Hey Chris

Not sure if you're a RC plane-nut like me, so sorry in advance if I write the obvious! This is a fuselage for a slope glider design affectionately called a "Plank". Its called this because its basically just a wing, often without a fuselage at all. I'll post a picture below of one of my favourite planks.

The reason the vertical stabiliser is so large is because its moment to CG (how far the fin is away from the centre of gravity - think of a lever) is short. This means there is very little lever-effect to keep the glider's yaw in check. End result is the glider tracks like its on rails with a decent setup including large fin. These are not slow gliders, the speed record for a type of gliding called Dynamic Soaring (DS) is approaching 500MPH - yep faster than a light aircraft. This sport uses the sheer-layers of air you get with wind as it crests a mountain slope.

And now you've got me rambling about my hobby :-)

The UberMoth: