Brief:
I built my first spool rocket out of two CD-ROMs and a tube from a roll of silver foil. I have always found the aerodynamics of spools interesting and wondered if they could be staged. This rocket is the result of that pondering.

Construction:
The parts list:

• Two BT-50, 6 and 8 inches in length
• Two 24mm engine blocks
• Three centering rings of a BT-50 tube in a BT-101 (Estes Saturn V)

To build the kit I used:

• CA gel glue
• White glue
• Model knife
• Spray paint

Not the most difficult of builds, the centering rings go on the ends of the sustainer. With an engine block put in place 2.344 inches from the front, this allows the D motor to stick out the back.

The booster had an engine block and the centering ring glued flush with the base.

There was no launch lug, other than three notches cut next to the center of the centering rings.

Finishing:
I sprayed the whole thing pink, solely because I had a lot of pink spray paint.

Flight:
Little to no prepping is needed for spool rockets. Just put in the motors and fly. The two motor are not taped together and use a small staged gap. No hole was drilled in the booster tube as I did not think there was enough cold air to be expelled to warrant any venting.

First flight. A D12-0 and a D12-5 were loaded. She lifted quite quickly given the draggy design. Sustainer ignition was perfect, and the sustainer continued to launch straight. The booster spun end over end and recovered close to the pad and without damage.

Recovery:
I'm pleased with this rocket, she is the first two-stage spool that I have come across. I still don't pretend to understand the aerodynamics, although I have read quite a bit about them.

Summary:
This is a nice addition to my small in number spool fleet. I will build an 18mm version--cheaper on the motors.