I LOVE my Delta Vortex!

The biggest modification I made was to move the engine back (as I recall) 1 1/2" or so to help with the CG situation; I still had to add tail weight. I almost had a problem when I installed the OS 91FX because the standard muffler came too close to the wing. I (barely) solved the problem with an OS exhaust extension. The OS exhaust extension opening didn't match (was smaller) the OS91FX exhaust/muffler openings but a little grinding to match them up took care of that.

I've found that the rudder speed brakes are very nice to have too. The landings are way too cool; nose high final approaches are neat. It is so easy to fly.

Next one I do, I'm considering putting an elevator between the rudder just for kicks to see how that does. I'll stick with a three blade prop because it just looks right on this thing. A rear exhaust 90 with a pipe looks right too, IMHO. And maybe floats.