RE: viper 500 engine
I have one of these almost finished. It's really really red. I wanted to keep it Q-500 legal so I'm using an OS 40 FSR and the matching tuned pipe from Mac's. I put two servos in the wing, hoping I can deploy a bit of flaps for drag and land with the V-Tail a little more slowly.
Also, I'm putting black and white checkerboard on the bottom of the wing for visibility and orientation.
Regards.