Double taps mosfet

[Dannn]

I've set it all up.... Angle of what's it has been set, had a shim tastic time on it on it, new piston with teeth made from supermans shit, big fat wire all over the place and I've got a new one to drop in as soon as this one goes bang haha

 

[Sitting Duck]

word of strong advice....

test on 7.4v first - especially if a neodym motor is in there

(or high speed gears - if using both neo and 13:1 then I advise ordering up new parts anyway - even on 7.4v coz that could hit 30)

whatever she is firing at - BPS app or record sound and count spikes on pc etc.......

then get a rough idea what rof is on 7.4v first

11.1v will be 50% more.....

if hitting 20rps on 7.4v you will expect to hit aprox 30rps on 11.1v

Warning 25+ very slight risk but 30 good chance of PE

(depends on spring strength returning piston faster/slower and also weight of piston - lighter is faster return/ swiss cheese crap etc..)

if you used a plastic toothed piston it will just strip

but all metal rack - no weak point to shred and it will really go bang due to all metal teeth gears etc.....

you could smash your piston to f*ck AND YOUR GEARS AND YOUR MOTOR PINION GEAR IF ALL METAL ON 11.1v

no $hit - it can happen if you go too nutz without homework on stock m100 or m105 springs

luckily I learnt the hard way but with plastic teeth shredding, now I have a rough-ish idea what to expect

so I got a reasonable idea of when I can and when I can't use all steel piston rack

(built up a collection of boned pistons to attain this knowledge of what NOT to do)

faster n faster stuff at 30+ has to have shortstroking and M110 - m120 is safer with 2 teeth removed

I got a rough maths table I think that works out about right - will know more as I build n bone more

 

[Lozart]

it is when you rewire with thicker wire + deans that the fet comes into its own and it is the other bits that give the faster response

not the mosfet - the fet just allows us to safely switch higher juice for heavier loads on juicy motors etc....

That is where the trigger response comes from - not the fet itself

the fet just manages the bigger juice safely keeping your contacts looking good rather than deep fried

That's....not entirely true. The capacity to switch larger currents is part of what makes the FET useful as it prevents all the current going through the trigger contacts which can then arc and lead to poor switching and conduction but it's also the ramp rate of the FET that makes the trigger response better. You could JUST fit a hardwired FET using all the original wiring and get a much improved trigger response because the FET can go from 0 to full current far quicker than a mechanical switch. Granted if you combine this with better wiring, Deans connectors etc then the trigger response will be better still but don't make the mistake of thinking that's where the greatest benefit in switching speed comes from.

 

[Dannn]

With 11.1 im getting around 40 odd per second , but that's testing it with a crappy iPhone app..I'm going to short stroke it with an m120 I think

Do you think plastic teeth are the way to go on really high speed stuff so only that goes bang ?

 

[Sitting Duck]

Not gonna get into a debate on it but fet is an additional device with additional wiring often sited further backwards....

then the current would flow from the fet to the motor after the fet's own delay or switch on time even in nano/milliseconds

it prevents trigger arcing/carbon which would cause resistance etc in switching

but like for like as you wouldn't fit a mosfet when the trigger contacts were shot

you would replace switch - but on clean good contacts under stock conditions at least

the fet does not in my mind improve trigger response....

as stated above additional device, additional wiring and has its own delay or switch on time

burnt out contacts are different - the point I am making is that many people assume the mosfet is improving trigger response

it on its own is not - it is safely allowing the use of higher juice to the motor using thicker wire/connectors

take two exact brand new guns and a soldering iron........

fit just a mosfet to one gun and to the other fit deans instead of small tamiya to other gun & battery

Then dean's gun will show trigger response than the mosfet only gun

maybe in time as carbon builds up on deans gun this may get so bad in terms of resistance the mosfet gun triggers faster

but like for like new clean contacts the mosfet will not show any improvement in my mind like I stated above

trouble is even if it did provide a smidge more, then often people would take it that most of the response must be down to the fet

it is not it is when all the items are upgraded and the fet operates to prevent additional resistance building up at switch

that trigger response is improved and maintained through the larger wire/connectors with little resistance

The mosfet is there as I said to prevent resistance taking place - on its own it does not in my book when fitted improve response

over time it helps maintain trigger response - I will admit that

but I can't see how on its own with new contacts the response will be improved in the fet Vs deans gun scenario

 

[Sitting Duck]

With 11.1 im getting around 40 odd per second , but that's testing it with a crappy iPhone app..I'm going to short stroke it with an m120 I think

Do you think plastic teeth are the way to go on really high speed stuff so only that goes bang ?

you are getting 40rps already ???

and the gun still lives ???? - let alone feeds ok

if that gun is cycling at 40rps on full stroke piston with a stock spring heck even with a m120 full stroke

I'm doing something very very wrong coz I've had numerous smashed boxes taking the pi$$ like than on full stroke

I'm finding that very hard to believe that she is still living at that speed - harder to imagine than the response/switch on time of the mosfet

On a full stroke piston you would need a mofo spring to get a piston to return quick enough before the sector tries to grab the piston again

Not tried it myself but reckon getting to say m140 min but probably still close so reckon m150 to avoid PE on full stroke pistons

but only on guns like AK47 & 455mm+ barrels would you need full or fullish stroke rather than SS for say 400mm barrels & below

with a full stroke - forget the cylinder porting the full stroke energy being released on m140/150 would place your gun at near 500fps

plus the extra strain on motor would reduce that 40rps

Can't get my head round 40rps if not full stroked unless mofo spring in there like I said

Everytime I started to take the pi$$ it ended in tears very very quickly

40rps on 11.1v would indicate a 27rps on 7.4v so to achieve that figure alone you are running a neo motor with 13:1 gears

27rps is starting to get close if still using a m100 full stroke setup

so I can't get my head round it that you can hit 40 unless you already have SS or dsg or mofo spring etc....

 

[Dannn]

That was 18-1 gear set with neo motor and 7.4 lipo

Got a spring and 13-1 on order ? if she's not hitting 50+ I'll be sad...

View attachment 16385

 

[Lozart]

Not gonna get into a debate on it but fet is an additional device with additional wiring often sited further backwards....

then the current would flow from the fet to the motor after the fet's own delay or switch on time even in nano/milliseconds

it prevents trigger arcing/carbon which would cause resistance etc in switching

but like for like as you wouldn't fit a mosfet when the trigger contacts were shot

you would replace switch - but on clean good contacts under stock conditions at least

the fet does not in my mind improve trigger response....

as stated above additional device, additional wiring and has its own delay or switch on time

burnt out contacts are different - the point I am making is that many people assume the mosfet is improving trigger response

it on its own is not - it is safely allowing the use of higher juice to the motor using thicker wire/connectors

take two exact brand new guns and a soldering iron........

fit just a mosfet to one gun and to the other fit deans instead of small tamiya to other gun & battery

Then dean's gun will show trigger response than the mosfet only gun

maybe in time as carbon builds up on deans gun this may get so bad in terms of resistance the mosfet gun triggers faster

but like for like new clean contacts the mosfet will not show any improvement in my mind like I stated above

trouble is even if it did provide a smidge more, then often people would take it that most of the response must be down to the fet

it is not it is when all the items are upgraded and the fet operates to prevent additional resistance building up at switch

that trigger response is improved and maintained through the larger wire/connectors with little resistance

The mosfet is there as I said to prevent resistance taking place - on its own it does not in my book when fitted improve response

over time it helps maintain trigger response - I will admit that

but I can't see how on its own with new contacts the response will be improved in the fet Vs deans gun scenario

All I will say in response to that is that I used to do this stuff for a living. A FET will improve your trigger response without changing the original wiring but not as much as changing the whole set-up as you rightly say.

 

[Sitting Duck]

That device is f*cked I said that before

the absolute best best best I have hit with 18:1 and 7.4v is 24.8rps

that is with meter tails soldered direct to motor on a v3

so for 35 to show up on stock gears and 7.4v and full stroke even with slippery as f*ck modify ceramic bearings & Lonex motor

that just rewrites all my findings........

unless you have got a mofo super frankenspeed motor or a dsg setup

The HC05 dsg hit 41rps on 7.4v so I'm finding it hard to swallow a regular gun can get so close to it

my recent 12:1 setup hit 33rps on 7.4v - so if your gun is beating that then I really really gotta get me some 60c lipo's asap

 

[Dannn]

I've noticed a huge difference in trigger response by hard wiring everything including the fet apart from the battery with 14g wiring.

 

[Sitting Duck]

All I will say in response to that is that I used to do this stuff for a living. A FET will improve your trigger response without changing the original wiring but not as much as changing the whole set-up as you rightly say.

I do enjoy the times we don't quite see eye to eye but we all know it is when it is all done properly the response really improves

I'm gonna leave it as is for now coz I'm trying to work out where I'm going wrong atm

 

[Sitting Duck]

The wire I'm using is thicker than 16awg turnigy

by my calculations it is close to 15awg's conductive surface area

silver plated copper wire eventually run as 1 wire for positive direct to motor

negative - only break was at fet and had its own dedicated fet supply & signal wire

which is run in shielded twin core ptfe or something

there are no extra joins at all in the final wiring to account for any additional resistance

the AK was the fastest 18:1 going from around 22 to 24.8 I mainly think from soldering direct to motor

v2's are soldered at the elbows of motor connectors as they do weaken when bent at right angles

solder applied top & bottom of connectors to maintain good connection/conductivity or whatever you wanna call it

So I really can't see how I can make the wiring much better than the above

Unless the 35c lipo's are really really holding me back - but saw ittle improvement between 25c & 35c 7.4v

and LiFe's just lost any real middle ground they gained as a filler between 7.4v & 11.1v

 

[Dannn]

It's not a standard motor lol

It's a lonex a3

 

[Sitting Duck]

Get the gun chrono'd properly

or

record the sound/wav file and run it through audacity on pc or something.....

we or I said this before in a previous post - the readings you are getting just don't add up

I'm done on this for now, got up to squeeze my lemon and lost some beauty sleep

(which I really desperately need a LOT of btw)

so I'm going back to bed and fairly sure I'm not gonna lose any more sleep over this atm

soz but I strongly strongly feel the readings are out or the gun is already SS DSG'd or something

 

[Dannn]

I've just rigged up a mosfet to a power source and wired it to s light instead of the motor and it seems as soon as I switch the power source on I get a very dim light but as soon as I connect what would be the trigger contacts it goes really bright, so question is are misfets supposed to let power through all the time ?

 

[Larry2007##]

I think you haft to have a etu to make the mosfet work properly 

Aka electronic trigger unit