Two interchangeable pods mount on the payload rail of any airframe (hexa or octo), on the CG. Shown here: the additional items beyond the airframe, and the operating sequence for each. The airframe is drawn faded for context — build it on the Airframes sheet.
Drop rig (MVP-1) — servo-released frangible paint pod
Mounting — flight direction ◄ left · pod items keyed to the BOM below
Bill of materials — additional to the airframe
#
Part
Product / source
Price
1
Payload release (pin/clip, servo-driven)
Generic RC servo-release unit (aluminium arm + pin/hook), AliExpress / Lazada SG — or DIY: a metal-gear servo + printed pin bracket (DSSERVO 150 kg · hobbysquare). Strap-on, no-mod alternative: Gannet Sport / X · dronefishing.com
~S$25–75 / Gannet US$59–115
2
Bungee sling cradle
Elastic shock-cord loop that cradles the container from below and hooks the pin — soft support, no clamp on the payload. Shock cord + 2 small hooks
~S$5
3
Frangible container + inert paint
Balloon route: latex balloon cradled by the sling — cheapest, most reliable burst. Capsule route: thin-wall ≤1 kg frangible capsule with a moulded loop — repeatable dose, hangs straight off a clip release (no sling). Washable dye fill; bench-test the burst height
Hold & release: the container is never clamped. A bungee sling cradles it from below and both ends hook a servo-driven pin; the pin is self-holding — the payload's weight keeps it seated, so the servo only retracts it (near-zero torque, fails safe: pin stays in on signal loss). Wire it to a spare autopilot output. Two routes: balloon + sling (cheapest), or a frangible capsule with a moulded loop hung straight off a clip release (Gannet) — no sling. Inert paint only.
Operating sequence — drop (schematic animation, 4 phases · 7 s loop)
1 · TRANSIT approach on the beam
2 · POSITION + ARM hover on CG, arm latch
3 · RELEASE straight-down drop
4 · IMPACT burst + persistent mark
Schematic only. Real aiming is overfly + timed release; first demo is against a static / slow target. Drop is the cheapest demonstrator of delivery; for a fast or moving target the marker (MVP-2) is the better method.
Mounting — forward ◄ left · pod items keyed to the BOM below
Bill of materials — additional to the airframe
#
Part
Product / source
Price
1
.68 paintball marker
Empire Mini GS (electro-pneumatic), or Tippmann TMC magfed · licensed dealer
US$379.95 / 247.95
2
Air source + regulator
Maddog 13ci HPA tank + reg (preferred), CO2 fallback
US$49.95 / 29.95
3
Feed
Magfed magazine (airborne), or Halo Too force-feed hopper — no gravity hopper
US$82.95
4
Trigger interface
Pololu RC-switch #2804 taps the trigger board · pololu.com
US$17.95
5
Boresighted FPV cam
RunCam Nano 2 + OSD pipper (on the barrel axis)
US$19.99
6
.68 barrel
Marker barrel, ~90 m/s (in the marker)
in 1
7
Vibration grommets
Rubber isolators — decouple marker recoil from FC / cam
~S$10
8
Pod mount frame
CF / printed forward bracket + fasteners
~S$40
Marker pod total
on top of any airframe
~US$550 (~S$740)
Safety floor (non-negotiable): inert, water-based paint or dye only — nothing else goes in the payload. The marker is a licensed item: buy from a licensed dealer and confirm local rules.
Why forward, boresighted, magfed: the marker points along the flight vector, so aim comes from flying (OSD pipper on cam 5); magfed / force-feed avoids the gravity-hopper jams a hovering or banking airframe would cause; HPA gives stable pressure vs CO2's temperature droop.
Recoil / boresight: grommets (7) isolate the marker so per-shot recoil doesn't de-boresight the cam or upset the FC. Keep the barrel axis through the CG to minimise pitch kick.
Detail B — feed & trigger interface (balloons 3–4)
RC-switch taps the marker's electronic trigger board — a flight-controller aux channel fires it. Anti-chop eyes are kept: no chopped balls, no dud fill.
Schematic only. Aim comes from flying the airframe so the boresighted camera's pipper sits on the mark, then a short burst. Persistent "won't-wipe-off" fill is a separate R&D workstream; regular paintball fill proves delivery.
Engineering · pods · companion to the Paint & Pain build brief and the Airframes sheet. Open → Print → Save as PDF (Landscape).