Nerf Vulcan Repair and Modification

I purchased a Nerf Vulcan some time ago and was disappointed in the rate of fire.  From the factory it chugged out a bit more than one round per second, or about 20 seconds to run through a 25 round clip.  The battery pack is 6 D cell batteries for a total of 9 volts.  I figured the motor should be able to handle more voltage, so I grabbed a couple VEX 9.6V batteries and wired them up.  Everything went great until I reached 4 batteries, 38 Volts.  The rate of fire was impressive as this video shows.  It emptied the clip in about 3 seconds, twice.  You can see how well the motor handled it below.  The brushes came unglued, snagged the windings on the rotor, and made a general mess.

The motor itself is a standard size and shape toy motor with no markings.  Just over an inch in diameter, and 1 1/4 inch long.  Unfortunately in this state I had no way of determining any of its characteristics.  I tried guessing the RPM by assembling part of the old motor in place and spinning the rotor with a pair of vice grips.  That got old and the gear kept slipping, so I resorted in trial and error.

The first batch of motors came from The Electronic Goldmine, but unfortunately while they fit fine, they did not have the power or speed I needed.  The best motor in that batch fired the gun at near the stock rate with 2x the stock voltage.

Second try was a success.  I ordered a handful of motors from American Science and Surplus.  The fastest of the motors runs at 13.5k RPM (at 12V) and will fire the gun at 4 rounds/sec at 27V.  A 60 second test firing indicates the motor and the gun can handle this rate.  The motor didn't heat up or smell funny after the test.

If you are looking for the motor, it is a Molon hobby motor rated at 6-12 VDC, at 280ma for 13.5k RPM.  AS&S has it here: Hobby Motors

The only problem so far is that the motor is about 1/8 inch too long to fit comfortably in the gun.  I'll need to use some longer screws to secure the orange top to the plastic standoffs, and Dremel out a little of the plastic to make it fit.  I'll post more pictures and video when I get it put back together and shooting.

See also:

Hobby Motors at American Science and Surplus
Nerf Vulcan set on Flickr

Update:
This motor should be a close replacement, although probably a little too big around.
http://www.sciplus.com/singleItem.cfm/terms/13587

24 thoughts on “Nerf Vulcan Repair and Modification

  1. Helpful info, but the site no longer carries the motor you talk about, could you possibly give us a model number or something?

  2. I’m not sure what you mean by specific.

    It’s really easy, just open the case, remove the old motor, put the new one in its place, solder the wires to the new one.

  3. They still offer the motor- but it comes as a combo with another motor for $3.95.

    http://www.sciplus.com/recommend.cfm/recommendid/11675

    Standard shipping for up to $15 is $5.95 (all US dollars)

    How much does it cost to get 27 volts inside the gun?

    Also, has this thing lasted? The motor still works?

    My son is 11. He’s not interested in ANYTHING in terms of building or science or engineering- but he will take apart a nerf gun to improve it. So I’m willing to invest a bit.

    But my hunch is that you’re using LiPo cells, and I can just imagine the fire we’ll end up with while charging. And a “safe” charger is pricey, isn’t it?

  4. Hi Anton, I’m in need of a replacement motor myself after burning out the stock one. While I’m fine with a Molon CMO-1237/Mabuchi RS-385SH, I’d like to explore other options.

    I read your comments in the link to the Youtube video you uploaded, where you said you’re looking into finding a brushless motor alternative for the mod. Could you briefly explain what a brushless motor is, what are its benefits to brushed motors (which I presume the Nerf stock, Molon 1237 and Mabuchi RS-385 are), and what are available brushless motors that are compatible with the Vulcan?

    I’m looking to widen my options largely due to living in the Philippines, where hobby stores are few and far between, where toy motors are likely to not be available, and where shipping from anywhere will be too expensive.

    Thank you very much!

  5. how do u install the motor to it and for some reason the wheel on my vulcan(the one that moves one dart to another holder) always jams when i use it, could u give me some help?

    Also how much did the motor cost and how many do

  6. The cost of the motor will depend on where you get it and which one you got. The 6 that I tried were all about $5 each. Look at surplus stores online and Google for the part numbers that I listed above for more info.

    If you are mechanically adept then you can figure out how to replace the motor just by taking the gun apart. If you aren’t, then I can’t help you.

  7. Hey Anton,

    Have you made any improvements yet?
    When upgrading my spring to a higher load and with AR removal, my Rate of fire has dropped. Since I use 15-16 volts to stock motor.
    I plan to upgrade my spring to an even higher load and change the gears to aluminum parts, as well as the plunger, etc.

    But an even higher load spring would reduce my RoF as well…
    Would I need a motor with higher RPM in order to compensate?
    Do higher voltages usually equate to a higher degree of RPM?

    Your article was a very interesting read, thanks 😉

  8. The is a wire soldered to the motor and the computer silicon chip. Is that important? If so, what is it and how did you use it on your new motor?

  9. Hey Anton excellent work. I own two old models and two new model Vulcans, and we’re modding the newer ones. There seems to be something keeping the Motor attached to the orange plastic ring that screws it in place (the one that you slip the screws thru that you say is 1/8th of an inch to far away). I was wondering if you also had this problem and how you overcame it.

  10. @David,

    The little circuit is not needed. I suspect it provides over current protection for the motor.

    @Cheese,

    I just screwed it down snug then cut away from the case plastic so it would go back together.

  11. Hey Anton

    First – thanks for all the notes on modding the Vulcan!

    I was having a bit of trouble with the motor, but after a close examination – it looks like it’s soldered. That was a bit unexpected…

    The circuit board looks to me like it does a bit of a “ramp-up” on the voltage, based on the coil & capacitors I see (I haven’t traced the circuit to be sure though). The biggest concern I see with a faster motor is that you might shock the parts if you start it up too fast. Might not be a bad idea to add a similar circuit if you go much faster.

    As for replacements for the gears & linkages – do you have any recommendations for sources for those parts?

  12. I’m not sure on sourcing the other parts. A motor ramp might be good to protect the plastic, but I don’t think it is necessary.

    My next step is to put a much stronger motor in it and a proper motor controller. Then it would be possible to vary the speed either with an automatic ramp, or at will. It isn’t on my immediate list of things to do, but it is on the list.

  13. I am about to start modding my vulcan as a gift, im adding a stronger spring bigger/better batteries and adding a new motor, but am wondering if you knew of a way to use a knob or dial to slow or speed up the rate of fire? i know this is a old post but any help would be very much appreciated.

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