We Scar H V2 Gearbox shell

[LordGeorge]

Hey Guys

My first post here, so will try keep it short B)

I have been making the most of every drop of power out of my gun, as we all do.

Around 2 months ago I first bought the latest addition to the growing family, my WE Mk17 Scar H.

Cutting straight to the chase, this gun uses a V2 shell layout, BUT has some small factory modifications to deal with the fire selector setup and the safety / anti-reversal latch release.

This becomes quite a problem when I want to plan for the future and save up for a strong CNC gearbox. Nobody to my knowledge makes the shells with these features.

When I buy a new case, in the event of the horrid V2 shell crack or just a thing of the moment. I have come to terms that I will have to buy any case of choice and have it custom machined.

I live in Staffordshire and wondered if anyone knows of a reputable company to machine the changes.

Luckily the changes are only removing and not adding to the shell.

Besides this, the gun its self runs amazing and had a complete internal refurb under a week after buying it due to shredded gears running 11.1 instead of 7.4... Oops....

The gun runs 11.1v with 18:1 m110 and Lonex A1 titan motor.

So the CNC isn’t necessary as nothing more than a M110 will ever go in to stick to the 350fps rules at my local sight, but its what i want.

Any help would be awesome.

Cheers

George

 

[Sitting Duck]

What is your rof with 7.4v & 11.1v ???

shreading gears can be done on 11.1v with a good motor and heavy piston

M110 would put you over 350 - 360+ usually if seals were good

as you approach high 20's to low 30's - don't matter how you do this:

11.1v on stock or 7.4v on high speed gears

you can get pre engagement - more on low m90 - 100 springs with a heavy 30gms piston

(metal piston head and all steel teeth etc....)

exactly how fast do you seek to fire at may I ask......

20-25rps, 30rps - can be done on 7.4v later is using higher speed gears btw

30-37rps to 45rps can be done on 11.1v but at 30+ you run risk of PE

to avoid this you need to fit stronger m120 spring and short stroke - remove 1 or 2 teeth

reducing full piston stroke from say 50mm to 44mm - (should be fine unless your gun has a 450 to 510 max barrel of normal piston)

I presume it has say a 300 to 400mm length with ported cylinder

your gearbox will be fine I'm sure if you have a sorbo pad to correct AOE and reduce impact

plus the front corners of cylinder-gearbox shell should be rounded or radius

this rounding of the corners reduces the chance of cracks appearing at front of box

Think about it - sharp 90 degree V corner will be more prone to fracture

than a curved - non-sharp pointed internal corner - many manufacturers are now starting to do this even in cheaper guns

However - be aware despit all efforts you take to reduce PE and cracking of shell

The faster your gun fires to quicker in theory she will fail due to heat & wear

(you cane anything enough and it will very likely fail - be it a car/motor bike or your aeg)

plus not all mags will feed perfectly at the higher speeds so like I say establish just how fast you wish to go

massive difference say from stock 14 to say 23 on the Lonex motor upgrade but not so easy to notice a massive difference 23 to 32 another 9 rps

(plus the extra work it may require and doubt if you will gain/notice a further 9 from 32 to 41rps say)

well said this all before a few times but look here:

http://www.airsoft-forums.co.uk/index.php/topic/26210-gearbox-internal-help-higher-rof/#entry196340

and the airsoft society link is a brilliant breakdown of what to do once you decide how nutz you wanna go

 

[LordGeorge]

Ok, a bit to get through here haha...

As far as FPS goes, i currently do not know. I am waiting for my xcortech to arrive so will know much then.

I did however find out the RPS, wile recording slow motion with my iphone 6+ and a stopwatch in the background.. I am getting 26rps.

I was very supprised considering its a 18:1 on a full stoke poly piston. I have ground the first tool half way to counter PE and allow clearance for the sector to hit the pickup.

The only thing i am having and it is only a very very small ammount of what i thing is overspin on Semi-Auto. Wich i can correct with my GATE mosfet.

The piston is a SHS poly full metal rack, the pison and cylinder head ar ASG ultimate POM parts. Very happy with those btw, the smooth porting and concave piston head gets a perfect soft contact on the cylinder head.

I have looked down the sorbo route but the OA is perfect and has a high level of padding from the ASG parts.

The cylinder is a 450-550mm, the standard scar was had a 460mm barrel. I changed the cylinder to match my new 6.03 madbull python barrel that was cut down from 590 to just under 565mm due to extending the barrel by 190mm with a beefy silencer.

And no, due to the barrel to cylinder cubic volume i am not using a ported cylinder

The Air seal internally "Pison,cylinder,nozzle" is perfect and looses nothing. Especially after PTFE taping the cylinder head up h34r: .

Where seal may be lost in the hopup, i have made no modifications to that as of yet as its by far the easiest and atleast gives me space to play if i need to loose or gain fps. Depending on what its currenly at.

I do agree and see where you are coming from with the rounding of the gearbox ports which it does have. Like i said, i have no plans to push this gearbox and especially dont want to crack the shell any time soon at all.

Only area i dont know is what my pison weight is, it really cant be much at all, the heaviest thing would be the bearing which i kept in both ends of the spring "again another area allowing me to tweak if too powerfull".

My aim is more hitting the 350fps consistently at anything around 20 rps. I dont want more than that, its just a insane waste of bb's and rather work my gun down the DMR route wich only needs a scope.

The gun from stock to silencer break is 1.02m, so its a big one for a assult rifle. Hence the plans for a scope for those longer shots.

Cheers for the link. One note from the video was HOLY CRAP the piston in that sounds like a jack hammer on solid steel. Mines nothing like that. Only the motor wine and air thump

I did spend 4 days shimming rinse repeat untill it meshed perfectly after beading the gears and bearings in a little. Using the gears only motor on 10s at a time with 30s cooldown.

I have been a bit of a perfectionist with this gun and still plan to make it quieter.

For the money i have thrown at this so far, i may have been better off setting up a HPA rig. B)

Cheers

George

 

[Sitting Duck]

for rough giggles what you get on a 7.4v lipo say 20rps

when you go to 11.1v lipo expect the rps to be aprox 50% more = 30rps

due to you going from 2 x 3.7v cells to 3 x 3.7v cells

good chrono - got one myself and does help

a little unsure of this bit:

The cylinder is a 450-550mm, the standard scar was had a 460mm barrel. I changed the cylinder to match my new 6.03 madbull python barrel that was cut down from 590 to just under 565mm due to extending the barrel by 190mm with a beefy silencer.

normally a standard aeg cylinder is really suited for barrels up to 455 to about 510max

(over this is usually for the longer L85/SR25/SVD aeg cylinders with 19 not 16 teeth sector gears)

I would of guessed stock barrel might have been in range of about 300 to 363 max for some scars

but could be up to 510mm on extended versions which is imho the max you can squeeze out of std aeg cylinders

anyway if your barrel is 565 you are a tiny bit over the limits but like anything see how it goes if you have perfect seals etc.....

tbb and bore up cylinders make little difference to volume ratios - performance yes but the ratios hardly change much

even if you bang in 6.08 or 6.02 barrels - it is 0.06mm or 1% difference - hardly matters to volume ratio

piston weight can vary a lot - 15gms to 30+gms

all steel teeth is not good if PE takes place - the first inital pickup tooth and the first few plastic teeth strip nicely

better than all steel teeth that don't strip - therefore no weakpoint and so nothing strips = BANG all metal PE

(metal teeth is fine if you are not getting too close to PE - if pushing it then 50/50 or a few plastic teeth is safer)

if this takes place short stroke & use a higher spring

I would of thought you might have nearer 30rps on 11.1v with A1 motor

anyway record it a sec or two and drop the wav file in audiocity on pc, counting the number of "spikes" in a second

do this on 7.4v give it 50% and you can get a rough idea of what to expect on 11.1v

I have been a bit of a perfectionist with this gun and still plan to make it quieter.

For the money i have thrown at this so far, i may have been better off setting up a HPA rig

We are all still learning - the more we build/break the more we learn = wisdom

It is all a fun learning curve that we hope to ensure our next build/tweak is better than the previous build

HPA - pah where's the mechanical "fun" in that though I'm sure one day I will get one too

the US link to high speed is good but peeps need to remember we got lower limits which m120 will put us well over

so we can go only so far on m100/105 before we need to short stroke m120 for over 30+rps builds to avoid PE

Hopefully your chrono will arrive soon to do some tests properly

m110 would put you over and tbb even more - some good m100 springs with good seals can hit 350+

so you "could" be @ 380fps or more - but all builds are different so see what she chrono's at

plus different makes of springs can give higher/lower figures

I have a feeling a SHS M100 is as strong if not a smidge stronger than an Element M105 spring

see what happens when ya chrono rather than we continue to speculate

 

[LordGeorge]

the US link to high speed is good but peeps need to remember we got lower limits which m120 will put us well over
so we can go only so far on m100/105 before we need to short stroke m120 for over 30+rps builds to avoid PE

Hopefully your chrono will arrive soon to do some tests properly

m110 would put you over and tbb even more - some good m100 springs with good seals can hit 350+

so you "could" be @ 380fps or more - but all builds are different so see what she chrono's at

plus different makes of springs can give higher/lower figures

I have a feeling a SHS M100 is as strong if not a smidge stronger than an Element M105 spring

see what happens when ya chrono rather than we continue to speculate

Ok so results day it is!! Got new xcortech x3500 instead Very good btw...

Anyway, the results are a little odd.

The Fps is as follows..

0.2g = 350fps

0.25g= 318fps

The rps is also lower, at roughly 21rps with a uncharged battery.

I am happy with the results and thankfully sits within the site legal numbers, but mechanically it does arrise some questions.

The sping is a lonex m110 spring and from what i have seen of spings so far is long but soft in comparison to others.

The rating of this spring is 350-370 so also fits on the lower end of the scale.

This lower result is most certainly down to the larger cylinder volume slowing the piston down on compression.

My next query is the battery...

I am using a we 1450mah 30c battery, along with the gate mosfet, 14awg cabling and deans connectors.

The cable does not get even slightly warm but the battery does, the battery was even getting warm when i was breaking the gears in with nothing but the motor and gears spining.

"also the same with only the motor and battery connected"

The only thing i can add is the temps seem to rise much quicker when firing in semi.

There is no change under load.

My only theory is that the motor is drwaing too much amp, thus causing risen temps on the battery.

It is a new battery and is in perfect condition as well as being charged correctly.

It only lasts roughly 2000rds.

So would a nuprol 11.1v 3200mah do the trick ?

I would like a battery that also doesnt run out so quick lol

Whats your thoughts ?

Cheers

George

 

[cyrexx]

LiPo batteries get warm under heavy load, you only need to worry when they get hot. If they get hot it means the load it too much for them and they will start to puff out and in some extreme cases set on fire. Also bigger batteries are always better, a nuprol 11.1v 3200mah shouldn't get as warm, plus it will increase trigger response and slight increase to RoF.

 

[Sitting Duck]

The temp is from active braking

If you have the merf fet in there or an AB Get

Which you don't really need.

The most I have got on stock is 24.8 RPS on a v3 with very thick wire soldered to motor.

V2 is a bitch to solder n remove wires to motor so your 21rps is about right on stock 18:1 gears

You can expect 27 to 30 on 13:1 gears.

Or try a 9.9 LiFe battery but limited range n Max 25c is what I have found.

If you connect 11.1v you will hit 30+ which is risky

If you have the merf 3.2 I don't know if you can enable/disable active breaking but that could be where some heat is generated.

Spamming trigger on semi - say 120 shots in 1 minute really strains the get n wiring far more than 5 mins on auto, guy on YouTube showed me that n he really knows his stuff. If a fet passes the 120 in 60 sec test it is good to go in my book but that is a normal 3034 fet - non an braking btw

 

[Sitting Duck]

Also a freshly charged 7.4v will put out at least 1v fresh off charge.

So you could charge up battery and see how she performs with say 8.4v to 8.5v from ya 7.4v lipo

Pointing this out coz sometimes you can just scrape by with a 11.1v but a fresh one pushing 12.2v+ could spell PE BAAAANNNNGGGGGG

 

[cyrexx]

The temp is from active braking

If you have the merf fet in there or an AB Get

Which you don't really need.

AB should not cause the increase in battery temperature, motor braking accomplished by shorting the motor outputs. The only type of braking that uses the battery is Regenerative braking (which actually recharges the battery).

If he's using a 7.4v LiPo probably doesn't need an AB mosfet but if he's using an 11.1v then he may need one considering the Lonex A1 is a high speed motor

 

[Sitting Duck]

It will increase on the motor, which may be slightly related to rise in temp on battery.

Pointed out spamming on semi greatly increases the strain and dunno how warm or hot peoples own definition is on what they call hot or warm.

I would of thought the wires of battery should get warm like most of the whole circuit but again how warm in exact temps is open to people's own interpretation of warm to hot.

30c battery is plenty for now on a lightly tweak build but better capacity would be good

AB is not really needed for most builds but know a few on here use AB fet's - it can increase load/heat on motor but all builds n motor makes can vary so see how it goes.

If you can see how she runs without AB might help,

Order up or see what size battery options n volts are available.

Try HobbyKing's battery locator to see what big capacity batteries might fit in your gun's stock etc....

Soz for any " get " 's n other typo's as my fone is mental with predicted text

 

[LordGeorge]

I charged the 11.1v and got 24rps fresh. The battery was pretty low before :lol: .

Cool thanks for the notes, my main issue is WE gave very little space in the crane stock to fit mcuh more than the nunchucks im using, I will have to be inventive to get the nuprol one in.. Wheres the fun with no challenge.

Unfortunately the merf 3.2 has no option to turn AB off, i have seen their new HARD model does allow on/off.

If its whats causing the issue then will look into getting another fet, but i do like the solid cycle with AB.

Well i was looking down the gears route and my main issue is, if i go to a lower ratio. My RPS is going to go mental, 24 is more than enough for my needs.

I was however toying with some 100:200 helicals from super shooter. I know allot of people are for or against. But from a mecanical mind, it should be much better. Both reliablility and sound.

Allot of people blame the teeth being too thin and causing breaks, if propperly shimmed this should never happen as the cross sectional surface is usually 10-20% larger than strait cut.
The biggest issue i see is the vertical torque of the gears.

I have aimed down the route of removing as much motor/gear wine as possible. The piston is very quiet. I am blaming the A1 for most the noise. Though it is a nice Motor

Also, has anyone ever seen any we mk17 mid/high cap flash mags ?
I have looked high and low and you can only get the mid cap wind mag. I ended up buying some lonex m4 flash mags and making my own mag extention to get the mag sitting snug in the well.

Cheers

 

[LordGeorge]

Quick update

I may need to take a bearing out.. or two..

I was adament that i was loosing power somewhere, after looking top to bottom i was left with the hop-up and barrel.

Barrel is a madbull 6.03 python. Its one of the best barrels i have seen to date.

Next, hopup.. The houpup on the WE scar H is not the best. But functional.

I did however notice that the hopup rubber and barrel were a bit loose... and under pressure allows air to pass between rubber and barrel.. not good.

So like everything else air/pressure related, i added only one wrap of gas ptfe tape under the end of the hopup rubber.

Squeezed the rubber back on and also added another wrap to secure the barrel O ring.

Plopped it back together and gave it a wizz.

My first few shots were on .25's and i got a solid 350 fps .

I then went to .2 and got a max of 387fps :blink: .

From ensureing a improved air seal on the hopup, i got roughly 30/40 fps improvement.

So going back to what i said.. time to remove one of the bearings to geth those numbers under control.

Cheers

 

[Sitting Duck]

Bearings???

Or teeth on sector

Or you talking about doing a way with piston bearing

Keep bearing spring guide though

Me thinks remove 1 tooth off START of sector

Do not remove teeth at back it will mean tappet timing goes out and doesn't have enough time to seal as piston releases

BUT you really need Max stroke on that barrel

So either great seal but lower spring

Or

Slightly leaky seal and stay at 350

Me I would remove one bit or wrap of tape

That should put you back near it.

If still over you can either remove other wrap

Or park spring pre-cocked overnight to bring down 365 to 350 ish

One thin to try if you are happy with everything....

If you don't wanna mess with hop no more then cut some thin strips of electricians PVC tape say 5mm x 20mm

Place say 2 strips on the very end of gearbox shell above n below the nozzle aperture....

Refit gun back and what you are trying to do is create say a smidge or push hop away say 0.25 or 0.5mm away from box and losing a tiny bit of perfect seal/fps....

Sounds bollox but say in 6 months when spring loses some tension and fps drops to say 320 from 350

Remove tape and bobs ya uncle you back with good seals and 350fps on a slightly worn spring

 

[Shizbazki]

Hi LordGeorge

I think if i am correct you watched my Video on the WE SCAR L on youtube and made a comment about CNC machined V2 gearboxes shells?

Let me just say that i think you are over tweaking this gun (no disrespect intended) as the WE Scar does not like to be opened and closed time and time again (trust me i know from experience from the SCAR L).

If your gun was hitting 350FPS on .2g BBs consistently (with at least a 2 to 5% +/- FPS) then i would have stopped there.

Only ever use .2g BBs as your test BBs, i have a bottle of ASG Blaster .2g BBs just for testing AEGs and normally use G&G .25g BBs for skirmishing but never use it for testing.

The reason i say stick to .2g BBs for testing is that this is the benchmark BB weight and most sites will use .2g BBs when chronoing guns using their own loaded mags to prevent cheating the chrono (my site does anyway).

With a heavier weight BB expect the FPS to drop, looking at your numbers it appears that you have a consistent Joule Power (dont look at FPS too much). I will refer you to the following link to a chart showing that heavier BBs = less FPS.

http://www.airsoftmaster.com/fps-chart-for-airsoft-guns/

Furthermore you state on

.2g BBs that you got 350FPS the first time and 387FPS the second time

and that on

.25g BBs you got 318FPS the first time and 350FPS the second time

If we look at this closely you will realise that

350FPS on .2g BBs = 1.13 Joules

318FPS on .25g BBs = 1.17Joules

and

387FPS on .2g BBs = 1.38 Joules

350FPS on .25g BBs = 1.42 Joules

The difference between the two BB weights and your FPS from the above is 0 change and an increase of 0.04 joules when going from .2g to .25g BBs, a job well done i would say.

HOWEVER depending where you play, when you approach to Chrono your gun they will likely load their own mag in to the gun, loaded with .2g BBs, this will show you gun firing HOT at 387FPS which won't pass, to cheat it slightly increase the hop a little as this gun is VERY hop sensitive.

Lastly stick to 7.4v LiPos, anything higher will rip the gears to shreds as they are WE Gears (AKA SHIT!), i know as i have shredded WE SCAR Gears on an 11.1 LiPo but got an amazing 28RPS before it broke. If you really want that higher ROF then i would refer you to a different gear ratio set or dual sector gears (though expect a lower FPS with dual sector gears).

 

[LordGeorge]

Hi LordGeorge

I think if i am correct you watched my Video on the WE SCAR L on youtube and made a comment about CNC machined V2 gearboxes shells?

Let me just say that i think you are over tweaking this gun (no disrespect intended) as the WE Scar does not like to be opened and closed time and time again (trust me i know from experience from the SCAR L).

If your gun was hitting 350FPS on .2g BBs consistently (with at least a 2 to 5% +/- FPS) then i would have stopped there.

Only ever use .2g BBs as your test BBs, i have a bottle of ASG Blaster .2g BBs just for testing AEGs and normally use G&G .25g BBs for skirmishing but never use it for testing.

The reason i say stick to .2g BBs for testing is that this is the benchmark BB weight and most sites will use .2g BBs when chronoing guns using their own loaded mags to prevent cheating the chrono (my site does anyway).

With a heavier weight BB expect the FPS to drop, looking at your numbers it appears that you have a consistent Joule Power (dont look at FPS too much). I will refer you to the following link to a chart showing that heavier BBs = less FPS.

http://www.airsoftmaster.com/fps-chart-for-airsoft-guns/

Furthermore you state on

.2g BBs that you got 350FPS the first time and 387FPS the second time

and that on

.25g BBs you got 318FPS the first time and 350FPS the second time

If we look at this closely you will realise that

350FPS on .2g BBs = 1.13 Joules

318FPS on .25g BBs = 1.17Joules

and

387FPS on .2g BBs = 1.38 Joules

350FPS on .25g BBs = 1.42 Joules

The difference between the two BB weights and your FPS from the above is 0 change and an increase of 0.04 joules when going from .2g to .25g BBs, a job well done i would say.

HOWEVER depending where you play, when you approach to Chrono your gun they will likely load their own mag in to the gun, loaded with .2g BBs, this will show you gun firing HOT at 387FPS which won't pass, to cheat it slightly increase the hop a little as this gun is VERY hop sensitive.

Lastly stick to 7.4v LiPos, anything higher will rip the gears to shreds as they are WE Gears (AKA sh*t!), i know as i have shredded WE SCAR Gears on an 11.1 LiPo but got an amazing 28RPS before it broke. If you really want that higher ROF then i would refer you to a different gear ratio set or dual sector gears (though expect a lower FPS with dual sector gears).

I did indeed Hey.. again

That is perfectly fine being honest, I am very new to the modding scene on airsoft. "I only took up the sport this year" But due to my dad and my job, perfection and efficientcy is OCD level.

So where the smallest change to improve could be done, I did h34r: .

Yeah like i stated in a earlier post, i really dont want to run hot.

I got smacked in the face by a polar star that got let loose on some un-godly pressure and at roughly 30m it Fu#kin hurt. From then on i had no intention of playing naughty.

I have been up untill now using .25s as my fps was much lower and allowed space to use them.

As far as downgrading the output, i am planning to take the piston bearing out. And most likely drop my m100 spring back in.

As long as 350fps on .2g almost every shot, im happy. My accuracy is pretty dam good aswell.

Yeah, i deffinately wont be short stroking the piston due to the volume issue.

The m100 spring should pop those numbers back down to a nice position.

I did think about winding the hop, but on the scheme of things. There is little point as it will most likely cause your bbs to fly every where else but the target. So naturally would undo it. Then running too hot again.

Yeah well when my sector broke in the exact same place, i eneded up getting a good set of 18:1 gears. So the 11.1v shouldnt do any shredding any time soon.

I stipped it down after 2000+ rounds and the gears has so little ware, i had to clean them down for re-lubing and look at every tooth. Still to find no paint marks etc..

As for mags onsite, my current local does not conduct this but are very hot on chrono and spot checks.

On a side note, i would love them to find a way of fitting a mag in the scar H without using my mags lol

Im not too fussed on rps, 20 to 25 is perfect if that a little high. I want a quieter set of gears and motor.

I think future, i will get some CQC gun and DSG that for as much rps as possible for the lols.