The condition and damage assessment of Hietanen OH-XEA Ressu and its restoration plan

Suomeksi

The Tuesday Club is starting the restoration of the Hietanen OH-XEA Ressu aircraft which has been stored at Lemu in the Turku area. The aircraft was built in the 1960s by Ari and Esko Hietanen from Turku. The first phase of the restoration will include the wings, horizontal stabilizer, elevator, rudder, tail wheel assembly, wing struts and fuel tank, which have been brought to the Finnish Aviation Museum from Lemu. The fuselage has no covering, but it remained at Lemu, and its turn will come later.

The first step in the renovation work is to assess the condition of the aircraft and its possible damage. Therefore we took the Ressu’s parts into the restoration workshop at the Finnish Aviation Museum and went carefully through the condition and damages of each part and made preliminary restoration plans for them.

We could see that the plywood covered surfaces of the wings, horizontal stabilizer and elevator are very dirty and have stains of red paint. The damages on the plywood covering are mainly small crushes or holes. However, on the underside of the left wing there is a large area around the registration mark where the plywood covering is badly broken. Or should we say has been intentionally broken – it certainly looks that way. The first phase in the restoration will be to clean the surfaces of the wings, horizontal stabilizer, and elevator and then to repair the damages on the plywood covering.

Ressu's rudder has metal structure and fabric covering, in similar manner as the tubular structure fuselage. The covering fabric is torn on one side of the rudder and a piece is missing.

The rusty metal frame of the rudder can be seen under the torn fabric. The metal frame will be cleaned and painted as it originally was. It seems that the frame has been painted with red Ferrex, the anti-rust paint which was commonly used in the 1960s. The red colour is visible under the rust. We will paint the frame using modern red Isotrol paint.

Finally the rudder will be covered with new fabric and painted pale blue, following the original paint scheme. Red stripes will be painted on both sides of the rudder, following the original look. Number 2 will be painted on the left side and a black bird figure on the right.

Ressu's tail assembly has metal structure and an air-filled tyre. The wheel bearings are completely stuck. We will try to repair the wheel into operating condition. The tail frame will be cleaned of rust and painted yellow, following the original paint scheme.

Ressu’s wings are supported with two wing struts, made of metal tube. Two of them are sturdier, fastened on the brackets on the wing’s front spar, and the two thinner ones are fastened on the brackets on the rear spar. We have both front struts but only one rear strut. The wing struts had been stored inside Ressu’s fuselage frame. The struts have been painted yellow but are now badly covered in rust. They will be sandblasted clean by a contractor and painted yellow as the original ones. We will make a new rear strut to replace the missing one.

The fuel tank is located at the root of the left wing, it has been lowered into place from the upper side of the wing. The fuel tank has dents, and they will be straightened. The fuel tank has had some kind of cap with a rubber seal, there are marks of it left on the wing as well as on the tank. The cap has disappeared. If we can find out what the cap has been like, we will make one. And if we can’t find what it has been like, a good alternative is to make a cap from e.g. 1,2 mm thick aircraft plywood.

The Hietanen brothers have obviously been planning to double the size of the 21-litre fuel tank. We can judge this from the fact that the wing rib next to the tank had already been removed and the wing’s plywood covering had been opened between the wing spars up to the following rib. We will, however, restore the wing structure to its original condition where there is only space between the wing root rib and the first rib for the original fuel tank. This means that the missing rib will have to be made and the opened plywood covering repaired.

Photos by Lassi Karivalo.

Translation by Erja Reinikainen.