full auto firing causes gun to stop mid cycle/mosfet question

[BABU]

firing semi its 1 trigger pull and one shot/ one full cycle in the mechbox

although when i shoot on full auto, sometimes(well most of the time) as soon as i let go of the trigger, the mechbox would stop and would not complete the last shot/cycle, i could see that the piston is almost never in its full forward position and generally is half pulled back more or less

after that happens i find usually the next shot i take in semi is just "plopped" out, it does not come out with the same fps as the other shots and usually drops down pretty quick, all shots on semi after that 1st one do come out normal

what im wondering is if i install the simple mosfet unit...

http://unconventional-airsoft.com/we...roducts_id=198

if that would stop this problem??
does the simple mosfet unit make the gearbox fully finish its cycle when firing on full auto or no?? if it doesn't, is there something out there that would??

take note i do know what the simple mosfet unit is mainly for, im just wondering if this is also something that it would do for me.

thanks

[ThunderCactus]

there's one that does, but the problem your having has nothing to do with cycling, it sounds like a compression problem.
Cycles only end with your piston all the way forward, or in it's spring compressing stroke, it can't end in a forward stroke, so the only thing to explain your fps loss is a compression issue.

[BABU]

see i was sooooo confused as to why it was doing that too, cuz i figure if piston stops halfway, its stopped halway on the back stroke and even when i fire later it wuld finish pulling it back and still shoot forward full force

guess ill have to do some more testing, but im pretty sure i never had a shot come out as poorly as it does after i just switched from auto to semi, its pretty good/consistent when just shooting semi, not like that one shot after switching from auto

so by what you're telling me im guessing the simple mosfet unit would not make sure it ends at the end of a cycle...but a different mosfet would...one of the pricier trigger masters??? or maybe a different brand?

[m102404]

You've got the thinking right. Regardless of where the piston stops...it's going to have to be pulled all the way back and let go for the next shot (so theoretically the same as any other shot).

No. That mosfet will not do what you want (complete the cycle on full auto). The only systems that do that now are either custom built "one-offs", SystemA's PTW/Revolution circuits and the very very new Airsoft Systems (AS) Smart Control Unit (SCU).

***edit***
don't mix up Active Braking (AB) MOSFET units with what you want. AB will stop the system as soon as possible after the completion of a shot...but only for semi-auto, not full auto.

[ThunderCactus]

Actually active braking does work on full auto, that's why my M249 doesn't spool down when I let go of the trigger anymore lol
But yeah, like Tys said, the only mosfet that will complete full auto cycling is the brand new SCU. It uses the PTW method for gear timing.

[m102404]

TC is correct in that AB will stop the motor as quickly as possible (freezing it) even in Full auto. I meant that AB in full auto wouldn't address the issue of fully completing a cycle in that the piston will freeze wherever it happens to be when power is cut in full auto.

Also...as far as I can tell...the new SCU doesn't "see" the cycle as a PTW does. The PTW is based on optical sensors reading light through the little holes in the gear. The SCU has a micro switch that is essentially bumped by the cutoff lever...so more of a mechanical system.

I might be wrong on the SCU...I haven't fiddled with one myself...but that's what the guys say.

[ThunderCactus]

Amos got a few swedish ones in that are optically based, I think he said it's the same one that's new on redwolf right now

[Amos]

They're not optical,

They use the cut-off lever and a little switch... It's more reliable than optical... unless you try it with a prometheus cutoff lever and snap off the sensor

[ThunderCactus]

BAHAHAHAHA awesome

[m102404]

LOL...I was wondering if that would happen eventually to someone.

I'm waiting for someone to stick it into a crappy cloner mechbox trying to make their JG into a PTW....

[coach]

Originally Posted by m102404

TC is correct in that AB will stop the motor as quickly as possible (freezing it) even in Full auto. I meant that AB in full auto wouldn't address the issue of fully completing a cycle in that the piston will freeze wherever it happens to be when power is cut in full auto.

Also...as far as I can tell...the new SCU doesn't "see" the cycle as a PTW does. The PTW is based on optical sensors reading light through the little holes in the gear. The SCU has a micro switch that is essentially bumped by the cutoff lever...so more of a mechanical system.

I might be wrong on the SCU...I haven't fiddled with one myself...but that's what the guys say.

You are correct but the ASCU is not 100% free of gearbox lockups. I still get the odd lock when I try to use a low battery. This would be in the event that you can't hear the low charge double beep which is the ASCU double parking the motor. There is not piezo or speaker on the sensor, it's the freaking motor. lol. I also have gotten a lockup due to the actual board because there's a loose contact that I can't see or touch up with a soldering iron. It's been ghetto fixed for now until I can get the time to drill out the rivets on the heat sink and go through every component and joint.

But, an ASCU lockup is a simple fix since there's no AR latch. Pop the motor plate and screw it back down and you're back in action. Don't even have to fully remove the screws. The gears will unwind and release the piston.

[BABU]

thnx for the info guys, very informative!

on a side note, i know i should probably do some more testing(to see if its consistent) and post up in the doctors corner, but any ideas as to why it would only shoot that one shot so poorly after i make that switch from auto to semi??

i get it could be a compression problem cuz obviosuly im loosing air somewhere along the line but i dont uderstand why it would only happen after i make that auto to semi switch...i played a whole day at FR shooting mostly on semi, and never had a problem

also shot about 3 shots on the chronograph, and all 3 came in consistently around 308 fps shooting .25

[m102404]

I realize that you never got an answer to that part of your question while we drifted off to geek-tech stuff...sorry.

Honestly...don't know. I suspect it's something to do with the hopup unit/rubber....but it's sounds like one of those quirky things that would have seen first hand to troubleshoot.

[BABU]

haha...never hurts to learn some more geek-tech stuff

ya i figured it wuld be difficult to guess wut it culd be...dam airsoft guns are so random, nvr know what exactly is causing the problem

when i get sum time ill do some more target shooting and see how often/consistent the problem is, maybe get sum1 at a game to check it out if it happens often enuf or is really bothering me

either way thnx guys, saved me buying the mosfet solely to fix that problem, now at least if i buy it it will be just to save the trigger contacts

thnx for all ur help!