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#306973 First fully auto lego Nerf gun: Raptor CS-35

Posted by wespelarno on 05 November 2011 - 08:47 AM in Homemades

This is the coolest homemade I have seen in a long time. Well done dude.

I assume you could alter the rate of fire by fiddling with the gear of the advancing arm?



#285860 Nerf Stampede - Voltage Increase / Rof & Firing Tests

Posted by wespelarno on 22 September 2010 - 02:43 AM in Modifications

Question: What about this: (Laptop Battery) Toshiba SATELLITE PRO A210-16V 9 Cell

- Type: Li ion
- Capacity: 7200mah
- Cell: 9

Is this possible?

or this?


Avoid those. They have high enough capacity and high enough voltage, but will seriously not appreciate being run around with nor the stop-start use that Nerf will put them through. I've seen a guy use a set of something similair in a RC car and it melted down. I doubt they would melt as you are using them at a fairly low amp draw, but you will get a really short lifespan out of them. In general avoid cheapo batteries, especially LiOn or lithium Ion as you really get what you pay for with batteries in terms of run-time, average voltage and recharge life.

Anybody chasing batteries, check out Towerhobbies.com for quality cells. Cells can be bought individually or pre wrapped and all are designed for rougher and higher amp use than we will put them through.

Pick a capacity and voltage you desire and make sure to use the same type of batteries if more than one is being used in a circuit.



#285138 Nerf Stampede - Voltage Increase / Rof & Firing Tests

Posted by wespelarno on 09 September 2010 - 02:35 AM in Modifications

Also, thanks for the new info regarding voltage. I wonder if it would work well to get a 9.6v pack connected in series with a 7.2v pack, for a total of 16.8v, which is right around your recommendation. I was considering getting another 9.6v pack in series, but that would be closer to 20v and probably too fast for the darts to load reliably.


Just a heads up to anyone considering this, mixing batteries is generally a BAD idea. Especially true for rechargeables. Try and keep them the same (Voltage, Amp-Hours etc.). When you are using mismatched batteries, they can drain at different rates and can "empty" at different times. This can confuse the sensors built into the batteries and cause all kinds of unpleasant surprises. They most likely aren't going to blow up, but it's better to be safe than sorry.

Go higher than what you want with your voltages, then bring it down to where you want in your circuit.

Can anyone with a Multimeter check the current draw on the stampede? I'm a bit curious.


The most likely event is that the battery that is emptying at the faster rate will discharge completely and enter a state of deep discharge. For NiCD batteries this is fine, but NiMH batteries will basically never work again properly, they will loose both peak voltage and capacity. LiPo/LiON/LiMn also won't appreciate this and are more likely to go up in a bang.



#284834 Nerf Stampede - Voltage Increase / Rof & Firing Tests

Posted by wespelarno on 05 September 2010 - 10:33 AM in Modifications

The mabuchi type silver can motors are usually fine up to 25V, although they prefer continous use as opposed to stop-start use which tends to lead to arc-ing on comm in the motor. If damage occurs, it wouldn't be too hard to find a replacement motor at an electrical store, and it shouldn't cost more than 7 or 8 bucks.

The use from nerf won't generate enough heat to damage the motor-I would be more concerned about some of the connections and circuitry giving up at 15-16V.

14.4V can be achieved nicely by running two RC car batteries in series, and cheapo (3000mAh) NiMh batteries should give literally hours of firing use without noticeable drop in voltage.



#281121 Nerf Stampede - Reviews & Internals Guide

Posted by wespelarno on 24 July 2010 - 06:43 AM in General Nerf

keeping this thing powered through a season of nerf is going to be a real pain.


RC car batteries-it will take about 9 seconds of sustained use for them to pay off.



#259809 Can Your Recon Do This?

Posted by wespelarno on 26 December 2009 - 10:26 AM in Off Topic

Is it really necessary to have EMP capabilities on a recon?


Absolutely. If it can't be made to fire any useful distance, it may as well have emp capabilities and an mp3 player built into it.



#220392 What Guns Do You Use?

Posted by wespelarno on 28 March 2009 - 10:40 PM in General Nerf

I mostly war in our house with friends and siblings, playing a forcings back style game. My usualy set up is a magstrike as primary and sawed off doubleshot as a back up. Having the high rate of fire is advantageous for the rules we play, and the two shots from the double shot are better than a single shot from a nightfinder in this context. When it is working, I use my homemade shotgun for clearing corridors (7 shots at once from a spring gun, plus interchangeable heads for an instant 7 shot reload)



#215470 New Raider CS-35 Speculation Thread

Posted by wespelarno on 27 February 2009 - 11:49 PM in General Nerf

Well, if it is coming out late July in Europe, Australia should see it before the next olympics. Maybe



#214396 Snowskate Help

Posted by wespelarno on 23 February 2009 - 06:38 AM in Off Topic

Compact the snow really thoroughly. Using the shovel, throw down a single shovel load of snow and compact by hitting with the shovel. Then step on it evenly. Don't stomp, just walk on it. Or even better, get a friend. Have one of you shovel snow and the other walk around continuosly. A tiny bit of water may help, but don't use too much or the snow will be soft and mushy until it refreezes

Build the ramp significantly bigger than you want the final jump to be. And for the moment don't worry about shaping it. You will need a lot of snow

Once you have a large, shapeless lump of rock hard snow it is time to shape the ramp. Use a shovel to carve the face of the jump into a beautiful, UNIFORM, curve. If the curve is jerky or sudden, you lose all your speed and will be thrown into the air in weird ways. So make sure you carve from the top down in a perfectly round curve. Leave it over night so it has time to set. This will leave you with a jump that will work perfectly and won't blow away.



#212372 Do You Remember?

Posted by wespelarno on 15 February 2009 - 04:55 AM in General Nerf

Powerclip. It was used almost exclusively for defending my room from my younger brother. I learnt to change clips and pump 1 handed so I could continue my current activity whilsts holding him off. Since then it has had ar removed, tank banded/tired, overpressure valve plugged and a few repairs. And it still functions as the first line of defence for my room. It is now teamed with a magstrike as main artillery and nightfinder, maverick, doubleshot and rapid fire rifle (that has completely custom internals) as backups.



#210773 Weird Magstrike

Posted by wespelarno on 09 February 2009 - 01:52 AM in General Nerf

I bought the old magstrike approximately a year ago, neither of the two purchased had the whole you guys found. Neither did the powerclip i bought before that.



#206207 I'm Looking For...

Posted by wespelarno on 25 January 2009 - 12:23 PM in General Nerf

And what if then, you learn that you could have done all the same things for maybe $45, by using sealed lead-acid (SLA) batteries? They don't have any of the problems claimed a few posts back, often cost less than ten percent as much, and the gear for charging them is cheaper, too.


The guy who runs my local hobby store was the one who explained the stated issues with lead acid batteries to me. And I have seen a lead acid battery die from being inverted whilst at the local RC track. That said, if Lead acid batteries are available that do not have the issues i mentionted then that is a good way to go. When I asked the hobby store owner he simply said they didn't exist. Otherwise, I stand corrected.



#206134 I'm Looking For...

Posted by wespelarno on 25 January 2009 - 03:54 AM in General Nerf

Considering the only thing I have to put my money on at the moment is video games and nerf guns, I'll probably be able to afford the better batteries. I'd prefer something of more quality anyway.

I could probably get something together.

Alright, I assume I can get those at a hardware store. And yes I can solder. I'm not great ATM, but I know people who are alot better, so if it gets over my head, I can go there.

I'm not hugely fast anyway. So I can deal with it being heavy.

The ten pounds will likely be connected by a gear system.

If I need one anyway, that would probably be good. Allow me to save some cost here.


Ok. Lipos are about $100 each for a 5000MaH battery that runs at 7.2V. So you are maybe looking at $300, $400 of batteries? NiMh would be about half that. Another thought I had. LiPo batteries tend to go up like a quarter stick if abused, overheated, punctured etc. In an application where they could concievably be landed on and punctured if you fall, or overheat if used on a hot day and there isn't much battery ventilation, NiMh batteries might be preferable. Unless you design a battery holder that offers puncture protection and very good ventilation.

Now. Onto cooling. Those motors will generate a lot of heat during continuos usage, maybe more so than normal because they will be under a lot of stress. So you will need to keep them cool. I would recommend CPU fans. If you can, have the motor situated in a a peice of PVC pipe that leaves about 4cm on either side of the motor can. Then attach a CPU fan at the end of the pipe. so it creates a wind tunnel around the motor. A design like this would keep the motor nice and cool. You will need to use a motor plate (That screws directly to the front of the motor) to hold the motor in place as opposed to a metal bracket. You may need something similair for the batteries. Look into heat sinks for the motor as well. That will be a cheap way to aid cooling. I've had motors heat up so much the solder holding the wires together melted. Plus the heat damages motors and batteries and reduces their useful like span. I would also drill ventilation holes into any case you make to allow more cool air into the components.

If you want an adjustable rate of fire, a resistor could be soldered in series with the firing mech to allow you to conserve ammo if needed.

Deans plugs are available from hobby stores. Just ask for deans ultra plugs. The store owners will know what you mean. I would use them for all battery connections. The motors should be hard wired (directly soldered to the wires) to give less resistance and one less point for stuff to go wrong.



#205812 I'm Looking For...

Posted by wespelarno on 23 January 2009 - 10:40 PM in General Nerf

If you are planning on moving with it you can't use a lead acid battry. The way most are set up, if they are inverted or tipped an an angle apart from vertical all the chemicals will mix and at best kill the battery, at worst melt down in your hands. If it is a moving project you will need to look in alternate battery sources which will be expensive in comparison. Because of the mass you are moving it will need a battry with a high MaH rating. I would recommend numerous LiPo batteries soldered in parallel so that six 5,000MaH batteries will act as one 30,000MaH battery. The other advantage is that LiPo batteries are light compared to lead acid batteries. You could use NiMH cells which will be cheaper than LiPo cells but weigh more and have a lower MaH rating so you will need more of them. You will also need chargers which are more expensive than lead acid chargers due to LiPo cells being more sensitive. So, Overall, LiPo batteries are lighter, higher MaH and more expensive. NiMH, heavier, lower MaH but much cheaper. I can give more details or cells I'd recommend if you want. If you can afford it, LiPo's would be better.

Other considerations:
You will also need to rig up something to hold all the cells in place.

Get your hands on some Deans ultra plugs. They are connectors that have very low resistance (they actually have less resistance thant he equivalent length of 12 gauge copper wire) so won't melt under the load they will be under. Normal tamiya connectors won't last long and would melt. I assume you know how to sodler?

I'm not doubting you can lift an oak log, but can you run round and duck behind cover carrying one? This much weight will be cumbersome to manouver with. I have no idea how fast you intend on moving with it, but this project is likely to weight as much as a pallet of bricks.

My question regarding the 10 pounds being centered or not. If it is attatched centrally to the motor's rotor, it won't need balancing and it will only be 10 pounds for the motor to spin. If it is attatched to an arm that spins around the rotor, it will need an equal weight on the opossite side to balance it (doubling the weight on the motor) and due mechanical advantage (the weight turns a larger circle when on an arm, and therefore moves faster) will require a much more powerful motor. I've got formulas to show the proportional increase in force for a greater arm length which I can dig out if you need. From memory, increase arm length by a factor x, the force required increases by a factor of x^2 (x squared)

Another thought towards motors is a gearbox that allows you to connect to motors to a central spur gear, giving you two motors to power it with. This will allow you to buy two smaller and more likely cheap motors as opposed to one huge and likely expensive motor.



#205591 I'm Looking For...

Posted by wespelarno on 23 January 2009 - 04:11 AM in General Nerf

I didn't expect it to be cheap when I made the design. So the cost won't really bother me.

Thanks for the ideas. I'll look into them.


I take it this will be a stationary project, ie not one you intend on moving with? Cause a motor and battery set up this large, plus 10 pounds of weight will be really heavy.

If so, I would look into a hobby size lead acid battery. Cheap, easy to charge and maintain a very steady 12 volts, but can not be used for moving projects.

Also, the 10 pounds you are spinning, how big a radius are you spinning it on, or will it be centered around the motor armature?

Motors, you will definately require a gearbox. With absolutely huge reduction. Electric motors excel at high RPM and aren't so great at massive torque. I would be surprised if you could obtain a motor than span much less than 5,000rpm at full power so you are looking at a lot or reduction. I would be looking into cordless drill motors (900 size from memory). Even they are likely to struggle at this effort. Maybe a lathe motor? Bear in mind most lathe motors are 120V. I

would seriously suggest going to a store that specialises in power tools and talk to them. They will quite likely be able to order replacement parts for the tools they stock so you should be able to pick up motors and gearbox (for a price). If you are lucky they might have some trashed tools out back you can stip for parts. Sorry to say I don't have much experience with motors laying out this type of power or of this size.



#205278 I'm Looking For...

Posted by wespelarno on 21 January 2009 - 09:54 PM in General Nerf

Mind if I PM you asking for a bit of advice? I'm looking for something with a very specific purpose.


Sure. Give me a buzz anytime. I'll see what I can do to help. If it is a very specific application I will need details about what you intend to use it for, size restrictions (if any) and any other stuff you consider relevant.



#205103 I'm Looking For...

Posted by wespelarno on 21 January 2009 - 03:41 AM in General Nerf

A couple items that I'm planning on using on a project of mine. Does anybody know where I can get them?

I'm looking for a simple battery operated motor, Preferably a rotary action motor. With a decent deal of power behind it.

And a old style film canister. Or something similar.

I'd like something cheap but as long as it gets the job done, I could deal with price.


Decent amount of power depens on application. Explain what you intend on doing with the the motor and I can suggest a motor to suit your needs.

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 use 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.

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.

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



#202041 Bmx

Posted by wespelarno on 09 January 2009 - 06:26 AM in Off Topic

I don't BMX but I Downhill, freeride, Dirt Jump and 4X.

I ride a 2006 Kona Stab deluxe (8 inches suspensiont travel front and rear):
Marzochi 888 Bombers
Fox DHX3
Hayes HFX 9
Truvatic Boxguide+bashring
Sunrims
Shimano running gear
Heavy as can be (20kg) but stable, flies very nicely and tough as hell. Has had all kinds of abuse thrown at it and I am yet to break anything.

Rokor, what are you riding?


I have a set of Dirt jumps I built and maintain out in the bush. Table tops, berms, doubles, pumps, stepdowns etc. About 20 features in total, all of which are a heap of fun.

Kind of frustrating but the BMX culture near me has attracted some right wankers. Not throwing down a stereotype, but all the times I have found our jumps vandalised or damaged it has been BMXer's. Found out either by talking to them when I got there, not mentioning they were my jumps or actually caught them in the act. They then have the arrogance to complain that stuff at the jumps isn't perfect or needs maintaining.

Have any of the BMXer's here ridden 4X? Same idea is BMX racing but the track has a greater elevation change, has more lines/overtaking opportunities and only has 4 racers instead of 8. It is ridden on 26" wheels, usually hardtail or short travel duelly.



#201482 Other Projects

Posted by wespelarno on 06 January 2009 - 06:06 PM in Off Topic

I used to race RC cars. It started as a stock electric duratrax evader ST, top speed about 18mph

Since then:

Custom brass roll cage/tube body
Novak 5200KV brushless motor
Team Orion battery pack
Monster Moab All terrain tires
Ace hobbies steering servo
Futaba 3PM remote
Carbide differential and thrust balls
Constant velocity drive shafts
Custom front bumper
Venom speed meter
Front and rear sway bars for racing
Different weight shock oil and heavier springs for improved suspension movement
Changed gearing to allow for increased diamter of moab tires

Top speed now 50mph and handling way better. Also has increased run times and due to the roll cage is near indestructable.

Trying to obtain photos but my computer is being real dodgy with the internet



#198242 500 Rpm Vulcan

Posted by wespelarno on 23 December 2008 - 01:58 AM in Modifications

To fix the burning motors buy a set of hobby grade motors. Mabuchi motors are designed to take that much current with ease so it isn't an issue and are available in so many sizes that one will fit. Or drop the voltage back to 7.2V and put in a larger/better quality motor (cheap and easy. 540 size motors would be rediculously fast)

Gears, check out towerhobbies. There are numerous hobby quality radiocontrol cars (fast ones, top at out at >60mph) so the correct size and pitch could probably be found. And even the plastic ones will have no issues with the load, the ones in my RC car have withstood 50,000 rpm and propel a 2kg vehicle to 40mph. Alternatively, work out the correct gear ratio and use different size gears that will produce the same or simliar ratio. This will require adjucting spacing. If a bigger motor is used, the gear ration can be increased as the larger motor will have more torque.

For correct spacing check out motor mounts for said RC cars. They are adjustable and hold motors in place at way higher loads and vibration than the vulcan can produce. Alternatively, look at the motor mounts and cut you own from thick brass sheet or aluminium. I've done it before and it isn't hard.

A sustainable version of this mod would be possible. I would try it but it is impossible to get you hands on a vulcan in australia. The local store had three in stock for 85 bucks a peice. Came back the next day and they were gone.



#196723 Matarials Of Mystery?

Posted by wespelarno on 17 December 2008 - 08:58 AM in General Nerf

In australia I have found 15mm PVC that was larger than 20mm PVC. Both were approximately 17mm. We tried fitting it to couplers etc and there was no hope of a real fit. If could achieve better manufacturing tolerances with a decent hobby knife and a block of raw pastic. You guys in the USA have it so good with modding materials. Actually, one benefit to this horrible production tolerance is the occasionaly piece of metric pvc that fits imperial measurement darts perfectly.



#196049 Australian Nerfer's List

Posted by wespelarno on 14 December 2008 - 07:18 AM in General Nerf

Hey, I'm in the ACT.



#195142 Electronics/motors

Posted by wespelarno on 10 December 2008 - 01:57 AM in Homemades

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



#193406 Big Snap Bow Made Into Nerf Shotgun

Posted by wespelarno on 01 December 2008 - 10:18 PM in Homemades

Wait, are you asking if someone else can design/make this thing for you to then buy off of them?


I intend on making it myself, i just wanted to see if it was feasible before I start hunting round for parts etc.

@ The inventor guy, the local hardware and plumbing stores sell very few pvc sizes and those they do sell are often 3-4mm from what is advertised. Getting my hands on materials for sounds like would have been a failed project would have sucked


So from what I gather, a springer won't shift the air volume required to launch that many darts?

the BBBB isn't available that I have seen. My local toys r us has the titan but it is $80. Plus a homemade is more fun.



#193380 Big Snap Bow Made Into Nerf Shotgun

Posted by wespelarno on 01 December 2008 - 09:36 PM in Homemades

I am looking at making a shotgun that will fire 8 darts simultaneously. I war inside and want it for clearing corridors. I don't need huge range, 40'-50' would more than surfice as that is more than the length of most of the rooms. Spring is preferable due to faster reload times. So, the larger snap variants come to mind as an ideal solution as they have a large plunger and put out a large volume of air (someone quoted 25ci). Is that sufficient air to push 8 darts 50'? If not, would any other spring based homemade be better?

I can make the shotgun head and adaptors etc with ease

Before anyone says "try it and see", I live in Australia and materials are very hard to come by so I don't want to throw a whole load of difficult to obtain resources into what could potentially be a project doomed from the start.

Thanks,

Wesp



#180984 Other Projects

Posted by wespelarno on 02 October 2008 - 04:34 AM in Off Topic

For power for the catapult we have two springs we bought from a hardware store. Extension springs, pulled by cables attatched to the throwing arm and mounted to the base of the catapult. We need more power, the catapult doesn't throw far enough. So we plan to keep adding springs until we can throw about 100m (bit over 100 yards)



#180756 Other Projects

Posted by wespelarno on 01 October 2008 - 07:22 AM in Off Topic

I'm currently working on a quarter scale catapult with some friends. It should be big enough to throw a watermelon by the time we finish. We are building the throwing arm and basket tomorrow, so I'll put up pics then

Otherwise, I used to race rc cars, had a brushless stadium truck which i built a brass tube roll cage for and converted into a desert truck. I also have a mini monster which sucked and a micro truck which is awesome fun, mentioned earlier by someone else a Losi micro dt

I ride mountainbikes, cross country, downhill, 4X and dirt jump. I've built my own jump set with upramps a bit under 5 foot high. Again, I'll post pics later when I get a decent one of me clearing them.

Next year I'll be buying a car so that will become my money pit. I'm coming to the USA for a year and plan on buying a camaro, then bring it back to australia with me.



#179038 How To Make A T20 Pistol

Posted by wespelarno on 23 September 2008 - 04:23 AM in Modifications

9v will not harm the gun at all. Unless I missed something, the cirucit components are switches and motors. The motors are silver can mabuchi motors and can handle up to about 20 volts long term with no ill side effects. The only loss of life will be because of how much faster it spins at 20 volts than at 4.5. The motors should degrade in about 1/4 of the time. The motor does wear out faster, but it is merely due to heavier use. And odds are it won't see enough use to wear out, something else is the gun will break first. Unless there are some circuit boards in there the extra volts won't hurt.

To the car battery guy, expect a whole variety of "interesting" side effects. To start with, the lead acid battery will be able to provide such a high amperage that the whole circuit will melt. It you put a steel bar accross the terminals of a car battery, it will weld itself to the terminals and glow red hot. Expect all the metal components to do something similair

And. If you invert or tip over a lead acid battery so that the contents spill inside the case, it dies. forever. it can't be brough back. so no sudden movements, no crouching, no jumping. Infact, I would stay still and hold it carefully lest you kill the battery.

Now. On to puncturing the cell. Not likely, but if you do everything goes wrong in a big way. 10 molar acid everywhere. Basically, if you dip your hand in 10 molar acid, all you will be able to pull out is the stump at your wrist. Your hand will be gone.

So apart from those limitations, a car battery is a fantastic idea.

If anybody wants more volts, buy some RC car batteries, 25 bucks for two rechargeable ones. Solder them in series and you have 14.4 volts of shooting goodness. And they will take forever to run flat. Any questions, send me a pm

By the way, I like the look of this. Good side arm for an indoor war.



#175553 Replacement Air Tanks

Posted by wespelarno on 06 September 2008 - 11:39 PM in Modifications

I've lost both range and rate of fire. Interesting thought though. I'll check out the seals to try fix range. And see if it somehow fixes the rate of fire



#175285 Replacement Air Tanks

Posted by wespelarno on 05 September 2008 - 10:22 PM in Modifications

I did that about a year ago, combined with rubber bands. It worked great for about 6 months. Since then there has been a steady decline in power. . I'm looking for a way to make a replacement air tank. I think adding additional tubing or bands would only perpetuate the problem and make it get worse faster.



#175275 Replacement Air Tanks

Posted by wespelarno on 05 September 2008 - 10:07 PM in Modifications

I have a nerf powerclip that isn't firing with the same vigour it used to. Slower rate of fire, reduced range etc. I've taken it apart and I think it is the air tank. The rubber looks slightly perished. So I want to make a replacement airtank. Has anybody done this succesfully? Any recommendations or things to avoid? As it stands my current plan is a pvc tank that occupies the space the fully expanded rubber tube did.

I searched and didn't find much. Before anybody says "try it and tell us how it goes", I live in Australia and nerf guns are rediculously hard to come by. I had my last one shpped from the US by a relative. As such I would prefer not to trash a nerf gun by doing something that could have been prevented.

Thanks



#175102 Splitlip's Vulcan Overhaul

Posted by wespelarno on 05 September 2008 - 03:21 AM in Modifications

I wouldn't recommend the 9.6V rechargeables

They aren't "hobby quality", they are "toy quality".

The 9.6V batteries are usually NiCd which means it has low capacity (From memory <1500 MaH) and won't maintain the 9.6V for long. They tend to spike for about 2 minutes then drop to close to 8V. They also have a cell memory so the charge capacity drops each charge and you need to discharge them completely each time.

The 7.2V batteries currently being used are propper hobby quality packs. I don't know what size packs he is using, but I would recommend a set of NiMH packs. You can pick up two 3000Mah packs for $30 from Tower hobbies. You could also look at LiPO packs or a higher capacity set of NiMH's. If you wanted 9.6 Volts you can open the packs up, pull out individual cells and solder it into whatever configuration you want. If you want more details, just ask. I can explain all.

I would also consider converting to "deans ultra plugs". The tamiya ones in the photos have a horrible connection and I've actually melted a set from the current a motor in my RC car was drawing. The deans plugs are a lossless connector that has less resistance than the equivalent length of 12gauge copper wire. you will notice a big pick up in performance.

Just whatever you do, please stay away from the 9.6V rechargeable packs. They suck.



#170205 Splitlip's Vulcan Overhaul

Posted by wespelarno on 18 August 2008 - 02:24 AM in Modifications

Generally, the rotational speed of a DC motor is proportional to the voltage applied to it, and the torque is proportional to the current.


Yes, but V=IR where
v=voltage
I=current
R=resistance

So increase in voltage gives increase in current. In a DC motor, Torque is proportional to current. But it is also proportional to the number of turns in the motor. The number of turns in the motor is inversely proportional to the current. But an increase in the number of turns of the motor gives gives a greater increase than the assosciated loss due to reduced current. This is assuming no gearing is used. Higher turn motors gives less current but way more torque, hence all the RC rock crawling guys use 55 turn lathe motors (application requires maximum torque) and the rc drag racers use 2 turn motors which allow way more current (application requring maximum rpm).



#165344 The Vulcan: Internals And Mods! New Mods Pg.9!

Posted by wespelarno on 30 July 2008 - 07:33 AM in Modifications

If you want to change the rate of fire, take my rc car componentry a step further. Buy a cheapo electronic speed controller (ESC) and a pistol grip remote. Take out all the electronics and fit the ESC, solder connections to the batteries. Cut appart the pistol grip remote. Put the throttle trigger, which is identical to a gun trigger in place of the trigger in the vulcan. House the rest of the electronics somewhere inside. Once connected up, the further you squeeze the trigger the faster it fires.

The use of an actual speed controller will restrict the voltage to 7.2, but with the power of rc car motors that shouldn't be an issue.

This could also be achieved with a variable resistor wired to the trigger, but i'm not sure how the heat generated by the resistor would go with the plastic casing. The advantage of a variable resistor is that you could use as a high a voltage as you wanted (Bar melting the case).

If you would prefer the switch to be an on/off switch as opposed to the rate of fire controller, a variable resistor could be soldered in series with the connection between trigger and motor. Turn the dial to select the rate of fire.

The above idea's would allow any rate of fire to be selected, from very slow to maximum. But if you hold the trigger in it will still keep firing, so it won't be a genuine single shot.



#164901 The Vulcan: Internals And Mods! New Mods Pg.9!

Posted by wespelarno on 28 July 2008 - 07:25 AM in Modifications

I'm not sure if this has been mentioned, but following this thread i haven't seen it. The gun relies on a motor to make it fire. The limiting factor so far has been the power of the motor. To increase this, two things can be done.

I am yet to see a clear picture of the motor inside, but odds are it is a mabucchi silver can motor. These are designed to take up to about 25V without arcing (the inside gets burnt). So, overvolt the motor, run it at a higher voltage by connecting up two or three rechrgeable battery packs from an RC car in series, giving 14.4 V/21.6V etc. The number of cells can be altered to find what works best. Experiment in steps so as to not cook the motor. And keep it lubricated, otherwise it won't be happy. If you want to go over the top, hook up a lithium polymer rechargeable (lighter weight, higher potential current draw.) You are talking 20 bucks for a reasonable NiMH battery which will last for hundreds of recharges and hundreds of hours of shooting.Should reduce weight too.
NiMH batteries: http://www3.towerhob...wti0093p?&C=CGD

Alternatively, try using a more powerful motor. If it is any vaguely standard size you can by motors that are more powerful (less turns, higher current draw) that will increase the rate of fire significantly. I have a motor for my RC car that turns 50,000 rpm. That is excessive, but something similair could be done.
Motors: http://www3.towerhob...K&MANUFACTURER=

If the motor is too fast, could a gear box be put in to reduce the RPM? This would allow extra torque to be created, improving way the chain feeds through the gun allowing full rate of fire while pulling the chain.

Some parts may need reinforcing and if there are any gears that are made of weak plastic you are very likely to strip them. But again, the gears could be replaced with ones from and RC car that are designed to take loads that will propel the car at 40mph.

Check out towerhobbies for all the supplies. I have dealt with them over many years and always had exactly what I want at the best price.

If anybody wants anymore info on the above stuff give me a buzz.

I would try it myself but I don't have access to the vulcan in australia.