trainer in the same showcase will eventually be Valmet Vinka when Finnish Air Force renounces the use of this type.

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SZ-25’s wings had been transported to Tikkakoski for interim storage already during spring, while its fuselage stayed at Finnish Aviation Museum to be finalised by Tuesday Club.

The last phase of renovation was making of missing locking parts for propeller by turning. Also exhaust tubs for cylinders had to be made. This was outsourced. Matching exhaust tubs, exhaust manifold and exhaust tube under the fuselage turned out to be difficult. However, finally all parts fell together and the fuselage was ready to be transported to Kauhava.

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Transportation was done on 13th of September by Finnish Army. Their truck arrived at Aviation Museum and SZ-25’s fuselage was hoisted into truck and secured with cargo straps. The propeller was moved separately and attached into a transport pallet. Also SZ- 25’s wings were transported to Kauhava from Tikkakoski. A dozen strong group of Tuesday Club members traveled two days later to Kauhava to assemble SZ-25 inside the gorgeous, newly built showcase.

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Even while we started working immediately after arriving, there were things to do also on the next day. It took seven hours for us to assemble SZ-25 plus wash both Stieglitz and Pyry.

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Renovating SZ-25 was an acceptable work for Tuesday Club. It was even more meaningful because while working we knew that this aircraft will be placed in an appropriate exhibition place. This new showcase includes even dehumidification equipment. It is sad that most of aircraft we renovate end up in storage areas or somewhere else than in actual aviation museums. This is because Finnish aviation museums are too crowded already now.

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It was heart warming to experience how serious was the attitude of the Air Force Academy Guild towards the preservation and presentation of Air Force aviation heritage. This new showcase built by Guild and our good co-operation between Guild and Tuesday Club is an example of this. And now the showcase glows with its bright lights like a jewel in Kauhava’s night.

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This photo: Timo Telen. Others: Lassi Karivalo.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, Focke-Wulf Fw 44J Stieglitz, SZ-25

MY-14's tail repairs, part four

Lauantai 1.10.2016 - Reino Myllymäki

We had an almost intact VL Myrsky II’s tail wheel. The only missing part was axle and it was made at Air Force Museum from piece of solid 20mm steel tube.

Tail wheel rim is made from Elektron-metal which is a trademark for a range of magnesium alloys. Same goes for brake shields of main wheels. These parts were badly corroded and thus tiresome to dismantle. Paint was worn out and bearings stuck.

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Both outer and inner tires turned out to be useless. Obviously corroding of rim had eaten rubber at rims edge. Inner tire had been patched up several times (!) and was no more usable.

The rim was dismantled into parts and new holes were drilled into retaining ring of bearing for tool. Clogs of retaining ring were left as is. Rim halves and bolts were blasted with glass beads, primed with Isotrol Klarlack and finished with Isotrol color tone RAL 7005.

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Bearing was replaced with a SKF 6304 bearing with new mounting nuts. Tires were replaced with commercial 12 by 4 inch inner and outer tires. Air valve had to be lenghtened with a stub of brass tube soldered in place.

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Isn’t it good looking now!

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

MY-14's tail repairs, part three

Keskiviikko 28.9.2016 - Reino Myllymäki

Even after MY-9 empennage was attached into MY-14 fuselage frame, there remained things to fix at Tikkakoski.

Tail wheel assembly was missing support tubes and some existing ones were eaten by rust. They had to be renewed. Tubes coming in from fuselage corners were good up to the original joint but even they had to be straightened.

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Replacement tubes were taken from MY-9 as possible but also new tubing was used. Original tubes included wall thicknesses down to as thin as 0.5 mm, but all new ones were of 1 mm wall thickness. Axle bushings were made of new commercial quality tube.

Further there were things to fix at tail wheel assembly’s upper supports and attachments. All six pipes leading there were either missing, broken or twisted. Replacements were again found from MY-9, but bushings and supporting lugs for retracting mechanism had to be made from new material according to drawings.

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Again all needed welding was done with TIG welding, partly by Rauno Pylväläinen from Patria and partly by Antti Lappalainen from Finnish Air Force Museum.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

MY-14's tail repairs, part two

Sunnuntai 25.9.2016 - Reino Myllymäki

Tuesday Club’s Matti Patteri made an assembly jig for joining of MY-14 fuselage and MY-9 empennage. Joining was done at Finnish Air Force Museum in Tikkakoski. Damaged tubes were straightened and cut where necessary. New pipes were taken from MY-9 fuselage as needed.

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Assembly and straightening was made as close to drawings as possible. Pipes were bended with the help of welding torch to align them exactly right. Also supporting wedges made of laminated wood were helpful during alignment.

Tube to tube joints were strengthened with sleeves. Corner joints where tube endings were shaped remained without extra support, unless there were original support flanges.

Myrsky’s fuselage is a welded frame made of chrome-molybdenum alloy steel tubes. Welding method was gas welding with unalloyed wire. By the time when Myrsky series was built, arch welding was just making its first steps at the State Aircraft Factory. Here it was decided to use TIG welding, which was done by Rauno Pylväläinen from Patria.

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Welding was done in two phases. When the fuselage and tail assembly were fixed into jig, some points could not be welded. For those last remaining points the fuselage was moved into a rotating platform.

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After welding, the tubes were first coated with phosphoric acid, then primed with Isotrol Klarlack and finished with Isotrol color tone RAL 7005.

Kommentoi kirjoitusta. Avainsanat: aviation history, restoring, old aircraft, VL Myrsky II, MY-14

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