Fitting the front parts of the Myrsky wing root fairings

Suomeksi

The wing and fuselage seam is covered in the VL Myrsky II blueprints by sheets called the wing root fairings. The Myrsky wing root fairings are made of thin aluminium sheet.

The Myrsky wing root fairing consists of two parts. The rear part covers the seam from the main spar to the trailing edge of the wing. The front part of the fairing in turn covers the area from the main spar over the leading edge of the wing to the lower surface of the wing and fuselage, reaching the main spar. The edges of the right-hand and left-hand wing root fairings meet under the fuselage in the centre line. The front parts of the wing root fairings are attached from their front edge to the tubular structure the heat shield’s fastening ring. To this same ring are also fastened the aluminium covering plates (engine cowlings) on the front fuselage, which can be opened.

The fitting of the wing root fairing front parts, made during the restoration process of the Myrsky II MY-14), is underway at the Tuesday Club. This phase was made possible when the Myrsky MY-14 wing and the MY-5 fuselage frame were joined, to test the fitting of the wing to the fuselage frame.

To fit the front ends of wing root fairings in place, we didn’t have the abovementioned fastening ring of the heat shield at our disposal. The MY-14 heat shield with its original fastening ring has already been assembled to the MY-14 fuselage under restoration at the Finnish Air Force Museum. We solved the problem of the lacking fastening ring by building a ring of sturdy plywood to the measurements of the original one.

The plywood fastening ring we made must be assembled to the MY-5 fuselage frame we used for the test fitting of the wing, at exactly the spot corresponding the fastening ring of the heat shield. The reason for this is that the front parts of the wing root fairings could be fastened to the plywood ring the same way they will in their time be fastened to the actual heat shield fastening ring, which is presently at the Air Force Museum.

To measure the exact situation of the plywood fastening ring, which emulates the actual heat shield ring, we used the fuselage centre points marked in the Myrsky blueprints. The important one being point 51 of the fuselage centre, which is the centre point at the end of the transverse tube, located on the lower part of the front fuselage frame. From that point the three measuring points of the plywood ring were defined. They are the reference line in the fuselage centre line, formed by the metal tube, and the centre of the two bolts, which lock the wing to the fuselage frame.

First the aluminium tube, which acts as the reference line was aligned to place. The top of the fastening ring was attached to the end of this tube. The plywood heat shield fastening ring was locked to the front bolts of the wing/fuselage joint with adjustable threaded rods from both sides. With the aid of these three fastening points the position of the plywood heat shield attachment ring could be defined to the millimetre in relation to the Myrsky fuselage frame. The top of the plywood attachment ring was propped to the fuselage frame with four metal supports, of which two are adjustable threaded rods. In addition the lower part of the attachment ring was propped to the floor.

After the plywood ring was locked into place to the fuselage frame, the fitting of the front parts of the wing root fairings was started. The wing root fairing front parts were fitted to place in turns. They were attached first to the wing surface with cargo straps to keep the fairing tentatively in place during the fitting.

In the fitting, the wing root fairings were attached from their front part to the plywood attachment ring with clamps. It was noticed with pleasure that the aluminium sheet wing root fairings settled very well into place in relation with both the wing surface and the attachment ring.

The front parts of the wing root fairings will finally be fastened to the fastening ring brackets with Dzuz-locks. In the test fitting of the wing root fairings the Dzuz-locks were replaced with plywood brackets, which were fastened to the plywood attachment ring. Because of the Dzuz-locks, a reinforcement ring will be made of aluminium sheet to the front edge of the wing root fairing. It has already been tentatively placed between the front part of the wing root fairing and the plywood brackets in the temporary fastening ring.

Photos by Lassi Karivalo.

Translation by Matti Liuskallio.