README with the payload bay's limits and the publication rule; a Payload brief issue template

.gitea/ISSUE_TEMPLATE/payload.yaml

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+name: Payload brief
+about: Tell us about a payload you would fly in the TerraHawk's belly bay
+title: "[payload] "
+labels: ["payload"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        The bay is in the belly, about 166 mm behind the CG. A payload of up to about 185 g
+        flies trimmed with it aboard, and a flush cover costs no drag. A drop needs the cargo
+        door, which is not on the first build. Estimates are fine: say what you know.
+  - type: input
+    id: what
+    attributes:
+      label: What is it
+      placeholder: A thermal core on a carrier board
+    validations:
+      required: true
+  - type: textarea
+    id: earns
+    attributes:
+      label: What it earns
+      description: What you would see, measure, carry or deliver, and for whom.
+    validations:
+      required: true
+  - type: input
+    id: mass
+    attributes:
+      label: Mass, g
+      placeholder: 40 (estimate)
+  - type: input
+    id: size
+    attributes:
+      label: Size, mm (length x width x height)
+  - type: dropdown
+    id: power
+    attributes:
+      label: Power
+      options:
+        - None
+        - 5 V
+        - Pack voltage (6S)
+        - Both
+  - type: dropdown
+    id: interface
+    attributes:
+      label: Interface to the flight controller
+      options:
+        - None
+        - UART
+        - CAN
+        - I2C
+        - USB
+        - PWM
+        - Other (say below)
+  - type: dropdown
+    id: mission
+    attributes:
+      label: Mission it flies
+      options:
+        - Survey grid
+        - Loiter over a point
+        - Vertical profile
+        - Point to point
+        - Hover
+        - Other (say below)
+  - type: dropdown
+    id: drop
+    attributes:
+      label: Does it drop
+      options:
+        - Stays aboard
+        - Drops once
+        - Drops several times
+  - type: textarea
+    id: notes
+    attributes:
+      label: Anything else
+      description: Links, a part number, what you have already tried.

README.md

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+# TerraHawk, public
+
+This is the public side of one builder's TerraHawk FPV: a 3D-printed 4+1 quadplane (the
+Nomadium Robotics kit) flying ArduPilot, with a mapping camera in its belly and an outdoor
+charging dock. The build log and reference live at https://terrahawk.warehack.ing.
+
+This repository carries two things:
+
+- **Releases.** This build's own work as files you can use: our printable parts, the parameter
+  files, print jobs and firmware.
+- **Payload briefs.** Ideas for what else could ride in the belly bay, filed as issues.
+
+## What is never here
+
+The kit's STL files, and parts made from them in full, belong to Nomadium and are not
+published here or on the site. Get the kit from Nomadium:
+https://hangar.nomadiumrobotics.com/terrahawk-fpv
+
+## The payload bay
+
+The bay is in the belly, behind the battery, and the payload is its cover: nine M3 x 8
+countersunk screws hold a cover to heat-set inserts, and whatever is on that cover is the
+underside of the aircraft. The first payload is a MAPIR Survey3W mapping camera. The limits,
+estimated on 2026-10-02:
+
+| Limit | Value | Note |
+| --- | --- | --- |
+| Mass, trimmed with the payload aboard | up to about 185 g | The CG stays inside its envelope after a drop |
+| Mass, trimmed empty | up to about 273 g | The CG stays inside its envelope when loaded |
+| Drag, cover fitted | none | A flush cover costs nothing |
+| Drops | need the cargo door | The door is not on the first build |
+
+These are estimates. The [payload ideas](https://terrahawk.warehack.ing/explanation/payload-ideas/)
+page explains them, with twelve candidates and what each would cost.
+
+## Propose a payload
+
+Open an issue with the **Payload brief** template. Estimates are fine: say what you know. The
+fields are the ones the aircraft and its simulator need (mass, size, power, interface, the
+mission it flies, and whether it drops), so a brief filed today is not asked for again.
+
+Opening an issue needs an account on this server, and registration is closed for now. A public
+form on the site is planned.