Just got done with a new project to improve headlight brightness on the F-3 or F-7 by AZL. Hardest part is getting the original light tube out of the shell! It's glued in well. Next, obtain .50 mm fiber optics - available online in small rolls. Cut fiber to length between the now-shortened headlight tube and the LED on the circuit board. Slightly flare each end of the fiber by holding it near a cigarette lighter flame for just a second or so (looking for only slight flaring on each end). I also glued a short length of shrink tubing at the front inside of the shell to make sure the fiber sits exactly over the headlight opening. Then, superglue the other end of the fiber directly to the LED front (I used accelerator to get the exact position and hold it fast). Result is a realistically bright headlight with the appearance of a small bulb inside, as with the prototypes. This was easier than I thought it would be and I'm happy with the result. Happy Thanksgiving everyone.