Overspin / double-firing on semi with 11.1v

[Rogerborg]

I've long stuck to 7.4V but having just tried 11.1V in my AEGs, well, I now embrace wanker-gunnery and would like to accept it as my personal Lord and Winr8 Saviour, m8.

My problem is that I'm getting consistent overspin and double firing on semi in two AEGs, one V2 / M90 spring / Tornado motor, one V3 / M100-105 / Big Dragon M140, both front-wired.  To be clear, one trigger pull, two separate shots.  Not double feeding: shot, then shot.

Neither gun currently has a mosfet.

I have their energies dialled in where I want them, so would ideally prefer not to change springs and then lop off teeth, but I am tentatively open to the idea.

Is an active-braking mosfet the way to go here?  If yes, is that from experience, or from belief (I already believe it, but I've got no evidence for that).

If so, do we have any particular recommendations, particularly in the context of the current parlous stocking levels?

 

[MagpieTactical]

I think I have seen videos where a perun mosfet with adjustable levels of active braking was used to solve just that issue. 

 

[RostokMcSpoons]

Haha, well I'm probably getting to the same point but in reverse... Ordered a mosfet this morning, and I've just ordered, well, made an offer close to the asking price for the same batteries, before seeing this thread ?

I've ordered the Gate merf so have active braking and rof reduction as options, if I have the same problem.

(Edit:. Rof reduction doesn't affect semi auto, they leave rof unaffected to aid snappiness)

This will be my first MOSFET fitting so might not go smoothly, but I will try to do it as soon as I receive it

 

[Rogerborg]

Mmm, Perun AB++ does look like a viable default choice, if only because they're actually available.

 

[Asomodai]

Have you considered my lord and saviour 9.9v Life as a nice halfway house? I can use my 9.9v batts in rifles that will double cycle on 11.1v.

 

[concretesnail]

Mmm, Perun AB++ does look like a viable default choice, if only because they're actually available.

A friend of mine has just fitted one o these and is over the moon with the performance.

He's just made the jump to 11.1 as well. Active brake should fix the over spin, the setting would be dependant on the system but the instructions are easy to follow.

 

[Adolf Hamster]

generally i consider there to be 4 categories of mosfets:

basic mosfers (nanoasr, the basic perun mosfet etc) that won't do anything here beyond save the trigger contacts from burnout

mosfets with fixed active brake (eg nanoaab, nanohard, merf, etc) which have active braking but no precocking

mosfets with precocking (warfet, ab++)

optical mosfets.

generally speaking category 1 is my default for guns that i'm not pushing performance out of and just want the contact protection.

category 2 is a tricky one, i'd generally avoid them as active brake may well help in the situation of double firing, but if you decided to run the gun on 7.4 again you might find there's the opposite problem of too much ab, with the system stopping too quickly and getting lockups on semi.

category 3 will solve both the semi firing and lockup issues as well as the added benefit that the precocking will do a lot for helping perceived "response" in semi, you might find that depending on your goals running these with 7.4 is good enough without the rof climbing too high.

and category 4 is basically for the perfectionists for whom good enough is never good enough.

so basically the ab++ would be a solid choice here, i'm not a fan of using the trigger for mosfet programming but for the most part these things you do them right once and forget about it.

 

[Rogerborg]

Have you considered my lord and saviour 9.9v Life

Hmm, interesting option.  However, I'm in the 11.1V foxhole now, and I like the size of the ones I've just bought.  I'd love to try something more than 7.4V in my MP5K with its small battery tube, but LiFe seem to run bulkier than LiPo.  I'll keep that in mind though.

A friend of mine has just fitted [a Perun AB++] and is over the moon with the performance.

Sold.  Or rather, bought.  Thanks, I've been tempted to treat myself to a trick mosfet for a while, I guess sunk costs was the way to go.

 

[ak2m4]

One other solution is to up the torque of the motor to 22TPA or 28TPA, can sometimes solve double-shot.  AB fet will sort as well, will add a little bit of extra strain on the motor but no pain no gain ?

 

[Asomodai]

One other solution is to up the torque of the motor to 22TPA or 28TPA, can sometimes solve double-shot.  AB fet will sort as well, will add a little bit of extra strain on the motor but no pain no gain ?

Indeed! Which segues conveniently into this advert by some guy!





The sale of which will help me buy a short type motor of the same heritage from the quoted poster above. 

Some may think I am being a cheeky bu**er, I say it's fate.

 

[ak2m4]

@Asomodai bargain ?  

 

[RostokMcSpoons]

@Rogerborg It'll be interesting to compare our experiences of the Perun AB++ versus the Gate Merf.    I was so close to buying that Perun, before tracking back to the basic version, and then jumping back up the complexity list to the Merf.   I'm wondering if I've now made a mistake, missing out on the pre-cocking option for the sake of a few quid.  

Time will tell...

 

[Rogerborg]

I'll report back, but it'll be a while, I have some IRL stuff queuing up that I'll need to prioritise.

One other solution is to up the torque of the motor to 22TPA or 28TPA

Hmm, I do have a Big Dragon M160 that's currently looking for a home, so I'll try the mosfet in one AEG and the higher torque motor in the other. Thanks.

 

[ak2m4]

I'll report back, but it'll be a while, I have some IRL stuff queuing up that I'll need to prioritise.

Hmm, I do have a Big Dragon M160 that's currently looking for a home, so I'll try the mosfet in one AEG and the higher torque motor in the other. Thanks.

@Rogerborg defaintely worth a try, problem with those BD motors is they don't give you any torque specs, only names High Speed, High Torque or High Speed/High Torque mix. which doesn't tell you much.  The closest match visually is ZCI to those motors where HT was 22TPA, HS 14TPA and HSHT was 16TPA but they could be anything.

 

[Rogerborg]

Hmm, well, I have the box for an M160, and it's not in the DMR where I had it last, so it's got to be around here somewhere.  [Looks at "work area", shudders].

 

[RostokMcSpoons]

I've fitted my Merf!

Good news: full auto's like a beast, noticeable increase of RoF in my F2000 with the SHS hi-torque motor + 1200mAH 11.1v Turnigy Nano Cell 15-25C.   Really snappy response in semi too.  

Bad news: it stopped firing after a few bursts.   Connected a couple of 7.4v batteries and nothing doing there either.  Tried them in the DE, worked.   Gutted.   But then I realised I hadn't set the battery type in the setup menu.  Connected the programming trigger, changed to 11.1v LiPo in the settings, *bingo* back to shooting again.   I've not really 'gone for it' since then, I'm setting it aside for the evening: I'd rather go to sleep with a working rifle than stay awake with a broken one  
I'll give it a workout tomorrow to see what's what.  I'll chrono and get a RoF for it, if it's running well.

Hopefully those 30C batteries will turn up soon, they'll be interesting
 

 

[RostokMcSpoons]

Quick update: Rate of fire up to 19rps.  Obeying the '20 is plenty' rule, at least for the moment! 

Bad news: gun stopped pew-pewing again.  It went for longer before stopping, but stop it did.  No warning lights on the Merf, start-up lights showed it was still happy.  Battery swap (to 7.4v) didn't fix it.  The 11.1v battery is down to 10% (~3.60v per cell) so I'm re-charging it now, in case the Merf is very conservative with its battery protection.   

The odd thing is if I do the trick of connecting the programming trigger to the Merf, it'll fire quite happily.  Maybe my signal wire is shorting after some vibration...?

 

[Rogerborg]

Well... I took my Perun out of the box.

I'm sorry, I'm sorry, I couldn't sustain the lie.  I didn't.  I took the Perun box out of the shipping box.

Soon though.

Probably not soon though.