> ## Documentation Index
> Fetch the complete documentation index at: https://docs.czautoz.co.uk/llms.txt
> Use this file to discover all available pages before exploring further.

# Barrel Helicopter

> A single-seat helicopter players build themselves from a cut fuel drum, ten salvaged parts and four wheels. Four colours, decided by the barrel.

The Barrel Helicopter is the only aircraft in the mod that players make rather than find. It starts as an ordinary fuel drum: cut it open with a **Barrel Cutting Torch** and you are left with a bare frame. Every other piece of the aircraft is a separate item that bolts into its own slot, and an **Airframe Assembly Wrench** builds each one in turn. Fourteen slots later it is a helicopter.

It seats one, flies slowly, carries almost nothing and climbs to about a third of the height the Merlin will. It is meant to be the aircraft a server gets before it gets a real one.

## Specifications

| Property              | Value                                                                                                                                   |
| --------------------- | --------------------------------------------------------------------------------------------------------------------------------------- |
| **Total seats**       | 1 (pilot only)                                                                                                                          |
| **Startup Time**      | \~12 seconds — the quickest in the fleet                                                                                                |
| **Walk about inside** | ✗ — it is an open frame                                                                                                                 |
| **Mass**              | 373 kg                                                                                                                                  |
| **Max Airspeed**      | 115 km/h                                                                                                                                |
| **Service Ceiling**   | 2,134 m                                                                                                                                 |
| **Sling Capacity**    | 120 kg                                                                                                                                  |
| **Fuel**              | 70 L, burning 55 L/hr                                                                                                                   |
| **Landing gear**      | Four wheels on three axles, sprung                                                                                                      |
| **Config Files**      | `CZ_BarrelHeli_Config.json` · `CZ_BarrelHeli_Green_Config.json` · `CZ_BarrelHeli_Blue_Config.json` · `CZ_BarrelHeli_Yellow_Config.json` |

Per-helicopter config files live in `$profile:\CZAutoz_Heli\HeliConfigs\`.

## Building one

<Steps>
  <Step title="Cut the barrel">
    Hold a **Barrel Cutting Torch** and cut an ordinary fuel drum. The torch runs on gas, so it needs a charged canister, and the flame is visible to everyone while it burns. What you get back is a bare frame — nothing else.
  </Step>

  <Step title="Bolt a part into its slot">
    Each part is an inventory item. Put it in the frame's matching slot, or hold it and attach it straight from the cursor. Fitting a part does not make it appear yet.
  </Step>

  <Step title="Build it with the wrench">
    The **Airframe Assembly Wrench** builds the fitted part. Only then does it show on the frame, collision and all. The wrench also takes parts back down, in reverse order.
  </Step>

  <Step title="Work up the aircraft">
    Slots open one stage at a time, in the order that keeps every part sitting on something: undercarriage first, then cage, cockpit, engine bay, tail boom, tail fin, wings and both rotors. The four wheel slots open once the undercarriage is built, and the battery and bulb slots open with the engine bay.
  </Step>

  <Step title="Sign it off">
    With every part built, a final assembly turns the frame into the finished aircraft, in the colour of the barrel you cut.
  </Step>
</Steps>

A part-built frame is a proper world object with a helicopter's lifetime, so an unfinished build survives a logout and a restart. It also sits down on whatever slope you put it on, and re-seats itself as its skids and then its wheels go on.

## Colours

The barrel you cut decides the aircraft you end up with, and every part of it comes in the same four colours. A frame only accepts parts in its own colour, and stripping one hands them back that way.

| Barrel cut       | Aircraft classname     | Frame classname              |
| ---------------- | ---------------------- | ---------------------------- |
| `Barrel_Green`   | `CZ_BarrelHeli_Green`  | `CZ_BarrelHeli_Frame_Green`  |
| `Barrel_Blue`    | `CZ_BarrelHeli_Blue`   | `CZ_BarrelHeli_Frame_Blue`   |
| `Barrel_Yellow`  | `CZ_BarrelHeli_Yellow` | `CZ_BarrelHeli_Frame_Yellow` |
| Any other barrel | `CZ_BarrelHeli` (red)  | `CZ_BarrelHeli_Frame` (red)  |

Each one names its own colour in the inventory and at a trader, so admins and traders can hand out a specific aircraft.

## Parts and tools

Ten body parts and four wheels. Add `_Green`, `_Blue` or `_Yellow` to a part's classname for the other colours — the engine bay and the tail rotor carry no painted surface, so they exist in one colour only.

| Classname                      | Part                                                              |
| ------------------------------ | ----------------------------------------------------------------- |
| `CZ_BarrelHeli_Undercarriage`  | Undercarriage — the first part, and what the wheel slots hang off |
| `CZ_BarrelHeli_Cage`           | Cage                                                              |
| `CZ_BarrelHeli_Cockpit`        | Cockpit                                                           |
| `CZ_BarrelHeli_EngineBay`      | Engine bay — one colour only                                      |
| `CZ_BarrelHeli_TailBoom`       | Tail boom                                                         |
| `CZ_BarrelHeli_TailFin`        | Tail fin                                                          |
| `CZ_BarrelHeli_WingLeft`       | Left wing                                                         |
| `CZ_BarrelHeli_WingRight`      | Right wing                                                        |
| `CZ_BarrelHeli_RotorMain`      | Main rotor                                                        |
| `CZ_BarrelHeli_RotorTail`      | Tail rotor — one colour only                                      |
| `CZ_BarrelHeli_FrontWheel`     | Nose wheel                                                        |
| `CZ_BarrelHeli_MiddleWheel`    | Main wheel — one each side, so two are needed                     |
| `CZ_BarrelHeli_RearWheel`      | Tail wheel                                                        |
| `CZ_BarrelHeli_CuttingTorch`   | Barrel Cutting Torch — opens the drum, runs on gas                |
| `CZ_BarrelHeli_AssemblyWrench` | Airframe Assembly Wrench — builds and dismantles every part       |

These thirteen parts and two tools are the only new items that spawn in loot, in Industrial. They are the route to the aircraft, so if you would rather sell them, set their `types.xml` entries to `nominal=0`. See [Required Items](/server-config/required-items).

## Landing gear

It rolls, which no other aircraft in the fleet does. Four wheels sit on three axles — a single nose wheel, two mains and a single tail wheel — each on its own suspension. The legs move with them: the nose leg swings on its pin and squeezes its coil spring, the main legs telescope, and the tail leg pivots on its upper arm with the shock sliding into its tube. The gear settles as the aircraft takes its weight and extends again as it lifts.

Wheels are ordinary attachments and can be knocked off, repaired and replaced like a car's.

## Taking one apart

The wrench dismantles a finished aircraft or a part-built frame, returning every part at the wear it had. The rules and the timings are in the `barrelHeli` settings block:

| Setting                     | Default | What it does                                |
| --------------------------- | ------- | ------------------------------------------- |
| `barrelHeli.allowStrip`     | `1`     | Whether anyone can strip an aircraft at all |
| `barrelHeli.stripOwnerOnly` | `1`     | Only the player who built it may strip it   |
| `barrelHeli.cutTime`        | `12`    | Seconds to cut the barrel open              |
| `barrelHeli.buildTime`      | `8`     | Seconds to build or remove one part         |
| `barrelHeli.assembleTime`   | `20`    | Seconds for the final sign-off              |
| `barrelHeli.torchUses`      | `8`     | Barrels one torch will cut                  |
| `barrelHeli.wrenchUses`     | `40`    | Jobs one wrench will do                     |

A locked helicopter cannot be stripped at all, whatever these are set to. The strip option hides itself from players who cannot use it rather than letting them start and fail.

## Cargo

The Barrel Helicopter has no cargo of its own. Owners can give it storage with `cargoModules.barrelheli` — `modules` defaults to `0`, and `cellsPerModule` defaults to `1000`. See [Cargo System](/features/cargo-system).

## Default Flight Tuning

| Parameter                        | Default |
| -------------------------------- | ------- |
| `flight.liftMultiplier`          | 2.20    |
| `flight.maxAirspeed`             | 62 kn   |
| `flight.dragForward`             | 0.42    |
| `flight.rotorSpoolRate`          | 0.04    |
| `flight.maxVerticalSpeed`        | 11.0    |
| `control.pitchStrength`          | 2.45    |
| `control.bankStrength`           | 2.95    |
| `control.yawStrength`            | 1.15    |
| `control.weathervaneStrength`    | 1.05    |
| `control.b2tStrength`            | 1.70    |
| `control.response.rollAccelTau`  | 0.045   |
| `control.response.rollDecayTau`  | 0.115   |
| `control.response.pitchAccelTau` | 0.045   |
| `control.response.pitchDecayTau` | 0.115   |
| `control.response.yawAccelTau`   | 0.070   |
| `control.response.yawDecayTau`   | 0.130   |
| `groundEffect.bonus`             | 0.16    |
| `groundEffect.altitude`          | 5.0 m   |
| `etl.bonus`                      | 0.18    |
| `etl.speed`                      | 34.0    |
| `autorotation.gravityFactor`     | 0.50    |
| `autorotation.descentCap`        | 10.0 kn |
| `altitude.liftStart`             | 5000 ft |
| `altitude.ceiling`               | 7000 ft |
| `camera.distance`                | 8 m     |
| `fuel.maxCapacity`               | 70 L    |
| `fuel.burnLPH`                   | 55 L/hr |

<Note>
  These are indicative dev-tuned defaults and can change between builds — the in-game **Admin Panel** always shows the live per-helicopter values.
</Note>

See [Per-Helicopter Settings](/server-config/per-helicopter-settings) for a full description of every parameter.