FAA Experimental Amateur-Built · Open Source

The aircraft you
build yourself.

The MAOS is a four-seat, series-hybrid, IFR-capable experimental aircraft engineered for the EAA homebuilder community. Designed in the open. Built from flat stock. Flown at altitude.

4seat
Configuration
20,000ft
Target ceiling
Serieshybrid
Propulsion
IFRequipped
Avionics
FAAE-AB
Regulatory basis
01

Inherently Safe Configuration

High-wing pod-and-boom architecture with conservative wing loading and positive static margin verified by AVL analysis at both CG extremes. Departure resistance is designed in, not trained in.

02

One Builder, Two-Car Garage

Every structural component is designed to be fabricated with tools that actually exist in a competent amateur's shop. No CNC mill. No autoclave. No professional machine shop required at any build step.

03

Open from Day One

All design files, analysis outputs, decision records, and build documentation are published openly. The knowledge that goes into this aircraft belongs to the homebuilder community permanently.

The Platform

Designed for the mission that matters.

The MAOS targets the capability gap between a well-equipped LSA and a certified piston twin — a capable, IFR-equipped four-seat platform that a single builder can complete, transport, and deploy from a standard general aviation airport.

Airframe

Pod-and-Boom Fuselage

A cylindrical pressure pod (~52"W × 58"H × 156"L) mounted above a tail boom provides a clean structural interface for wing attachment, pressurization provisions, and crew/passenger accommodation. The pod-and-boom separation means no pneumatic systems cross the wing-to-pod boundary.

Wing

High Wing, Removable Single-Piece

V-strut braced high wing with twin Honda 400cc motorcycle-derived ICE generators mounted at mid-span. The wing is a single removable piece — removal and stow is accomplished by a one-person crew using the integrated trailer crane system, without a hangar or ground power equipment.

Environmental Control

Full Climate Control + Pressurization Path

Dual-compressor ECS: a closed-circuit EV scroll compressor vapor-cycle system for climate control, and an open-circuit compressor for pressurization. The v1.0 airframe carries all structural provisions, bulkhead fittings, and wiring for pressurization — v1.1 installation requires no structural modification.

Target Specifications

Platform Parameters

All values are design targets under active development. Performance figures subject to revision as analysis matures.

Crew + Passengers1 + 3 (four total)
Target Ceiling17,500 – 20,000 ft MSL
PropulsionSeries hybrid — dual ICE generators + contra-rotating rim-drive electric motors
Ice ProtectionTo be determined
Landing GearFixed faired tricycle
Tail ConfigurationConventional aft-tail
Regulatory BasisFAA Experimental Amateur-Built (51% rule)
TransportRoad-legal enclosed gooseneck trailer with integrated crane
AvionicsIFR-equipped, EFIS-based glass panel
Propulsion Architecture

Series hybrid
done right.

The series hybrid approach decouples the engines from the drivetrain entirely. ICE generators run at their efficiency peak regardless of flight phase. Electric motors provide instant torque and clean power management. The architecture provides meaningful redundancy at every stage.

01

Dual ICE Generators

Two Honda 400cc motorcycle-derived engines, each ~50 hp, mounted at mid-span in the wing. They run as pure generators — no mechanical coupling to the propulsor. Either engine can sustain cruise independently.

02

High-Voltage Bus

Generator output feeds a common HV DC bus alongside the flight battery pack. The bus arbitrates power between generation, storage, and consumption continuously, managed by the custom ESP32-S3 FADEC.

03

Rim-Drive Electric Motors

Contra-rotating axial-flux or rim-drive motors on the tail boom eliminate the gearbox entirely. Motor candidates include the Donut Motor rimless rim-drive and Beyond Motors AXM2 axial flux units.

04

Custom FADEC

ESP32-S3 based controller with dedicated sensing and power driver boards — builder-fabricated from published schematics, PCB fabrication outsourced. All firmware open-source.

The series hybrid architecture means no single failure produces a total power loss. Both generators must fail, the battery must be depleted, and both motors must fail before the aircraft has no propulsive power — three independent failure modes instead of one. This failure matrix is central to the MAOS safety case.

Ground Operations

Fly it anywhere.
Tow it home.

The MAOS is designed to operate without hangar support. The purpose-built trailer is not just a storage solution — it is the ground support system. Transport, deployment, and recovery are engineered operations, not afterthoughts.

01

Road Transport

Aircraft stows in an enclosed aluminum gooseneck car hauler (~8.5' × 28'–32') meeting Texas road-legal envelope requirements. Wing removed, fuselage supported on custom cradles. No permit loads, no escort vehicles.

02

Crane System

A longitudinal overhead beam with traveling hoist runs the full length of the trailer interior. The crane handles wing removal, aircraft positioning, and battery access without external ground equipment.

03

Wing Attach

Single person crew installs the single-piece wing using the trailer crane. Wing-to-fuselage interface carries only structural and electrical loads — no pneumatic crossings, no hydraulic couplings. Assembly time targets under 60 minutes.

04

Preflight & Power

Shore power connection via standardized ground support connector charges the flight battery pack while the aircraft is on the trailer. The aircraft arrives at the flight line with full battery state and a completed weight-and-balance check.

05

Recovery

Field landing and recovery is the design case — not the exception. The trailer can be positioned at any location accessible by a pickup truck. Wing removal is performed in the open field using only trailer-carried equipment.

The trailer is not
just a transporter.
It is a mobile flight operations base.

8.5 × 30 ft
Trailer envelope (road legal, TX)
1-person
Minimum crew for deployment
< 60 min
Trailer to flight-ready target
Zero
External ground support equipment required
Development Methodology

AI-assisted design
from the ground up.

The MAOS development process treats AI not as a search engine but as a structured design team. A multi-agent board system assigns specialized roles to independent AI agents, surfaces inter-disciplinary conflicts early, and produces formal decision records at every gate.

Structured Agent Roles

Six specialist agents cover Aerodynamics, Structures, Propulsion, Systems, Manufacturing, and Safety. Each maintains its own design constraints and flags conflicts with other agents before they become build problems.

Formal Decision Gates

Every open design decision is tracked as an explicit gate with the current recommendation documented. Design state is versioned. Nothing is resolved informally — every decision has a record, a rationale, and an owner.

Living Documentation

Session outputs produce numbered, revisioned formal documents. Weight budgets, failure matrices, ECS architectures, and trailer plans are maintained as living documents — not engineering sketches. The repo is the single source of truth.

Analysis Integration

AVL stability analysis, propulsion failure matrix modeling, and ECS thermal calculations are performed iteratively alongside design decisions — not as a final-stage validation. Problems surface at the design phase, not the build phase.

Conflict-Driven Design

Inter-agent conflicts are anticipated and structured into board meeting agendas. When the Structures agent and the Manufacturing agent disagree, that tension is surfaced explicitly — the resolution is a design decision, not an implicit compromise.

Open Methodology

The agent system, SKILL files, board agendas, and decision records are published alongside the design files. Any builder can fork the methodology alongside the design. The process is as open as the product.

Design Board Agents
Chairman
Aerodynamics
Structures
Propulsion
Systems
Manufacturing
Safety

The Chairman agent orchestrates board sessions, assigns agenda items to specialist agents, collects conflicting recommendations, and produces a structured resolution record. All agent interactions are logged as part of the project's permanent design history.

Manufacturing Philosophy

Flat stock.
Real tools.
One builder.

The MAOS design philosophy treats manufacturing accessibility as a primary constraint — not an optimization. If a structural component cannot be produced by a competent amateur with tools available through normal commercial channels, the design has failed before the first part is cut.

Primary structure is designed around aluminum sheet and extrusions, foam-core fiberglass composite, and flat-cut plywood formers. Parts are designed to ship flat from online services like SendCutSend and OSH Cut, then assemble on-site with basic hand tools.

Cut

Laser & Waterjet

Aluminum sheet, steel gussets, and plywood formers ordered as DXF files from SendCutSend or OSH Cut. Parts arrive flat, deburred, and ready to assemble. Unique part count is minimized at the design stage.

Form

Foam-Core Composites

Hot-wire cut foam cores over shaped formers — the Rutan-proven path to efficient airfoil shapes without a CNC mill. Fiberglass or carbon cloth over shaped foam. No autoclave. Vacuum bagging where needed.

Print

3D Printed Tooling

FDM printing for non-structural components, drilling jigs, assembly fixtures, and fit-check parts. Resin printing for precision tooling and mold plugs. Printed parts are never primary structure.

Source

COTS Hardware

Structural hardware from McMaster-Carr and Aircraft Spruce. Certified fasteners where required by design. Electrical and non-structural components from standard commercial sources. No single-source dependencies in primary structure.

The 51% rule
is the design rule.

FAA Experimental Amateur-Built certification requires the builder to fabricate more than 51% of the aircraft by value. The MAOS is designed so that the 51% is the interesting, capable, and achievable part — not a compliance technicality.

All files in open formats. STEP, STL, DXF, and SVG — no vendor lock-in. FreeCAD and OpenVSP as primary CAD tools.

Minimum unique part count. Every part that can be shared between assemblies is designed to be shared. Fewer jigs, fewer setups, fewer single-use operations.

Field-repairable. Any structural repair that could be required by a hard landing or hail damage is achievable with materials stocked in the trailer and basic hand tools.

Weight is tracked from day one. Every component carries a weight budget. No component is added without justifying its mass against its function.

The Commons

Everything
we learn
is yours.

AeroCommons publishes every design file, every analysis output, every agent session, every decision record, and every build document in the public repository. Not after the project is complete. From the first session.

The goal is not just to build one aircraft. It is to build the methodology, the toolchain, and the knowledge base that makes the next aircraft easier for the next builder.

What's in the repo

billmallard / aerocommons

github.com/billmallard/aerocommons
  • Formal design drawings (DWG MAOS-GA-001, PM-002)
  • Trailer and ground support development plan (MAOS-TRL-DEV-001)
  • Environmental control system architecture (MAOS-ECS-DEV-001)
  • Agent SKILL.md files and board session transcripts
  • AVL stability analysis outputs and weight budgets
  • Open decision gate register with current recommendations
  • CAD files in open formats (STEP, DXF, STL)
  • Brand identity standards and assets
Get Involved

This aircraft gets
built by a community.

The MAOS is a serious engineering project. We're looking for builders, pilots, engineers, and makers who want to work on something real. If you have relevant skills or just want to follow along, reach out.

contact@aerocommons.org
Star the repo on GitHub