Beautiful flight. It really did look like things were being controlled very smoothly. When you can modulate tilt to 1 degree you really are locked in.
I did a VOS2 flight Saturday at San Angelo. It's a pretty new field that is really nice. West Texas doesn't have a lot of trees.
The purpose of the flight was to start investigating the use of the system for roll control only. When controlling yaw/pitch, the main objective is just to keep the rocket from spinning rapidly and from exceeding the gyro range. For roll-only, the objective would be for video. Since I haven't previously done roll control only, I decided to start with lower gains than we typically use, knowing that these will need to increase to actually hold at the desired bearing through the flight. So, I would say the flight was reasonably successful and there is potential for significant improvement. There is a video of the flight linked below with some data at the end of the video.
Speaking of the VOS2 systems, the second batch of six systems has been claimed. I'm not sure if it will be possible to make more - I hope so - but there is uncertainty just now. Our group should be able to do quite a few flights this year, so I'm looking forward to that.
Jim
No build thread, sorry. I have been doing VTS since 1995. The first one used Futaba rate servos with actual spinning mass inside!VTS SkunkWorks --
Very interesting idea for attitude control !
Do you have a build thread here on TRF ?
-- kjh
I like your approach. It solves many of the problems associated with canard control and is a nice implementation of rear control. I've seen some "flat" servos that could almost be embedded completely within the fin.No build thread, sorry. I have been doing VTS since 1995. The first one used Futaba rate servos with actual spinning mass inside!
I used an EagleTree MicroVector flight controller which also has memory. That was driven by a tiny zero arduino. The computer turns everything on and runs a control surface test prior to initialization.
The first version used small linear servos surface mounted on the fins. I upgraded to standard nano servos mounted through the fin. The upgraded fins were two sheets of aluminum glued together with JB Weld with a third thinner layer of aluminum inside like a sandwich. I did that so I could sandwich the hinges. The inner layer of aluminum is the same thickness as the hinge material. The hinges and linkage are large scale RC aircraft equipment. The fins are connected with a "fin can" of flanges so I can change the fins for development.
It has a 54mm motor mount. Obviously I used a plugged motor with tripple redundant recovery.
The aft control system was suggested by Ken Biba so the controled section could make a booster for a 2 stage rocket. That way stage 2 would be ignited while vertical.
I would be glad to answer any questions.
BTW, what I have seen on this forum is beyond what I have done, and much more skilled construction!
Hmmm ...I like your approach. It solves many of the problems associated with canard control and is a nice implementation of rear control. I've seen some "flat" servos that could almost be embedded completely within the fin.
Jim
Look up "wing servos".Hmmm ...
Flat servos embedded completely within the fin -- VERY interesting idea for just 'a little guidance' !
-- kjh
Your system could be coupled with the flight computer and program that I use. You would need to be able to mount the board in the pic vertically in the air frame (it's 1.5" x 2.75"), and the servos would need to operate with PMW signals at a 1500 center point. Want to give it a try?I figured after I got it working properly, I might add some 3d printed aerodynamic covers over the servos.
The Nano servos can run at a higher voltage than the linear servos, so they are easier to integrate with the flight controller.
The Controller is set for 2 opposite fins to be "rudder" for yaw control and two opposite fins as "elevons" to provide pitch and roll control.
If you wanted a type of thrust vector included you can add graphite tabs to the fins extended into the exhaust flow, much like the redstone rocket.
However, that did not seem to be necessary as you can see in the video.
The purpose of the VTS system was to allow the rocket velocity to be close to the optimum and still go straight up without a gravity turn.
Check out Apogee Newsletter # 455, 456 and 457 for details on optimum velocities.
Well, we're on Post 912 of the development thread, and along the way, I've flown the system roughly 35 times. Can't wait for the next flight - it's fun.Jim, very nice controller! I am 72 and retired from flying the VTS rockets. Although I would prep the rockets at home, and load the motor, it was too much to do at the pad for one person! I passed the rocket on to Tom Fetter who also flys a VTS system in N CA.
Your controller looks much cleaner than what I was using. Great work! Hve you flown your system?
Great video's thanks for the connect. I liked your 15k my way video!Well, we're on Post 912 of the development thread, and along the way, I've flown the system roughly 35 times. Can't wait for the next flight - it's fun.
You can find many flight videos along this thread, or search YouTube for Jiminaus50.
Jim
I've been studying your thread for WEEKS and I am still only up to Page 9 of 31 !Well, we're on Post 912 of the development thread, and along the way, I've flown the system roughly 35 times. Can't wait for the next flight - it's fun.
You can find many flight videos along this thread, or search YouTube for Jiminaus50.
Jim
Thanks Steve. Seems like I know you from somewhere?Great video's thanks for the connect. I liked your 15k my way video!
Are you familiar with "the Goddard problem"? I wrote some software to solve part of that iteratively for amature rocketry. The solution is different for each rocket but it computes the velocity profile that will get you the highest for a given total N-S motor. That is what is discussed in the newsletters I mentioned above.
Thank you for sharing the lessons learned and construction techniques!
steve ainsworth TRA 2454
Sometime over the next three weeks or so, I'm planning a single-stage flight to look specifically at improving roll control. This is a follow-on to the San Angelo flight, but hopefully, with gains that result in better control. I mentioned it earlier in this thread, but roll control has both a rate gain (to slow down the roll rate when there is roll) and heading hold (to return the roll angle to that at the start of the flight). The two roll gains are tied together.Jim --
When, where and what do you plan for your next flight ?
Thanks
-- kjh
Hi Jim, I have been following your thread for a while now. I am curious, do you have a supply of these controllers stashed away? Because I can't seem to find them anywhere.
No, I don't have a supply, although I have a few extras. If I had more, I would make some additional systems. I'm hoping a new version of the control board will be produced, and if not, there are some other options.Hi Jim, I have been following your thread for a while now. I am curious, do you have a supply of these controllers stashed away? Because I can't seem to find them anywhere.
There is a project that I am planning down the road that involves vertical stabilization, which I why I am asking.
As it turns out, I'm currently working with Tom Fetter on analyzing the roll control problem. He certainly knows the subject. Small world.Jim, very nice controller! I am 72 and retired from flying the VTS rockets. Although I would prep the rockets at home, and load the motor, it was too much to do at the pad for one person! I passed the rocket on to Tom Fetter who also flys a VTS system in N CA.
Your controller looks much cleaner than what I was using. Great work! Hve you flown your system?
Agree. The only limitation, which we probably can't get around, is that gains can't be modified until roughly a half second into the flight. That's the typical time required for launch detect. Maybe not that big of a limitation?Looking great Jim. The gain scheduling will be a game-changer too.
The NAR posted a video of my presentation on the Vertical Orientation System at NARCON this past January. It just goes over the development and capabilities of the system and some of the interesting flights along the way. I hope the quality of the presentation itself was better than the video!
Jim
Thanks Steve. Yes, lots of lateral force on the canards. When we figured out how to protect the servos from that force, things started working.Jim
Just found time to watch your NAR presentation video. Thank you for taking the time to do the video and post it here! Outstanding presentation and quite informational. You have developed a very impressive system! As my flights got faster, I found the same issue that you did with canard supports, see picture. Did you fly at club launches? Any issues with LCO's?
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