Altitude hold

[Hpinter 1]

Hi guys,

 

first of all I would say thank you to the team for a great airplane.

 

I have in my flights a problem to hold the altitude it decrease the verticalspeed when I have set a FL for example FL100. The it is changes between FL95 and FL109. This happens when I increase or decrease the speed an when i do turns. The variation is then up to 1000 feet per minute. May you can help me to solve the problem?

 

Best regards

hpinter

[Hans Hartmann [OLD] 1419]

When the aircraft does this pitch-up/pitch-down thing, it's most likely that it's overloaded or that the center of gravity is outside its limits. Try to change the payload to be distributed more evenly.

[Hpinter 1]

Ok I will try it :).. Thx

[Hpinter 1]

Sorry it still overshoot in the Alt with speed increase and turns.

[Hans Hartmann [OLD] 1419]

Of course it deviates a bit. Additional thrust turns into additional lift, turns cause a loss of lift. The change has to occur first before it can be corrected. And you see the result of that as an altitude deviation.

[Hpinter 1]

Sure you are right, but the deviation is sometimes 1500 feet per miunte.

 

The altitude increase round about 500 feet above or below the ALT in the Autopilot

[Hans Hartmann [OLD] 1419]

I just tried and got a deviation of less than 5 feet when I flew a turn with HDG HOLD at full bank angle at FL100. If it's 500 feet, then something else is wrong.

 

Can you save the flight where this happens to you and upload it here? (.fxml, .wx and .crj file please. To be found under <Documents>\Prepar3d v4 Files or similar if another sim).

[Hpinter 1]

I will pefrom another flight so and try it again. Thx for your help.

[Hpinter 1]

Hi,

 

I still have the problem. These are the files :(.

 

Gruß

hpinter

EDDMLSZHCRJ900.crj

EDDMLSZHCRJ900.FLT

EDDMLSZHCRJ900.WX

[Hpinter 1]

Hi,

 

are you already able to take a look on the files?

 

Best regards

hpinter

[Hans Hartmann [OLD] 1419]

Yes, I did. But with that little weight, it's hardly a CoG issue. I'm going to discuss with this Alexander (flight dynamics). May be he has an idea.

[Hpinter 1]

But in real it also works.

Thx for help. I hope you can find a solutuion.

[Hpinter 1]

Is the weight really low?

[Hpinter 1]

hey guys,

 

I have done several flights with the CRJ.

The hold of the altitude is every flight heavy weight or light weight.

 

I have diffenrent times turbulent weather, but in my opinon this can not cause so much variation. It still the situation, that when a assigned Alitude the vertical speed increase the descend rate to -2000 ft/min.

What do i wrong?????

 

Best regards

hpinter

 

[Hpinter 1]

On 11.8.2017 at 08:43, Hans Hartmann sagte:

Yes, I did. But with that little weight, it's hardly a CoG issue. I'm going to discuss with this Alexander (flight dynamics). May be he has an idea.

 

But what shows this files I sent in this Topic? I do not understand, why this depends on the low weight. I can send you some Photos about the Situiation???

 

 

[metzgergva 40]

With very low weight the CoG is very much rearward and the trim may run against its most nose down position. Check in the LM if your CoG is within limits.

[Hpinter 1]

it was at 28.7

[metzgergva 40]

That should be fine. I will check with your files tonight.

[Hpinter 1]

that would be great

[Hans Hartmann [OLD] 1419]

2 hours ago, Hpinter said:

that would be great

Please also try version 1.0.1 which is available now. Alexander made some changes in the flight dynamics. May be it affects how the altitude hold works for you.

[Hpinter 1]

sounds good thx

[metzgergva 40]

I have loaded the provided files and that puts me on ground in LSZH. So I took off from there and flew direction EDDM in FL100 which was straight through thunderstorms. 

I think you must use a weather program which may set turbulence by default too high, like AktiveSky does, to see such altitude variations you described.

Nothing I can do about this if that is the case.