Slaving autopilot to a VOR?

Jay Honeck wrote:
I suspect what you have is something like a Piper Autocontrol? Two axis?

You

mean it has altitude-hold?


Hmm. I thought 3-axis was altitude-hold? Whatever, all mine does is hold
the wings level, and follow the bug...

You're right. In common usage, wing-leveler plus heading mode equals a two-axis
autopilot. I've always rebelled against that usage. To me an axis is
roll-pitch-yaw. Unless the autopilot controls two of those, it's a one-axis
autopilot... but I'm swimming against the tide.


Thanks for the tips! I'd be interested to hear from folks who have these
things -- do they hunt all over, or can that be damped?

Dave
Remove SHIRT to reply directly.

lets see.. wing leveler and heading control... sounds close to roll and
yaw..

BT

"Dave Butler" wrote in message
...
To me an axis is
roll-pitch-yaw. Unless the autopilot controls two of those, it's a
one-axis
autopilot... but I'm swimming against the tide.

BTIZ wrote:

lets see.. wing leveler and heading control... sounds close to roll
and
yaw..

"Dave Butler wrote:

To me an axis is
roll-pitch-yaw. Unless the autopilot controls two of those, it's a
one-axis
autopilot... but I'm swimming against the tide.

Dave is correct here. The # of axes in an autopilot refers to how many
axes of _controls_ it has feedback for - i.e. one for roll/ailerons (for
wing leveling and/or heading via roll), two for pitch/elevator (for
altitude and/or climb/descent rate) and three for rudder/yaw. Almost no
small GA autopilots are more than two axis, and many are only one axis.

With one axis, you can easily control heading - when you're at cruise
speed in most small GA aircraft, and you change direction with the
ailerons in anything less than a 30 degree roll, you hardly use the
rudders at all (I said MOST). Now consider that the autopilot generally
will roll no more than 5-10 degrees, and you can see that rudder control
is not required.

Pitch as a second axis, however, is nice to have.....

--
Marc J. Zeitlin
http://marc.zeitlin.home.comcast.net/
http://www.cozybuilders.org/
Copyright (c) 2004

BTIZ wrote:
lets see.. wing leveler and heading control... sounds close to roll and
yaw..

The ones I've seen have only one servo - the ailerons. They track heading by
controlling roll.


BT

"Dave Butler" wrote in message
...
To me an axis is

roll-pitch-yaw. Unless the autopilot controls two of those, it's a

one-axis

autopilot... but I'm swimming against the tide.