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PHOTOGRAPHY: GREG MOORE


When things go ouch! here’s a practical way to make it look as good as new.


Composite wing Repair


By Greg Moore I 42


t seems that regardless of the size of the airplane, composite wings are the rage. For years, Composite-ARF (now known as CARF) has utilized very strong composite wings and their prowess begat the early offerings from BVM. Now, even small (90mm) edf jets, like some of HET’s offerings, are manufactured this way. For years, we have made wings either with wooden ribs and spars covered with balsa sheeting, or foam core wings sheeted with balsa. Both have their advantages; however the stiffness that a well-made molded composite wing imparts does im-


prove flight stability—if done accurately— and does allow for a “live-hinge”. That being said, we “know” how to repair both built-up and foam-sheeted wings, since the vast majority of the time we built them, but how do you fix a broken composite wing? When a pin-mounted main-gear strut comes loose on the takeoff roll, the airplane will do some weird and uncontrollable things, like veer sharply towards the steel posts supporting pilot safety fencing. When that happened, one of the photos shows the damage it inflicted on my CARF Flash wing as shown in the lead shot.


A long discussion took place with several very experienced builders as to the best way to fix this, and several options—from insert- ing a series of Styrofoam™ blocks to fill the void, to fabricating several ribs and sheeting them to buying a new wing—were dis- cussed. The foam-blocks option was eventu- ally dismissed since it was felt that the dif- ference in mass and thermal changes (hollow space vs. solid space) on such a large repair might affect the wing in hot summer temperatures.


A close look at the surviving piece of lead- ing edge breakage showed that the wing


FEBRUARY 2014


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