I designed most of my carded models to wrap around a BT-5 tube.
The wrap skin was drawn up to roll and fit a body tube.
I found most single layer carded model tubes to be weak and not last through many launches.

These smaller models have friction fit engines.

Here's the entire carded model build from finished model to start:
http://modelrocketbuilding.blogspot...ch/label/A.S.P.

__________________
Hans "Chris" Michielssen
Old/New NAR # 19086 SR

www.oddlrockets.com
www.modelrocketbuilding.blogspot.com
http://www.nar.org/educational-reso...ing-techniques/
Your results may vary
"Nose cones roll, be careful with that."
Every spaceman needs a ray gun.
Look out - I'm the Meister Shyster!