Junkers Ju 52 (oz14402)

About this Plan

Junkers Ju 52. Radio control scale model. Wingspan 2200 mm.

Quote: "Good old aunt 'Ju'. Semi-scale model, by B Schmalzgruber.

The Junkers Ju 52 was a byword for reliability all over the world. It was not for nothing that more than 40 airlines put this aircraft into their scheduled service, where it achieved legendary fame for its reliability, robustness and flying good nature.

The Ju 52/3 m as a model: One should not only build a model exactly according to a prototype, but it should also fly accordingly. It therefore made sense to design the model as a motor glider. With a wingspan of 2.2 m and a flying weight of approx. 3.3 kg, a low wing loading is achieved, which has a favorable effect on the flying speed.

The most striking feature of the Ju 52, which is missing from the model, is the corrugated iron planking. Attempts were made with corrugated cardboard. This was sprayed three times with hard primer and twice with synthetic resin paint. After the paint had dried, there were still dull spots. So more paint would have to be applied to the cardboard to get an even surface. The whole model would have to be covered with such corrugated cardboard, and that would add another 1 kg to the weight. Furthermore, the corrugation of the cardboard is probably a little harder due to the paint, but it is unavoidable that after a short time clearly visible fingerprints can be seen. For this reason, corrugated planking was not used on the model.

The structure of the model: this is kept very simple. The hull is of box construction with a cambered back. The canopy is removable and held firmly on the fuselage with a rubber ring. The 200 ccm tank is located under the hood. It is possible to check the fuel level through the cabin window. After removing the hood, the tank can be easily removed from the model. The engine is installed on the side and almost disappears from the overall view of the model. The NACA ring can be removed, making the engine very accessible. The carburetor is located right under the ring, so you can no longer inject without creating an opening in this ring. There is plenty of space for the RC system.

The tail unit does not cause any difficulties during construction, you just have to remember that the elevator does not tolerate as much deflection as the conventional tail units of the RC models. The rudder, on the other hand, can have a deflection of approx 15 to 20° without being too hard. The surface is designed as an undivided design, as this construction is simpler than with a divided surface. It's fully planked, making it a bit heavier but extremely stiff, which is important for the aerobatics that some will no doubt do with it.

The aileron mounting looks like a lot of work, but it isn't. This arrangement should be left as it is, because that is what is very obvious with the Junkers machines. The landing flaps are not necessary for slow flight. But if you value it, you can make it flexible.

The model has so far only been launched on grass runways. The first starts were only carried out with one engine. At the 3rd start, the small COX were also put into operation. These engines were chosen because they have excellent starting and running characteristics when the air cleaner is free of dirt. With the 40 ccm tanks, the two engines continue to run even when the central engine has been idle for a long time. First, the two external motors are started and regulated. You can hear it very clearly if these are not properly adjusted. Since the middle motor emits a completely different sound, this can also be adjusted by ear. Although the propellers of the side motors protrude only a little over the engine cowling, you can still see an increase in performance during take-off and during flight.

If a side motor fails, don't worry, the Ju isn't that easily upset. The model is never rotated over the surface. So it is not necessary to be on the lookout like a lynx during the flight when a side motor might cut out in order to take immediate countermeasures. We got sick of it, so we tried aerobatic maneuvers, which were all satisfactory. It is easily possible to fly a roll with three engines..."

Direct submission to Outerzone.

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