As you've discovered, the Aerobird Challenger is best flown in very light winds. Completely calm to 5 mph winds are ideal for beginning flight attempts.

You should protect the center section of your wing with fiber reinforced box tape. You want to reinforce the areas where the rubber bands connect the wing to the fuselage and especially to protect the wing's trailing edge just in front of the propeller. It seemed like every time I put a new wing on my Challenger, the first time I tried to fly it the plane would come down and the wing would get shoved into the prop and chewed up.

The Aerobird Challenger can fly surprisingly well, but it needs to be trimmed out properly and it needs to be flown only in very light wind. The 12v peak charger that came with my Challenger had a habit of false peaking. I had several early flight attempts spoiled by charging up my battery and driving to a field only to discover the battery would run out of juice after just a minute or so. I bought the Hobbyzone wall wart charger for $9.99, and I found this was more reliable for completely charging my battery. I only used my car charger for "topping up" the battery on my way to the field.

Keep plugging away. It will take a lot of practice to get good at flying your Aerobird Challenger. Protecting your wing from your propeller and making sure your battery is really charged before you try to fly are two good ways to improve your odds.