VFC HK416 CAG AEG High Cycle Custom FCU Setting Guide

In the previous installments, we completed the assembly of the VFC HK416 CAG and the initial setup of the FCU Leviathan.

This time, I intentionally designed it so that it won't function properly without FCU control, so I'll be setting up the electronic controls.

Introduction to the configurable settings of the FCU Leviathan

This guide will explain what can be configured in FCU Leviathan.

Connect the device to the battery and link it to your smartphone via Bluetooth, and the following screen will appear (download the app).

You can set your preferred mode for each selector.

The available modes are as follows:

For safety reasons, we strongly recommend setting Safe to SAFE.

Each shooting mode can be selected in the middle of this screen.

You can set the burst rate from 2 to 20 rounds as you like, and have about three different settings available. You can then assign each of these individually set burst rates to the respective selectors.

Next, motor control can be performed at the bottom of this screen.

We'll use each of these items effectively to make it work properly.

Scrolling further down will reveal new adjustment options.

Here, you can set a virtual magazine (0 to 400 rounds) and the gun will stop firing once that number of rounds is reached. If you set the "zero remaining rounds" warning (0 to 50 rounds), the motor will emit a sound to warn you when you have fired the specified number of rounds. Finally, setting the reload delay (0 to 15 seconds) determines how many seconds it takes to resume firing after the virtual magazine runs out of ammunition.

I'm not particularly interested in these features at the moment, so I probably won't use them.

Next, I'll show you the screen that appears when you tap the wrench icon.

This is the screen for checking the status of each sensor and initial setup, which I've shown before. Since the number of shots fired is tracked, it's extremely useful for determining when to perform an overhaul.

Finally, tapping the bar graph-like image will allow you to view various data.

I will omit the explanation of each item. The detailed data is very helpful.

We will use these tools to set everything up.

Operation settings via FCU

I'm planning to run it with an 11.1V 3-cell LiPo battery, but I'm a bit scared to do that, so I'll start by setting it up with a 7.4V 2-cell battery.

With this custom setup, it's obvious that without control, the overrun will be severe and the system won't work, so we'll adjust each parameter.

After much trial and error, the following seems to be the best option for 7.4V.

　　　

With these settings, the precocking also engaged properly.

This is a video of it in actual operation.

VFC HK416 CAG Custom Semi-Automatic LONEX A4 7.4V

VFC HK416 CAG Custom Full Auto LONEX A4 7.4V

The active brakes are slightly weak, and the pre-cocking position is unstable.

Next, I'll connect the forbidden 11.1V LiPo battery and adjust the settings. I think the active brake isn't strong enough, so I'll disable the precocking and reduce the full-auto cycle to 90%.

　

This is a video of it in actual operation.

VFC HK416 CAG Custom Semi-Automatic LONEX A4 11.1V

VFC HK416 CAG Custom Full LONEX A4 11.1V

It somehow managed to operate without errors, but the pre-cocking function didn't work, so the fully automatic cycle wasn't quite right.

We will measure the muzzle velocity and actual cycle under the following conditions: G&G 0.2g bio BBs, hop-up adjusted, 11.1V DCI LiPo 1200mAh full charge 12.6V, 25c~50c.

The cycle was as follows:

If you're interested, please also check out my review of the chronograph.

The performance is pretty good, but a few problems have emerged.

Furthermore, because the active brakes are used so aggressively, the motor gets quite hot and the brushes wear out very quickly.

To address these issues, I'll be using LONEX A1 (probably samarium-cobalt magnets) with high magnetic force to enhance the active braking system, along with Maple Leaf's hardest silicone gasket with a hardness of 70.

Lonex A1 Motor

Maple Leaf, Hardness 70, Silicone

Let's assemble this.

Gearbox readjustment and hop-up chamber reassembly

I'll transfer the pinion and brushes from a LONEX A4 motor and break in the LONEX A1 motor.

We'll finish the shim adjustments during the break-in period.

Next, since the hop packing is a new type I haven't used before, I'll investigate its compatibility with the nozzle.

It looks like it will be airtight, so I'll proceed with the assembly.

Since the gasket is made of silicone, applying silicone-based grease will cause it to swell, so install it carefully with dry grease.

Finally, we'll check how to land the hops and then we're done.

I'm not sure if it makes any difference, but to help with motor heat management, I attached graphite sheets, which have high thermal conductivity, to the motor to increase its surface area.

The idea is to intentionally make contact between the motor and the grip to efficiently transfer heat to the grip, effectively using the entire grip as a cooling device (though this will cause the grip to get hot).

By the way, the seat specifications are as follows:

I actually wanted to make the heatsink out of brass, which has a higher heat transfer rate, but I decided against it because it needed to fit in a confined space, and I had to consider the difficulty of processing it.

I'm not sure if this was the cause, but when I measured it later, the motor temperature had dropped from around 60°C to 40°C.

Heat transfer sheet　
It's originally for CPUs, so it's a bit expensive.

Now that the assembly is complete, it's time for a test drive.

Test drive, trouble occurred.

I was doing a test drive to find the right settings.

The performance with the found settings is as follows:

The rate of fire consistently exceeded 30 rounds per second.

However, a problem arose. The bearings in the gearbox shattered.

I noticed it because there was a strange noise and resistance when switching the selector.

I quickly opened the gearbox and found that the bearings were shattered.

I'm so disappointed.

It seems that the VFC's stock 8mm bearings can't withstand firing more than 30 rounds per second, so I've decided to switch to metal bearings for greater durability.

Next time, I'll show you how to reinstall the system.

If you'd like, please join me.