Active Stabilization with the help of Thrust Vector Control (TVC)

Discussion in 'Rocketry Electronics and Software' started by Raikhan Kushekova, Jan 10, 2019.

Help Support The Rocketry Forum by donating:

  1. Jun 10, 2019 #31

    JimJarvis50

    JimJarvis50

    JimJarvis50

    Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    2,187
    Likes Received:
    290
    It's pretty hard to offend me (possible, but difficult). For those of us that fly at Blackrock, and for Balls anyway, there is a 15 nm radius for the COA. Strickly speaking, it is illegal to fly a rocket outside of that radius. Just for fun, try running some simulations where you allow staging to occur at different angles. You will be very surprised at how low the angle is where you land outside of that radius. Then, add a jet stream.

    Each year, we report back to the FAA on the results of the high altitude flights and where they landed. For flights outside of the waiver, we report on what happened and why. If there are an increasing number of flights over 100K or much higher, you have to wonder what the response of the FAA will be when those rockets start regularly landing outside of the waiver. Over the last few years, most of those attempts have not been successful. More people will try, though, and this will become an issue.

    Up to the present time, there has been a technical issue that contributes to the above problem. Specifically, the methods used for tilt detection have an amount of drift in the gyros that is on the order of the setting that would be required to stay within the waiver. It is really tough to use a tilt value that actually would control dispersion when the result of doing that would be to have a perfectly good flight inhibited due to gyro drift.

    This year, I'm hoping to fly a rocket over 300K. Who knows, it could happen. This particular flight can't use the stabilization system. However, I will be using gps to determine the actual trajectory, rather than an inertial system, so at least if the flight is inhibited, it will be at an angle where I truly don't want to fire the sustainer. This is a really important capability.

    Jim
     
    plugger and heada like this.
  2. Jun 12, 2019 #32

    plugger

    plugger

    plugger

    Well-Known Member

    Joined:
    May 1, 2009
    Messages:
    369
    Likes Received:
    89
    You're correct Tony, I've never had to do a dispersion analysis. Down here if we are looking to do a high altitude flight the standard process is we submit a High Altitude Flight form as well as a sim file and the High Altitude Review Committee does a dispersion analysis.

    But is anyone actually doing this? Up thread Jim mentions
    Given that Jim's the only person I'm aware of that's leveraging active stabalisation on high altitude staging attempts and during boost he's only leveraging roll control, not vertical control, seems to imply that no one is currently doing what you mention above. Also I do believe many if most of the people flying their own active stabilisation systems are parking them during boost/at high Mach. I'm happy to be proven wrong though.

    Agreed, but as I mentioned up thread there are other dumber ways of optimising verticality during the booster burn. Also, I think you're almost implying here that off trajectory flights are the primary cause as to why staging shots have a low probability of reaching their theoretical altitude. I'm not sure I agree with that.

    Can't argue there either. I'd go as far as to say any 100k' + shot is a combination of hard work and luck.

    When you look at Curt's PHX4 flight where he hit roughly 250k' MSL and consider he didn't use any active stability system and still recovered the sustainer 6.36 miles from the launch point I think we can both agree that there is still a lot of room for people to attempt high altitude two stage flights, stay within cylinder, and still achieve quite incredible results.
     
  3. Jun 12, 2019 #33

    plugger

    plugger

    plugger

    Well-Known Member

    Joined:
    May 1, 2009
    Messages:
    369
    Likes Received:
    89
    That's what I expected and I appreciate you stating that. As mentioned I'm not out to offend anyone and I really enjoy the fact that given your accomplishments you're still available (for lack of a better term) to people in the hobby like myself.

    I've got to run and go cut some wood for the fireplace as it's bloody cold down here but I'll respond to you soon. Thanks again for the response.
     

Share This Page