Solenoid airsoft gun

GimpyJoe, Wed Mar 29 2006, 03:01PM

Would it be possible to make an electronic airsoft rifle by using a solenoid and capacitor to move the piston instead of using the spring? What changes would have to be made to a coilgun solenoid to make it suitable for pulling efficiently instead of switched reluctance firing? If this works, it seems like a viable alternative power source for airsoft sniper rifles and the like.
Re: Solenoid airsoft gun
Bjørn, Wed Mar 29 2006, 03:59PM

It would not be very practical, the efficiency would be very low and you would need to lug around a number of large capacitors. A better solution would be a small compressor that is connected to a reservoir.

For highest efficiency the air would work on the projectile directly. For high energy and supersonic capability the air must work on the piston and it will all become fairly complicated.
Re: Solenoid airsoft gun
GimpyJoe, Wed Mar 29 2006, 04:43PM

Here's what I had in mind. Even with poor efficiency I think this might still work with reasonably sized capacitors, since the projectile energy in airsoft is about 1.5j max. Here's what I had in mind. The charging circut is not shown.
Re: Solenoid airsoft gun
rupidust, Wed Mar 29 2006, 10:38PM

Yes, the air from the piston working directly on the projectile load would make it feasible. The piston can "compress" the air medium by funnel action thereby converting a not so fast piston into a very fast airflow. Forming the optimum fluid dynamics of air speed in to air speed out exit aperture is the key just as correct coil, load, swich combination of electromagnetic means. This permits fast airflow up in the 100+ m/s for airsoft. But the question for you to answer once you have built a device is, "How many cap Joules did it take to be done".

This device may or may not use air but you get the idea. http://www.em-gun.ru/

Re: Solenoid airsoft gun
Bjørn, Wed Mar 29 2006, 11:30PM

If we assume 3% efficiency in both steps then we need 1.5 * 33.3 * 33.3 = 1666 Joule worth of capacitors.
Re: Solenoid airsoft gun
rupidust, Sat Apr 01 2006, 02:42AM

Re: Solenoid airsoft gun
Bjørn, Sat Apr 01 2006, 04:03AM

The numbers came from a common efficiency for simple coilguns and a memory of having to pull quite hard over a significant distance to compress a spring on a rifle that may have been of a different type and less efficient.
Re: Solenoid airsoft gun
rupidust, Thu Apr 13 2006, 08:58AM

Re: Solenoid airsoft gun
GimpyJoe, Thu Apr 13 2006, 03:40PM

Cool! I have a collection of parts from an airsoft m16, so I'm in the process of fooling with this too. Thanks for trying it out!
Re: Solenoid airsoft gun
Evgenij, Sat Apr 15 2006, 07:40AM

rupidust wrote ...

This device may or may not use air but you get the idea. http://www.em-gun.ru/

Cautiously. This project mystification and a deceit. Do not pay!
Re: Solenoid airsoft gun
Electroholic, Mon Apr 17 2006, 12:18AM

Just a thought, an inductance type like a disk launcher would be a lot more efficient for pumping air, right?
Re: Solenoid airsoft gun
Bjørn, Mon Apr 17 2006, 06:37AM

Where did that come from? Are you saying there is a good probability of requiring 1.6KJ of capacitors to speed an airsoft BB to 1.5J 123m/s? via air compressed from an cg soleniod piston?
I recall now that it used a lead projectile and reached 220 m/s so the efficiency was significntly higher. If we assume an efficiency of 20% in the last step we get 1.5*33.3*5 = 250 J.
Re: Solenoid airsoft gun
Dr. Shark, Mon Apr 17 2006, 02:28PM

Electroholic wrote ...

Just a thought, an inductance type like a disk launcher would be a lot more efficient for pumping air, right?

Thats a very interesting though. Disc launchers are very efficient, and they would be extremely good at moving a plunger. Since even major research facitlitys use this plunger principle (they call it "gas gun"), this should be good for some insane projectile velocitys.
I think we should suggest Pulslaser to build it, if anyone can do it, he can!