Center of Pressure with Oddly Shaped Rocket External Protrusions

rocket sok
madcow rocketry
eggtimer rocketry
The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
A

alecslo

New Member
Joined
Apr 7, 2015
Messages
1
Reaction score
0
I am trying to do some stability analysis of a rocket I have been working on.
I have designed some mounts which will extrude from the rocket.
They are oddly shaped and don't seem to map to any components in rocksim or openrocket.
Is there a way to create your own parts not based off standard components(fins etc.) that I could look at?
Do you all have any recommendations on how I might go about finding center of pressure with these components included so I can be confident in my design before assembly?
 
Build it, stick a motor in it and fly it naked. If no one is injured, paint it! :surprised:

IMG_0272.jpg
 
In OR (and I assume other software) you can design single fins and set their widths, location and rotation. Could this help model the extrusions you are thinking of?
 
How big is the rocket? Failing all else, there's always the swing test...

I didn't even try to bully Rocksim into approximating this:
dg9.jpg

With rockets like this where the vertical fins are wildly different from the horizontal fins, two swing tests are needed - one with the wingtips horizontal (so you're looking straight at one wingtip) and one with the wingtips vertical (so you're looking at the top or bottom of the rocket). If it "flies" correctly both ways, it's probably alright to load up and put on a pad.
 
Speaking of rockets with wildly different fins, does anyone here have any first hand experience with the Skonk Wulf by Douglas Shrock? Swing testing this will be a challenge because of the large "wing fins" that will make attaching the string rather challenging and other methods such as shadow cutouts or computer simulator programs would also be daunting. (My Cosmic Catfish flew well but the canard fins were removable and the tail fins were really nothing more than a three 120 degree configuration.) I've already got too much invested in both paint and time and really don't want to turn this one into confetti!
 
tmacklin said:
Speaking of rockets with wildly different fins, does anyone here have any first hand experience with the Skonk Wulf by Douglas Shrock? Swing testing this will be a challenge because of the large "wing fins" that will make attaching the string rather challenging and other methods such as shadow cutouts or computer simulator programs would also be daunting. (My Cosmic Catfish flew well but the canard fins were removable and the tail fins were really nothing more than a three 120 degree configuration.) I've already got too much invested in both paint and time and really don't want to turn this one into confetti!
Click to expand...
There's been several build threads on the Skonk Wulf. I think the most recent was by afterburner. I haven't seen any negative reviews so I'm willing to bet if you follow the plans you should be good to go. Most of the stuff I do is scratch built and because of the reasons you mentioned I can't swing test them. I think over time you develop an --EYE-- for the rockets you build. Most of the time you'll know if your pushing the stability envelope and step back and rethink the build.
 
alecslo said:
I am trying to do some stability analysis of a rocket I have been working on.
I have designed some mounts which will extrude from the rocket.
They are oddly shaped and don't seem to map to any components in rocksim or openrocket.
Is there a way to create your own parts not based off standard components(fins etc.) that I could look at?
Do you all have any recommendations on how I might go about finding center of pressure with these components included so I can be confident in my design before assembly?
Click to expand...
Like everybody else here says, It might help with a little insight--maybe a sketch would do the trick. Most of us have tried everything you can think of at some point , so new ideas are few and far between. Just our execution differs. When you start talking about things poking out of the rocket, all my alarm bells go off thinking about drag induced instability long before I worry about A CP/CG challenge.
 

Similar threads

J
My Center of Pressure Test Models
Replies
16
Views
559
cwbullet
cwbullet
Anonymous
Optimizing Fin Shapes in Rocksim
2
Replies
31
Views
2K
Brandon.L
Brandon.L
A
Is this model rocket complete? Do I need anything else?
Replies
18
Views
623
cwbullet
cwbullet
SteelyEyed
Project Aether Breather
2
Replies
40
Views
2K
Aeva
Aeva
Anonymous
Seeking Insights on Water Rocket Fins Optimization
2
Replies
31
Views
2K
NTP2
NTP2

Latest posts

Back
Top