Yay! This thread is not dead! I just completed my Viper 500 ARF build. Plain vanilla with .46 OS (cheapest in class), and enhanced landing gear with 4" wheels which I hope will do fine for grass takeoffs and landings.

The gas tank area is glassed and seems decently reinforced from the factory. With this engine, I don't think it needs more, but I will go ahead and sneak some epoxy and glass around the landing gear block.

I just completed the engine break-in and am happy that there is minimal vibration and no fuel foaming.

Now I'm just waiting for decent weather for the maiden. Just need final balancing and range check...