magnetic recovery system
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I am visualizing this huge electromagnet at the launch pad, turned on at Apogee to pull the rocket back to the pad (along with all the cars in the parking lot, all the big pads and rails, various other flight line metallic magnetic objects......)
End result is huge pile of metal with your rocket nose cone sitting like a cherry on top.
End result is huge pile of metal with your rocket nose cone sitting like a cherry on top.
Need more info. What do you mean by recovery system?
Speaknoevil
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Just make sure you have a mechanical switch disconnect.
jlabrasca
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I think you mean you want to use magnets in the mechanism that will open the rocket to release the parachute?
If this is correct, you will need to talk to the Range Safety Officer about this before you launch.
Neodymium magnets are hard and dense.
The rule on hard metals in rockets depends on how much you use in the rocket.
The local Tripoli Prefect will be able to give you better advice than you can get here.
We do need more information, but is this what you are talking about?
https://rebelrockets.wordpress.com/chutes/magnetic-deployment-device/
ktc
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Can you explain more detail?
Speaknoevil
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Scott_650
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Our pyrotechnic rockets are much easier to build than big water rockets!
ktc
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two ring magnet,one is in nose cone,other one is in body.They attract each other so nose cone doesn't fall.when the rocket is in apogee,reverse polarization was made that magnet is in tube.Then nose cone fall.You think is it okey?and Can you share documents about that?
Probably looking for a non-pyro deployment method.
Don't see how you can reverse the polarization unless one is a electromagnet.
Having the nose cone come off is only half the problem, the ejection charge is as much to eject the parachute as remove the nose cone.
Having the nose cone come off is only half the problem, the ejection charge is as much to eject the parachute as remove the nose cone.
Possibly relying on gravity or drag separation? As for the polarisation reversal- watch this space! Electromagnetic deployment - maybe. Hopefully more details will be forthcoming.
jlabrasca
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This will be hard to write about without specialized vocabulary.
There are reasons that it would be better to do it the other way.
Use an altimeter or an accelerometer to control the servo motor.
Use the magnets like a compressed spring to push the nose cone off.
The parachute will need to be packed so that it will fall out of the rocket. You must build it so that the parachute will not need to be pushed or pulled to get it into the air.
There is not much information about how to do this kind of deployment, because almost nobody does anything like this.
Most of the people who post on this forum will use a pyrotechnic to separate the parts of the rocket and push out the parachute. It is simpler and there are systems that you can buy.
If you want to pursue this search on line for "non-pyrotechnic deployment" or "non-pyro deployment".
The people who fly water rockets have worked out a couple of different solutions for this. You could start here.
https://www.uswaterrockets.com/construction_&_tutorials/ServoChron_2/tutorial.htm
https://www.instructables.com/id/Water_Rocket_Parachute_Deployment_Mechanism/
ktc
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what is the aim of servo?why is it there? Can you explain more detailed.I think that swich on current to magnet
jlabrasca
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The servo opens a latch to release the nosecone.
Yes. I think I understood what you want to do. You want to use an electromagnet to hold the nosecone on while it is going up, and to push the nosecone off to release the parachute.
It will be hard to explain all of the reasons that this will be difficult. I worry about using phrases like "magnetic flux density" and "power dissipation" Not all of the native english speakers on the forum would be able to follow this discussion.
I will try to explain:
If the electromagnet holds the nosecone on, you will have to push current through the coil all of the time (from launch pad to apogee) to keep the rocket closed. This means a high current power-supply. This means a big battery. This will be heavy. If you use lithium batteries it will also be more dangerous. Lithium batteries burn and release poison gas when they rupture, It is a bad idea to put big lithium batteries into a rocket that might crash out of the air, or burn on the launch pad.
Your system also means that the nosecone can come off if the current through the coil stops for any reason. If a wire comes loose while the rocket is accelerating upwards, it will separate the nosecone.
Even if you only want to push the nosecone off, you will still need to a large current through the coil to move the mass of the nosecone fast enough, far enough, to be sure that the parachute gets out.
A mechanical latch that has to be OPENED only requires current while the servo is running. It will require less current, for less time, and will not open the rocket if the current fails.
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DAllen
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This sounds like an interesting idea but is probably going to weigh a bunch.
Still though, I am interested in seeing what everyone has to say.
Still though, I am interested in seeing what everyone has to say.
ktc
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I think that when rocket is apogee,system switch on current to magnet.Thus nose cone fall
ktc
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1)Magnets attract each other because one is N other is S.When switch on current to magnet,both of them is N or S so nose cone will fall.Is it okey.Is that sturdy?
2)I dont know what is that mean
jlabrasca
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It might be a language problem. What you describe is not how electromagnets work.
I think you do not know enough about rockets, or about electromechanical systems, to build what you are describing.
I don't know any good physics resources in Turkish.
Can you understand any of the mathematics here?
https://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/curloo.html
or here
https://teacher.pas.rochester.edu/phy122/Lecture_Notes/Chapter31/chapter31.html
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This might work better for rear ejection as it allows you to put your heavy magnets up front to help improve CG. BIG MAGNETS up front, polarity on boost attracts. Aft magnet is attach to plunger. When electronics detects apogee, reverse polarity of one magnet, shoves everything out the back.
Numerous challenges, one is that I think magnet force falls off pretty fast with distance, so may not push far enough to get everything out.
On the other hand, if you can open a hatch enough to get a small drogue out that might be enough to pull out the rest of the laundry.
Numerous challenges, one is that I think magnet force falls off pretty fast with distance, so may not push far enough to get everything out.
On the other hand, if you can open a hatch enough to get a small drogue out that might be enough to pull out the rest of the laundry.
ThreeJsDad
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Some of us have been discussing a chute release for DD and magnets ran across my attic once or twice but how to make them let go is the issue.... I use them in all kinds of projects but in those cases I an standing there to make them release...
jlabrasca
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Honestly, I think the the best application is to use the repulsion of magnets as a source of potential energy to do the work of opening a shroud, or to use the attraction to do the work of pulling a pin to release a mechanical connection.
Using magnets to hold the rocket together is tricky. The force of attraction (or repulsion) is strong along one axis, but falls off pretty rapidly as you rotate away from that axis. Think about how you "peel" magnets apart. A magnetically secured structure will not be very rigid against shear stress.
But used as a magnetic "spring", neodymium magnets provide a higher energy density than would an elastic solid (like a spring or a rubber band).
ThreeJsDad
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I agree on all counts and thanks for the ideas. I would very much like to help come up with a non-pyro DD system.
At the end of the day, you’ve got to rapidly deliver X joules of energy to separate the rocket and shove the recovery system out. Energy is energy, and being electrical doesn’t make it any less dangerous.
Every electronic / engineering instructor I ever had took glee in exploding electronics behind blast shields — partly to show that “electrical” is by no means safe. (But mostly because everyone loves explosions...)
jlabrasca
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There is no reason that anything has to be "shoved".
Watch John Beans' presentation.
Take a look at the water rocket recovery systems
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