KA M4: Stock Lipo Ready?

[ThunderCactus]

What you're saying doesn't make any sense.
You can run an AEG off a 60C LiPo and it will put very close to the same voltage and amperage through your trigger contacts compared to a 15C. A 60C has lower internal resistance, so you'll get a slight increase in current, but not like going from an 8.4v to a 9.6v or anything.
A LiPo can't put more amperage through your motor than your motor needs. If your motor draws 8A, then it will draw 8A whether you use a 10C or a 60C LiPo. The only way your motor can draw too much amperage is if it has a bent armature or arcing poles (like on the systema magnums) where it effectively creates a short in the motor and draws lots of current.

Your contacts burned out because of the higher amperage provided by the LiPo, more amperage coupled with the inherent high resistance of the stock trigger contacts, means a shit ton of heat buildup, which means melting the plastic housing. Arcing should be fairly minimal however due to the lower voltage.

I run as high of a C rating as I can fit in my guns, my LMG runs off a 40C, and my PTW off a 20C battery. You shouldn't NEED anything above 20C since your motor typically won't draw more than 12A, but having a high C rating shouldn't cause any extra stress on the system.

Again, this is why I recommend EVERYONE upgrade to a MOSFET switch when using LiPos

[Fuzzy]

Thundercactus is correct. OP would be wise to follow his advice.

As for Mosfets, unless you are running a 11.1 lipo I would not consider a MOSFET as mandatory, although it would be preferred. All the Aeg's I use with 7.4v lipo show very little trigger contact damage. If I use 11.1 lipo, I would see the obvious buildup from arcing.

[M.Garcia]

Yes I'm thinking I will get something around 20C as I'm going to be putting this into my handguard.

Ok I will read up AoE, was just seeing if you had an article that you'd recommend reading.

I won't be going over 400FPS as that is the limits for our games. Not sure why people would be going over that limit to be honest.

I most likely will not be running 11.1 lipo, probably 7.4 but again if someone is saying I should that is a different story. Just trying to see what I should be doing with my brand new KA M4 that will be here tomorrow.

This is the battery and charger I'm looking at getting:

Battery: http://www.hobbyking.com/hobbyking/s...SOFT_Pack.html
Charger: http://www.hobbyking.com/hobbyking/s...cessories.html

[Stealth]

Originally Posted by M.Garcia

Yes I'm thinking I will get something around 20C as I'm going to be putting this into my handguard.

Ok I will read up AoE, was just seeing if you had an article that you'd recommend reading.

I won't be going over 400FPS as that is the limits for our games. Not sure why people would be going over that limit to be honest.

I most likely will not be running 11.1 lipo, probably 7.4 but again if someone is saying I should that is a different story. Just trying to see what I should be doing with my brand new KA M4 that will be here tomorrow.

This is the battery and charger I'm looking at getting:

Battery: http://www.hobbyking.com/hobbyking/s...SOFT_Pack.html
Charger: http://www.hobbyking.com/hobbyking/s...cessories.html

Don't forget the power supply for the charger.

[M.Garcia]

Yup I have it just didn't think to post the link lol.

So with that being said with what I'm purchasing I should be fine for now without doing any modifcations?

I YouTubed AoE and understand now, will I absolutely have to do that? Or wait until that piece breaks then just replace it?

[lurkingknight]

I have a very 'if it ain't broke, don't fix it' policy... so I run it till it breaks then fix it :P provided that the failure isn't catastrophic, like blowing apart the gearbox shell, so I prep a few things and check the basics.

if you don't feel like opening up the gearbox, no you don't absolutely have to do it, but realize your piston will fail prematurely if you don't What can happen a number of things,
like pre engagement where your sector gear rotates faster than your piston will return and impact the middle teeth and shear them off, Or the entire pickup tooth at the back of the piston shears off with the back of the piston in a nice ring.

I myself did a minimal AoE adjustment in my p90 with a steel rack piston, it's had about 3000 rounds through it with an 11.1v lipo without me touching the shims, but I have a computerized mosfet running the entire setup at 60% motor speed, (probably slower than if the gun ran with a 8.4v nimh) so preengagement is not as big an issue, only initial torque on the pickup tooth. But I will be ordering some sorbo to adjust the AoE eventually, I just have to take a measurement next time I have the gearbox open.

[Stealth]

Originally Posted by M.Garcia

I YouTubed AoE and understand now, will I absolutely have to do that? Or wait until that piece breaks then just replace it?

That depends if you want to open up the gearbox to do preventative maintenance now or open it up later to replace the broken piston.

[iKliiu]

If you don't have sorbo to adjust AOE with, use some rubber washers or even mouse pads. Another thing to watch out for is if the piston fits well. Sometimes, it can ride up too high on the gearbox shell, thus losing contact area with the sector gear, which can result in a stripped piston.

[Stealth]

Originally Posted by iKliiu

If you don't have sorbo to adjust AOE with, use some rubber washers or even mouse pads. Another thing to watch out for is if the piston fits well. Sometimes, it can ride up too high on the gearbox shell, thus losing contact area with the sector gear, which can result in a stripped piston.

Seriously?... mechbox work has hit a new low standard.

If you can't find or buy a sorbo pad (it's $5), then what you can do is add a nylon or metal washer between your piston head and piston. Don't use a torn-up mousepad.

[lurkingknight]

seriously, I don't see how it can take the beating of the piston cycle.

[M.Garcia]

Ye and I probably won't change it unless it breaks or I'm bored and have some spare cash laying around lol.

What does adding this sorbo pad do?

[ThunderCactus]

seriously reduces the impact force of your piston on your mechbox shell
It's really only necessary if you're above 370fps, at a high rate of fire, or using a weak shell to begin with

People seem to forget we didn't have sorbo for years, and we managed to build guns that lasted for years without breaking lol

[lurkingknight]

it also has the side effect of adjusting your AoE by amounts depending how thick the pad you choose. So rather than shim your piston head and piston with washers, you can shim the impact area of the cylinder head.

[iKliiu]

Originally Posted by Stealth

Seriously?... mechbox work has hit a new low standard.

Actually, some of the harder ones work quite well. Then again, the use of mouse pads was one of the first materials used to adjust AOE.