Very Nicely done.
I've always liked the design of the NASA Pegasus, my original was badly damaged by a C6-5 Cato. When I rebuilt the body I decided to add two 13mm motor mounts to the Side motor tubes making the model and Inline 13mm, 18mm 13mm 3-motor cluster. Fly's very nicely on either a single C6-3 now or a C6-5 with 2- A10-0T's in the booster tubes.
I liked flying the model so much when I started downscaling favorite models for Micro Maxx motor power I just had to do a NASA Pegasus. it also flies on either a single MMX-II without extra nose weight or with 3- MMX-II's with nose weight package plugged in. Very KEWL flights.
Both Rocket are still in my flying fleets. Hope you have as much fun flying your 13mm downscale as I've had with both of my NASA Pegasus rockets.