The Rocketry Forum

Help Support The Rocketry Forum:

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

    Determining stability as a function of center of mass

    Hello, I have a question regarding stability and how to design for a stable rocket. I have an initial center of mass for the full rocket without fuel/propellant, and one for a fully loaded rocket with propellant. As the mass changes, and due to the placement of the tank, the center of mass for...
  2. E

    Moon Burner Center of Mass

    I am part of a collegiate rocketry team and we are looking at using a moon burner design for a KNSB O-motor we're developing. As the core of the grain is off the central axis of the rocket, the center of mass is also off the axis, causing some moment. Does this cause any stability issues with...
  3. Samarth Barshi

    What stability is too less and too much ?

    The competition that I am participating requires a min stability of 1.5 cal during boost and to satisfy this my static margin is 2.2 cal. Is this normal? Its a 130 mm dia rocket of length 219cm with an L class SRAD motor. What stability is too much ? What factors would it depend ?
  4. C

    Zephyr Stability (Openrocket vs. RockSim)

    Hi Everyone, I am currently working toward an L1 certification using the Zephyr kit from Apogee. I am basically done with construction, but when I started looking at the OpenRocket model to determine my delay for motor ejection I noticed a really disconcerting discrepancy between the...
  5. tugkau

    Over Stability Is a Issue?

    Hi everyone. I have a question. I have a rocket design which have 278cm length and 12cm diameter. In this design Cg = 163cm, Cp=210cm. Accordingly to OpenRocket datas my stability is 3.88. When i want to plot simulation graph, the stability values that i get are between 5 and 6. And i think...
  6. R

    Questions about BPS Space System

    I have some questions regarding the BPS Space system and perhaps others that are developing similar systems. I hope this helps others too. What's the status of usable motors for the BPS Space system? I've seen that Joe Barnard is testing the new system he is working on using the G8. Please...
  7. R

    Stabilization and trajectory control

    I believe the following applies to both model and high-power rockets. I have the referenced sections of NFPA 1122, Model Rocketry that's in the California Fire Marshal handbook. The following is from the handbook. California codes for amateur rockets also stipulate mechanical methods to...
  8. Miles Goodson

    Open rocket stability number?

    Hi all, I just got Open Rocket to simulate an F powered rocket that I'm building, and for some reason, I can't get the stability number past 0.6! I've tried everything. Any ideas on what to fix?
  9. L

    Falcon 9's stability

    If you look at the Falcon 9 rocket, it is basically a straight pipe with an enlarged nose. I've been told that the center of gravity of a rocket must be above the center of aerodynamic pressure, so how come the Falcon 9 (or really any other rocket that seems to be breaking this rule) is a stable...
  10. M

    Rocket Center Of Pressure CFD Analysis

    I am an fourth undergraduate aerospace engineering student. I need to find the rocket center of pressure by using CFD programs for my thesis. Now I have some experiences fluent and OpenFoam. How can I make this analysis?
  11. M

    Spin Stabilization vs "Spin-Can"

    I want to clear up what I believe is my own misunderstanding. I'm very familiar with the concept of spin-stabilization, and my understanding of it revolves around giving the vehicle a very high spin rate in order to resist aberrations in thrust, aerodynamics, etc and average out forces during...
  12. Interstellar

    Tips and Guidelines for Aerodynamic Stability?

    I've been designing a simple one stage rocket with OpenRocket, which allows the user to design and simulate their designs. I was always told that a general rule of thumb for a rockets stability is that the center of gravity should be 1-2 calibers above the center of pressure. With this rule...