soundclip of 30 bps blowback cycling (no paint yet)

[314159]

i want to see what type of results i can get with a warp....

but for testing purposes, a 10 round tube with the end chopped off, a dowel, and a rubber band, and some duct tape should suffice.

[Sinnet]

Originally posted by 314159
but for testing purposes, a 10 round tube with the end chopped off, a dowel, and a rubber band, and some duct tape should suffice.

make sure you have a very loose rubber band... that sounds a lot like a paint-masher to me

[Cristobal]

Ok, well I was curious to see what the waveform would look like, and as I figure there are other curious sorts I'll post a couple screen-shots. First up is a broad view of the whole clip.

[Cristobal]

Now, here's a zoomed-in look at the highlighted shot-string from the first pic. My first impression is that the quality of recording doesn't help the analysis -- while the vocals look pretty normal, the shooting waveforms aren't what I was expecting. Its hard to tell what's realy going on here. However, by guessing at peaks it looks like there may indeed be ~15 shots in this approximately half-second string, which is most impressive indeed!

Furthermore, at least in the middle of the section the peak amplitude is roughly consistent, which I would guess means that the velocity is consistent as well. The way the peak amplitude is higher in the middle section than at the ends is rather interesting, though, and I'm not sure what to say that signifies.

Edit: for those of you not familiar with SoundForge, the total time for the highlighted section is down in the lower-right corner and is 0.576 seconds

[Muzikman]

I for one am impressed with what PI has done. He took cheap hardware and quite a bit of electronics know how and made something that most people laugh at and make it cycle at a VERY high rate of fire. I think the more people shoot this down, the less likely you are to see more people trying things like this. I say support it, if you don't like the results, then quit reading the threads.

As for this turning into "I've been here longer than you" type pissing match, does this have any relevance? I think not.

[shartley]

Originally posted by Muzikman
I for one am impressed with what PI has done. He took cheap hardware and quite a bit of electronics know how and made something that most people laugh at and make it cycle at a VERY high rate of fire. I think the more people shoot this down, the less likely you are to see more people trying things like this. I say support it, if you don't like the results, then quit reading the threads.

As for this turning into "I've been here longer than you" type pissing match, does this have any relevance? I think not.

I agree... but I suggest people actually READ what people wrote and WHEN (look at the order). My initial comments could have been easily ignored by the author of this thread.

I would advise people not making this into a personal issue.

[314159]

oh, the tank is a 2 year old 114 ci 3k crossfire screw in, this is not being run off of a scuba tank at 850 psi or anything like that. it is not one of the new "high flow" ones.

(a little side note: this used to be a friends tank, he acidentally ripped out the macroline fittings from the tank, it flew around and put 2 gashes in my back.)

[FutureMagOwner]

but i like pissing matches

[Butterfingers]

Yes the airsystem is definately your problem.

You need to find a higher flowing airsource before you can even consider sustaining a ROF at 30 bps.

Darn, I need to find don so I can re-upload that file and bring the analyze this thread back to life

[Cristobal]

If you're actually doing what it looks like you are I'm quite impressed -- particularly, as has been pointed out, for the relatively little out-of-pocket expense. When you get it all working fully, I would suggest a higher-quality recording, as this one does leave some doubt as to what exactly the marker is doing.

Also, I have a question: Maybe this is obvious and I'm just missing something because I'm not an expert when it comes to tweaking blow-backs, but I'm curious how you know that the sear is latching each cycle.

[mercury]

I must also say that I'm quite impressed and hopefully I'm allowed to say that being such a new member and all. Keep on truckin'.

[314159]

Originally posted by Cristobal
Also, I have a question: Maybe this is obvious and I'm just missing something because I'm not an expert when it comes to tweaking blow-backs, but I'm curious how you know that the sear is latching each cycle.

i timed the time it took the marker to do 1 cycle, it was 20 milliseconds. so if i held the sear continously down, it should cycle at 50 shots/second. i might just do that with the rest of the tank.

Originally posted by Butterfingers
Yes the airsystem is definately your problem.

You need to find a higher flowing airsource before you can even consider sustaining a ROF at 30 bps.

i don't think so, because when the marker stops firing at the end of each string, the bolt is in the back position resting on the sear. i think that i can get past that problem by taking the sloppiness out of the sear.

[314159]

dragun black, cycling no electronics, sear held down

http://www.speakeasy.org/~aaronw/SearDown.mp3

note: i stoped the marker firing at the end of the string

[Butterfingers]

how do you know its not a half cycle.

Even if cycle time is 20 MS dosent mean it is completing a full cycle. The marker could fail to return to that position due to the limatations at which the valve system can flow air.

[314159]

this is the way i obtained the number 20ms.

i took a push button (single pole single throw, momentary, normally open) and took one lead connected it to +5v from my power supply. i connected the ground of the power supply to the ground of my storage ocilloscope. i connected the probe of the ocilloscope to the other lead of the push button. now when i press the button, you can see the line on the scope go from 0v to 5v. i positioned the switch on the marker (held in place by a lot of electrical tape) so that when the knob on the bolt was cocked back, it would press the button. when i fired the marker, it would let go of the button, and press it again when it went to recock. the time that the button was not pressed was 20 milli seconds. (measured on the storage scope)