I remember writing Fortran code to run the Barrowman equations on my Kaypro II. I couldn't believe how overstable all of my Estes rockets were. Started building from scratch in order to get stability down to 1-2 calibers.

Yes, apparently most commercial kits were (are) way, way overly stable.

I recall a latter 70s Model Rocketeer magazine article (NAR mag) by G. Harry Stine where he took several commercial kits and showed them built stock side by side with a version he did of each showing the amount of fin area needed to make it one caliber stable. The reduction in fin area on his redesigned versions were dramatic; really dramatic.

Earl

Kaypro II . . . A "Blast From The Past" !

"The Kaypro II has a 2.5 MHz Zilog Z80 microprocessor; 64 kB of RAM; two single-sided 191-kilobyte 5¼-inch floppy disk drives (named A: and B: ), and an 80-column, green monochrome, 9" CRT that was praised for its size and clarity (the Osborne 1 had a 5" display)."

Dave F.

Siblings named Gent and Merry; they were into watersports...


Bill

RockSim was first released in 1997.

https://www.apogeerockets.com/RockSim/Version_History


Bill

Undoubtedly to account for the way some people are poor at following instructions.

At least the big companies like Estes did. Some designs from smaller companies were less conservative.

in the beginning was Gary Crowell's VCP....https://sites.google.com/site/vcpro...tor/vcp-history copyright 1995

I've always wondered about this Estes Technical Report, TR-9 , "Designing Stable Rockets", by a William J. Taylor, III.

The CP calculations look really close to Jim Barrowman's original equations. The Masters thesis Barrowman Report came out in March 1967. This TR-9 in 1965. ??

There is no "Learning Curve" with those Manual Calculations . . .

Simply measure your rocket and enter the numbers in the proper location.

NASA didn't have "MoonSim" in the 1960's ( Slide Rules, Pencils, & Brains "ruled the day" ) !

Dave F.

Estes TR-9 ( 1965 )

Barrowman Report ( NARAM - 8 / August, 1966 )

Barrowman Master's Thesis ( March, 1967 )

LaBudde - "Barrowman Extended" ( 1999 ).

"What Barrowman Left Out" - Robert Galejs ( M.I.T. - Year ??? )

Dave F.