Auto pilots?

[201guy]

When I had a STEC 30 installed in my 64 M20E, I had the GPSS adapter installed with the system.  Worked flawlessly, provided a higher level of precision in the operation of the plane.

When I bought a 79 201J two years ago, it had a KFC-150 in it.  First thing it went to the shop and had a GPSS adapter installed.  Well worth the money!

[M016576]

Personally, I think the GPSS is overkill in an aircraft going 150-200kts.  If you have the money and are dead set on letting the automation fly lead turns to your next point, then go for it.  It does not make for a safer system, though.

The airspace structure allows for +/-4nm of route deviation.  Even if you were completely asleep at the yoke, with an older style autopilot tracking in NAV, which overflew a 90 degree course correction at a turn point, and you were a fast cruise (lets say 155kts), you would only blow through about 1.5nm of overshoot before your AP corrected back to course.  well within the airspace structural limits. 

Don't get me wrong... you should not STRIVE to allow your autopilot to do this.  If I was coming up on a turn like that, I'd lead turn it manually, then re-set the autopilot.  BUT.  for most of your course corrections, they will be slight jogs to the left or right (as you're most likely trying to go somewhere... and your route is most likely taking you to that place in as direct a manner as possible). 

In the approach environment, even with my C41, I can set the heading bug to get me a 45 degree intercept (or 30, or whatever) and with NAV selected, it will fly the intercept and fly the approach for me.  The NAV mode will fly the approach to the tighter approach standards, as well (.3nm-.1nm depending on the approach).  If I go missed, I'm hand flying it at least until a positive rate of climb is established and I'm configured.  I try not to configure with my autopilot engaged.

So, I guess my point is that a GPSS makes you feel good inside when it intercepts each radial smoothly without overshooting, but the overshoots that you do see with autopilots w/o GPSS, at the speeds we are flying, do not violate the airspace structure, and in most circumstances (turns of less than 30 degrees), you probably wouldn't even notice the difference... JMHO  

I think I'd rather have an Aera 560 or a Aera 796 than a GPSS....

[jetdriven]

Well, on the Century IIB and III you must set the heading and the radial to the inbound course.  it then gives a 45 degree intercept.  Flying over a waypoint requires either a new heading bug, OBS, and another 45 degree intercept, manually driving it in a turn just inside the waypoint to the next leg, or if you have GPSS, another sip of coffee while it does its thing. 

[M016576]

Quote: jetdriven

Well, on the Century IIB and III you must set the heading and the radial to the inbound course.  it then gives a 45 degree intercept.  Flying over a waypoint requires either a new heading bug, OBS, and another 45 degree intercept, manually driving it in a turn just inside the waypoint to the next leg, or if you have GPSS, another sip of coffee while it does its thing. 

[jetdriven]

you are right about the < 30 degree change in your route.  GPSS is not needed.  But a 90 degree or say a 130 degree turn you are going to have to do it manually. 

[ToddDPT]

We fly our J with the Aspen and Century IIB.  It works flawlessly and I agree with Jetdriven and M016576 that having GPSS with a Century IIB is a significant upgrade.

[jetdriven]

We should start a thread about the Century IIB.  I have the service manuals for it and lots of data. 

 

i like the thing. It works pretty well.  With an S-TEC altitude hold unit and GPSS it does everything but vertical nav or a glideslope.  But lots of capablity for a 30 year old analog autopilot.

 

[dougmilam]

Have owned an S-Tec 50 in the previous plane and an S-Tec 60-2 in the current J.

I added GPSS to the 50. It didn't change my world, but it is pretty good value for the money.  Not many other useful add ons to our birds for <$2,000.  That being said, flying in a terminal radar environment, I use the heading bug most of the time until nearing the FAF.  At that point the 60-2 really shines.  When flying in real soup, I find the glideslope capture (ILS or GPS/LPV) much more useful than GPSS.

[ToddDPT]

The S-Tec alt hold is our next purchase.  Does anyone know what I can expect to pay for purchasing and installing the S-Tec 30 alt hold?

[Jeff_S]

Quote: M016576

Personally, I think the GPSS is overkill in an aircraft going 150-200kts.  If you have the money and are dead set on letting the automation fly lead turns to your next point, then go for it.  It does not make for a safer system, though.

 

[jetdriven]

Quote: ToddDPT

The S-Tec alt hold is our next purchase.  Does anyone know what I can expect to pay for purchasing and installing the S-Tec 30 alt hold?