About¶

Concise reference for all physical components, mass targets, and hardware specifications. Single source for cross-referencing CAD, slicing profiles, and field maintenance. Covers structural printed parts, electronics, connectors, propellers, and mass budget.

MM Hardware Reference V2.4.6¶

Updated to V2.4.6: GX12-7 polarity corrected (male panel mount in drone), version references updated.

This document describes the structural, mechanical, and electrical hardware of the libdrone V2.4.6 airframe. Supersedes V2.4.6 hardware reference.

Concise reference for all physical components, weight targets, and hardware specifications. Single source for cross-referencing CAD (FreeCAD), slicing (PRUSA profiles), and field maintenance (DMOM/DSRA).

1. Architecture Summary¶

• Frame class: 6-inch True-X (330 mm wheelbase)
• Body: 5-layer X sandwich — PETG 3mm / PCCF 3mm / PCCF 3mm / PCCF 3mm / PETG 4mm, 16 mm total height
• Rods: 4 × 2.0 mm OD CF rods, 333.0 mm, passing through all sandwich layers
• Arms: Split design — PETG shaft (printed vertically) + PETG tabs (printed horizontally)
• Tab lock: T-profile mechanical lock in PCCF T-slot. No adhesive. No inserts in PCCF.
• Motor mounts: Floating silicone system with PETG-CF passive cover
• Bumpers: ASA Natural sacrificial tip bumpers
• Electronics: Distributed nose-to-tail on Platform (middle layer, 283mm × 40/50mm stepped PETG). Three-layer architecture: sandwich / Platform / Backplane.
• GPS/Camera: Single front bracket above camera, removable in 60 s
• Platform (V2.4.6): Middle layer PETG (283×40mm). Integral battery rails, dual GX12-7 chimneys, MIPI channel, wire channels, fan slot, attachment post pairs. Extends fore and aft beyond X body. Battery side-slides RIGHT.
• Backplane (V2.4.6): Diamond/hexagonal PETG lattice crash exoskeleton. 187×50mm, ~7g, ~65% open area. Spans battery front (+39mm) to fan rear (-148mm). RIGHT side open in battery zone for sideways battery swap without removal. Posts at Y=+39, -39, -148mm. Two GX12-7 boss rings at Y=−66mm, X=±25mm. Payload modules mount on top.
• Battery (V2.4.6): Side-slide mount — exits RIGHT laterally on rail system, no payload removal required
• Payload connectors (V2.4.6): Two GX12-7 males (panel mount, pins face upward, IP65, screw-lock), drone-side permanent, top-facing at X=−25mm (Connector A, left) and X=+25mm (Connector B, right), both at Y=−66mm. Dust caps mandatory when no payload fitted. Payload cable carries female (cable-mount) connectors.
• Payload interface (V2.4.6): 2× M3 heat-set boss pads on top surface, 20 mm spacing
• ESC: Pilotix 75A AM32 4-in-1 6S (TVS integrated)
• Payloads: Optional modular masts via dual GX12-7 connectors — see payloads/LD_-_Payload_SDK_v246.md

All geometric dimensions driven by reference/LD_-_Variables_v246.md.

2. Rod Architecture (Unchanged)¶

4-rod box-girder spine, now passing continuously through all 5 sandwich layers:

• 4 × 2.0 mm OD carbon fibre rods
• Rod length: 333.0 mm cut length
• Rod channels: #RodDiaChannel = 2.2 mm
• Channel positions in arm and tab: Z +5.0 mm and Z +2.0 mm (same side)
• FR/RR arms inverted → −5.0 mm and −2.0 mm in sandwich
• Four distinct heights through entire structure: +5.0, +2.0, −2.0, −5.0 mm

Rod threading through sandwich aligns all layers during assembly — rods serve dual purpose: structural spar + assembly alignment tool.

hw_rod_cf_2mm_single_weight_target  = 2.0 g
hw_rod_cf_2mm_set4_weight_target    = 8.0 g

3. Printed Parts (V2.4.6)¶

Backplane: PETG Natural, diamond lattice, 187×50mm, ~7g target, ~65% open area. Platform: PETG, 283×40/50mm (stepped), mass TBD after first print. Both: print flat, 4 perimeters minimum, 0.20mm layer height. Backplane post-process: heat-gun pass optional. Epoxy not required.

3.1 X Body Layer Stack¶

Layer 1 — PETG Bottom (×1, 3mm)

hw_xbody_petg_bot_target            = 7.0 g

Material: PETG. Impact face. Rod interference fit in core zone (2.1mm channels). M3 hex nut capture pockets on bottom face for sandwich bolts.

Layers 2–4 — PCCF Structural (×3, 3mm each)

hw_xbody_pccf_layer_single_target   = 9.0 g
hw_xbody_pccf_layers3_target        = 27.0 g

Material: PCCF Black. T-slot pockets. Rod channels (2.2mm). Sandwich bolt holes.

Layer 5 — PETG Top (×1, 4mm) — V2.4.6 Sealed Platform Surface

hw_xbody_petg_top_target            = 18.0 g   # V2.4.6 — simple (stack holes, bracket holes, mast boss pads only)

Material: PETG. Permanently sealed — never removed for routine operations. Integral features (all printed as one piece): - MIPI cable channel: 16 mm wide × 1.5 mm deep, centreline, nose-to-tail -- IN PLATFORM, not X body top layer - Wire routing channels: LEFT (signal, −20 mm) and RIGHT (power, +20 mm), 4 × 1 mm - Battery lead relief notch: 8 × 4 mm at rear centreline - Mast boss pads: 2 × Ø9 mm × 7 mm tall, rear centreline ±10 mm — M3 heat-set inserts - Stack mounting holes: 4 × Ø3.3 mm on 30.5 mm pattern - GPS bracket mount holes: 2 × Ø3.3 mm, front centreline - Battery rails: LEFT + RIGHT, 22 mm tall × 31 mm inner width — integral, no separate part - Endstop wall: closes LEFT end of RIGHT rail — battery seats against this - Lateral strap slots: in rail top faces, 20 × 3 mm, buckle on RIGHT - Connector A chimney (LEFT): boss Ø14 mm × 3 mm proud, through-hole Ø12 mm, chimney Ø18 mm OD × 25 mm deep, wire exit slot LEFT-facing, at X=−25 mm, Y=−66 mm - Connector B chimney (RIGHT): boss Ø14 mm × 3 mm proud, through-hole Ø12 mm, chimney Ø18 mm OD × 25 mm deep, wire exit slot RIGHT-facing, at X=+25 mm, Y=−66 mm

Print support required inside both GX12 chimney bores. All other features self-supporting. Remove chimney bore supports with a pick — do NOT ream with a round drill (destroys D-D anti-rotation flats). See LD_-_PRUSA_v246.md §Platform and Coupon 10.

3.2 Arm Shafts (×4)¶

hw_arm_shaft_petg_single_target     = 15.0 g
hw_arm_shaft_petg_4x_target         = 60.0 g

Material: PETG. Printed VERTICALLY. ~125 mm shaft + motor head. Rod channels. Pinch slit. MR30 strain relief.

3.3 Arm Tabs (×8 — 2 per arm)¶

hw_arm_tab_petg_single_target       = 1.5 g
hw_arm_tab_petg_8x_target           = 12.0 g

Material: PETG. Printed HORIZONTALLY. T-profile lock. 20 mm engagement depth. 2× M2 screw holes.

3.4 Arm Cover Active (×4)¶

hw_cover_active_petg_single_target  = 4.0 g
hw_cover_active_petg_4x_target      = 16.0 g

Material: PETG. Cable protection, dovetail groove, 2× M2 retention.

3.5 Arm Cover Passive (×4)¶

hw_cover_passive_pccf_single_target = 5.0 g
hw_cover_passive_pccf_4x_target     = 20.0 g

Material: PETG-CF. O-ring bosses, captured nyloc nut pockets. FFP3 respirator mandatory during printing.

3.6 Bumpers (×4 + spares)¶

hw_bumper_asa_single_target         = 3.0 g
hw_bumper_asa_4x_target             = 12.0 g

Material: ASA Natural. Hollow, geometry-compensated.

3.7 GPS/Camera Bracket (×1)¶

hw_gps_cam_bracket_target           = 8.0 g

Material: PETG Natural. Carries GPS antenna (top) + camera (middle) only. VTX is in Platform electronics zone (V2.4.6).

3.8 Payload Masts (optional, per payload)¶

hw_payload_mast_short_target        = 15.0 g   # 40 mm height
hw_payload_mast_medium_target       = 18.0 g   # 80 mm height
hw_payload_mast_tall_target         = 22.0 g   # 120 mm height

Material: PETG Natural. All mast heights use identical base footprint. Base: 2× M3 × 8 mm screws into drone boss pads (20 mm spacing). GX12-7 male cable connectors (A and B) on payload cable — two plugs for full electrical interface. Physical master enable switch (latching SPDT) integrated in mast body.

Note: with Pi bay fitted (always), effective mast boss pad height is 6mm above Backplane surface. Mast height references remain unchanged — the bay is accounted for in the stack geometry.

Reference: air quality mast (medium height, SEN66 + ESP32-S3): payloads/LD_-_Payload_SDK_v246.md (Appendix A) Payload API: payloads/LD_-_Payload_SDK_v246.md

3.9 Pi Bay (×1 — always fitted on all platforms)¶

hw_pi_bay_empty_target              = 4.0 g    # PETG tray + cover plate — always present
hw_pi_zero_2w_target                = 11.0 g   # optional — order separately (LCM-1)
hw_pi_buck_converter_target         = 5.0 g    # optional — fitted with Pi only
hw_companion_harness_target         = 3.0 g    # 4-wire loom — always pre-installed

Material: PETG Natural. Thin-walled tray, 72×38×6mm internal, 2mm walls. Sits on top of Backplane in mast zone. Raises mast boss pad surface by 6mm. Pre-installed companion harness (4-wire JST-SH) inside drone routes from FC UART6 through Platform signal channel to Pi bay base connector.

Pi bay is mandatory on every build across all platforms. Empty bay uses a printed cover plate. Pi Zero 2W installs in 15 minutes when ordered.

When Pi is fitted (LCM-1 option): - Pi Zero 2W sits on M2.5 standoffs (58×23mm spacing) - Companion harness plugs JST-SH into Pi GPIO header - Dedicated 5V buck converter (XL4016 or equivalent) taps battery rail - Buck converter output: 5.1V, NOT from FC BEC — independent power rail - Pi runs WiFi hotspot, MAVLink bridge, REST API, flight data logger

Companion UART reserved on all platforms:

UART6  →  COMPANION (JST-SH 4-pin at Pi bay) — reserved permanently
           Betaflight: MSP passthrough at 921600 baud
           ArduPilot: MAVLink2 at 921600 baud

3.10 GX12-7 Payload Connectors — Universal Platform Standard¶

3.11 Structural totals¶

hw_xbody_all_layers_target          = 52.0 g   # 7 + 27 + 18 (V2.4.6 simple top layer)
hw_structure_pccf_petg_total_target = 60.0 g   # X body layers + tabs
hw_arms_total_target                = 60.0 g   # shafts only
hw_tabs_total_target                = 12.0 g
hw_covers_total_target              = 36.0 g   # active + passive ×4 each
hw_bumpers_total_target             = 12.0 g
hw_bracket_total_target             = 8.0 g
hw_frame_structural_total_target    = 140.0 g  # gate; all above minus payload masts

3.10 Platform (×1) — Middle Layer¶

hw_platform_target                  = 60.0 g   # 283×40/50mm (stepped) PETG — rails, chimneys, posts

Material: PETG. Print flat (largest face on bed). 4 perimeters minimum. Stepped width: 40mm (nose/battery zone), 50mm (electronics zone from Y=−44mm). Integral features (all in Platform — NOT in X body top layer): - Battery rails: LEFT + RIGHT, 53mm tall, 41mm inner width. Battery exits RIGHT. - Battery lead relief notch: 8×4mm at battery rear zone - Lateral strap slots: 20×3mm in rail top faces, buckle on RIGHT - MIPI channel: 16mm wide × 1.5mm deep, centreline, nose-to-tail - Wire channels: LEFT (signal, −20mm) and RIGHT (power, +20mm), 4×1mm - Connector A chimney (LEFT): boss Ø14mm × 3mm proud, D-D bore (11.87mm OD / 10.80mm flat-to-flat), chimney Ø18mm OD × 25mm deep, wire exit slot LEFT-facing, at X=−25mm, Y=−66mm - Connector B chimney (RIGHT): same geometry, wire exit slot RIGHT-facing, at X=+25mm, Y=−66mm - Fan slot: 30×30mm at rear shroud face, rear-facing - Attachment posts: 3 pairs at Y=+39, −39, −148mm, Ø6mm × 54mm tall

Print: chimney bores require internal supports (D-D bore, 25mm deep). Remove support with pick — do NOT ream with a round drill (destroys anti-rotation flats). See LD_-_PRUSA_v246.md §Platform and Coupon 10.

3.11 Backplane (×1)¶

hw_backplane_target                 = 7.0 g    # 187×50mm PETG lattice

Material: PETG Natural. Diamond/hexagonal open lattice, ~65% open area. Width: 50mm (matches #PlatformWidthElec — updated V2.4.6). Post-process: heat-gun pass optional. Epoxy not required.

4. Floating Motor Mount System (Unchanged)¶

Per motor: - O-rings: 2 × silicone, ID 4.0 / OD 7.0 / CS 1.5 mm, 40–50A - Sleeves: 4 × silicone, OD 6.0 / ID 3.5 / L 11.5 mm, 30–40A - Screws: M3 × 20 mm stainless. Nyloc nuts captured in passive cover. - Torque: motor_mount_screw_torque_target = 0.4–0.5 N·m - Replace: every 20–30 flight hours

Passive cover must NOT contact arm head surface except via o-ring bosses.

hw_motor_isolation_oring_2x_target      = 0.5 g
hw_motor_isolation_sleeves_4x_target    = 1.0 g
hw_motor_isolation_hw_per_motor_target  = 1.5 g
hw_motor_isolation_hw_total4_target     = 6.0 g

5. Electronics (V2.4.6 Platform Layout)¶

5.1 Core components¶

• FC: Mateksys H7A3-SLIM
• ESC: Pilotix 75A AM32 4-in-1 6S (TVS integrated) — ships with XT60H-M connector ✓
• Motors: 4 × BrotherHobby Avenger V2 2507 1750KV
• Receiver: RadioMaster RP2 ELRS
• GPS: Matek M10Q-5883 (on front bracket, above camera)
• VTX+Camera: HDZero Freestyle V2 — input voltage 7–25V (2S–6S), 6–15W — XL4015 9–12V rail ✓
• Buzzer: Vifly Finder 2
• Capacitor: 1000 µF 35V low-ESR
• TVS: SMBJ28A on VBAT/GND pads
• Cooling fan: 30×30×10mm 5V brushless, ball bearing, Gdstime 3010 — hardwired to FC 5V pad, always on. No thermostat. Mounts in rear face slot. Exhausts rearward — sucks air front-to-rear through the FC/ESC stack. Ram air in forward flight enters through front arm root gaps, crosses the stack, fan pulls it out rear.
• Battery: Tattu R-Line V3 1800mAh 150C 6S (side-slide rail mount)

5.2 UART Assignment — H7A3-SLIM (6 UARTs available)¶

UART1  →  HDZero VTX (MSP/OSD DisplayPort)
UART2  →  GPS M10Q-5883 (GPS protocol, 57600 baud)
UART3  →  RadioMaster RP2 V2 ELRS (CRSF, 420000 baud)
UART4  →  Connector A PIN 3/4 — payload primary channel (MSP telemetry from payload → OSD)
UART5  →  Connector B PIN 3/4 — payload secondary channel (camera UART, actuators)
UART6  →  spare

UART4 routes to Connector A (left). UART5 routes to Connector B (right). Whatever payload is plugged in uses UART4 for MSP telemetry back to the OSD, and UART5 for secondary functions (e.g. Caddx Peanut camera UART control). When no payload is fitted, UART4 and UART5 are idle — no impact on core flight.

All UARTs have built-in inversion on H7A3-SLIM — no external inverter needed. Verify pin mapping against H7A3-SLIM pinout diagram before soldering.

5.3 Compass mounting note¶

M10Q-5883 must be mounted with its orientation arrow pointing forward, module flat. If bracket geometry causes any tilt, enter manual alignment offset in Betaflight Configurator → GPS → Compass alignment before maiden. Compass is at nose — maximum distance from ESC, battery leads, motor wires. ✓

5.4 V2.4.6 layout¶

Electronics distributed nose-to-tail on Platform middle layer. Three-layer architecture: X body sandwich (bottom) / Platform (middle) / Backplane (top). FC+ESC at centre-rear on 30.5 mm pattern. Camera+GPS on front bracket — removes as one unit (60s). VTX in electronics zone on Platform at -104 to -133mm from body centre. Battery side-slides into integral PETG rails on Platform — exits RIGHT, no backplane removal needed. MIPI cable (225 mm) runs nose-to-tail in Platform MIPI channel. Camera-to-VTX distance ~198mm, 26mm service loop. Connector A (GX12-7, left) at X=−25 mm, Y=−66 mm, top-facing, in printed chimney — wire exit LEFT into signal channel. Connector B (GX12-7, right) at X=+25 mm, Y=−66 mm, top-facing, in printed chimney — wire exit RIGHT into power channel.

hw_motor_2507_single_target     = 40.0 g   # BrotherHobby spec (motor + 20cm cables)
hw_motor_2507_4x_target         = 160.0 g
hw_fc_h7a3_slim_target          = 12.0 g
hw_esc_pilotix75a_target        = 19.0 g
hw_rx_rp2_target                = 2.0 g
hw_gps_m10q_target              = 15.0 g
hw_vtx_hdzero_fs_v2_target      = 18.0 g
hw_cam_hdzero_target            = 7.0 g
hw_buzzer_vifly_target          = 5.0 g
hw_cap_1000u35v_target          = 5.0 g
hw_fan_25mm_5v_target           = 3.0 g    # fan + 2-wire harness to FC 5V pad
hw_battery_tattu_1800_6s_target = 210.0 g

6. Connectors & Wiring¶

6.1 MR30 motor connectors¶

• 4 × MR30 pairs (motors ↔ ESC), gold-plated, 30A continuous
• Wire gauge: AWG28 (signal-weight optimised, adequate for MR30 30A rating)
• Motor side pigtail: mr30_motor_pigtail_length_target = 40–50 mm
• ESC side pigtail: mr30_esc_pigtail_length_target = 60–80 mm
• Label M1–M4 on heatshrink

6.2 Tab-to-shaft hardware¶

• 16 × M2 × 6 mm stainless screws (2 per tab, 2 tabs per arm, 4 arms)
• Access from arm shaft end face

6.3 Sandwich bolts¶

• 8 × M3 × 20 mm stainless (through all 5 sandwich layers, now 16mm total)
• M3 hex nuts captured in PETG bottom layer pockets
• Torque: 0.3 N·m — firm, not crushing PCCF

6.4 Power domain¶

• Main connector: XT60H-M (confirmed — Pilotix 75A ESC ships with XT60H-M) ✓
• Battery lead: 12–14 AWG
• ESC to motors: AWG28 via MR30 connectors
• Logic/signals: 26–28 AWG
• Buck converter: XL4015, 9–12V rail → HDZero VTX (7–25V input range, ✓)
• Cooling fan: 28 AWG, 2-wire (5V + GND), hardwired directly to FC 5V pad. Always on. ~70mA @ 5V.

hw_mr30_connectors_total_target     = 8.0 g
hw_main_wiring_looms_target         = 30.0 g
hw_tab_shaft_screws_m2_target       = 2.0 g
hw_sandwich_bolts_m3_target         = 2.0 g

6.5 GX12-7 Payload Connectors — Universal Platform Standard¶

Both GX12-A and GX12-B connectors are mandatory on every libdrone platform. This is a non-negotiable architectural requirement. A payload built for any libdrone variant must work on any other without modification. Partial connector implementations fragment the ecosystem and are not permitted.

Platform | GX12-A | GX12-B | Status Pro | fitted | fitted | mandatory Ghost | fitted | fitted | mandatory Bandit | fitted | fitted | mandatory Core | fitted | fitted | mandatory Wing | fitted | fitted | TBD — fixed-wing integration

Cost per build: ~€4 for both connectors + dust caps. Weight: ~22g for both connectors, dust caps, and internal wiring loom. Non-negotiable.

Two GX12-7 waterproof aviation connectors replace the original single GX12-12 (GX12 series maximum is 7 pins). 12 signals split across two connectors. IP65 ingress protection. Screw-lock engagement. Rated >500 mating cycles. Drone-side: male (panel mount, pins face upward toward payload). Payload-side: female (cable mount).

connector_type              = GX12-7 (7-pin aviation, 12 mm body diameter)
ingress_protection          = IP65 (when locked)
retention                   = screw-lock ring — finger tight is sufficient
mating_cycles               = >500
drone_side_gender           = MALE (panel mount, pins face upward — dust cap mandatory when payload removed)
payload_side_gender         = FEMALE (cable mount on payload loom)
housing                     = integral PETG chimney — printed as part of Platform (middle layer)
dust_cap                    = mandatory on both connectors when no payload fitted

Connector A — Left (X=−25 mm, Y=−66 mm) — Power + primary comms: Wire exit slot faces LEFT → routes into signal channel (−20 mm).

Connector B — Right (X=+25 mm, Y=−66 mm) — Secondary comms + aux: Wire exit slot faces RIGHT → routes into power channel (+20 mm).

Wiring: all 12 wires (6 per connector) soldered during drone build (WBS §5.12). Permanent. Connector A: twist pairs I2C SCL/SDA, UART4 TX/RX. 5V and GND run separate, no twisting. Connector B: twist pairs UART5 TX/RX. GPS TX, GND shield, and GPIOs run separate.

hw_gx12_connector_A_drone_side_target = 8.0 g    # male + panel nut + dust cap
hw_gx12_connector_B_drone_side_target = 8.0 g    # male + panel nut + dust cap
hw_gx12_wiring_loom_A_target          = 3.0 g    # 6 wires, ~200 mm average length
hw_gx12_wiring_loom_B_target          = 3.0 g    # 6 wires, ~200 mm average length
hw_gx12_total_target                  = 22.0 g   # both connectors + both looms

6.6 Payload Board (per payload — not on drone)¶

Each payload mast carries a small PCB hosting:

All payload board components are listed in Shopping list §9 (items 72–72d). Board is not a drone component — it is part of the payload and documented in payloads/LD_-_Payload_SDK_v246.md §7.

7. Propellers¶

Two sets of HQProp 6" tri-blade polycarbonate props. Both sets include 2× CW + 2× CCW. 5mm shaft, no adaptor rings. Balanced before first use with magnetic prop balancer.

Set A — HQProp 6×3×3 (higher pitch, more thrust)¶

hw_prop_hq_6x3x3_diameter   = 6 inch (152 mm)
hw_prop_hq_6x3x3_pitch      = 3
hw_prop_hq_6x3x3_blades     = 3
hw_prop_hq_6x3x3_weight     = 5.4 g each / 21.6 g set of 4
hw_prop_hq_6x3x3_hub_dia    = 13.2 mm
hw_prop_hq_6x3x3_hub_thick  = 6.3 mm
hw_prop_hq_6x3x3_shaft      = 5.0 mm
hw_prop_hq_6x3x3_material   = Polycarbonate

Use for: standard mapping flights, moderate wind, efficiency priority.

Set B — HQProp 6×2.5×3 (lower pitch, lower current draw)¶

hw_prop_hq_6x25x3_diameter  = 6 inch (152 mm)
hw_prop_hq_6x25x3_pitch     = 2.5
hw_prop_hq_6x25x3_blades    = 3
hw_prop_hq_6x25x3_weight    = 5.3 g each / 21.2 g set of 4
hw_prop_hq_6x25x3_shaft     = 5.0 mm
hw_prop_hq_6x25x3_material  = Polycarbonate

Use for: calm conditions, maximum flight time, lower motor temperature.

Prop selection rationale¶

Both sets are polycarbonate (durable, consistent weight, balanced from factory). Lower pitch (2.5) = lower current draw = longer flight time but less authority in wind. Higher pitch (3.0) = more thrust = better wind penetration but higher motor temp. Start maiden with Set B (6×2.5×3) — conservative, cooler motors, easier PID tuning. Switch to Set A (6×3×3) once PID baseline is established.

Betaflight has two profiles configured: one per prop set. See Software doc.

hw_props_4x_weight_setA     = 21.6 g
hw_props_4x_weight_setB     = 21.2 g

8. Environmental Reliability¶

• Conformal coating: required on FC, ESC (non-pad areas), VTX, RX, GPS PCB
• Temperature: PETG arms not recommended below 0°C (V2.4.6 baseline)
• Ingress: hardware layout must allow moisture to drain/dry after wet crash
• Tab T-lock: inspect after any hard crash. Replace tab if T-lock shows cracking.

9. Mass Budget (V2.4.6)¶

hw_epoxy_delta_arm_shaft_max        = 1.0 g
hw_epoxy_delta_tab_max              = 0.5 g
hw_epoxy_delta_xbody_layer_max      = 1.5 g
hw_epoxy_delta_frame_total_max      = 8.0 g

hw_xbody_all_layers_target          = 52.0 g   # 7 + 27 + 18 (V2.4.6 simple top)
hw_platform_target                  = 60.0 g   # 283×40/50mm (stepped) PETG — rails, chimneys, posts
hw_backplane_target                 = 7.0 g    # 187×50mm PETG lattice
hw_frame_structural_total_target    = 265.0 g  # all printed structure + rods + isolation + bolts
hw_electronics_stack_target         = 246.0 g  # motors (160g) + all electronics (86g)
hw_gx12_connector_wiring_target     = 22.0 g   # dual GX12-7 connectors + looms (drone side)
hw_fan_system_target                = 3.0 g    # 30×30×10mm fan + 2-wire harness
hw_props_target                     = 21.6 g   # Set A (heavier of two sets)

hw_total_dry_nopayload_target       = < 607 g  # target (drone, no battery, no payload)
hw_total_dry_nopayload_gate         = < 617 g  # gate
hw_mtow_bare_target                 = < 817 g  # + battery, no payload — EASA Open A1 ✓
hw_mtow_bare_gate                   = < 900 g  # A1/A2 boundary — must not exceed
hw_mtow_80g_payload_target          = < 887 g  # + battery + 80g payload — EASA Open A2 ✓ (13g headroom)
hw_mtow_150g_payload                = ~957 g   # + battery + 150g payload — exceeds A2 limit ❌
hw_payload_maximum_a2_compliant     = < 93 g   # hard max for A2 compliance (900g − 807g bare AUW)

TWR (BrotherHobby Avenger 2507 1750KV, 6S, HQ 6×3×3): Peak thrust per motor ~2400–2600g (40–55A). Total 4-motor peak: ~10,000g.

Hard payload limit for A2 compliance: 93g (900g − 807g bare AUW). Typical sensor payload (SEN66 mast) must remain ≤ 93g to stay below the 900g A2 boundary.

Payload weight budget (for reference):

hw_payload_target_light             = < 40 g   # light payload (video module)
hw_payload_target_typical           = < 80 g   # typical payload (air quality)
hw_payload_maximum_a2               = < 93 g   # HARD MAX for EASA Open A2 compliance
hw_payload_maximum_physical         = < 150 g  # physical/CG limit — but breaks A2 compliance

10. Cross-References¶

• Master Spec: reference/LD_-_Master_Specification_v246.md
• Variables: reference/LD_-_Variables_v246.md
• Manufacturing: build/LD_-_PRUSA_v246.md
• CAD: build/LD_-_FreeCAD_Cookbook_v245_Complete.md
• Software: build/LD_-_Software_v246.md
• Payload API: payloads/LD_-_Payload_SDK_v246.md
• Maintenance: operations/LD_-_DMOM_v246.md
• Safety: operations/LD_-_DSRA_v246.md

END — libdrone V2.4.6 Hardware Reference

Revision History¶