HingingElevons

Hinging Elevons

The heart of your model is the guidance and control system. This includes you as the pilot, the radio, the push rods, and the elevons. Flaws in any of these components of the guidance and control system can mean anything from poor flight performance to danger and risk of injury. Your elevons should be the highest quality and reliability that you can make them, as should the hinges as well. The hinges should provide low friction and positive centering when approaching neutral from either direction, and they should hold the elevons securely to the rest of the airframe. Pay attention to detail when setting up the guidance and control for your model, and it will pay you back with hours of rewarding flight time and minimal upkeep.

Here is a pair of rather short, wide elevon blanks for a half span version of a Trick RC Zagi-THL, called the "WingTip". In case you missed how we got this far with these carbon fiber reinforced balsa wood panels, you may want to check out the steps before this one, specifically Carbon Reinforcing and Building Elevons, for more explanations and imagery. Mean while, as is the case on most of these HLAerobatics web site Pages, clicking on the still image will bring up a larger version to allow a more detailed inspection. CHECKITOUT. There is clear tape on the elevon in each of these two images. Can you see it? It bonds directly to the wood of the elevon, and overlaps with the covering to keep the wood sealed from moisture. Exposed wood may gain weight and/or warp if it gets wet. Either of these conditions is very bad for the performance of our HLAerobatic model. Make sure you lay the tape out flat, on a flat surface, nothing underneath it, and NO TENSION on it. Any of these thing could put a wrinkle or crease in the tape, which will impeed the action of the hinge and degrade you flight performance. UNACCEPTABLE.

HIn the photo on the left, the covered and taped elevon from above has been applied to the trailing edge (TE) of the wing with the exposed half of the tape. It is applied with the tape ON TOP, while bent at the hinge line in a DOWNWARD DIRECTION. This insures that the top tape will not bind the downward motion of the elevon, even at full travel. In a similar fashion, the elevon is deflected very far upward before applying the bottom hinge tape, as shown in the image on the right. The white surface is the elevon, the orange line to the right is the trailing edge (TE) of the far wing. Notice also that the elevon is beveled from the top forward edge to allow full downward motion when hinged on the top. The TE of the foam has a similar bevel for the same reason. The elevon is bent up until the bevel on the elevon and the wing make up a flat surface. Then the tape is applied by holding it at both ends with MINIMAL TENSION and gently tacking it in place. Once the alighment looks good, it should be depressed firmly to the two beveled edges with a spanwise motion of the fingers.

Now the bottom tape may be stuck to the elevon, and then to the wing. The bottom tape shown here is wider than it needs to be. This small span model will actually do fine with top tape only on the hinge, and the bottom tape was added here to be on the safe side. Thinner tape such typical Scotch brand tape may be a better choice for the bottom tape of both this small model and the full span variety. Thin tape weighs less, induces less friction in the hinge, and keeps debris from sticking to the top tape in the gap between the elevon and the wing. Don't forget to stick the bottom tape to the wing as well, even though the pictures don't show it. Click on the photos to enlarge them for a better look.

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