Elfi (oz14414)

About this Plan

Elfi. Radio control biplane sport trainer model.

Quote (google-translated from the German): "For peaceful hours. Biplane 'ELFI' by Bruno Schmalzgruber.

Friends of true-to-original flight models may please forgive me for the infidelity I made this time in the construction of the ELFI double-decker. It often takes a very long time to get the required documents for the reproduction of prototypical models, and so in the meantime a double-decker has been created, which is characterized by a very simple structure and good flight characteristics. This model is not only intended for the beginner, but by making minor changes to the model, it can be used for aerobatics.

When constructing the model, care was taken to ensure that RiC beginners can also build and fly it. If the pilot is familiar with the flight characteristics of the model, the possibility exists. sharpen the model on the airfield. If the model is built exactly according to plan, there will hardly be any disappointments, and this is of great importance, especially for the R/C newcomer.

I deliberately went this route because it is much easier for an experienced pilot to sharpen a good-natured model than the other way around. A beginner will hardly know the tricks of taming a sharp model.

The experienced model pilots will assess their skills before building and run the model accordingly. The most obvious change to the model is the V-shape of the wing. This can be reduced to 00, but must then be equipped with ailerons. since the rudder loses its effectiveness with this change. The adjustment of the upper wing can be done later, when the pilot is familiar with the flight characteristics of the model. to be changed. To build you need a flat building board, which most model builders have at hand. I don't want to waste any more words on the further construction of the model, the most important things can be found in the assembly instructions.

Features of the model: The engine is installed upright, and is preferred in this position by most model pilots. The tank cap, which is designed as a dummy cabin, can be easily removed. This makes the tank easily accessible. The tank vent is routed through frame 2 to the front using a hose. After removing the upper wing, a large interior offers enough space for all common RC systems. The rear part of the fuselage has no frames and is open at the end. The elevator linkage can be routed straight through this opening to the rudder horn, this enables easy and precise gluing to the fuselage.

The tricycle undercarriage does not necessarily have to be used. For lovers of the two-leg landing gear, the location for this is noted on the plan. If the model is later to be used for waterflight, the possibility of attaching the floats can already be taken into account.

To cut out the ribs, it is best to make a pattern rib out of plywood, after which all the ribs can be cut out. The wingtips are simple in construction and stable. Experienced model pilots can screw the surfaces together.

Flight characteristics: The model was built as indicated on the plan. The ground launch runs smoothly. After a short run-up, the model had to be corrected with short rudder deflections and then held the direction at high speeds. After approx. 30 m it is released by pulling and then goes into a steady climb. The rudder deflection was reduced after the first flight and the model can be steered perfectly with a small rudder deflection. Single aerobatics were already performed on the second flight. The elevator doesn't feel harsh, loops are very easy to fly, and if nothing is warped, the model comes out straight again. Curves, especially the raised hairpin bends, can be taken very tightly.

Despite the approx. 1.6 m wingspan, the model is incredibly manoeuvrable. During the first roll, which can only be flown very well with a rudder, I couldn't believe my eyes, because the two surfaces touched on the outside for a three-quarter turn long, although I had stretched them crosswise with six rubbers per face. The rubbers were then tightened before the next start..."

Direct submission to Outerzone.

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