High altitude piston engine performance

[Dillon 2,197]

Just did a flight out of KBJC (who's squawking as KDTW for both ground and tower for some reason) in Denver and found that high altitude has no baring on piston engine performance (flying the Baron).  In sims of the past going back to FS2000 I always had to lean the fuel a bit to get the engines to start.  In FS2020 that is not needed for not only engine start but once aloft.  I reported this but wondering what are other's experiences with pistons at high altitude airports.

Edited September 5, 2020 by Dillon

[Hyperfocal 186]

Leaning gives a performance increase in the 172 and Bonanza; however, it doesn’t do anything until I lean to around 50%. This seems odd, but I don’t have the real world experience to determine if that is correct. I suspect it isn’t.

Edited September 5, 2020 by Hyperfocal

[MartinRex007 390]

By chance were you flying a turbocharged piston?

[Flyfaster_MTN002 412]

The Cirrus leaning does nothing regardless of any other parameter(s). Just doesn't work :(. OTOH the turbines do seem to be affected by altitude, as ITT's and Torque seem to redline up higher and need to be pulled back (correctly).

 

[Dillon 2,197]

2 minutes ago, MartinRex007 said:

By chance were you flying a turbocharged piston?

I've tried this with the Cessna 172, G36, and Baron so far.

[Flyfaster_MTN002 412]

3 minutes ago, Dillon said:

I've tried this with the Cessna 172, G36, and Baron so far.

Did you check OAT to see if that makes any difference or not as well?

OT: looking at Alienware also - with your setup what have you noticed is limiting? CPU/GPU/RAM etc.?  Wondering where to allocate $ to my build 🙂

[MartinRex007 390]

I don't have MS 2020 installed yet, but that hopefully will be address in an update. Prior versions of MS like you mentioned needed to be lean too much, which was very unrealistic.

Cheers

Martin

Edited September 5, 2020 by MartinRex007

[cantremember 27]

In the Cennsa 152 leaning does do something, but the behavior seems quite different to FSX (only other sim I have experience in)

In FSX the effect was gradual, when you were at high altitude leaning would gradually restore power as you lean.

In FS2020 I feel like leaning has no effect until you hit a very specific range and then performance shoots up, and the travel range is very limited before you lean too far and performance cans again.

I don't fly IRL so I can't say what is more realistic.

[robert young 2,897]

53 minutes ago, Dillon said:

I've tried this with the Cessna 172, G36, and Baron so far.

Dillon, have you checked in settings that you have auto mixture turned off?

[Dillon 2,197]

30 minutes ago, robert young said:

Dillon, have you checked in settings that you have auto mixture turned off?

No, all settings are set to the 'Hard'. What's been your experience with the pistons?

[robert young 2,897]

3 minutes ago, Dillon said:

No, all settings are set to the 'Hard'. What's been your experience with the pistons?

I've only tried the Bonanza in detail as I'm working on it. The mixture lever does work and apart from requiring a bit too much lean it is not bad. However to fine tune for high latitude, as with sims before, you need to lean too much to get optimal performance. The Bonanza should be around 20% greater than lean peak for high altitude cruise, but it needs more in the sim to get anywhere near passable performance. I'm trying to fix that right now.

Edited September 5, 2020 by robert young

[Dillon 2,197]

1 hour ago, Flyfaster said:

Did you check OAT to see if that makes any difference or not as well?

OT: looking at Alienware also - with your setup what have you noticed is limiting? CPU/GPU/RAM etc.?  Wondering where to allocate $ to my build 🙂

The system is great.  FS2020 runs great for only lacking in the video card RAM department.  Only issues is the bugs in FS2020 itself.  I highly recommend Alienware hardware for what we have now with FS2020.  The days are gone of tweaking, another $1000 for a video card on top of what we spent for the computer, and more RAM than any other comparable software needs.  Now we can buy a new computer (from a reputable vendor) and what we have under the hood after checking recommended specs for FS2020 and runs it without issue.  I'm soo glade the old FSX way of doing things is over in this hobby... 

[Dillon 2,197]

5 minutes ago, robert young said:

I've only tried the Bonanza in detail as I'm working on it. The mixture lever does work and apart from requiring a bit too much lean it is not bad. However to fine tune for high latitude, as with sims before, you need to lean too much to get optimal performance. The Bonanza should be around 20% greater than lean peak for high altitude cruise, but it needs more in the sim to get anywhere near passable performance. I'm trying to fix that right now.

I remember at around 5,000ft or above you couldn't start the engines with full mixture.  You had to lean it somewhat to get the engines to start let alone climbing out of a 5,000ft runway.  Not seeing this simulated in FS.  I'm going to do a flight from KBJC to Aspen right now to see what I get.

Edited September 5, 2020 by Dillon

[Flyfaster_MTN002 412]

49 minutes ago, Dillon said:

The system is great.  FS2020 runs great for only lacking in the video card RAM department.  Only issues is the bugs in FS2020 itself.  I highly recommend Alienware hardware for what we have now with FS2020.  The days are gone of tweaking, another $1000 for a video card on top of what we spent for the computer, and more RAM than any other comparable software needs.  Now we can buy a new computer (from a reputable vendor) and what we have under the hood after checking recommended specs for FS2020 and runs it without issue.  I'm soo glade the old FSX way of doing things is over in this hobby... 

Thanks for confirming my suspicion. Will save some $ on processor(s) and spend it on the RAM and Card/VRAM. Was hoping to get away with 3080 but looks like 3090 would really help.

[Los 416]

1 hour ago, Dillon said:

The system is great.  FS2020 runs great for only lacking in the video card RAM department.  Only issues is the bugs in FS2020 itself.  I highly recommend Alienware hardware for what we have now with FS2020.  The days are gone of tweaking, another $1000 for a video card on top of what we spent for the computer, and more RAM than any other comparable software needs.  Now we can buy a new computer (from a reputable vendor) and what we have under the hood after checking recommended specs for FS2020 and runs it without issue.  I'm soo glade the old FSX way of doing things is over in this hobby... 

Excellent! I’m waiting on my Alienware, same specs as yours, but with a 2070S. So glad it’ll run FS2020 well out of the box😃