Maintenance Log: A well-worn Velocity Arms VA36 / JG G36 (56k warning!)

[Styrak]

I don't like those modify purple pistons. I've replaced many of them on other people's guns when the teeth stripped.

[lurkingknight]

did you by chance take a look at the trigger contacts? one of the guys I run with has a VAm4 and his trigger is cooked, we haven't opened up the gearbox yet, but there's no sign of any current running through the trigger when we close the circuit, wondering if it's unique to his VA gun or not. Another one of our guys has the same va36 and has had more rounds through it than the m4 and it's still running strong.

[Kos-Mos]

Originally Posted by Styrak

I don't like those modify purple pistons. I've replaced many of them on other people's guns when the teeth stripped.

+1

They are not polycarbonate, they are acrylic... so they shatter in a patern similar to glass when they fail... breaking every other component with it.

They also won't bend under stress, they just break, so the teeth are usually ripped right off and fly somewhere else in the mechbox, causing extra damage.

The White Modify ones are insanely nice though.

[Wrath144]

G&P motors are liable to perform poorly stock, if you get one tuned up on a motor lathe then it releases its true potential! Someone into RC racing should be able to help you out, or at least point you in the right direction.

[MaciekA]

Originally Posted by lurkingknight

did you by chance take a look at the trigger contacts? one of the guys I run with has a VAm4 and his trigger is cooked, we haven't opened up the gearbox yet, but there's no sign of any current running through the trigger when we close the circuit, wondering if it's unique to his VA gun or not. Another one of our guys has the same va36 and has had more rounds through it than the m4 and it's still running strong.

They actually look pretty good where the contact is made inside the gearbox. I could imagine the outside part next to the selector plate maybe being the first thing to go if one were to drop the gearbox or something, but otherwise, pretty tough.

As far as your VA M4, the trigger assembly in the VA36 is going to be quite differently-shaped, and probably even made in a different factory, so it would be hard to compare them. My (limited!) experience so far has shown me that version 2 (M4) trigger contacts aren't as hefty and massive as V3 ones, I think the trigger assembly and its contacts in the VA36 will last quite a long time... I find a lot of small differences with the whole V3 gearbox in general impress me relative to the V2. I'm not experienced to know whether these design details make a big difference, but a bigger, bulkier trigger assembly, motor cage (makes pinion-bevel alignment a snap), bigger flaps for the spring guide, etc, make a good impression.

BTW, I think with the VA M4, any trigger problems should be dead obvious just from visual inspection. Should be an easy fix... And in my experience Toronto Airsoft has been quite accommodating with minor repairs of their products.

[MaciekA]

Originally Posted by Kos-Mos

+1

They are not polycarbonate, they are acrylic... so they shatter in a patern similar to glass when they fail... breaking every other component with it.

They also won't bend under stress, they just break, so the teeth are usually ripped right off and fly somewhere else in the mechbox, causing extra damage.

The White Modify ones are insanely nice though.

Thanks for sharing this! The purple piston is in my spare parts bin, so I'll keep that in mind if I get around to trying to use it. Much appreciated.

[MaciekA]

Originally Posted by Wrath144

G&P motors are liable to perform poorly stock, if you get one tuned up on a motor lathe then it releases its true potential! Someone into RC racing should be able to help you out, or at least point you in the right direction.

Never realized this was possible until you suggested it. Is this a common procedure in the RC world? (It seems they are always several steps ahead of us airsoft folks in so many technical experiences...)

[Kos-Mos]

Originally Posted by MaciekA

Never realized this was possible until you suggested it. Is this a common procedure in the RC world? (It seems they are always several steps ahead of us airsoft folks in so many technical experiences...)

Yes but not anymore.

This was standard on brushed, competition-grade motors back in 1994...

Now all high-end motors are brushless, require zero maintenance and are about twice as powerful.

I was working on a brushless motor driver for airsoft but got carried away going back into RC... I might just need to work on it again...

[MaciekA]

Updates:

1) Finally noticed that the reason the gearbox was seizing wasn't the G&P M120 motor but the metal bearing spring guide not allowing the stock spring to compress enough to allow the piston to move all the way back. It reduced the travel path of the piston by a couple mm and it seemed to be enough to stop the cycling in its tracks fairly often (but thankfully not blow anything up). Went back to the stock spring guide and the problem went away.

2) Tested the above update until I was satisfied things were stable. Wanting to toy around with compression and power, I replaced the stock spring, which fires about 360fps, with a new spring, a Modify S110+. The stock spring is one of the ones that attaches to the piston head, so I replaced the piston with it. I tossed in a spare Madbull X-Factor piston I had lying around (picture below), and the finger-over-the-nozzle compression test yielded some encouraging results. I chronoed the gun, and it now fires about 400fps. Hopefully the hopup bucking keeps up with the faster velocities.



3) Having convinced myself that the upgrade motor I originally got for this gun probably doesn't have any gremlins in it, I re-attempted to update the motor from the stock JG motor to a G&P M120 short type motor. This motor's pinion shaft isn't as long as the JG's, so it requires quite a bit of motor height adjustment. Unfortunately, the motor cage on this AEG is made of a very soft metal, so the entire cage actually bends its shape slightly if you apply motor height. This means that the motor adjustment screw and the motor cage screw at the bottom of the pistol grip do not align with the pistol grip's bottom! I had to unbend it a bit and complete the height adjustment with the gearbox placed in the lower receiver. A new gearbox and motor cage might be on my list in the future, pending some research.

At the moment though, it runs great.

Here's a video comparing the motor RoFs on a half-discharged 7.4V 800mAh LiPo:

JG G36 Motor Upgrade - YouTube

I'm still really pleased with this rifle and hope to keep nudging its specs upwards as I experiment with various upgrades. I'd like to gradually turn it into a monster as I learn things.