nerobro
05-29-2002, 02:08 PM
Blowbacks are an interesting subject. I'm aware that AGD has done some research on them, and actually passed up the idea for a gun that was "always cocked" as it was explained in the video ;-)
I've seen a lot of blowbacks, many work well, but their preformance is somewhat lacking. The bigger and heavier the hammer and bolt are in a blowback the more reliable they seem to be.
For example, tippmans have a reputation for reliability. They all have large hammers. The VM-68, where the manufacturer never reccomneded the use of oil, would run forever in a condition such as that.
Now this brings up another point. We have seen what's in common between the guns that are supremely reliable. What about the guns that have some preformance to boot. This basicly brings us to the F1 style blowbacks. A scaled up version of which has become the ubiquitous spyder style blowback. That is the subject I want to get to.
Recently there's been a surge in the popularity of electroframe spyder style blowbacks. For quite a while electroframes have been available. PMI was the first to start, by selling e-pirhana's.. but for some reason those guns have never taken off. in the last 8-10 months a few other guns have come to market. Most impresively the Dragun black series of guns from M3. Kingman has also released their own set of electroblowbacks. (amg, e99, flash)
Now these guns are finally getting some respect. Matching an electrotrigger to a gun that most people considdered a toy is making them into pretty serious contenders. In my experience, they seem to have a lot going for them.
First their velocity consistancy is first class, my usual is seeing a 5fps or less range. (275-280fps) Being a blowback means they can somewhat self regulate the velocity even over varying pressure. My 5fps range was with just an antisiphon tube.
Now if you want to talk efficancy, I was gettnig 65shots/oz out of my stock gutted spyder. That seems to be about normal for a spyder. With the kit fom AKALMP you can pull as much as 130shots/oz out of a spyder. That is better than what AKA's parts will get out of a cocker.. by a signifigant margin.
The number I heard, and have been sticking by, is the the gun will cycle 40bps. Now, that seems a little funny due to the fact i've yet to see a reg that can keep up with that. *thinks a bit* I have a pair fo 20lb co2 tanks in teh basement.. maybe that would let us get a good reading of the free cyclic rate of a spyder. This brings us to the problem 314159 and I have been having with his pirhana.....
The pirhana works fine single shot. It's a fatty striker gun, so it's recriprocating weight is higher than a dragun ( a slim striker gun ). From experience the fatty sriker guns cycle better. The slim striker guns are more sensitive to contamination, and funny valves in the gun. They also seem to be slightly more efficant.
Well now that I've brain dumped.... The final questions are... What can be done to improve the preformance of blowback spyder style guns. And what can be done to assure their reliability.
314159 has issues when we crank the rof to 20bps. the gun fires a few shots ok then it beats down. It seems like the gun is getting starved. We are using a screw in n2 system. (I'm not sure of the brand at the moment) It feels a lot like the problem i had saturday with my dragun on a 9oz co2 tank. I got off 10-15 shots VERY VERY fast, then it beat down.
Well there's an idea, a tapered valvestem to assure enough of a recock jet, and to make the valve opening greater. As was discussed in the cocker mROF thread, maybe we could simulate palladins stacked valvesprings with a staged valvestem.
I've seen a lot of blowbacks, many work well, but their preformance is somewhat lacking. The bigger and heavier the hammer and bolt are in a blowback the more reliable they seem to be.
For example, tippmans have a reputation for reliability. They all have large hammers. The VM-68, where the manufacturer never reccomneded the use of oil, would run forever in a condition such as that.
Now this brings up another point. We have seen what's in common between the guns that are supremely reliable. What about the guns that have some preformance to boot. This basicly brings us to the F1 style blowbacks. A scaled up version of which has become the ubiquitous spyder style blowback. That is the subject I want to get to.
Recently there's been a surge in the popularity of electroframe spyder style blowbacks. For quite a while electroframes have been available. PMI was the first to start, by selling e-pirhana's.. but for some reason those guns have never taken off. in the last 8-10 months a few other guns have come to market. Most impresively the Dragun black series of guns from M3. Kingman has also released their own set of electroblowbacks. (amg, e99, flash)
Now these guns are finally getting some respect. Matching an electrotrigger to a gun that most people considdered a toy is making them into pretty serious contenders. In my experience, they seem to have a lot going for them.
First their velocity consistancy is first class, my usual is seeing a 5fps or less range. (275-280fps) Being a blowback means they can somewhat self regulate the velocity even over varying pressure. My 5fps range was with just an antisiphon tube.
Now if you want to talk efficancy, I was gettnig 65shots/oz out of my stock gutted spyder. That seems to be about normal for a spyder. With the kit fom AKALMP you can pull as much as 130shots/oz out of a spyder. That is better than what AKA's parts will get out of a cocker.. by a signifigant margin.
The number I heard, and have been sticking by, is the the gun will cycle 40bps. Now, that seems a little funny due to the fact i've yet to see a reg that can keep up with that. *thinks a bit* I have a pair fo 20lb co2 tanks in teh basement.. maybe that would let us get a good reading of the free cyclic rate of a spyder. This brings us to the problem 314159 and I have been having with his pirhana.....
The pirhana works fine single shot. It's a fatty striker gun, so it's recriprocating weight is higher than a dragun ( a slim striker gun ). From experience the fatty sriker guns cycle better. The slim striker guns are more sensitive to contamination, and funny valves in the gun. They also seem to be slightly more efficant.
Well now that I've brain dumped.... The final questions are... What can be done to improve the preformance of blowback spyder style guns. And what can be done to assure their reliability.
314159 has issues when we crank the rof to 20bps. the gun fires a few shots ok then it beats down. It seems like the gun is getting starved. We are using a screw in n2 system. (I'm not sure of the brand at the moment) It feels a lot like the problem i had saturday with my dragun on a 9oz co2 tank. I got off 10-15 shots VERY VERY fast, then it beat down.
Well there's an idea, a tapered valvestem to assure enough of a recock jet, and to make the valve opening greater. As was discussed in the cocker mROF thread, maybe we could simulate palladins stacked valvesprings with a staged valvestem.