- Joined
- Apr 5, 2013
- Messages
- 1,545
- Reaction score
- 71
This is irritating the inner Mr. Monk in me.
I have built a Wildman Gizmo with the new metal tipped nose cone. I added 15oz of nose weight, assembled it and the CG was about 2" below the top of the body tube. When I insert a simulated engine, the CG moves all the way down to about 1" before the fins (which is about where the CP is).
I took the nose weight out and weighed everything and entered it into OpenRocket. The sucker is marginally stable if not unstable with any 1-3 grain CTI motor. Hmmm.
But then I applied a cone using the math here: https://www.apogeerockets.com/downloads/Newsletter154.pdf
5.125" x 3.14 (Pi) = 16.09" long
And it becomes "stable". But is this true in real life or just in theory?
When I add the weight (15 oz.) back to the nose cone it is over 1.0 caliber stable.
This is the OpenRocket file. I hope it doesn't reset things.
View attachment Gizmo with Drag Cone.rkt
These are what the overided weights should be:
Nose Cone = 47.35 oz.
Body= 64.40 oz.
These weights are just painted parts, epoxied fins, etc... but no recovery devices (chutes, shock cords, etc.).
Basically, without the base drag, this sucker is unable or marginally stable (on paper at least).
Feedback?
I have built a Wildman Gizmo with the new metal tipped nose cone. I added 15oz of nose weight, assembled it and the CG was about 2" below the top of the body tube. When I insert a simulated engine, the CG moves all the way down to about 1" before the fins (which is about where the CP is).
I took the nose weight out and weighed everything and entered it into OpenRocket. The sucker is marginally stable if not unstable with any 1-3 grain CTI motor. Hmmm.
But then I applied a cone using the math here: https://www.apogeerockets.com/downloads/Newsletter154.pdf
5.125" x 3.14 (Pi) = 16.09" long
And it becomes "stable". But is this true in real life or just in theory?
When I add the weight (15 oz.) back to the nose cone it is over 1.0 caliber stable.
This is the OpenRocket file. I hope it doesn't reset things.
View attachment Gizmo with Drag Cone.rkt
These are what the overided weights should be:
Nose Cone = 47.35 oz.
Body= 64.40 oz.
These weights are just painted parts, epoxied fins, etc... but no recovery devices (chutes, shock cords, etc.).
Basically, without the base drag, this sucker is unable or marginally stable (on paper at least).
Feedback?
Last edited:
