More Systema PTW Infinity news from Japan’s Hyper Douraku – this time about the inside of this most innovative gearbox.
The following article is a based on Hyper Douraku’s text and pictures, with a mixture of Google translate and some editing on my part. So, hopefully it makes more sense to English speakers than a basic Google translation. I’ve also abridged parts to make it more readable.
It’s a continuation of Hyper Douraku’s original Infinity article (English translation).
I couldn’t show the inside of the PTW INFINITY gearbox in Part 1 due to Systema’s patent application, but I now have permission to do so.Hyper Douraku
To remove the INFINITY gearbox from the lower receiver, first remove the bolt catch.Hyper Douraku
Note the plastic cap over the fire selector screw. This is an attempt to make the selectors look more normal, compared with Systema’s other INFINITY prototypes.Hyper Douraku
Remove the cap then remove the screw, to remove the selector lever on the left hand side.Hyper Douraku
Remove the four screws on the top of the gearbox.Hyper Douraku
This cover encloses the interlocking gear shaft for the selector.Hyper Douraku
Pull out the plate that secures the selector lever on the right hand side.Hyper Douraku
Now remove the selector lever on the right hand side.Hyper Douraku
Remove the two screws from the top of the gearbox.Hyper Douraku
Remove the buffer tube cap.Hyper Douraku
Pull the gearbox out of the lower receiver.Hyper Douraku
The PTW INFINITY gearbox is revealed.
The motor, gears, trigger switch, and electronic control board are housed inside.Hyper Douraku
There is a selector plate on the left hand side of the gearbox. By rotating the selector lever, the micro switch on the electronic board side switches from safe, to semi, to auto.Hyper Douraku
The gearbox is opened by removing the six screws on the left and right hand sides.
A small brushless motor replaces the conventional bevel gear. The black box in the middle of the battery cord is the fuse case. Even if the battery is accidentally inserted backwards, no current will flow beyond the fuse box.Hyper Douraku
INFINITY’s brushless motor is smaller than a PET bottle cap. Surprisingly small !!!Hyper Douraku
At the time of review the final gear ratio was still being tested. It’s likely to be either 24: 1 or 27: 1.Hyper Douraku
With the 1st and 2nd spur gears removed.Hyper Douraku
The sector gear removed. It’s a dual sector gear (DSG), which fires one BB at half normal cycle.Hyper Douraku
The DSG is chromoly steel. Think DSG and you think high rate of fire. Here, Systema uses it primarily for improving trigger response and power efficiency.Hyper Douraku
Remove the trigger/bolt stop switch board.Hyper Douraku
This is the small brushless motor which Systema designed exclusively for INFINITY.
It consists of 12 stators and 14 magnets. The stator is fixed to the gearbox side, and the steel rotor rotates. Since it is brushless, it has good transmission efficiency, and because it is small, it has low inertia and high acceleration.
Small brushless motors have become mainstream, with the evolution of drone technology.Hyper Douraku
Open the cover on the left hand side of the gearbox and you will find the control board.
Due to the patent, some of the board’s surface is blurred, but it utilises a high-speed processing chip – an ARM core – and dedicated firmware.
The selector plate moves back and forth via the rack gear, and the semi/auto position is switched by the micro switch. The plate operates with a detente to give a click to the fire selector lever.Hyper Douraku
In this prototype, the trigger and trigger spring are the same as that of a conventional PTW.Hyper Douraku
However, due to other structural changes, the trigger pull is lighter. The prototype has a pull of about 520g. For the production model it’s likely the spring will be changed for a pull of about 720g.Hyper Douraku
Motor, integrated with the control board, removed from the gearbox. There is a reverse rotation prevention mechanism behind the motor.
Compared to a conventional PTW there is less ‘felt’ magnetism from the motor. E.g. screws do not stick to the receiver (if you currently own a PTW you’ll know what I mean).Hyper Douraku
PTW INFINITY has an automatic pre-cock adjustment function. By connecting the battery while pulling the trigger, it automatically cycles three times, then holds the retracted position that matches the cylinder spring strength.
This makes it easy to calibrate for cylinders of various powers; or, compensate for aging springs.Hyper Douraku
In addition, switching between full auto and 3-round burst can be actioned via the trigger; and, the pre-cock function can be turned off in this way also.Hyper Douraku
With an optional programmer, you can adjust the sector gear position during pre-cocking in 0.5 degree increments.
You can also set the voltage warning value, voltage cut off value, motor heat generation warning value, motor heat generation stop value, and firing rate (rpm) with this programmer.
The rate of fire is set to 800 rpm as standard. However, the setting can be changed between 400 and 1200 rpm.
At the time of the review, the motor mobility rate and electromagnetic brake rate could be changed, but it will lead to lower response than necessary and increase power consumption.Hyper Douraku
PTW INFINITY will be available first as a Value Kit only.
The contents of the value kit are:Hyper Douraku
- 150mm Inner barrel/hop group (6.03 mm ID)
- M130 Cylinder assembly spring
- INFINITY Ambi gearbox of ambi selector
- Dummy motor to which a conventional PTW grip can be attached
With the conventional PTW there is no value kit of the same configuration. When the existing parts are added up for comparison, they come to about 170,000 yen (approx £1160.00 GBP).
INFINITY may be about the same price, or a little cheaper for early adopters. This is pure speculation, however.Hyper Douraku
Comparison with Conventional PTW
This time, I brought in two of my own PTWs and compared compatibility and shooting performance.Hyper Douraku
The lower receivers are compatible, so you can simply change gearboxes by purchasing a the INFINITY Value Kit.
However, cylinder compatibly is still to be decided. It will depend on the final ratio/size of the second spur gear.Hyper Douraku
INFINITY’s very different sound and feel can be perceived with a single shot.
Compared to a conventional PTW it is super quiet. There is no real sound of motor or gears – only the piston striking and burst of fire. Also, since the gear rotation axis and the motor rotation axis are the same, there is no sideways torque from the grip like a conventional PTW.
When the trigger is pulled, the BB is fired – fast! Then, the pre-cock function prepares for the next BB. This is the same order of action as an RS M4. For reference, I turned off the pre-cock. This time I felt the sector gear start to turn, but it is still much more responsive than a conventional PTW.Hyper Douraku
One point of concern is the inauthentic look of the fire selector. Currently this is the only obvious downside with INFINITY.
However, looking at the big picture, INFINITY will allow totally new PTW form factors to be built around it by third party receiver manufacturers – like NBORDE.Hyper Douraku
Speaking to its developers, Systema does not want to expand it model line up. It wants to actively collaborate with shops and manufactures to create new PTW types.Hyper Douraku