Ye Olde Rocket Forum

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


Reply
 
Thread Tools Search this Thread Display Modes
  #31  
Old 11-21-2019, 11:37 AM
LeeR's Avatar
LeeR LeeR is offline
Retired with Way Too Many Kits
 
Join Date: Jun 2007
Location: Colorado
Posts: 3,222
Default

The BNC-55AO balsa nose cone is available from eRockets:

http://www.erockets.biz/semroc-bals...l-sem-bnc-55ao/
__________________
Lee Reep
NAR 55948

Projects: Semroc Saturn 1B, Ken Foss Designs Mini Satellite Interceptor
In the Paint Shop: Nothing! Too cold!
Launch-Ready: Farside-X, Maxi Honest John, Super Scamp
Reply With Quote
  #32  
Old 11-21-2019, 01:38 PM
Rocketcrab Rocketcrab is offline
Wasted away again.......
 
Join Date: Jul 2005
Location: M&T Bank Stadium
Posts: 261
Default

Quote:
Originally Posted by A Fish Named Wallyum
BNC-55AO


Thanks. Color me embarrassed. Just after I posted my question, I noticed another Goblin thread that contained the answer. I even dug in to my stash of SEMROC parts and discovered at BNC-55AO! Now, another question - if I swap out the plastic cone for the balsa, will nose weight be needed?
__________________
Got a Caribbean soul I can barely control.....
Reply With Quote
  #33  
Old 11-21-2019, 07:00 PM
erik442's Avatar
erik442 erik442 is offline
The Alpha Kid
 
Join Date: Mar 2012
Location: central PA
Posts: 419
Default

I have an original from the early 70's and it doesn't have any nose weight added. I think it would depend on what type of streamer you use. Mine is crepe paper and maybe 7ft long. When coiled it has some substance. If I was going to use a shorter, plastic streamer I would most likely put a washer under the screw eye.
Reply With Quote
  #34  
Old 11-21-2019, 08:54 PM
Rocketcrab Rocketcrab is offline
Wasted away again.......
 
Join Date: Jul 2005
Location: M&T Bank Stadium
Posts: 261
Default

Quote:
Originally Posted by erik442
I have an original from the early 70's and it doesn't have any nose weight added. I think it would depend on what type of streamer you use. Mine is crepe paper and maybe 7ft long. When coiled it has some substance. If I was going to use a shorter, plastic streamer I would most likely put a washer under the screw eye.


Thanks, sounds good! Might have to try the old string stability method . I can see it now. Our neighbors wondering why their 63 year old neighbor is whipping a rocket around his head!
__________________
Got a Caribbean soul I can barely control.....
Reply With Quote
  #35  
Old 11-22-2019, 07:14 PM
Earl's Avatar
Earl Earl is offline
Apollo Nut
 
Join Date: Dec 2006
Posts: 4,894
Default

I would suspect the stock Goblin is a very, very stable design. Those are some pretty big fins, and I would almost conjecture that it might be stable with just three fins (mounted in a standard three fin 120 degree configuration).

But, checking via a swing test or some CP/CG calculations won’t hurt. The quickie ‘cardboard cutout’ CP test would be easy on this one.

Earl
__________________
Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970
Reply With Quote
  #36  
Old 11-22-2019, 08:50 PM
Rocketcrab Rocketcrab is offline
Wasted away again.......
 
Join Date: Jul 2005
Location: M&T Bank Stadium
Posts: 261
Default

Quote:
Originally Posted by Earl
I would suspect the stock Goblin is a very, very stable design. Those are some pretty big fins, and I would almost conjecture that it might be stable with just three fins (mounted in a standard three fin 120 degree configuration).

But, checking via a swing test or some CP/CG calculations won’t hurt. The quickie ‘cardboard cutout’ CP test would be easy on this one.

Earl


Thanks! I dug up a copy of the original Estes kit instructions, and there is no nose weight listed in the parts list. So I'll still check the stability but I think we're good.
__________________
Got a Caribbean soul I can barely control.....
Reply With Quote
  #37  
Old 11-22-2019, 10:51 PM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Nunya Bizznuss, Michigan
Posts: 13,443
Default

Guaranteed that a properly filled/sealed/sanded/painted BNC-55AO weighs more than a PNC-55AO.
You will not have any stability issues with the balsa cone.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
Reply With Quote
  #38  
Old 11-23-2019, 08:13 AM
PaulK PaulK is offline
BAR
 
Join Date: Nov 2005
Location: WI
Posts: 1,847
Default

The Semroc version doesn't have nose weight either, and it flies fine on D12-7s. I tried an E12, but it went KABOOM on the pad. Entertaining, in any case!
__________________
Paul
If we weren't all crazy, we would go insane - Jimmy Buffett
NAR #87246 www.wooshrocketry.org
Reply With Quote
  #39  
Old 11-23-2019, 09:07 PM
Rocketcrab Rocketcrab is offline
Wasted away again.......
 
Join Date: Jul 2005
Location: M&T Bank Stadium
Posts: 261
Default

Quote:
Originally Posted by ghrocketman
Guaranteed that a properly filled/sealed/sanded/painted BNC-55AO weighs more than a PNC-55AO.
You will not have any stability issues with the balsa cone.


Thanks!
__________________
Got a Caribbean soul I can barely control.....
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 08:38 PM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe © 1998-2024