Assembling the Myrsky wing root fairings and the oil cooler

Suomeksi

Apart from the Myrsky-project other activities of the Tuesday Club are on hold for the summer break. So the parts of the OH-XEA “Ressu”, Caudron C.59 (CA-50), Valmet Tuuli III (TL-1) and the Link Trainer, heaped in the former Aviation Museum coffee room, can wait for the work to continue halfway through August, when the autumn season 2024 for the Tuesday Club will commence.

The project members of the Myrsky restoration team at the Tuesday Club have toiled “day in and day out” to finish and assemble the wing root fairings covering the wing/fuselage seam and the oil cooler, with its intake and exhaust air horns. Both these projects have taken more time than planned, so the Myrsky II (MY-14) roll-out, planned for the beginning of August, will be delayed. The summer holiday season both at the Finnish Air Force Museum and at Patria industries have affected in the delay.

Oval-shaped openings and a flapped hatch were made to the lower surface of both the right and left-hand side wing root fairings. The narrow oval openings are for cooling the wing root fairings, which for their part cool down the engine oil cooler, sheltered by the fairings. The edges of the openings cut to the aluminium plate were strengthened with a 1 mm thick aluminium strip.  The strips were fastened with rivets.

The wing root fairing edges were likewise strengthened with aluminium strips on both fairings. That way the fairings stay better in form and are easier to handle when they are more rigid. The strips were riveted to the wing root fairings with countersunk rivets.
In addition to the abovementioned ventilation openings, an opening was cut to the right-hand side wing root fairing, for the horn for the exhaust air from the oil cooler. The exhaust air will be conducted through the opening in the fairing onto the lower surface of the wing. The edges of the opening for the exhaust air horn were strengthened with 1 mm thick aluminium strips.

Photo by Heikki Kaakinen

When the openings in the right-hand side wing root fairing were ready, the fairing was fitted in place. After that, the end of the horn for the exhaust air could be pushed into the opening in the fairing and fasten the other end of the horn to the oil cooler. It was noted that the exhaust air horn fitted its opening just like it should.

Left hand side photo by photo archive of Finnish Aviation Museum.

Next in turn was the making of the cover for the space for the mouthpiece of the intake air horn. The mouthpiece of the horn is situated in the leading edge of the wing in an area limited by two ribs and the front spar. Cooling air for the oil cooler is taken through an opening in the wing’s leading edge. The horn for the oil cooler intake air is for the most part located under the left-hand side wing root fairing, but the mouthpiece of the intake air horn reaches outside the fairing edge.

Photos by Heikki Kaakinen.

When the intake air horn for the oil cooler and the left-hand side wing root fairing had been installed once again, we checked once more that the air intake horn’s mouthpiece was exactly flush with the wing’s leading edge. Now we could start to make the cover for the space for the mouthpiece of the air intake horn. The space will be covered with a shield made of aluminium sheet, with an opening for the air intake horn. The shield will be fastened to the wing ribs and the edge of the front spar.

The blank for the shield was cut from 1 mm thick aluminium sheet. The blank was bent to match the leading edge shape. After that an opening for the air intake horn for the oil cooler was made. The half-ready shield was fitted to its place. It was observed to sit well. The edges of the opening of the shield were bent inwards by forcing.

Photo by Jorma Laakkonen.

The aluminium shield covering the mouth of the oil cooler intake air horn will be fastened at its edges with screws and flange nuts to the wing ribs and the wing spar. On the fairing side the right-hand edge of the shield remains in between the stem fairing and the metal wing rib, i.e. it will be fastened to its place simultaneously with the edge of wing root fairing. Holes for screws were drilled at the edges of the shield. The holes were strengthened with “crickets” or brass strengthening rings.

Photo by Heikki Kaakinen.

The shield was now ready to be test-fitted together with the left-hand side wing root fairing. So the shield was screwed at its edges with a few screws to the leading edge rib and the front spar’s upper and lower edges. After this the left-hand side wing root fairing, next to the oil cooler, was fitted to place. The outer edge of the fairing curved snugly over the air intake horn’s mouthpiece shield’s edge. Assembling the wing root fairing and the shield needs only some fine adjustment.

When the fittings of the oil cooler air intake and exhaust air horns, wing root fairings and the air intake horn mouthpiece shield are ready, the aluminium parts that haven’t been chromated will be taken to Patria Industries for yellow chromating. The chromating will take place at the beginning of August.

By now it’s clear that the preplanned roll-out event of the MY-14 Myrsky fighter will be postponed. But, as they say, it’s worth while waiting for something good.

Photos by Lassi Karivalo except if otherwise mentioned.

Translation by Matti Liuskallio.