Dear community, I would like to ask, which autopilot vertical mode do you use in climb? I am succesfully using C550 with famous ISG mod v.1.7. prepared by Janek Bln, however would like to know, how do you climb with this bird? I have to use V/S mode, as using IAS mode is not reliable, at least in my case. The plane is jumping up and down, unable to keep selected IAS during climb, even if properly loaded and trimmed. Did I miss any patch prepared by Bert / anyone else or is there any other solution? Maybe I missed something in this forum. Many thanks in advance for the advice. 

I have found IAS/FLC modes to be finnicky and sometimes unreliable in both the Citation and Hawker.

 

If you are climbing at a steady rate at 250 knots, and then turn on IAS/FLC, the autopilot will hold that speed.

 

You can adjust the throttles to vary the vertical climb rate.

 

If you spin the speed dial, however, the autopilot has a lot of trouble adjusting and can easily go unstable.

I have found IAS/FLC modes to be finnicky and sometimes unreliable in both the Citation and Hawker.

 

If you are climbing at a steady rate at 250 knots, and then turn on IAS/FLC, the autopilot will hold that speed.

 

You can adjust the throttles to vary the vertical climb rate.

 

If you spin the speed dial, however, the autopilot has a lot of trouble adjusting and can easily go unstable.

 

Dear Bert, ROGER OVER, or everything is clear to me now:-))) MANY THANKS, Petr

Dear community, I would like to ask, which autopilot vertical mode do you use in climb? I am succesfully using C550 with famous ISG mod v.1.7. prepared by Janek Bln, however would like to know, how do you climb with this bird? I have to use V/S mode, as using IAS mode is not reliable, at least in my case. The plane is jumping up and down, unable to keep selected IAS during climb, even if properly loaded and trimmed. Did I miss any patch prepared by Bert / anyone else or is there any other solution? Maybe I missed something in this forum. Many thanks in advance for the advice. 

Ditto, so I use V/S, gradually decreasing the feet per minute as I ascend. Sometimes I step climb if I'm loaded.

 

Although I did just buy the WeFly gps-autopilot ($4.00, so what the heck) and it has an IAS button. So maybe I'll try it on the Citation 2

I found if you change the ISG Citation cfg file to the vnav climb of 2500' per min, VNAV(full throttle) will hold that climb rate to about FL280, after that change to VS of 1800 fpm up to FL 350 then VS 1000 fpm to a max of FL 380. Most time the FMS descent from TOD is accurate down to the desired altitude throttling back to 60-70% to prevent overspeed. Assumptions are that fuel is 80% full.

Bert's recommendations are fairly much on target. I was able to use IAS mode with Jane's and Bert's modifications. Basically, as Bert states manually set the aircraft pitch by hand flying or use VS until the desired IAS is reached. Then you can select IAS. The aircraft will initially pitch down to 500 fpm before pitching back up to hold your selected IAS.

 

To adjust IAS you need to do so in small bits. Anything more than about +- 5 KIAS will cause instability in the autopilot. If you are going to make a major change in IAS then select VS, manually adjust your speed then reselect IAS.

 

This is not how the real Sperry SPZ-500 works but I think we are at an impasse in ability of .xml based gauges.