AutoPilot practical in a very light aircraft?
I believe Alan has an autopilot in his Gull. I'm wondering how complex it is to install, what brand do you recommend, how reliable is it, what does it weigh and how much does it cost?
I can see how having one on a long trip as well as rough air would be a great advantage.
Thanks, Skot
AutoPilot?
-
blaswichk
Re: AutoPilot?
There are several installed in the copy-cat airplanes. A bit of bracketry is involved, but it is doable. I think that they are mostly wing levelers, and they attach to the bellcrank that the torque tube going up to the wing is connected to.
kb
kb
-
cossitt.alan
Re: AutoPilot?
Sorry forgot to reply. I like mine. Will comment more when home.
-Alan Cossitt
>From my iPhone. Please excuse typos and terseness.
-Alan Cossitt
>From my iPhone. Please excuse typos and terseness.
-
cossitt.alan
Re: AutoPilot?
I have a autopilot (wing leveler) in my JT2. Love it. Mine is a TruTrak AP
and I now would not want to fly without it. I've flown in very turbulent
conditions with the autopilot and GPS sending me my merry way and the AP
performed very well. I was buffeted around and had a little nose yaw due to
the turbulence, but the aircraft flew fine and I just relaxed and let the
plane fly itself. A couple of times I experimented by taking the controls
manually, but I soon went back on the AP. The workload in the turbulence
was just too great.
When the air is smoother, the AP follows your GPS track very precisely so
that you gain added efficiency in flight (via shortening your track in
flight by not having deviations). The GPS controlling the AP does not have
the capability a curve through a track waypoint if a turn is required to
move between waypoints. Only very expensive IFR GPS' have this
functionality. My VFR GPS flies through the waypoint and then curves back
onto the track. So some of the straight line efficiency is lost there. You
can overcome this by manually telling the GPS to go to the next after
waypoint just before reaching the next waypoint. But this requires you to
do something, rather than taking a nap ;).
Also if I get sick or disoriented in flight the AP will fly the airplane to
the nearest airport where, hopefully, I will be able to summon the strength
to quickly land the airplane.
Currently I have the AP motor mounted under the front right part of the
seat. It is attached to a lever arm welded to the steel tube controlling
the aileron push rod. This has the disadvantage of being a danger to me in
a crash (but was relatively easy to make and put the motor weight forward).
This is part of the reason I'm building up my seat with Kevlar and
fiberglass. At some stage I'm might move the motor and lever arm to the
area behind the seat near the push rod and either attach to the push rod
directly, or to the steel tube behind the seat where I have more protection
from the lever arm and motor.
More likely, I'll modify the lever arm in a way that it would collapse if
the steel tube contacted the bottom of the seat (rather than the arm poking
through the seat and then through my leg). I'm not worried about the motor
causing me harm in a crash since it fairly large and won't come through the
seat. It is also located off to the side in near the front of the thighs,
so it won't damage my back if I have a crash.
It might also be possible to mount the motor in the wing.
I've had great support from TruTrak and would not hesitate to recommend them
to others. Make sure whatever AP you buy works on the (relatively slower)
LSA. My AP will control my airplane down to 50 MPH or so but works better
as I go faster. I often fly around 70 mph (about 3600 RPM on my 3701 Hirth
and a place where the engine is quiet and very smooth) and the AP works
fine, there.
APs work best if you don't have much slop in the aileron control system.
Everything nice and tight works best. Another reason a mount and attach
point in the wing might work well (closer to the ailerons with fewer slop
points in the system).
I'll take photos if you would like.
_____
and I now would not want to fly without it. I've flown in very turbulent
conditions with the autopilot and GPS sending me my merry way and the AP
performed very well. I was buffeted around and had a little nose yaw due to
the turbulence, but the aircraft flew fine and I just relaxed and let the
plane fly itself. A couple of times I experimented by taking the controls
manually, but I soon went back on the AP. The workload in the turbulence
was just too great.
When the air is smoother, the AP follows your GPS track very precisely so
that you gain added efficiency in flight (via shortening your track in
flight by not having deviations). The GPS controlling the AP does not have
the capability a curve through a track waypoint if a turn is required to
move between waypoints. Only very expensive IFR GPS' have this
functionality. My VFR GPS flies through the waypoint and then curves back
onto the track. So some of the straight line efficiency is lost there. You
can overcome this by manually telling the GPS to go to the next after
waypoint just before reaching the next waypoint. But this requires you to
do something, rather than taking a nap ;).
Also if I get sick or disoriented in flight the AP will fly the airplane to
the nearest airport where, hopefully, I will be able to summon the strength
to quickly land the airplane.
Currently I have the AP motor mounted under the front right part of the
seat. It is attached to a lever arm welded to the steel tube controlling
the aileron push rod. This has the disadvantage of being a danger to me in
a crash (but was relatively easy to make and put the motor weight forward).
This is part of the reason I'm building up my seat with Kevlar and
fiberglass. At some stage I'm might move the motor and lever arm to the
area behind the seat near the push rod and either attach to the push rod
directly, or to the steel tube behind the seat where I have more protection
from the lever arm and motor.
More likely, I'll modify the lever arm in a way that it would collapse if
the steel tube contacted the bottom of the seat (rather than the arm poking
through the seat and then through my leg). I'm not worried about the motor
causing me harm in a crash since it fairly large and won't come through the
seat. It is also located off to the side in near the front of the thighs,
so it won't damage my back if I have a crash.
It might also be possible to mount the motor in the wing.
I've had great support from TruTrak and would not hesitate to recommend them
to others. Make sure whatever AP you buy works on the (relatively slower)
LSA. My AP will control my airplane down to 50 MPH or so but works better
as I go faster. I often fly around 70 mph (about 3600 RPM on my 3701 Hirth
and a place where the engine is quiet and very smooth) and the AP works
fine, there.
APs work best if you don't have much slop in the aileron control system.
Everything nice and tight works best. Another reason a mount and attach
point in the wing might work well (closer to the ailerons with fewer slop
points in the system).
I'll take photos if you would like.
_____
-
cossitt.alan
Re: AutoPilot?
from TruTrak faq:
Q - What if I don't have a GPS?
A - We sell a GPS-35 for $175, which is an antenna/receiver in one unit that
that is not programmable, but will allow the AP to function in its BASIC
TRACK MODE. The GPS-35 is roughly the size of a computer mouse and is
usually mounted on the glare shield.
Q - What is GPS Nav?
A - GPS Nav is similar to GPS Steering but not as sophisticated. GPS Nav
signals are on the RS-232 output (GPRMC and GPRMB sentence in the data
string) from most GPS's. This is the same RS-232 connection that is
required for the autopilot to be functional so no additional wiring is
necessary. Virtually all GPS's (handhelds included) have the output that is
required for GPS Nav. GPS Nav flies a preprogrammed route with multiple
waypoints. The course intercept feature of GPS Nav allows the autopilot to
seamlessly intercept courses regardless of the aircraft's initial direction
of flight. When the last waypoint is flown over the autopilot reverts to
the track mode. All Trutrak autopilots have GPS Nav Mode.
Q - What is GPS Steering?
A - GPS Steering is a new way to fly a flight plan that is programmed into a
GPS. Some GPS's have the required output for GPS Steering. With GPS
Steering the GPS calculates a desired bank angle for the autopilot to fly.
There is no overshoot of the desired course in any course change. GPS
Steering allows the Trutrak family of autopilots to fly complex patterns
such as holding patterns and DME arcs with stunning precision.
Q - What is the difference between GPS Steering and GPS Nav?
A - GPS Nav does not anticipate a course change. Thus when one leg is
finished the autopilot has to intercept the next leg after over flying the
waypoint. With GPS Steering the autopilot does not have to intercept the
new leg because it starts intercepting procedure before reaching the
waypoint so that when the intercept turn is complete the aircraft will be on
the next leg. GPS Steering will also fly complex turns such as DME arcs and
holding patterns. If you want the increased capability of GPS Steering you
must be sure that your GPS supports GPS Steering.
Q - Which GPS systems provide the GPS Steering signal required for GPS
steering?
A - Most panel GPS that are IFR certified Garmin 250/300XL, Garmin GNC
430/530, 480, Apollo GX50/55/60/65 and, King KLN 90/90B, Sierra Flight
Systems, Chelton Flight System, and Grand Rapids EFIS. In most cases the
signal used for GPS Steering is the ARINC 429 Roll Steering signal, however
the Apollo GX50/55/60/65 units provide GPS Steering over the RS-232 line.
Q - Can I couple the autopilot to a hand-held GPS?
A - Coupling the autopilot to a hand-held GPS's interface RS-232 must be
either NMEA 0183 (GPRMC and GPRMB sentence in the data string) or Aviation
format. The desired update rate is every second, but the system will
function at an update rate as slow as every other second. Most new handheld
units have fast update rates and reliable output, and will couple with a
Trutrak autopilot very well.
_____
Q - What if I don't have a GPS?
A - We sell a GPS-35 for $175, which is an antenna/receiver in one unit that
that is not programmable, but will allow the AP to function in its BASIC
TRACK MODE. The GPS-35 is roughly the size of a computer mouse and is
usually mounted on the glare shield.
Q - What is GPS Nav?
A - GPS Nav is similar to GPS Steering but not as sophisticated. GPS Nav
signals are on the RS-232 output (GPRMC and GPRMB sentence in the data
string) from most GPS's. This is the same RS-232 connection that is
required for the autopilot to be functional so no additional wiring is
necessary. Virtually all GPS's (handhelds included) have the output that is
required for GPS Nav. GPS Nav flies a preprogrammed route with multiple
waypoints. The course intercept feature of GPS Nav allows the autopilot to
seamlessly intercept courses regardless of the aircraft's initial direction
of flight. When the last waypoint is flown over the autopilot reverts to
the track mode. All Trutrak autopilots have GPS Nav Mode.
Q - What is GPS Steering?
A - GPS Steering is a new way to fly a flight plan that is programmed into a
GPS. Some GPS's have the required output for GPS Steering. With GPS
Steering the GPS calculates a desired bank angle for the autopilot to fly.
There is no overshoot of the desired course in any course change. GPS
Steering allows the Trutrak family of autopilots to fly complex patterns
such as holding patterns and DME arcs with stunning precision.
Q - What is the difference between GPS Steering and GPS Nav?
A - GPS Nav does not anticipate a course change. Thus when one leg is
finished the autopilot has to intercept the next leg after over flying the
waypoint. With GPS Steering the autopilot does not have to intercept the
new leg because it starts intercepting procedure before reaching the
waypoint so that when the intercept turn is complete the aircraft will be on
the next leg. GPS Steering will also fly complex turns such as DME arcs and
holding patterns. If you want the increased capability of GPS Steering you
must be sure that your GPS supports GPS Steering.
Q - Which GPS systems provide the GPS Steering signal required for GPS
steering?
A - Most panel GPS that are IFR certified Garmin 250/300XL, Garmin GNC
430/530, 480, Apollo GX50/55/60/65 and, King KLN 90/90B, Sierra Flight
Systems, Chelton Flight System, and Grand Rapids EFIS. In most cases the
signal used for GPS Steering is the ARINC 429 Roll Steering signal, however
the Apollo GX50/55/60/65 units provide GPS Steering over the RS-232 line.
Q - Can I couple the autopilot to a hand-held GPS?
A - Coupling the autopilot to a hand-held GPS's interface RS-232 must be
either NMEA 0183 (GPRMC and GPRMB sentence in the data string) or Aviation
format. The desired update rate is every second, but the system will
function at an update rate as slow as every other second. Most new handheld
units have fast update rates and reliable output, and will couple with a
Trutrak autopilot very well.
_____
-
wsweidemann
Re: AutoPilot?
Thanks for the info on the autopilot. I think for a lot of cross country (which Mark does...and I'm sure some of you others) a wing leveler or a pitch control would be great. What cross country trips I have done get pretty frustrating at times in rough air when I look down to read a map, I find myself either turning, climbing or both when I look up.
Skot
Skot
-
dickoreilly
Re: AutoPilot?
I used to enter unwanted turns in GA planes when I changed frequencies, looked
at chart, etc. An instructor finally told me the secret cure -- let go and keep
the wings level with the rudder. Works like a charm. Just make sure you're
trimmed for straight and level flight. Your peripheral vision will easily keep
you aware of whether you're level. Push on the foot next to the high wing. It's
even easier in the Gull than a Piper or Cessna. Takes less effort. And
peripheral vision is so much better.
Dick O'Reilly
dickoreilly@yahoo.com
(818) 261-8669 or (818) 780-4776
at chart, etc. An instructor finally told me the secret cure -- let go and keep
the wings level with the rudder. Works like a charm. Just make sure you're
trimmed for straight and level flight. Your peripheral vision will easily keep
you aware of whether you're level. Push on the foot next to the high wing. It's
even easier in the Gull than a Piper or Cessna. Takes less effort. And
peripheral vision is so much better.
Dick O'Reilly
dickoreilly@yahoo.com
(818) 261-8669 or (818) 780-4776