KAP 140 autopilot FAQ

Post any technical issues here. This forum gets priority from our staff.
User avatar
renaissanceman
Technical Sergeant
Posts: 597
Joined: 13 Apr 2008, 08:29
Location: Bedford, Texas

Re: KAP 140 autopilot FAQ

Post by renaissanceman »

Hi Wayne,

Yes, you can display frame rate by pressing Shift+Z twice. I limit my frame rate to 30 and run at 30 95% of the time. I would think with your rig you would run about the same. Is your Win 7 the 64 bit version? If it is and you have at least 4 GB of RAM, the one tweak I recommend is adding Highmemfix=1 to the Graphics section of your FSX.cfg:

[GRAPHICS]
HIGHMEMFIX=1

Hope this helps.

Jim

P.S. I see Lewis has replied before me, upping the limit to 30 should help.
i7-6700K @ 4.0 GHz | ASUS Maximus VIII Formula | 32 GB DDR4 | EVGA GeForce GTX 980TI Classified |
Win 10 Pro 64 | FSX SE | Registered FSUIPC | All Accu-Sim Birds | Accu-Feel v2 | TrackIR5 | AS16 | PRO-ATC/X

wrkempson
Airman First Class
Posts: 79
Joined: 17 Apr 2012, 17:26

Re: KAP 140 autopilot FAQ

Post by wrkempson »

Thanks to all for the help.

I was surprised how low my fps was - in the 10 range. By degrading all the scenery (yuk) I got it up to around 19 and the AP started to behave properly. It was then that I read the posts by Lewis and Jim. So I went back up with the limit set to 30, saw great improvement with fps in the high 20's. Since I kind of like to see buildings and things, I upped the limit to 45 and reset scenery for max autogen, density and half water effects. The fps fell back into the 19 area, but the AP seems to be working fine. I'm satisfied with this progress, but will probably try something longer in the air tomorrow.

I had the limit set at 20 as per the instructions for megascenery. Tomorrow I'll fly over that area and see what happens.

I cannot find the FXS.cfg file, not even with a search. If someone has a hint I would appreciate it.

The whole day has been spent going up and landing at LaGuardia with AP sessions. Thanks to this forum, I think we can say the problem is definitely the frame rate. I knew this could be a problem, but I had thought with my machine's horsepower and with taking out addon's it would have been higher. Live and learn, I suppose.

Thanks so much to everyone who has taken the time to address this issue for me.

Wayne

User avatar
renaissanceman
Technical Sergeant
Posts: 597
Joined: 13 Apr 2008, 08:29
Location: Bedford, Texas

Re: KAP 140 autopilot FAQ

Post by renaissanceman »

Hi Wayne,

On a Win 7 system the FSX.cfg should be here:

C:\Users\<user name>\AppData\Roaming\Microsoft\FSX

FSX.cfg is a text file so it can be edited with Notepad or any text editor. Always a good idea to back up a file before editing. The HIGHMEMFIX=1 (or =0) line will probably not be in your FSX.cfg, so just add it under the [GRAPHICS] heading.

For me, running FSX is all about smooth flight. I don't worship at the altar of frame rate. Frame rate is one of many tools that help us understand what is going on. It's a balancing act between good visuals and smooth flight. Sounds like you are on the right track. :)

Jim
i7-6700K @ 4.0 GHz | ASUS Maximus VIII Formula | 32 GB DDR4 | EVGA GeForce GTX 980TI Classified |
Win 10 Pro 64 | FSX SE | Registered FSUIPC | All Accu-Sim Birds | Accu-Feel v2 | TrackIR5 | AS16 | PRO-ATC/X

User avatar
Great Ozzie
A2A Test Pilot
Posts: 2054
Joined: 16 Feb 2008, 15:49
Location: KUMP

Re: KAP 140 autopilot FAQ

Post by Great Ozzie »

wrkempson wrote: I cannot find the FXS.cfg file, not even with a search. If someone has a hint I would appreciate it.
Isn't the fsx.cfg in a Hidden Folder? (Tools > Folder Options > View - to enable)

I cannot remember as it is one of those things I do (enabling "show hidden files, folders...") right after install of the OS.
renaissanceman wrote:
wrkempson wrote:I knew this could be a problem, but I had thought with my machine's horsepower and with taking out addon's it would have been higher. Live and learn, I suppose.
I don't worship at the altar of frame rate. Frame rate is one of many tools that help us understand what is going on. It's a balancing act between good visuals and smooth flight.
Ah, but so many of us, since the release of FSX, have bowed (more than once) at the altar of perpetual delight hoping that "the next system upgrade" will bring us to the paradise of "All Sliders to the Right".

-Rob
Rob Osborne
Flight Instructor - CFI, CFII, MEI, MEII
A & P Mechanic


FAASTeam - Safer Skies Through Education
Professionalism in aviation is the pursuit of excellence through discipline, ethical behavior and continuous improvement. NBAA

User avatar
renaissanceman
Technical Sergeant
Posts: 597
Joined: 13 Apr 2008, 08:29
Location: Bedford, Texas

Re: KAP 140 autopilot FAQ

Post by renaissanceman »

Rob you are right about the hidden folder. I tend to forget since that is one of the first settings I change when installing an OS.

Thanks. :)

Jim
i7-6700K @ 4.0 GHz | ASUS Maximus VIII Formula | 32 GB DDR4 | EVGA GeForce GTX 980TI Classified |
Win 10 Pro 64 | FSX SE | Registered FSUIPC | All Accu-Sim Birds | Accu-Feel v2 | TrackIR5 | AS16 | PRO-ATC/X

wrkempson
Airman First Class
Posts: 79
Joined: 17 Apr 2012, 17:26

Re: KAP 140 autopilot FAQ

Post by wrkempson »

Just finished using the AP in dense weather with REX over my megascenery. It bit into the fps, but managed the whole flight on the AP, even landed ILS without touching the yoke, just throttle adjustments (but a little rough on the front wheel). Found the fsx.cfg and inserted the HIGHMEMFIX=1 line.

Thanks to all.

Wayne

GrandpaKim
Airman
Posts: 26
Joined: 27 Jan 2014, 22:20

Re: KAP 140 autopilot FAQ

Post by GrandpaKim »

Also, when using the ILS, set the OBS to the runway heading as well as the heading bug. Easy to forget since the needle doesn't care what the OBS is set to but the autopilot does!

barryoo
Airman
Posts: 18
Joined: 24 Feb 2014, 21:10

Re: KAP 140 autopilot FAQ

Post by barryoo »

some1 - A2A wrote:HSI was an option, but pretty expensive one, so very few c172s out there have it installed.
Ha, Ha. I like this quote. Yes, you as an A2A 172 owner could install Reality XPs HSI and install it in your airplane. Like the man said " it's an option, but pretty expensive one".

adrianlee30
Airman Basic
Posts: 1
Joined: 26 Apr 2014, 16:41

Re: KAP 140 autopilot FAQ

Post by adrianlee30 »

The autopilot in the a2a c172 can't get it to set. Plane going up and down. How do you set it 

User avatar
Lewis - A2A
A2A Lieutenant Colonel
Posts: 33284
Joined: 06 Nov 2004, 23:22
Location: Norfolk UK
Contact:

Re: KAP 140 autopilot FAQ

Post by Lewis - A2A »

Hello Adrian,

you will want to update to the latest Accu-sim core update (1.6 as of date of this post) and then also have a read of the auto pilot manual and also the FAQ in this thread. If you still have any issues please start a new thread so we can troubleshoot the issue for you.

thanks,
Lewis
A2A Facebook for news live to your social media newsfeed
A2A Youtube because a video can say a thousand screenshots,..
A2A Simulations Twitter for news live to your social media newsfeed
A2A Simulations Community Discord for voice/text chat

terrydew
Airman First Class
Posts: 75
Joined: 06 May 2014, 08:02

Re: KAP 140 autopilot FAQ

Post by terrydew »

Are the AP on,hdg,nav,apr,rev, and alt commands listed in the input configurator using the same events as fsx (p3d). I am using the saitek multipanel and these switches appear to work using the standard fsx offsets? If so why are they in the configurator as I thought it was for events that are unique to A2A C172?

hermannk1
Airman
Posts: 41
Joined: 05 Jan 2009, 14:25

Re: KAP 140 autopilot FAQ

Post by hermannk1 »

some1 - A2A wrote:Basically for all modes that involve the use of CDI (NAV/APR/REV) you have to set the HDG bug to match OBS setting (NAV) or ILS course. This is because the HDG bug is the only source of plane heading AND course reference. The autopilot doesn't get that signal from the OBS gauge. The flashing HDG after you arm one of those modes is a reminder for that.
For example if you are following VOR radial 250, but you have your heading bug at 330, the autopilot will think that the desired course is 330, but will still try to match the CDI which is set for radial 250. This will cause completely erratic behavior.
It's a limitation of an KAP autopilot coupled with simple directional gyro. If we had a HSI installed, it would work more like the other autopilots you are used to. But that would be boring, wouldn't it?
I had the same problem regarding the KAP 140 autopilot. I was so used to other AP's and their "workings". Out of frustration I downloaded the Bendix King Kap 140 manual from Bendix King itself. :cry: And, Eureka! This AP from A2A is truely a masterpiece. The HDG bug was the missing link for me. Sorted that out and now everything works fine. Thanks A2A for another remarkable aircraft! :o
The site for downloading the pdf from Bendix King: http://www.bendixking.com/HWL/media/PDF ... KAP140.pdf

Yann
Airman Basic
Posts: 1
Joined: 30 Oct 2014, 20:48

Re: KAP 140 autopilot FAQ

Post by Yann »

Gents, I'm really a big fan of the products a2a developes. Actually you're one of the best developers for me. All plames hsve exceptional quality, and the C172 is no exception. Everything is bery good except ( and that's a big exception) the autopilot. I'm sorry but it's worthless. It's completely bugged, in my opinion. I've already read the manuals, but I can't get it to work regularly, and I'm pretty confident I understand how it works. But the truth is, sometimes it works fine, but the majority of the times it doesn't. I was able to finish a couple flights with it working just fine from the beginning. But most times it's incapable of capturing a given altitude. The nose starts rising until the plane stalls. The only way to counteract this is to turn the autopilot off. And finally sometimes it starts working well,but after a while out of nothing the autopilot completely loses the control of the plane, which has led to many crashes. And I'm sure I know how it works. To change altitude you have to turn alt hold off and then use alt and vs to determine the rate of climb or descent. But for some reason most times when climbing it will just keep increasing the angle of attack until the plane stalls and falls, even if you have a low rate of climb set. That's ridiculous.

Matthew Flies
Airman Basic
Posts: 8
Joined: 21 Dec 2014, 21:51

Re: KAP 140 autopilot FAQ

Post by Matthew Flies »

Lewis - A2A wrote:
awash2002 wrote:The altitude hold just goes crazy up and down +/- 1500fpm will not hold altitude severe porpoising up and down 1500 fpm up and down I will hold off on flying the 172 until this problem is fixed
Check your FSX frames, if they are low you are experiencing FSX deterioration and no fix we give will fix the issue as its an FSX issue. FSX has a feature/issue/bug that is well known but has been forgotten by many. As the frames lower and FSX struggles to perform the program will start to turn stuff off and degrade performance of things like flight models and such. This in turn will have an affect on our realistic simulated autopilot and will cause issues such as some users have experienced. This also explains why we have not been able to reproduce the issue on our machines and why most users run OK. The issue was found and a reproducible case made by one of our testers and community member Oracle by setting his settings to max. The resulting low FPS causes all manner of issues and was cured when he set his PC back to his normal playable settings.
I have had the same issue. But turning the FPS limiter from 20 to Unlimited did it solve for me (I think). But maybe it would be worth an idea to provide a "working" simple autopilot (maybe FSX like) for people with slower machines.

new reply

Return to “C172 Trainer Tech Support”

Who is online

Users browsing this forum: No registered users and 8 guests