12 replies to this topic

[UpperHand]

After the completion of my most recent homemade, I have decided that I want to build a nerf gun based off flywheels. A semi or fully automatic any other way would seem to hard to me, and I am not really interested in range as much as sheer output of foam . Now I'm not gonna say "Can one of you tell me how, so I can do it?" I know people have made this kind of blaster, but I'd like to be original. I would, however, appreciate it if someone directed me towards a good book/internet source for begenning motors that I could apply to a flywheel design. A book would be great too, considering christmas is coming up. Thanks.

-Upperhand

Edited by UpperHand, 09 December 2008 - 07:10 PM.

[slienced assassin]

You could make a auto or semi auto pump gun and then buy an eletric pump.

[Llama Boy]

Anders did this a while back. And Bpso did a turret like one too. I would say you should make it look like a M4 and somehow get a clip to go out the bottom. Like this.

[CaptainSlug]

I know people have made this kind of blaster, but I'd like to be original.

Then search.
And for the rest of your post, use google.

[UpperHand]

I know people have made this kind of blaster, but I'd like to be original.

Then search.
And for the rest of your post, use google.

Perhaps you misunderstand me. I would simply like to know where I could go to learn more about motors and such, and apply it to a flywheel design. I had trouble finding a book or something that could help me with this.

[TantumBull]

I find it incredibly hard to believe that you could not find a source that would inform you about basic electronics. You are either retarded or need to try harder. We aren't here to hand you information or even give sources of information if the topic is really easy to find. If it were something that no one knew except for a select few nerfers, then okay, but not for something as easy to find as this.

Edited by TantumBull, 09 December 2008 - 06:29 PM.

[UpperHand]

I find it incredibly hard to believe that you could not find a source that would inform you about basic electronics. You are either retarded or need to try harder. We aren't here to hand you information or even give sources of information if the topic is really easy to find. If it were something that no one knew except for a select few nerfers, then okay, but not for something as easy to find as this.

I didn't mean simple electronics, but more like motors, torque, what is a reasonable RPM, etc. I was just seeing if people have read a book like that they could reccomend. Jeez!

[TantumBull]

I find it incredibly hard to believe that you could not find a source that would inform you about basic electronics. You are either retarded or need to try harder. We aren't here to hand you information or even give sources of information if the topic is really easy to find. If it were something that no one knew except for a select few nerfers, then okay, but not for something as easy to find as this.

I didn't mean simple electronics, but more like motors, torque, what is a reasonable RPM, etc. I was just seeing if people have read a book like that they could reccomend. Jeez!

You don't have to make exact plans for the project down to how much RPM you'll need to launch a dart X amount of feet. Just fucking get a couple motors, wire them to one of those switches that will control the amount of power that can run through the circuit, experiment with different batteries, and find what works. If you stop asking for people to do stuff for you and stop trying to get everything exact ahead of time, it honestly cannot take you that long to figure out what kinds of parts you'll need and to find out how to assemble them. If for some god forsaken reason you can't do that, then go to radioshack and ask someone! You're making this way more complicated then it needs to be.

[analogkid]

As far as the build goes, you want potentiometers to control motor speed, battery clips, and 6 to 12 volt DC motors, depending on your choice of power source. If you're unsure about any of this stuff, look it up on google, or if you really can't find anything, PM me.

Also, see if you can track down a Technology teacher at your school. They probably know all about that stuff and can help you. My school even offers basic and digital electronics classes.

Edited by analogkid, 09 December 2008 - 11:05 PM.

[UpperHand]

Thanks analogkid, and yes, thank you TantumBull. I suppose I was over complicating things. I guess I will just have to do a bit more research before I head over to Radioshack or wherever. I don't want to end up asking him what a proper amount of torque would be for launching nerf darts! . Sorry about overcomplicating things, and I'm off to do some more research. No need for further posts, unless someone has a book in mind that I could learn more about motors from.

Edited by UpperHand, 09 December 2008 - 10:30 PM.

[wespelarno]

No need for further posts, unless someone has a book in mind that I could learn more about motors from.

I can't give you a book, but here is a fairly good summation of what to expect out of a motor

If you use a DC power source (batteries), there are three basic motor types

Brushed
Brushless
Coreless

In this instance you want a brushed motor as they are cheapest and will provide suitable power. Brushless are for really high rpm high power applictions (i have one that turns 42000rpm at 7.2V) and coreless won't have sufficient torque.

Once you are into brushed motors, there are a whole variety of types. I would recommend a mabuchi or silver can motor (two different names for the same thing). They are again simplest and will be least hassel in a nerf gun.

The brushes aren't replacable, so when the motor burns out it is dead. You can buy motors with replacable brushes, but again for this application it is unnesescary. And in a nerf application expect quite a few hundred hours of continous firing before you will want to replace it.

Mabucchi motors come in a variety of sizes. Here are some rough guidelines:
The number of a motor indicates its size. 540 is smaller than 550 but bigger than 380.

The bigger the motor, generally the more torque it will have. Once up to speed, anything larger than a 370 motor should be able to cope easily, as long you don't have a massive flywheel. The larger and heavir the fly whell the larger motor you will want. Anything over 540 will be absolute overkill

The rpm is controlled by the number of turns the motor has. This is how many loops of wire there are around the commutator. More loops=more resistance=lower rpm. However, lower rpm gives longer motor life. a 27 turn 540 motor will turn 20,000rpm unloaded. a 8 turn 540 motor will turn 50,000rpm unloaded (both at 7.2V)

There is a sacrifice in having higher rpm. Because there is less mass rotating around the commutator, the motor will have less torque. To compensate for this, motors come in a variety of winds. You can basically ignore this as it doesn't make a huge amount of difference.

Out of all that, this is my pick of motors.
http://www.horizonho...ProdID=LOSB0835
Powers an rc car I have and it hauls out.

If you need more power, you can increase the voltage to the motors up to about 15V before they get unhappy. They are designed to be run at 7.2 but they are robust enough to be run at higher power. Again, this will reduce motor life so "ye be warned"

Goodluck, to get a solid understanding of electric motors takes quite a bit of effort

Edited by wespelarno, 10 December 2008 - 01:59 AM.

[nerfnut23]

No need for further posts, unless someone has a book in mind that I could learn more about motors from.

I can't give you a book, but here is a fairly good summation of what to expect out of a motor

If you use a DC power source (batteries), there are three basic motor types

Brushed
Brushless
Coreless

In this instance you want a brushed motor as they are cheapest and will provide suitable power. Brushless are for really high rpm high power applictions (i have one that turns 42000rpm at 7.2V) and coreless won't have sufficient torque.

Once you are into brushed motors, there are a whole variety of types. I would recommend a mabuchi or silver can motor (two different names for the same thing). They are again simplest and will be least hassel in a nerf gun.

The brushes aren't replacable, so when the motor burns out it is dead. You can buy motors with replacable brushes, but again for this application it is unnesescary. And in a nerf application expect quite a few hundred hours of continous firing before you will want to replace it.

Mabucchi motors come in a variety of sizes. Here are some rough guidelines:
The number of a motor indicates its size. 540 is smaller than 550 but bigger than 380.

The bigger the motor, generally the more torque it will have. Once up to speed, anything larger than a 370 motor should be able to cope easily, as long you don't have a massive flywheel. The larger and heavir the fly whell the larger motor you will want. Anything over 540 will be absolute overkill

The rpm is controlled by the number of turns the motor has. This is how many loops of wire there are around the commutator. More loops=more resistance=lower rpm. However, lower rpm gives longer motor life. a 27 turn 540 motor will turn 20,000rpm unloaded. a 8 turn 540 motor will turn 50,000rpm unloaded (both at 7.2V)

There is a sacrifice in having higher rpm. Because there is less mass rotating around the commutator, the motor will have less torque. To compensate for this, motors come in a variety of winds. You can basically ignore this as it doesn't make a huge amount of difference.

Out of all that, this is my pick of motors.

Powers an rc car I have and it hauls out.

If you need more power, you can increase the voltage to the motors up to about 15V before they get unhappy. They are designed to be run at 7.2 but they are robust enough to be run at higher power. Again, this will reduce motor life so "ye be warned"

Goodluck, to get a solid understanding of electric motors takes quite a bit of effort

Well said. How an electric motor works:

Click here for electric motor function.

And for flywheel mechanisms, use a gearbox that starts as low RPM and high torque, and for the end, high RPM and low torque. Once it is complete, I will post pics.

Edited by nerfnut23, 15 December 2008 - 10:08 PM.

[Darthrambo]

Consider the flywheel size as well. The velocity will increase proportionally to the radius, as long as the RPM remains constant. (v=pi x 2r x rpm)

Also consider the fact that if you just get a motor attaching a flywheel that isn't already the correct size to accept the motor will be VERY hard to get totally centered, and you may be better off finding ones that are already attached.