Problem with Vario

[VulcanB2 5]

Hi,

The vario is upsetting FSX vertical updates. I can have a rate of descent of say 1000 ft/min, but the aircraft will only descend in steps, and be perfectly level in altitude in between.

It also affects other add-on aircraft that don't use it, and is particularly bad when near the ground.

If I remove the instrument from FSX, all is normal. It also causes the earth to jump around sometimes when on the ground.

Does anyone else see this odd behavior? It seems totally independent of frame rate, but gets worse as the frame rate drops (the jumps get bigger). It jumps up to 100 ft a time. 500 ft to instantly 400 ft for example, despending on rate of descent.

I'm running FSX SP2.

Best regards,

Robin.

[J.Schweigler 203]

Hey Robin,

I have another guess.

Wich operating system and wich CumulusX! version do U use?

Cheers Joachim

[VulcanB2 5]

Hi,

I saw it particularly badly on Win 7 64-bit. CumulusX! 1.5.

CumulusX was not running though when I saw the issue with other aircraft.

Removing the vario fixed the issue.

I see it to a lesser extent on XP SP3.

Best regards,

Robin.

[J.Schweigler 203]

But the Vario is an instrument, wich READS variables from the sim and don't writes any of them. So the Variometer can't cause an issue, where the plane jumps. Especially not if it isn't loaded (you say, it happenes with other planes also)

Anyway, I will ask Ian.

Cheers Joachim

[B21 19]

The interesting part of this is the fact you can change something and fix your 'altitude jumping' issue... it does sound like something is *writing* a value into your 'plane altitude', unless taking the vario out simply means you no longer have a good indication to know you're still having 'altitude jumps' (see below).

The C4 gauge in the glider by itself absolutely cannot alter the altitude of the aircraft - first of all the gauge code in the C4 is definitely only *reading* various environment parameters (like every gauge) and secondly even *if* the gauge writes to an FSX variable (say PLANE ALTITUDE) it still doesn't work because the FSX api doesn't support writing variables from within a gauge, which has handicapped gauge designers for years. Writing to FSX variables requires either SimConnect or FSUIPC.

FYI the 'C4' gauge in the Discus is actually moving the needles in *all* the varios on the panel (each is a variation (netto, te, etc) of the same calculation...) so if you remove the C4 gauge that will stop all the varios functioning - in this case it is not clear you're getting good info on the 'vertical jumps' - I assume you're relying on the view out the cockpit in this case.

Without further info, I suspect by far the most likely candidate for your 'altitude jumps' is a SimConnect or FSUIPC program that is intended to alter your altitude - CumulusX certainly does this and it is easy to temporarily pause the CumulusX function by clicking its 'Disable Lift' button. There are other programs you could have e.g. a fancy weather program that also simulates vertical air movement - in each case the software has to do 'micro-altitude-adjustments' because there's no inbuilt interface in FSX to enable an addon program to simply inject lift or sink (well, without complicating this discussion further there isn't)...

So have a go at the 'Disable Lift' CumulusX button, and report back... keep us in the loop and I'm sure we'll narrow it down.

B21

edit:

It also affects other add-on aircraft that don't use it

hmmm, I can't think of a case where this would be possible - when you said you removed the C4, what did you actually do?

is particularly bad when near the ground

Any possibility this is because altitude jumps are a lot more noticeable near the ground, rather than there actually being any change in the effect?

[J.Schweigler 203]

Although you said, you haven't run CumulusX!, this was my idea, because unlicensed versions of CumulusX! causes exactly this problems on Win7 mashines.

The problems are solved if you buy a cumulusX! license.

Best regards Joachim

[VulcanB2 5]

Hi,

When I removed the vario, I simply moved its DLL out of FSX and re-tested. No vario = fine. Vario = not fine.

Both CumulusX and WinchX auto-start with FSX, but I close these completely. I presume this causes them to unload and not run anymore? They're not somehow still running in some way that I'm unaware of (e.g. purely UIs for controlling background code)?

The problem, when it manifested itself, was both visible outside the window and on the altimeter. It would freeze, then jump, in sync with the jumping of the view out of the window. If I was very low to the ground, the instant update could cause the aircraft to crash.

Imagine the vertical speed reading 300 ft/min rate of descent, but the altimeter constantly reading 1000 ft, then suddenly jumping to 500 ft. At the same time, it is clear the aircraft is not descending when you look out of the window, then is suddenly closer to the ground.

Best regards,

Robin.

[B21 19]

Thanks - I understand your description of the FSX behaviour - these sudden adjustments of the altitude. I'm assuming FSX is otherwise behaving pretty much normally, i.e. the screen isn't frozen between updates - just the altitude suddenly changes.

This issue has been seen before with FSX in Win7 but always with a SimConnect module that adjusts the aircraft altitude. The 'queuing' of simconnect requests (between FSX and an addon module) behaves quite differently in Win7 (maybe only 64, I forget) and in a few users a set of simconnect messages can get backed up periodically and passed to the addon module in batches of up to a second's worth, instead of the usual immediate transfer. The addon module then responds to the delayed set of messages in rapid succession and you see a step-change in the altitude (or other behaviour). Your comments are helpful for us to narrow down the source.

When I removed the vario, I simply moved its DLL out of FSX

Could you confirm the dll name and what you did with it? The C4 gauge itself is actually in the SimObjects/Aircraft/Discus/Panel folder - did you leave that alone? So the varios in the cockpit all actually still work normally? The DLL that goes into the Modules folder only does a couple of things - it request CumulusX (if present) not to modify the vario sound, and it updates the FSX 'VARIOMETER RATE' variable so the sound follows the C4 needle - neither of these things would affect the aircraft altitude. If this DLL is not present then CumulusX updates the VARIOMETER RATE variable instead, using the same formula.

Both CumulusX and WinchX auto-start with FSX, but I close these completely.

If you hit the [X] in the corner of the CumulusX window then it will close. It is worth checking the 'Addons' menu on the main FSX flying screen to confirm the Addons->CumulusX menu has gone.

B21