This engine chassis is meant to replace the gearbox inside of the airsoft rdb. Once installed, it can fit your battery, FCU, hose, and engine all inside. Even better is that you don't need to remove the chassis to remove the engine, the engine pops out the top.

This conversion is non-invasive, requiring no permanent modification, so you can always switch back to an AEG.

Double-check nozzle alignment; 3d printer tolerances could shift the hop-up and engine alignment. Make sure the hole the nozzle sticks out (the hole where the hop-up plugs into the engine) is centered and round. This is a sensitive area, and 3d printer tolerances can shift the alignment in this spot. Some sanding may be required to get the spot round and center the nozzle.

The current files are version 2.5. which updates the top bracket to be a snug fit and fixes an issue where the Engine would slide backward over time. Please print the newest version of the chassis to avoid this issue.

You'll still need a few things outside the print files: the electronics. You have several options for electronics.

P90 option (most simple and most compact)

1. P90 HPA trigger
   https://www.wolverineairsoft.com/product/electronics-kit-for-hydra/

2. smaller micro switches
   https://www.digikey.com/en/products/detail/omron-electronics-inc-emc-div/D2F-L/83251

3. 24-22 AWG wires

Wolverine Universal wiring kit (easier to fix and replace parts than the p90 but is a lot more cramped on space.)[the next method after this one is the same, but better in everyway]

1. Black Leaf universal kit
   https://ampedairsoft.com/blackleaf-airsoft-universal-board-for-wolverine-hpa-units/

GORILLA FCU option (best performing, most versatile, easiest to repair, but most expensive)[Also my recommended option]

1. Gorilla FCU (INSANLEY powerful FCU)
   https://ampedairsoft.com/gorilla-airsoft-fcu-with-bluetooth/

2. Polarstar or Black leaf trigger board (The black leaf is cheaper and better)
   https://ampedairsoft.com/blackleaf-airsoft-universal-board-for-polarstar-hpa-units/

3. 7" wire harness
   https://ampedairsoft.com/polarstar-wire-harness-75-for-jack-f1-f2-fusion-engine/

4. Solenoid leads
   https://ampedairsoft.com/polarstar-solenoid-wiring-harness-for-jack-f1-f2-solenoid/

5. trigger lead (should come included with black leaf version)
   https://ampedairsoft.com/polarstar-hk417-trigger-lead-kac-lmg-tavor-jack-f1-f2/

WOLVERINE REAPER ONLY
Reaper Electro-Mechanical (requires no FCU, only a battery and one micro switch)[By far cheapest, simplest, most robust option]

1. Electro-Mechanical harness.
   https://www.wolverineairsoft.com/product/electromechanical-wire-harness-for-the-reaper/

2. Micro Switch
   https://www.digikey.com/en/products/detail/omron-electronics-inc-emc-div/D2F-L/83251

Assembly video down below

This new version 2 is now printer friendly, and has a co2 stock version. Version 2.5 fixes a n issue where the engine sags backwards overtime.