VFC HK416 CAG AEG High Cycle Custom Motor

Last time, I introduced my approach to customizing the VFC HK416 CAG AEG and the story of how I broke my own FCU Leviathan and had to buy a replacement.

In particular, the destruction of the FCU Leviathan last time was due to my own carelessness, and I was shocked and felt foolish.

The new FCU Leviathan has finally arrived, and I've confirmed that it's installed, so I'll start assembling the gearbox.

Assembling the gearbox

Since I was able to confirm the assembly of the parts inside the gearbox in the previous step, I will now proceed with shim adjustment.

Since the shim adjustment will be done according to the usual bevel gear standard, we will attach the grip and motor to one side of the gearbox, which already has only the bevel gear assembled.

This time, we'll be changing the grip to a PTS EPG Enhanced Grip, so let's take a closer look.

First, assemble the motor position adjustment unit.

Next, I'll insert the motor and check if there are any size issues.

It looks like there won't be any problems, so I'll install it into the split gearbox with bevel gears.

After that, I adjust the shims using my usual method with a thickness gauge.

If you're interested, please check out my method for adjusting sims.

I'll break in the motor while I'm adjusting the shims. The shim adjustment will take about 15 minutes, so it should be just right.

I usually run it with two AA Eneloop batteries for 3.7V, but even with the LONEX A1+, the output wasn't enough, and it ran very weakly.

I'm introducing a motor break-in kit, so please take a look if you're interested.

Once the shim adjustment is complete, apply grease to each component.

This FCU has an optical sensor, so ideally you should apply a thin layer of grease, but I didn't want to risk damaging the gearbox, so I applied it as usual.

The idea was that if the optical sensor displayed an error, I could just clean it (which turned out to be no problem at all).

The greases I'll be using are the usual Bellhammer No. 2 Gold and GAW's extreme pressure grease.

First, I apply Bell Hammer grease to the metal-to-metal parts of the gearbox, and GAW grease to the rest using a brush.

One thing to be careful about here is that if ball bearings are used in the bearing system, make sure that grease is properly applied inside the bearings.

Bearings are generally durable, low-friction, and good quality, but they will be ruined instantly if the oil film breaks down.

We will apply grease thoroughly to the remaining parts as well.

I took a little extra care and didn't apply grease to the cutoff portion of the sector gear.

All that's left is to assemble it carefully.

Incidentally, VFC gearboxes are easy to assemble because the anti-reversal latch has a deep slot. The QD (Quick Discharge) design is also a nice feature.

Once you've closed the gearbox, apply Tokyo Marui high-viscosity grease to the Airsoft97 M100 spring and assemble it, and you're done.

This completes the assembly of the gearbox.

Bellhammer No. 2 Gold Grease
This is a classic, top-quality grease. No. 2 has the same ingredients as No. 0 but with a higher viscosity. I primarily use it for metal-to-metal connections.

GAW G-GREASE
This is a standard grease. It has a lower viscosity compared to the Bellhammer Gold series, so I use it inside the cylinders of both electric and airsoft guns. It's a bit pricey, but the quantity is large, so in the end, it doesn't feel overpriced.

Gearbox test drive

Now that the gearbox is complete, I'll assemble just the grips and motor and do a test run before putting it into the receiver. From here on, I encountered a series of problems, so I don't have many photos, but I'll write about it in a little more detail for my own reference.

FirstConnect a 7.4V LiPo battery (storage voltage 7.6V) and connect it to the app, then pull the trigger.ThenThe motor twitches for just a moment, then stops, beeps, and doesn't move.Looking at the app's Air Log,The battery voltage is too low to operate."That's what it said."

Apparently, a protection function activates when the 7.4V LiPo battery voltage drops below 5.5V.

At this point, my interpretation was that the LONEX A1+ motor required a lot of power and the battery's storage voltage was insufficient, so I fully charged it to 8.2V and tried again.

However, it's not working and is throwing the same error as before.

My thought was that I might have failed to adjust the shims properly, putting extra load on the motor and preventing it from working. So I disassembled it again, adjusted the shims, and tried again, but there was no change.

Therefore, in order to isolate the cause, we tested it using various patterns.

So, I'll try changing the conditions slightly and testing it.

Trial and analysis of modified conditions

My initial thought was that the LONEX A1+ motor has a high power requirement and therefore wouldn't work with a 7.4V LiPo battery, so I bought an 11.1V LiPo battery and tried using it.

This is a DCI GUNS 11.1V LiPo 1200mAh 25~50C battery.

I thought this battery would definitely work, so I tried it. But then, even in broad daylight, in my room, I saw a spark, and then it stopped responding. It turned out the included 40A fuse had blown.

I initially thought it was an anomaly, so I tried again with a 40A fuse I had on hand, but the result was the same.

Blown fuse

I decided to change the settings because I thought that trying any more would damage the FCU.

The next condition I tried was to install a LONEX A4 motor, which has relatively standard specifications, and run it.

It worked perfectly fine after that.

Considering these points,I concluded that, with my current skill level, I cannot create the conditions necessary to operate the LONEX A1+ when using the FCU Leviathan.

The load is relatively soft, using an Airsoft97 M100 spring with only a 3-tooth cut from the single sector gear, so it's not that high.

Despite this condition, attempting to operate the LONEX A1+ motor requires a large amount of power, which I believe exceeds the limits of what the FCU can handle.

I think that a standard analog switch would probably work with the LONEX A1+ motor, but unless you use a battery with a very large capacity, it will forcibly release a large amount of power and damage the battery.

Because of this, I decided to give up on the top-of-the-line LONEX A1+ motor and use the LONEX A4 motor instead.

So I replaced the motor's pinion gear, replaced the brushes, and readjusted the shims for break-in before reassembling it.

My poor LONEX A1+ motor, stripped off due to my lack of skill.

However, the performance of the LONEX A4 motor with a 7.4V LiPo battery was just average.

The performance values ​​of a 7.4V LiPo battery at a storage voltage of 7.6V are as follows:

This data shows that the engine overruns in semi-automatic mode without any pre-cocking or other settings, so a slight application of active braking is being performed.

The numbers aren't bad, but they're not particularly impressive either. While it's true that pre-cocking can shorten the semi-automatic cycle time, it still feels somewhat underwhelming.

So, I decided to go with the 11.1V LiPo battery I had purchased, as it worked fine when I tried it out.

Using 11.1V won't cause any fatal problems, but it will introduce some issues, so the idea is to control those with the FCU.

Now that the basic specifications are decided, we will assemble the remaining parts.

So next time, I'll show you how to assemble and set up the remaining parts.