WYMMS-1 adds a dedicated yaw-moment servo to any two-axis Dynon SkyView autopilot installation. It measures the asymmetric yaw produced by wing loading, slipstream, and P-factor in real time, and trims it out before you ever feel the ball move.
Two-axis autopilots hold heading and altitude, but leave the rudder to the pilot. Every change in power, airspeed, or bank produces a yaw-moment the airplane has to absorb somewhere: in the ball, in the passengers, and in your right leg. WYMMS-1 closes that loop with a dedicated servo driven by the SkyView ADAHRS.
The control module samples lateral acceleration and yaw rate at 100 Hz and commands the servo to null the residual yaw-moment. The ball stays centered without your feet on the pedals.
Uncoordinated flight is what makes passengers reach for the bag. WYMMS-1 was tuned for smooth, passenger-first ride quality, especially in the turns and the descent.
No separate control head. WYMMS-1 appears as a third servo in the SkyView autopilot setup menu, with its own status, calibration, and engage/disengage logic on the SV-AP-PANEL.
WYMMS-1 rides on the existing SkyView Network. The control module listens to the ADAHRS, computes the yaw-moment correction, and drives the servo through the same slip-clutch architecture as the pitch and roll servos. If the module ever loses network, the servo goes limp and the pedals are yours.
All values at 25 °C, 14 VDC unless noted. Refer to WYMMS-IM-001 (Installation Manual) for airframe-specific limits.
Servo — WYMMS-1
| Part number | 101-WYMMS-1 |
| Rated torque | 42 in·lb (4.75 N·m) |
| Slip-clutch range | 8 – 42 in·lb, adjustable |
| Output | Arm, 1.25 in / 1.75 in hole spacing |
| Slew rate | 60°/s no-load |
| Weight | 2.8 lb (1.27 kg) |
| Envelope | 4.62 × 2.90 × 3.10 in |
| Mount | 4 × AN3, flange pattern 3.50 × 2.00 in |
| Operating temp | -30 to +55 °C |
Control module — WYMMS-CM
| Part number | 101-WYMMS-CM |
| Input power | 10 – 30 VDC, 0.4 A idle, 2.6 A peak |
| Interface | SkyView Network, DB-9 |
| Loop rate | 100 Hz |
| Weight | 0.6 lb (0.27 kg) |
| Envelope | 3.30 × 2.20 × 1.05 in |
| Firmware | 1.4.2, field-updatable via SkyView USB |
| SkyView software | 17.2 or later |
| Circuit protection | 5 A breaker, dedicated |
Kit contents
| 101-WYMMS-1 | Servo assembly |
| 101-WYMMS-CM | Control module |
| 102-WYMMS-HRN | SV-NET harness, 6 ft |
| 103-WYMMS-BRKT | Universal bracket + hardware |
| WYMMS-IM-001 | Installation manual |
| WYMMS-CL-001 | Servo activation checklist card |
WYMMS-1 requires an existing two-axis SkyView autopilot. It is a servo expansion, not a standalone autopilot, and does not replace the pitch or roll servo.
Typical installation is 6 to 9 shop hours plus one validation flight. Full procedure in WYMMS-IM-001.
Every WYMMS-1 installation is signed off with one activation flight. The checklist card lives in the cockpit and walks the pilot through preflight checks, first engagement in cruise, and a short set of coordination checks before the servo is left in service.
Flow items are read challenge-and-response. A second crew member may read the challenges; the pilot in command performs and confirms each item.
Current revisions of all WYMMS-1 documents. Installers should confirm the revision on the card matches the firmware installed.
This page. Servo and control module data, kit contents, compatibility.
Airframe-specific mounting, slip-clutch values, SkyView setup. Available to authorized installers.