"Ernest Christley" wrote in message
.. .

Ernest:

This reply is going to sound like a flame, and I really honestly don't mean
it to be, but I gotta step in and say something to ease my conscience in
case you go out and get yourself killed. If I were around and you were about
to go hop in your airplane to test something developed with this attitude,
I'd feel obligated to wrestle you to the ground, take away your keys, then
send you back to the lab to do a very thorough and formal system design
before allowing you to procede.

If I were ever to say the kinds of things you said in a design strategy
meeting, my coworkers would laugh their asses off, then beat the hell out of
me for suggesting such a thing. Then I'd probably end up in the tech pubs
department or fired or something like that.

Dan, did you ever get a chance to work with fuzzy logic?

I have. It's been a while. I'd never, ever use it on an airplane. Maybe a
washing machine controller or something like that. I'm not saying that it
can't be done, but just that it's a risky design approach. There are other
methodologies much better suited for aircraft.

Rule #1 of Flight Controls Design: KNOW YOUR PHYSICS! At the end of the day,
F still equals ma, and you ain't getting past that doing any fuzzy stuff.

It would require a stepper motor to control the control surface

Another big no-no. Steppers are fine for inkjet printers and stuff, but
initialization of position (need to be able to do a power-on reset in
flight), hazards of getting the windings out of sync (immagine you hit a
bump, and your underpowered servo gets knocked off a few ticks....now it's
running backwards.....yes, I've seen this happen), complexity of the power
electronics to drive it...... all these problems disappear with a decent
servo.

could easily maintain wing level or altitdude with grace and smoothness.

The way you say this, I can tell that you've never tackled a problem like
this before. There are tons of things to consider.

Have you ever seen the balancing trick with the mortorized car.

This is the undergraduate "intro to controls" lab experiment. It's meant to
illustrate the basic concepts of closed-loop control. Mastering this problem
only gives you a very small taste of what it takes to design even a simple
autopilot. If you've gotten that far, then next step is to either take a
flight controls class (grad level), or maybe start building some R/C models
if you don't want to go for more school (I'd suggest doing this anyway). The
school of hard knocks is fine with R/C, since the knocks aren't really all
that hard on you.

PLease, get yourself more experience with aircraft control before putting
yourself at risk. I'm guessing you already have a start in learning this
stuff, and don't think you should abandon your goals. However, take baby
steps.

Pete