"Fly-by-wire" / aided mode

Instead of controlling the plane's control surfaces directly, you can engage "aided" mode and simply tell Ruby what you want the plane to do by moving your transmitter controls intuitively. Ruby can take care of airspeed, altitude, pitch, roll, heading or turn rate for you, or let you control or "nudge" any or all of in a simplified way. It's a kind of "cruise control".

For instance, holding the aileron halfway to the right holds the plane in a 30 degree right bank regardless of turbulence or other disturbances. Holding the stick all the way to the left holds the plane in a 60 degree left bank. Letting go of the stick levels the wings and locks the plane on current heading.

Likewise, holding the elevator forward tells Ruby to maintain an airspeed above normal cruising speed, and pulling it all the way back slows it down to just above stall. Pushing the throttle all the way forward tells Ruby to maintain current altitude using the throttle as necessary.

Using aided mode with altitude hold means that child with no prior experience can steer the plane around the sky intuitively without having to worry about hitting the ground, regardless of what he/she does with the right stick. Ruby will apply or reduce throttle as needed during maneuvers to stay within feet of locked altitude. This is what we mean by "training wheels".

This is not just for beginners, however. It can be indispensable to expert pilots in situations such as degraded visual contact, fatigue from turbulence or instability, uncertainty about airspeed, difficult launching or landing, distraction, or an itchy nose.

For instance, if you find that you are no longer able to make out the orientation of your airplane and can only see a "speck", you can use aided mode to guide it back to better visual range using aided mode, moving just the aileron slightly to perform turns, leaving the elevator centered to maintain best cruise speed, and keeping throttle all the way forward to tell Ruby to use as much throttle as needed to maintain altitude. Even if the plane is being bounced by turbulence, you can simply hold the stick still knowing that Ruby will keep restoring it quickly to the desired bank, airspeed, and altitude.

By managing airspeed and stabilizing roll and pitch, Ruby also makes landing easier for experts and beginners, especially in gusty wind.

While this mode does not support acrobatic flight, upcoming free firmware upgrades will include variations of aided mode including one that allows direct control of pitch, one that behaves like a traditional gyro stabilizer to control pitch and roll rates rather than absolute values, and perhaps a "cheater" mode or two for performing fun acrobatic stunts.

Ruby loitering a Multiplex Merlin in a 75 foot radius circle at 15 knot airspeed in 5 knot wind.

Autonomous Loiter

You can tell Ruby to loiter your aircraft at a fixed altitude at its current location, or to return to "home" and loiter.

This is particularly useful if you lose sight of your plane completely or something distracts you.

In light wind, Ruby will orbit the target in a nearly perfect circle. In heavier wind, Ruby will pace back and forth perpendicular to wind in a line centered on the target. In wind stronger than target airspeed, Ruby will increase airspeed as necessary to enable it to hover directly over target.

Loiter can be invoked by moving a designated switch on your transmitter. It also automatically engages if the airborne receiver loses signal.

Ruby loitering and landing a "Hellbat" acrobatic plane. (click to enlarge)

Autonomous Landing

Without human intervention, Ruby can land a plane consistently on a narrow runway, even in crosswind. It intelligently manages landing pattern and glideslope to minimize overshoot or undershoot.

If remote control contact is lost and cannot be reestablished for some reason such as dead transmitter battery, Ruby will initially return to home location and loiter. Once the battery becomes low, Ruby will automatically enter landing mode.

See a video of fully autonomous landing in strong crosswind [here].

Panic Button

When in manual mode, Ruby stays out of the way and lets you control the plane directly. You're free to do anything, including get into trouble. Flipping the switch to engage aided or autonomous mode will cause Ruby to immediately assist or assume control and quickly act to bring the plane to desired roll, pitch, and airspeed. Even if your plane happens to in a steep inverted dive with runaway airspeed. Unless invoked too close to the ground, Ruby can probably save your plane.

When pulling out of dives, Ruby doesn't just "yank back on the stick". It manages wing load to ensure that structural or accelerated stall limits aren't exceeded. If pulling out of a dive close to the ground, Ruby progressively pushes that load limit as the ground gets closer, betting that it's better to risk overloading the wing than hit the ground.