Thrust vectoring for saturn V?

This person here https://bps.space/ was able to create thrust vectoring for model rockets so would it be possible to make a 3-stage saturn V using the same technology? I know that such a project would be incredibly complicated but would one be able to do it using model rocket motors?

I am building a BPS thrust vectoring rocket right now. I asked the inventor, Joe Barnard, about this very thing. He told me that his system isn’t ready for that just yet.

Here is Joe’s response to my question: “Signal doesn't work too well as a second stage since thrust vector control starts on the ground and would be accumulating error in the PID controller throughout flight.”

For now I’m just building a single stage thrust vectored Saturn V. My goal is to get a cool, slow liftoff.

Doesn't the estes saturn have a really slow liftoff? And are you using a 5 motor cluster for your rocket to make it more realistic?

My goal is to make a swappable motor mount so I can use either a 5-motor cluster or the BPS system. But at this point that's just a hypothesis. I need to get to work on it.

@afadeev installed a BPS system into a Saturn V... https://www.rocketryforum.com/threads/bps-space-thrust-vectoring-control-rocket-build-thread.151207/

Slow liftoffs may be realistic, but they may also violate the model rocket safety code. We like rockets to get off the pad quickly to ensure that the fins can guide the rocket as it goes up. Slow liftoffs don't provide much speed and therefore have little air flowing over the fins.

Thrust vectoring with model rocket motors is difficult due to the short burn time for most motors. Three seconds is the longest for motors people typically use. There are longer burning motors, but they are very low thrust and you get back to the issue of being too slow off the pad to be safe, especially if the rocket has extra weigh due to a thrust vectoring system.

Zeus-cat said:

Slow liftoffs may be realistic, but they may also violate the model rocket safety code. We like rockets to get off the pad quickly to ensure that the fins can guide the rocket as it goes up. Slow liftoffs don't provide much speed and therefore have little air flowing over the fins.

Thrust vectoring with model rocket motors is difficult due to the short burn time for most motors. Three seconds is the longest for motors people typically use. There are longer burning motors, but they are very low thrust and you get back to the issue of being too slow off the pad to be safe, especially if the rocket has extra weigh due to a thrust vectoring system.

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Most of Joe's airframes have no fins, relying on only thrust vectoring to remain stable. His powered decent rockets have fins at the top. With the stoutness of what Joe builds and the automatic landing legs setup I'd think an Estes Saturn V with TVC would still be lighter than his basic testbed.

I didn't want to imply it couldn't be done, just that it is a very advanced model rocketry project.

Zeus-cat said:

Slow liftoffs may be realistic, but they may also violate the model rocket safety code. We like rockets to get off the pad quickly to ensure that the fins can guide the rocket as it goes up. Slow liftoffs don't provide much speed and therefore have little air flowing over the fins.

Thrust vectoring with model rocket motors is difficult due to the short burn time for most motors. Three seconds is the longest for motors people typically use. There are longer burning motors, but they are very low thrust and you get back to the issue of being too slow off the pad to be safe, especially if the rocket has extra weigh due to a thrust vectoring system.

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I'd imagine combining slow liftoffs with thrust vectoring, you wouldn't be looking at the type of motors normally used today in model rocketry. You'd be looking at high total impulse and low average thrust motors such as new AeroTech G8 (https://www.thrustcurve.org/motorsearch.jsp?id=1122). 136Ns of impulse, but only only 8N of average thrust (peaks at only 15N). 16+ seconds burn time. Because you wouldn't need that high average thrust to get the rocket up to speed quickly before it leaves the rail as you need with passive fins-only stability control. If thrust vectoring becomes more widespread, I'd expect we'll see more motors with low thrust to total impulse ratio being developed.

Yep. I’m thinking the Apogee F10 or the AeroTech G8. But I think I heard that the G8 has been recalled due to overheating. Is that right?

I could see where staging with one of these would be difficult a lot of variables to keep track of. What I think would be an amazing use for the BPS system would be a full up, no fins, shuttle stack with a gliding (maybe even RC) orbiter. That however is way out of my hobby budget.

BDB said:

I am building a BPS thrust vectoring rocket right now. I asked the inventor, Joe Barnard, about this very thing. He told me that his system isn’t ready for that just yet.

Here is Joe’s response to my question: “Signal doesn't work too well as a second stage since thrust vector control starts on the ground and would be accumulating error in the PID controller throughout flight.”

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He also told me that the system doesn't work well at high speed. My first thought for this system had been to use a finned booster to gain a lot of speed and then a finless sustainer to shed the drag. Joe said no; his system doesn't like going fast.

udid9iv99 said:

Doesn't the estes saturn have a really slow liftoff? And are you using a 5 motor cluster for your rocket to make it more realistic?

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There's slow, and then there's slow. You should look at the BPS Space web site and You-Tube channel. Slow for a model rocket with fins is still pretty fast. Slow with the BPS system is really slow.

Zeus-cat said:

Slow liftoffs may be realistic, but they may also violate the model rocket safety code. We like rockets to get off the pad quickly to ensure that the fins can guide the rocket as it goes up. Slow liftoffs don't provide much speed and therefore have little air flowing over the fins.

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Not a concern when there no fins. Because you don't need them.

Thrust vectoring with model rocket motors is difficult due to the short burn time for most motors.

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amiliv said:

I'd imagine combining slow liftoffs with thrust vectoring, you wouldn't be looking at the type of motors normally used today in model rocketry. You'd be looking at high total impulse and low average thrust motors such as new AeroTech G8 (https://www.thrustcurve.org/motorsearch.jsp?id=1122). 136Ns of impulse, but only only 8N of average thrust (peaks at only 15N). 16+ seconds burn time. Because you wouldn't need that high average thrust to get the rocket up to speed quickly before it leaves the rail as you need with passive fins-only stability control. If thrust vectoring becomes more widespread, I'd expect we'll see more motors with low thrust to total impulse ratio being developed.

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It's true, he likes long burning low thrust motors.

Zeus-cat said:

I didn't want to imply it couldn't be done, just that it is a very advanced model rocketry project.

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The point of the BPS system is that Joe has incorporated the difficulty into his controller. You do need to measure the rocket's CG and pendulum swing periods in pitch and roll (from which he deduces the moments of inertia) but his software takes it from there. Very, very cool.

mjennings said:

I could see where staging with one of these would be difficult a lot of variables to keep track of. What I think would be an amazing use for the BPS system would be a full up, no fins, shuttle stack with a gliding (maybe even RC) orbiter. That however is way out of my hobby budget.

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An Italian group did that. I don't know if they were using the BPS system. They take off very slowly (if it's not BPS then it must be another thrust vectoring system) on a three motor cluster in the SME position plus motors in the SRBs. When the SRBs burn out they drop off and deploy parachutes while the SMEs keep burning. When they burn out, the ET drops off and comes down on it's own 'chute. The orbiter comes in as an RC glider. It's bloody incredible!

Wow, that setup is cool. Any idea when hes selling again? Just went to the website to check it out and it says not for sale anymore.