[jhb_airlines] Re: Autopilot APPR HOLD problem

  • From: "Bones" <bones@xxxxxxx>
  • To: <jhb_airlines@xxxxxxxxxxxxx>
  • Date: Sat, 15 Oct 2005 19:16:14 +0100

It sounds almost as if you are talking about a totally different aircraft to
the one I fly! The C550 flown manually is a real softy and I can fly visual
circuits in it without any problem. As mentioned on the web page I did
increase aileron authority a bit because roll rate was awful but I have
otherwise made no tweaks.

The other comments you make seem more related to the autopilot functions but
I will test my version again to make sure. I've not had any problems so far
capturing speed or the glidepath.

I might just delve into the .air file because I agree that rolling left
seems faster than rolling right. This may be due to incorrect values for the
aileron ratios.

bones

-----Original Message-----
From: jhb_airlines-bounce@xxxxxxxxxxxxx
[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Gerry Winskill
Sent: 15 October 2005 17:52
To: jhb_airlines@xxxxxxxxxxxxx
Subject: [jhb_airlines] Re: Autopilot APPR HOLD problem


I've downloaded tis aircraft, used the FS Panel Studio panel ant tried a
flight. Only two comments. I think it may be a bit overpowered, since
AutoThrottle couldn't reduce sufficiently quickly to stop it exceeding
240 kias, in the initial climb.
Approaching IOM, it captured the Localiser very efficiently, usin APPR.
 From then on it was downhill. When it caught the Localiser, still below
the Glideslope, and with Alt Hold still selected, it started to descend,
rapidly, from the setting of 2500'. It's not the only a/c to do this. No
idea why.
Things then got worse. I tried to fly the ILS manually. Maintaining GS
was no problem. The Localiser was a different matter, since at what I
thought was a high finals speed of 120 kias, any turn to the right
needed full right ailerond AND full right rudder pedal. Once the speed
was taken to about 130, full aileron authority returned though, unlike
the real aircraft, it still needed full deflection to initiate turns.

Gerry Winskill

gwinsk@xxxxxxx



Bones wrote:

>Give me the name of this panel and I'll download it and have a hunt
>around. If the autopilot is an XML file I should be able to track down
>why the APPR button isn't working. OTOH if it's and old GAU file then
>that's beyond my abilities as I have no C++ skills.
>
>I've built an autopilot for the Aztec and the code is very simple. An
>APPR button isn't very hard to do so I could probably add this to the
>Citation if the original is faulty.
>
>bones
>
>-----Original Message-----
>From: jhb_airlines-bounce@xxxxxxxxxxxxx
>[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Lucas
>Sent: 15 October 2005 12:48
>To: jhb_airlines@xxxxxxxxxxxxx
>Subject: [jhb_airlines] Re: Autopilot APPR HOLD problem
>
>
>bones
>
>Thanks for this info, and your other reply on gauge design.  I have no
>desire to enter a minefield ....
>
>I may try a different panel with the Citation and see if I can get
>APPR_HOLD to work.
>
>Think I've got the AP autothrottle and IAS hold sussed now ... <g>
>
>Mike L
>
>Bones wrote:
>
>
>>You are walking into a minefield here Mike so it may be best to leave
>>well alone. I don't know anything about the panel you got for the C550
>>but it would need a much closer look at the gauges supplied to see
>>what was included in the package and what was not.
>>
>>The gauge line you quote doesn't mean a lot to me as I don't have a
>>fsd_generic.ap.appr.gau (it could be a CAB file too). It becomes
>>tricky because just because the line is in the panel.cfg file it
>>doesn't automatically mean the gauge itself is in your gauges folder.
>>Although likely I can't even say this is an APPR hold function either.
>>It's unusual if it is because ALL the autopilot functions are normally
>>contained in a single autopilot gauge.
>>
>>The FS command AP_IAS_HOLD is a different beast to AP_AUTOTHROTTLE. If
>>you set a P8 button for the latter then (assuming the aircraft is
>>fitted with an AP and AT in the aircraft.cfg file) you have access to
>>speed control - it is, effectively, the Autothrottle Arm function.
>>
>>The AP_IAS_HOLD function is the same as the IAS button on the
>>autopilot panel on most aircraft. This is an engage/disengage button
>>but it has no effect if the Autothrottle isn't armed in the first
>>place. You don't need to allocate this button to a P8 switch because
>>it should already be programmed into the HOLD button below the
>>IAS/Mach rotary switch on your MCP. It's the same as the NAV and HDG
>>hold buttons alongside - press to engage or disengage.
>>
>>So, what you should really have is the AP_IAS_HOLD command set to the
>>HOLD button below the IAS/Mach panel on the MCP. On the P8 you
>>allocate a button for the AP_AUTOTHROTTLE function. When flying the
>>aircraft you hit the P8 to arm the autothrottle, dial in a speed you
>>want and then press the HOLD button to engage.
>>
>>You can mostly ignore the reference speeds in the aircraft.cfg as they
>>are only used in one of the FS menus - I think Weight and Balance.
>>They have absolutely no effect on the sim itself. The speeds are
>>actually the wrong way round but they are correct - the Citation has a
>>very low stall speed. It was intentionally designed for slow flight as
>>it gave the aircraft the ability to operate out of very short strips -
>>something no other jet is capable of. It was an impressive feat by
>>Cessna as the aircraft doesn't have any complex wing devices at all,
>>but there again it is quite a light aircraft.
>>
>>What is good about the Citation is that at 100kts the aircraft still
>>has excellent roll rate. It is a very nice aircraft indeed for a pilot
>>and doesn't really deserve its "toy jet" title from the Lear/Falcon
>>brigade.
>>
>>bones
>>
>>
>>-----Original Message-----
>>From: jhb_airlines-bounce@xxxxxxxxxxxxx
>>[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Lucas
>>Sent: 14 October 2005 19:29
>>To: jhb_airlines@xxxxxxxxxxxxx
>>Subject: [jhb_airlines] Re: Autopilot APPR HOLD problem
>>
>>
>>bones
>>
>>I'm afraid I don't know what it is I'm looking for in the panel and
>>aircraft.cfg files ...
>>
>>Panel.cfg contains the line -
>>
>>gauge37=fsd_generic.ap.appr,  213,517,20,23
>>
>>which suggests to me that there should be a working APPR_HOLD
>>function.
>>
>>As regards the GoFlight autothrottle, I have disabled the "arm when
>>CMD is activated" option.  But I cannot get the IAS/Mach hold to work
>>from a P8 button.  The appropriate P8 light comes on but it doesn't
>>activate the IAS/Mach hold (yes, I have designated the correct
>>function in GF config).  I can only get IAS/Mach hold to work using
>>Ctrl+R.  Any ideas??
>>
>>Going back to the Cessna Citation specifically, I found the following
>>in aircraft.cfg -
>>
>>[Reference Speeds]
>>flaps_up_stall_speed=77.0      //Knots True (KTAS)
>>full_flaps_stall_speed=80.0    //Knots True (KTAS)
>>cruise_speed=262.0              //Knots True (KTAS)
>>max_indicated_speed=350.453125
>>max_mach=0.75
>>
>>Surely flaps up stall speed should be higher than full flaps stall
>>speed?? - and I would have expected both to be 100+ kts.
>>
>>Confused.
>>
>>Mike L
>>
>>Bones wrote:
>>
>>
>>
>>>First thing to suspect is the panel because it suggests the autopilot
>>>gauge it uses may not be working properly. If it works in other
>>>aircraft but not the C550 then it may be the interaction between the
>>>panel and the aircraft.cfg file. In my copy both the autopilot and
>>>autothrottle are flagged as available.
>>>
>>>Check the MCP options in the GF Module. You should have two radio
>>>buttons which enable/disable autothrottle with AP activation. I don't
>>>actually use this myself as there are times when I want to keep AT
>>>active when flying manually and so I have one of the T8 switches set
>>>for AT engage/disengage. This works perfectly well. The command you
>>>want is called AP_AUTOTHROTTLE.
>>>
>>>bones
>>>
>>>-----Original Message-----
>>>From: jhb_airlines-bounce@xxxxxxxxxxxxx
>>>[mailto:jhb_airlines-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Lucas
>>>Sent: 14 October 2005 16:09
>>>To: jhb_airlines@xxxxxxxxxxxxx
>>>Subject: [jhb_airlines] Autopilot APPR HOLD problem
>>>
>>>
>>>For one sector of my FPI session on Wed evening I flew the Cessna
>>>Citation by VENEAVIONES in JHB livery, with panel by Brian Williams.
>>>Unfortunately, I discovered that APPR HOLD didn't work (at EGTE).
>>>Can someone with more expertise than me in this area tell me if this
>>>is a problem somewhere in one of the config files (aircraft.cfg or
>>>panel.cfg?) that can be easily fixed?
>>>
>>>Still coming to terms with the new GoFlight autopilot module, in
>>>particular the apparent lack of an autothrottle arm switch.  Only an
>>>IAS/Mach Hold and although I have configured one of my P8 buttons as
>>>A/Thr Arm it doesn't seem to activate and I have to resort to Ctr+R -
>>>which rather defeats the purpose of this all-singing, all-dancing
>>>autopilot module (I can even get BBC2 on it .... <g>)
>>>
>>>Mike L
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
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