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RC Airliner Design
In 2009 EDFmodel changed its focus to the building of custom ready to fly models. EDFmodel does not mass produce models rather each airliner built is a unique custom built airliner.
With each new model built there is always some design improvement or update and even hardware changes. The model is always in a state of re-design as the collective experience of building the airliners accumulates.
From this work the 301 airliner evolved through the designations A-E. Thus the 301-E model is available.
EDFmodel views the 301 as an experimental model design. EDFmodel differs from most other model manufacturers in that all models supplied are deemed "work-in-progress" models.
Design background
One answer is model designs that are modular offering improved impact resistance and better ease of maintenance. One of the most
demoralizing feelings any modeller can have is to return from the flying field with a handful of pieces that was once a model. Either the model is totally destroyed or a large amount of rework is required. Perhaps the challenge in scale modelling is to fly the model and
keep it flying. If an accident occurs a repair should not take so much time and effort that it destroys the modelers enthusiasm. Build dislikes - wood in the construction of models (inconsistent mechanical properties and the need for finishing)
- the same part replacement approach to building that is clearly evident with RC cars & helicopters Fuselage design The vacuum molded fuselage shells are an intrinsic part of the fuselage design. It is a simple and light weight result that has sufficient flexibility. The plastic fuselage shells are joined with the use of a joiner strip. Upon impact the shell can move slightly to absorb some forces. Decals are applied on the outer fuselage surface.
Wing design
The Clark-Y section works well with the thicker aerofoil tending to have relatively blunt leading edges which makes the stalling characteristics quite benign. This aerofoil is easier to fly because it provides a broader range of model air speed. Washout is three degrees with four degrees dihedral.
Engines & nacelles Lower wing mounted engines are vulnerable to ground strike. A quality cowling design would offer good scale, impact resistance and ease of maintenance. The engine mounting design has to allow the engine to break free in an accident. If it does not serious damage to the engine pylon mounted in the wing will occur.
Intake lips, cowlings and tail pipes are molded from impact resistant plastic with machine screws securing parts together. The engines are easily maintained.
Undercarriage design The DSR-30 servo less retracts units are used on the 301 and offer an excellent solution. Without doubt there is nothing more frustrating at the airfield than wasting time repairing U/C. A quality designed set of undercarriage is essential along with the ability to easily maintain them. This means they should be capable of easy removal from the model. Permanently fixing U/C in place is not a good idea.
Molding nose cones from impact resistant plastic produces a strong and light weight answer. Cone replacement is easily achieved.
In the air For the reasonably confident modeller the airliner configuration should present few problems. Rotation and landing on a well trimmed grass or hard
runway is easily achieved. The all-moving tail plane design produces effective responses in the air. A rudder is used to correct yawing, but is unlikely to be effective if one engine fails because of the turning moments involved.
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