Airframe concept · RL1-100 Rev D

Relay One

A 1000 mm quadcopter that holds a Starlink Mini in the air for an hour. Drag to turn it — or switch the printed shell off to see the structure underneath.

STRUCTURE CARBON PLATE + TUBE
SHELL 3D-PRINTED ASA-GF
WHEELBASE 1000 mm · PROPS 24 in
PAYLOAD STARLINK MINI, 1.10 kg
TRANSPORT ENVELOPE 390 × 390 × 470 mm
Arms folded down · payload plate and landing gear removed · propellers stowed
0.09 m³ against 1.56 m³ deployed — 18× smaller, fits one 40 × 40 × 60 cm case
All-up weight12.2 kg
Hover, still air72 min
Plan for52 min
Thrust margin3.7 : 1
View
Exploded view0 %
Drag to orbit · scroll to zoom
FOLD shows the transport envelope
Endurance52 min
Planned mission, after climb, wind and a 20 % reserve
Airframe + propulsion$2.3–4.5k
Battery and terminal already owned
Lead time4–8 wk
Carbon kit from China, assembled in-house
ComparableDJI M350
895 mm, 9.2 kg MTOW, ≈ $12k without payload

Why this is buildable, not a sketch

The model above is not an illustration. Every plate in it is extruded from the same DXF files that would go to the factory — same octagon, same bolt circles, same 52 holes in the upper deck.

The performance figures are not brochure numbers either. The hover model is momentum theory with its figure-of-merit calibrated against DJI's own published M350 data — 6.47 kg on 21-inch propellers for 55 minutes on 526 Wh. Applied to this airframe and the 1 554 Wh semi-solid pack already in the building, it returns 72 minutes of still-air hover at 12.2 kg.

Nothing here needs to be invented. The propulsion is an off-the-shelf integrated unit, the flight controller is a standard Pixhawk-class board, and the airframe is carbon plate and tube — the same construction as every agricultural drone flying today.

It folds for transport. The arms hinge down at R110, the landing gear braces unbolt, and the payload plate lifts off its four standoffs — 390 × 390 × 470 mm, or 0.09 m³ against 1.56 m³ deployed. That is the difference between freight and one hard case travelling as cargo baggage. Press FOLD in the viewer to see it.

Rev D adds an enclosed printed shell — a top crown, four side panels with a connector bank, position and battery-status lights, and a battery shroud, all in glass-filled ASA. None of it is load-bearing, which is exactly why printing is the right process for it: it protects the electronics from weather and dust, cleans up the airflow, and turns a bare frame into something that reads as equipment rather than a prototype. Switch it off in the viewer and the carbon structure underneath is unchanged.

Already done

  • ✓Full airframe specification, mass budget and power architecture
  • ✓Seven A3 manufacturing drawings, general arrangement to spec sheet
  • ✓Five DXF cut files, dimensioned and toleranced
  • ✓Bill of materials with named suppliers and price bands
  • ✓RFQ pack ready to send to five carbon shops
  • ✓Printed shell set — top crown, side panels, lights, battery shroud
  • ✓Fold-down arms — 390 × 390 × 470 mm transport envelope

Still open

  • 1Weigh the battery — the design assumes 4.78 kg
  • 2Fix the arm hinge model, then match the deck hole patterns to it
  • 3NCAA registration and operating permit, started in parallel
Relay One RL1-100 Rev B · 1000 mm X-quad · 4 × Hobbywing XRotor X6 Plus G2 on 24 × 8 folding propellers · 12S 35 Ah / 1 554 Wh semi-solid pack · Starlink Mini on a 65 mm tower, rotated 45° to clear the propeller discs.
Geometry in this viewer is generated directly from the released cut files. Finish, fasteners and cable routing are indicative.