wing levelers

You can get really nice R/C servos for way under $100. Ball
bearingsand the works. The quarter scale size servos would probably be
about right to fly a control surface.

Piezo gyros are also under $100 for R/C applications.

Regards

Pete Schaefer wrote:

"Dan, U.S. Air Force, retired" wrote in message
news:MUAVd.21080$Sn6.16679@lakeread03...

I am a tad old fashioned. Besides, I have yet to see a glass display I
like.


I'm kinda liking the looks of the Blue Mountain EFIS Sport these days. I
think it can even support a slave display. Would be nice to spread out the
data and declutter the individual displays. A lot of the EFIS type products
out there just look too damned busy for my tastes. Gonna order the Blue
Mountain for a work project pretty soon. I'm using my current project at
work to evaluate stuff I'd eventually like to stick in an RV-8.

When you get a chance to play with it I'd like to hear your impressions.


I think there is such software at Crossbow's site. I can imagine a PDA
as a back up device or temprary upgrade.


I haven't seen a PDA that I'd want in the cockpit, myself.

I have never used a PDA for anything. Then again I don't have a cellular
phone, FAX, etc. Retired life is SO rough


clip. Where do you put the AHRS?


They're not very big. You would probably build a small shelf and mount it
behind the firewall. You typically have to mount devices like that at a
structural node - right under the pilot's ass is often a good spot.
Otherwise, structural vibration will clutter up your data.

I was thinking along the lines of a temporary installation which I
assumed was the whole idea of a PDA system.


passenger. I don't know if it would be worth it.


I don't think I'd ever bother to mess around with such an expensive device,
especially when there are complete instrument packages for less.


Agreed.

Dan, U.S. Air Force, retired

wrote:

You can get really nice R/C servos for way under $100. Ball
bearingsand the works. The quarter scale size servos would probably be
about right to fly a control surface.

Piezo gyros are also under $100 for R/C applications.

Regards


The hard part is the electronics package between the two. I know the
systems I worked on, but I would be reluctant to attempt builing a
system. Not my bowl of rice, but I'd like see what others come up with.

Dan, U.S. Air Force, retired

On Wed, 2 Mar 2005 08:30:27 -0800, "Pete Schaefer"
wrote:


"Roger" wrote in message
.. .
To paraphrase the manual for my auto-pilot. When encountering more
than moderate turbulence, turn off the autopilot. I believe Pete
touched on this as well.

Driving an auto-pilot too hard can put your servos on the rate limit. On a
rate limit, a servo develops serious amplitude-dependent lag, which can
destabilize your loop closures. THe way arount this problem? Big, huge,
powerful, fast servos. This solution opens up a whole other can of worms.

Ahhh... That's not what I was getting at.
They have you disconnect to protect your airplane as the servos can do
too good a job of holding altitude. It wasn't lag they were worried
about.

Just as the question asks on the FAA exam. What do you do when
entering an area of moderate to severe turbulence?
The AP doesn't know the correct answer for that one and it's going to
hold altitude, and/or attitude even if it has to break something to do
it. (depends on the AP)

There really is such a thing as "too much of a good thing".

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Dan, U.S. Air Force, retired wrote:
wrote:

You can get really nice R/C servos for way under $100. Ball
bearingsand the works. The quarter scale size servos would probably be
about right to fly a control surface.

Piezo gyros are also under $100 for R/C applications.

Regards


The hard part is the electronics package between the two. I know the
systems I worked on, but I would be reluctant to attempt builing a
system. Not my bowl of rice, but I'd like see what others come up with.

Dan, U.S. Air Force, retired

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

It would require a stepper motor to control the control surface, but it
could easily maintain wing level or altitdude with grace and smoothness.
Have you ever seen the balancing trick with the mortorized car.

A weight on the end of a stick is hinged on top of a programmed electric
car. The car acclerates quickly to flip the weight vertical, and then
jostles back and forth to balance it there. All with not input except
an indicator of the angle of the stick holding the wieght. Impressive.

I have the information for the EZTrim altitude hold system. After I
have everything else on the plane working, I have a goal of reworking
the software to use a fuzzy algorithm.

"Dan, U.S. Air Force, retired" wrote in message
news:g%KVd.21109$Sn6.5222@lakeread03...
I'm kinda liking the looks of the Blue Mountain EFIS Sport these days. I
When you get a chance to play with it I'd like to hear your impressions.

Will do. Not sure when we'll actually get it delivered (prolly in April).
Sure looks good on paper, though. I looked at their smaller unit (the Lite).
Pretty small display, but bright. Too much info crammed in too small a space
for my tastes. Might be able to declutter it a bunch, though. THe EFIS One
is just too damned big. It eats most of an instrument panel. I don't like
the idea of using one piece of equipment for so many functions when it's so
big that I have no room for backups. The Sport seems just about right.

I have never used a PDA for anything. Then again I don't have a cellular
phone, FAX, etc. Retired life is SO rough

I don't have any of the above, either. Clutters up life and desk space too
much. The only portable electronic device I own (besides a watch), is my
hand-held GPS.

They're not very big. You would probably build a small shelf and mount
it
I was thinking along the lines of a temporary installation which I
assumed was the whole idea of a PDA system.

Oh. I was thinking of where to mount the sensor unit (Crossbow or other
6-dof sensor package), not the display. Need to level them (or do a bunch of
calculations for correcting for off-level installation).

"Dan, U.S. Air Force, retired" wrote in message
news:rhLVd.21112$Sn6.10965@lakeread03...
The hard part is the electronics package between the two.

It wouldn't be that bad, really. At least not for just a rate damper. The
R/C gyros put out pulse-width modulation signals, which are pretty easy to
work with. Also, there are a lot of decent servos out there that can read
it.

I think the hard part of the rate damper project is making sure you don't
overtorque something important in your airplane, and setting things up so
that, when the damper servo goes haywire, that you can turn it off and
revert to a normal airplane quickly and without hurting anything/anybody,
and that while you're busy figuring out that something is going wrong, that
you can overpower anything it's doing that you don't like.

More than a few people and quite a few airplanes have gotten killed in the
process of engineers trying to figure out how to do all this automatic
stabilization and fly-by-wire stuff. It's not something approached casually,
unless it's for a toy that's OK to crash (R/C model). In my somewhat short
career as a flight controls engineer (12 years), I've seen 3 airplanes lost
and more than a couple of close calls due to control design issues. Even
when everything works as designed, there are man-machine interaction
problems that can kill you. Even apparently innocuous things. Think back to
that Airbus that busted up a couple of years ago in New York. I think
there's an article in Flying this month about it. Nothing there that jumps
out at you as an obvious hazard, but it got a couple hundred people real
dead.

I'd really hate to see someone on this newsgroup go out and get himself
killed trying to invent something without full cognizance of the hazards.

Pete

"Roger" wrote in message
...
Ahhh... That's not what I was getting at.
They have you disconnect to protect your airplane as the servos can do
too good a job of holding altitude. It wasn't lag they were worried
about.

Yeah, there are a couple of issues there. The autopilot might command
surface deflections beyond what is safe for the control surface. Could rip a
surface off. And, as I already said, the autopilot could get into an
oscillation if it rides a rate limit.

Just as the question asks on the FAA exam. What do you do when
entering an area of moderate to severe turbulence?

Yup.

There really is such a thing as "too much of a good thing".

Roger that...uh..Roger.

"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

Pete Schaefer wrote:

"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


Agreed.

Dan, U.S. Air Force, retired