Airframe types
The Airframe type dropdown at the top of the Builder console is the authoritative picker for the flight model. Choosing a type sets the flight regime (multirotor, VTOL transition, fixed wing, quadplane, or tiltrotor), a default motor count, and the coaxial flag, and the console shows or hides the type-specific input groups accordingly.
Picking a type is a starting point, not a lock: motor count, the coaxial switch, and everything else stay editable afterward. The same dropdown appears in the Setup Wizard's first step.
Supported types#
| Airframe type | Flight model | Motors | Coaxial |
|---|---|---|---|
| Quad X | Multirotor | 4 | No |
| Quad H | Multirotor | 4 | No |
| Tricopter | Multirotor | 3 | No |
| Hexa | Multirotor | 6 | No |
| Y6 (coaxial) | Multirotor | 6 | Yes |
| Octo | Multirotor | 8 | No |
| Octo X8 (coaxial) | Multirotor | 8 | Yes |
| VTOL transition | VTOL transition | 4 | No |
| Fixed wing (tractor) | Fixed wing | 1 | No |
| Fixed wing (pusher) | Fixed wing | 1 | No |
| Fixed wing (twin) | Fixed wing | 2 | No |
| Quadplane (lift + tractor) | Quadplane | 1 cruise + 4 lift | No |
| Quadplane (lift + pusher) | Quadplane | 1 cruise + 4 lift | No |
| Quadplane (lift + twin) | Quadplane | 2 cruise + 4 lift | No |
| Tiltrotor (tricopter) | Tiltrotor | 2 tilting + 1 fixed lift | No |
| Tiltrotor (tilt-quad) | Tiltrotor | 4 tilting | No |
All multirotor types share the same momentum-theory hover core and differ by motor count, coaxial flag, and layout. Quad H sizes identically to Quad X; the layout distinction is informational for now. The coaxial flag adds a hover-power penalty and halves the disc count, which is why Y6 and Octo X8 hover less efficiently than their flat six- and eight-motor counterparts.
What each regime changes#
- Multirotor: the props carry the weight in every phase. Forward flight uses the induced-plus-profile-plus-parasite power curve when you set a flat-plate drag area.
- VTOL transition: a tailsitter-style craft whose airfoil arms become a wing in cruise while the props become pushers. Selecting it reveals the VTOL transition (wing) group (airfoil arm chord, wing CL max, wing Cd0, span efficiency, cruise prop efficiency) and fills a starting arm chord if none is set. The readout adds stall and transition speed, wing loading, and a transition-feasibility check. See Forward flight and VTOL.
- Fixed wing: a plane with no hover. Selecting it reveals the Fixed wing (wing) group (wing span, wing area, wing chord, CL max, Cd0, span efficiency, cruise prop efficiency) and fills starting wing dimensions and a starting drag area you can edit. The hero cards switch to stall speed, cruise endurance, and range.
- Quadplane: dedicated lift rotors for vertical flight plus a wing and cruise motors for forward flight. Selecting it reveals the wing group, the Lift rotors (dead in cruise) group, and the Lift rotor motors group (lift motor Kv, lift prop diameter and pitch, lift ESC current), with starting values filled in.
- Tiltrotor: motors that tilt to hover and rotate forward for cruise, optionally with fixed lift rotors that are dead weight in cruise. Selecting it reveals the wing group and the Lift rotors (dead in cruise) group.
The motor count column above is the default the type sets. On quadplane and tiltrotor types the Motors field counts the cruise or tilting motors, and the Lift rotor count field in the Lift rotors group counts the rotors that lift in hover and are dead weight in cruise.