Extreemly wild fluctuations in airspeed?

[Dragonmount 5]

I'd go from overspeed to undersspeed to somewhere inbetween to back to one of the others in matters of seconds, and if you are just slightly low speed your aircraft will dip in the MD 11s case, and it can be frustrating dealing with RC4, What causes the random fluctuations?

 

Patrick Boynton

[Alpha Floor 237]

Unless you give some more info I doubt nobody will be able to help you...

 

What phase of the flight?

Manual flight or AP?

What's your weather (the weather you're using, the engine, etc)?

What's the wind doing?

 

etc

[Dragonmount 5]

Well I was flying at about 34k ft, I don't know what the temperature was, didn't think to save it, also no idea on the wind, and I was almost at cruise altitude. I did get a cabin pressure warning seconds before the weird fluctuations.

 

Patrick Boynton

[flibinite 18]

If it's a recurring problem, I'd start by disabling any weather addons/settings you have, see if the problem still occurs.

[Dragonmount 5]

I tried it again, and this time it happened at a lower altitude, and this bird will not stay at upper altitudes at all, and I looked at the winds they were at 50-60 kts and pointed right at the aircraft.

 

Patrick Boynton

[por930 51]

I tried it again, and this time it happened at a lower altitude, and this bird will not stay at upper altitudes at all, and I looked at the winds they were at 50-60 kts and pointed right at the aircraft.

 

Patrick Boynton

Check the outside temps, as some times the weather engine can error out and create very 'hot' temps at high altitude.

 

As a test, turn off all weather, both FSX and your weather engine if you are using one, then try a new flight. Do not use saved flights, as these may have saved weather issues.

[Dragonmount 5]

Check the outside temps, as some times the weather engine can error out and create very 'hot' temps at high altitude.

 

As a test, turn off all weather, both FSX and your weather engine if you are using one, then try a new flight. Do not use saved flights, as these may have saved weather issues.

From what I remember it was at -9 or -10 Right before it happened I could swear it was at 0 I have been attempting to fly out of KLAX, and this happens around KLAS

[por930 51]

Hi Patrick,

For some reason, the temps get too high for the altitude...they should, at FL340, some thing like -45...so if you saw zero or not much higher, then maybe temp is an issue. As I said earlier, turn off all weather, try a new flight, and see how she goes. I really like the MD11 in FEDEX paint.

 

Remember to sign your full name in the PMDG forums....

[Dragonmount 5]

Hi Patrick,

For some reason, the temps get too high for the altitude...they should, at FL340, some thing like -45...so if you saw zero or not much higher, then maybe temp is an issue. As I said earlier, turn off all weather, try a new flight, and see how she goes. I really like the MD11 in FEDEX paint.

 

Remember to sign your full name in the PMDG forums....

Thanks I thought it seemed off, but wasn't sure I haven't flown in a long time, is there a fix for the weather problem for REX? Sorry thought I signed that time .

 

Patrick Boynton

[por930 51]

I do not know if there is a fix as such. I only had the issue once, and when I re-ran the flight, it was not there, so...maybe one of those things! Can you reproduce the high temp flight? 

 

I use REX for the cloud graphics and ASN for my weather engine.

 

Possibly some of the other guys may chime in who have had the issue and how(if?) they 'fixed' the high temp issue. 

 

As for the names...Stick it in the signature area of your profile, then you need not think about it again.

[Icon 22 11]

I'd go from overspeed to undersspeed to somewhere inbetween to back to one of the others in matters of seconds, and if you are just slightly low speed your aircraft will dip in the MD 11s case, and it can be frustrating dealing with RC4, What causes the random fluctuations?

 

Patrick Boynton

 

 

The first thing I would check for is icing.

[pcubine 143]

I'd go from overspeed to undersspeed to somewhere inbetween to back to one of the others in matters of seconds

You already have a thread about this issue - http://www.avsim.com/topic/486558-weird-underspeed-issue/. Why would you start another one?

 

As for REX weather, I am not familiar with the latest version. However, I can tell you when I used it, it sucked. I have used their various cloud packages but not the weather. Buy ASN and use REX for the clouds.

 

As for your signature, set it up so that is done automatically. Try this - click on your user name in upper right corner, click on My Profile, click on Edit My Profile, click on Signature, in Edit Signature enter your first and last name, click save and your name will be on all of your posts.

[Dragonmount 5]

You already have a thread about this issue - http://www.avsim.com/topic/486558-weird-underspeed-issue/. Why would you start another one?

 

As for REX weather, I am not familiar with the latest version. However, I can tell you when I used it, it sucked. I have used their various cloud packages but not the weather. Buy ASN and use REX for the clouds.

 

As for your signature, set it up so that is done automatically. Try this - click on your user name in upper right corner, click on My Profile, click on Edit My Profile, click on Signature, in Edit Signature enter your first and last name, click save and your name will be on all of your posts.

I forgot about that post to be honest, and it seemed to go away when I flew on the east coast and Europe.  I tried getting ASN, and so far no issues at all. 

 

Patrick Boynton