Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Work Bench > Building Techniques
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 04-23-2021, 03:11 PM
Dugway's Avatar
Dugway Dugway is offline
Irken Invader
 
Join Date: Dec 2010
Location: Utah
Posts: 10
Default

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.
__________________
Let us create vessels and sails adapted to the heavenly ether, and there will be those who will not shrink from even that vast expanse. - Kepler to Galileo in 1610

NAR 86500
Level 2
Reply With Quote
  #12  
Old 04-23-2021, 04:13 PM
Earl's Avatar
Earl Earl is offline
Apollo Nut
 
Join Date: Dec 2006
Posts: 4,052
Default

Quote:
Originally Posted by Dugway
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
__________________
Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970
Reply With Quote
  #13  
Old 04-23-2021, 04:25 PM
Ez2cDave's Avatar
Ez2cDave Ez2cDave is offline
Master Modeler
 
Join Date: Mar 2005
Location: Raleigh, NC Area
Posts: 1,380
Default

Quote:
Originally Posted by Dugway
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.


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 5-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.
Attached Thumbnails
Click image for larger version

Name:  kaypro-ii.jpg
Views: 26
Size:  801.0 KB  
__________________
"Failure Is Not An Option . . . Adapt & Overcome ! "

NAR # 26128 L2
TRIPOLI # 517 L2 ( inactive, at present )

Last edited by Ez2cDave : 06-17-2022 at 05:21 PM.
Reply With Quote
  #14  
Old 04-24-2021, 03:24 AM
Bill's Avatar
Bill Bill is offline
I do not like Facebook
 
Join Date: Sep 2008
Location: North Tejas
Posts: 2,722
Default

Quote:
Originally Posted by ghrocketman
Does this Bruce Lee also have a sister named Ugh ?


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


Bill
__________________
It is well past time to Drill, Baby, Drill!

If your June, July, August and September was like this, you might just hate summer too...

Please unload your question before you ask it unless you have a concealed harry permit.

: countdown begin cr dup . 1- ?dup 0= until cr ." Launch!" cr ;

Give a man a rocket and he will fly for a day; teach him to build and he will spend the rest of his days sanding...
Reply With Quote
  #15  
Old 04-24-2021, 03:25 AM
Bill's Avatar
Bill Bill is offline
I do not like Facebook
 
Join Date: Sep 2008
Location: North Tejas
Posts: 2,722
Default

Quote:
Originally Posted by shockwaveriderz
this is what OpenRocket is for. or RockSim or RASAero 2



RockSim was first released in 1997.

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


Bill
__________________
It is well past time to Drill, Baby, Drill!

If your June, July, August and September was like this, you might just hate summer too...

Please unload your question before you ask it unless you have a concealed harry permit.

: countdown begin cr dup . 1- ?dup 0= until cr ." Launch!" cr ;

Give a man a rocket and he will fly for a day; teach him to build and he will spend the rest of his days sanding...
Reply With Quote
  #16  
Old 04-24-2021, 03:28 AM
Bill's Avatar
Bill Bill is offline
I do not like Facebook
 
Join Date: Sep 2008
Location: North Tejas
Posts: 2,722
Default

Quote:
Originally Posted by Earl
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



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.
__________________
It is well past time to Drill, Baby, Drill!

If your June, July, August and September was like this, you might just hate summer too...

Please unload your question before you ask it unless you have a concealed harry permit.

: countdown begin cr dup . 1- ?dup 0= until cr ." Launch!" cr ;

Give a man a rocket and he will fly for a day; teach him to build and he will spend the rest of his days sanding...
Reply With Quote
  #17  
Old 04-24-2021, 01:32 PM
shockwaveriderz shockwaveriderz is offline
rocket dinosaur
 
Join Date: Mar 2005
Location: My Old Kentucky Home
Posts: 1,141
Smile

Quote:
Originally Posted by Bill
RockSim was first released in 1997.

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


Bill


in the beginning was Gary Crowell's VCP....https://sites.google.com/site/vcpro...tor/vcp-history copyright 1995
__________________
"Old Rocketeer's don't die; they just go OOP".....unless you 3D print them.
Reply With Quote
  #18  
Old 04-24-2021, 01:51 PM
shockwaveriderz shockwaveriderz is offline
rocket dinosaur
 
Join Date: Mar 2005
Location: My Old Kentucky Home
Posts: 1,141
Smile

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. ??
__________________
"Old Rocketeer's don't die; they just go OOP".....unless you 3D print them.
Reply With Quote
  #19  
Old 04-24-2021, 04:36 PM
Ez2cDave's Avatar
Ez2cDave Ez2cDave is offline
Master Modeler
 
Join Date: Mar 2005
Location: Raleigh, NC Area
Posts: 1,380
Default

Quote:
Originally Posted by shockwaveriderz
this is what OpenRocket is for. or RockSim or RASAero 2


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.
__________________
"Failure Is Not An Option . . . Adapt & Overcome ! "

NAR # 26128 L2
TRIPOLI # 517 L2 ( inactive, at present )
Reply With Quote
  #20  
Old 04-24-2021, 04:42 PM
Ez2cDave's Avatar
Ez2cDave Ez2cDave is offline
Master Modeler
 
Join Date: Mar 2005
Location: Raleigh, NC Area
Posts: 1,380
Default

Quote:
Originally Posted by shockwaveriderz
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. ??



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.
Attached Files
File Type: pdf EstesTR9.pdf (694.0 KB, 15 views)
File Type: pdf BARROWMAN REPORT.pdf (734.5 KB, 15 views)
File Type: pdf BARROWMAN - MASTERS THESIS.pdf (1.90 MB, 16 views)
File Type: pdf Labudde_1999_CP - BARROWMAN EXTENDED.pdf (286.4 KB, 17 views)
File Type: pdf WHAT BARROWMAN LEFT OUT - Robert Galejs.pdf (146.4 KB, 19 views)
__________________
"Failure Is Not An Option . . . Adapt & Overcome ! "

NAR # 26128 L2
TRIPOLI # 517 L2 ( inactive, at present )

Last edited by Ez2cDave : 04-24-2021 at 05:25 PM.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 11:14 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe 1998-2022