Thursday, March 06, 2008

Sport Rocketry, March/April 2008 teaser/spoiler?

Got it today, and it looks like another great issue. Two tech/build articles (tube fin performance and a 2-stage HPR), launch coverage of NARHAM's ECRM-34 (yeah, I'm biased on this one), and a plan for an 1/32 scale Aries-1. There's also a NARAM-50 teaser, 3 student/educational blurbs, and several missile-aneous items.

The tube fin article is part-2 of Larry Brand's tube fin performance work (part-1 appeared in the last issue, read about it here). Here, Larry further tests the theory he proposed in the first installment. He built a stubby 5.5", J powered tube fin rocket whose Cd is lower than it's 4" cousin. The trick is to keep the Lff/D ratio low (Lff is the length forward of the tube fins and D is the body diameter). He further proved the theory by showing that shortening the 4" version improved its Cd. And finally, he built a version of one of his test rockets with the tube fins mounted a mere inch further forward (lowering the Lff but not its overall length). Yup, its Cd was also improved. As a bonus he discusses how he builds his somewhat unique 7-finned birds.

The top photos of the issue are: the cover photo showing a rocket built with Propel bottles, a 'RSO-teaser' made from a G80 casing, and Micromeister holding an immaculate Orbital Transport upscale (definitely NOT micro).