How does PM behave with default FSX Autopilot?

[Peter Dowson]

I didn't realize that PM is using now his own autopilot. As long I know, it is working in combination with the FS autopilot. There is a flag in the ini file of the MCP to activate a beta-version, but as far I know this is now de-activated by Enrico.

The problem with the beta version A/P was that it needs specific tuning for each aircraft (much as FS is partially so tuned via AIR and CFG file parameters), and investigating what parameters were needed and how to document them sufficiently for users to do the job for their favourite FS aircraft, was a much bigger job than Enrico had time for with everything else on his plate.

I tried to help by supplying faster feedback loops operating to supplied parameters but inside FSUIPC (hence inside FS), but the speed control was still a problem -- generally the Pitch/Bank/Heading guidance was good, not needing much tuning, but it was difficult to deal with the throttle to set correct speed without unwanted oscillations, at least without much more and specific tuning.

The feedback control facilities are still available within FSUIPC, though generally not published, and should work with FSX too (though totally untested at present).

I know that for PMDG, who do this sort of thing for very specific aircraft, it takes many many man-hours to get their autopilots just so. In fact this is the main reason they give for not publisihng an interface to it which could be better used in PM (for example).

So, you see, PM has a difficult problem unless you are going to restrict its use to specific models.

The way the default AP works in PM's MCP module does make use of FS's inbuilt AP modes, but it doesn't just set things and leave it to it -- it is constantly adjusting the parameters so that the A/P does what the MCP wants. It has always worked pretty well -- but you should be aware that the FSX default models are not the same as the FS2004 ones. The 737-800 isn't bad, but I still prefer the PMDG 737-700 and -800 air and CFG files, with some changes made by Thomas.

And the pilot must always take care to keep the aircraft operating within the A/P's capability envelope. Once outside chaos ensues!

Regards

Pete

[737aqua]

So, Peter, you are saying that a 737 will not maintain speed properly or VNAV properly with PM under FSX? It really doesn't work well at all?
I want an accurate A/P if I'm spending hundreds for PM software.

To all those who critized my first post, I was right about what I said originally!! It DOES use FSX.


According to users, FSX does not have an accurate A/P with its default planes. I think this is very dissapointing -- we spend so much on a cockpit only to have an A/P worse than a 40$ add-on like PMDG. So, does this mean that FSX has worse A/P performance with FSX than earlier versions?

Really, for the price they charge for PM, they should be working on at least one or two popular flight models and A/P...Its ridiculous that they arn't even trying and yet they are raising their prices. I'm sure they could focus on the two most popular aircraft and develop a version. Why do they have this annoying "must please everyone" phillosophy.

Do you know if they would develop a custom A/P for a specific aircraft? Is this what the Pro contracts that they deal with use, because I doubt the Pros use an inaccurate A/P for flight training with PM. Am I right here Peter?

Thanks
Aqua

[mgrant]

I must admit PM seem to be suffering with a few problems with their software and FSX, i am having the same problem with vnav speeds all goes wrong, take a look at what happens when i try to slow down, engine number 1 doesn't retard number 2 however does. How strange im sure they will sort it out though.



Mark

[737aqua]

Yes,

Every function of the MCP has been recreated with impeccable accuracy , in fact... Project Magenta's FCU Airbus suite is just as accurate for those that like to drive the Bus.

Regards,

Trev

How can what you say be believed after reading the posts by Peter and mgrant.???

[mgrant]

Hi Guys back with a report, these guys at PM are lightning quick and worth every penny, A/T problem resolved just a case of editing the default aircrafts cfg file... Happy Days......

Thanks PM

Mark

[michelmvd]

Hi Pete,
Thanks a lot for the very professional way you explained the working of the PM -autopilot. This is one of thing I appreciate a lot. Constructive information can help all of us, to give us a better view of the situation and the possibilities. Pete can we use this parameters in FSIUPC still today in FS2004 ? or are they "grey out"

Bob or Trev, are you using the professional version of the PM software for a specific type of B737 ?

Blindness admiration is maybe nice for PM, but will not help us out of the problems. Only by communicating our problems can help, to improve this software, which is in my opinion unique in his kind. Nevertheless this doesn't mean it can not be improved on a lot of levels and certianly for type specific things. We all know Enrico is a hard worker and he has "time" against him, but with feedback for a good team he must be able to do a lot

B. rgds
Michel

[737aqua]

I e-mailed Johnathan at PM to inquire. He said there is no planned development of the A/P system.

Michael, do you know what cost the pro version of the software is? Does it have much more accurate sytems? Will they sell it to private users?

[Peter Dowson]

So, Peter, you are saying that a 737 will not maintain speed properly or VNAV properly with PM under FSX? It really doesn't work well at all?

No, I am not saying that! Where do you read that?

It seems to work pretty well with the default 737-800, but I have better & smoother results all round with the PMDG models, air and CFG files (as modified a while back by Thomas), using the appropriate 737 files in PM.

I don't know why I bothered trying to explain anything. You seem to have misread just about everything I wrote!


Pete

[Peter Dowson]

Pete can we use this parameters in FSIUPC still today in FS2004 ? or are they "grey out"

The feedback facilities are still in place. As I said, the pitch/bank/yaw loops were working reasonably well with little tweaking for different aircraft, but the airspeed and mach hold loops are in need of a lot of work to tune them for different aircraft, else they induce oscillation.

Are you a programmer thinking of writing your own external autopilot?

Regards

Pete

[Peter Dowson]

I must admit PM seem to be suffering with a few problems with their software and FSX, i am having the same problem with vnav speeds all goes wrong, take a look at what happens when i try to slow down, engine number 1 doesn't retard number 2 however does.

Are you saying that the FSX throttle doesn't respond to your throttle changes? You aren't expecting PM to do the retarding are you? It is not likely (nor supposed to) override your own throttle inputs. Even when using AutoThrottle I always place the throttle levers at full max in normal climbs, and pull them right back to idle during cruise so that on descent, when the VNAV system relinquishes throttle control, the settings are correct.

From your illustration it looks like either you only have one throttle lever and have not selected both throttles (E + 1 + 2, or use the FSUIPC shortcut key), or you have set the (unrealistic, I think?) PM option for A/T control during descent and somehow your real throttle inputs are interfering with the settings FSX is trying to make on PMs behalf.


Regards

Pete