The RV-6 is a great airplane. Mine will typically cruise at about 180-190 mph on 7.5 gallons of fuel per hour. Do the math, that’s about 25 mpg! I don’t believe that there are any cars that can get you somewhere at 180 mph while only consuming 25 mpg. It’s the Honda Civic of airplanes except that it runs on 100LL.
Anyhow, the RV-6 is a two person side-by-side experimental airplane that comes as a kit sold by Van’s Aircraft. It is one of the most popular kit airplanes ever produced -a tribute to it’s incredible performance. It is rated for all kinds of aerobatic maneuvers and it’s high speed makes it a great cross country airplane as well.
Unfortunately, some of the aspects of the airplane that make it a great aerobatic airplane become drawbacks when flying cross country. Typically maneuverability is achieved with low stability, however stability would be really nice when flying cross country. It’d be great to have a plane that just tracked a course with little no pilot input. Well, that’s where the autopilot comes into play. We will use a feedback look to take what is an unstable system (or at least not very stable system) and make it stable.
Here are the steps necessary to get to where I have an autopilot in the RV.
- Control servo with microcontroller
- Control multiple servos with microcontroller
- Incorporate buttons and control servos with microcontroller and package it all
- Incorporate servo into elevator to control the trim tab
- Put entire mechanism into RV-6
- Verify that the trim tab has sufficient control authority (test flights)
- Add servo control to ailerons
- Verify that aileron servo has sufficient control authority (test flights)
- Add sensor package to airplane that interface through microcontroller
- Interface microcontroller with Matlab/Simulink
- Develop control algorithms
- Verify stability of control algorithms
- Gain tuning
- Port control algorithm from Matlab/Simulink to C