Need some help with PMDG 800

Hello,

i have a strange problem with the PMDG 737-800! Until today i worked with the PMDG 737-700 and the CDU-File from PM-site. Off course i corrected the Netto-weight and Payload in this file. It worked for me nice for long time.

Since the new Version of TOPCAT supports the 737-800 i want to use the PMDG 737-800. But this A/C wont work correct with PM!
I added 94.000 Netto Weight and 27.000 Payload in the cdu-file by Steve Reyling. These values cames from the aircraft.cfg.

I trim the A/C with the data from TOPCAT or CDU (4-5 Units) but always after takeoff,the A/C overshoots and i must trim nose down to 0!?!

I tried with and without cargo, with more ore less netto weight, but nothing seems to help. Off course i setup the Performance Page correct and also the other Pages!




Any ideas are welcome:-)

THX

Thomas

Hi

When you say 'overshoots', what do you mean exactly, can you descibe what you are seeing? Also, have you 100% cross checked your weights from the aircraft cfg to what is shown in the CDU? Note that if you have the bracket option for GW then the non bracket weight should match once you have entered your ZFW.

Regards
Jonathan Richardson

Jonathan,

thanks for the quick answer. Its easy to describe what i see...just after takeoff, i must trim down about 5 units (near 0). Otheerwise the aircraft goes over 20 degrees nose up and run into stall.

Ok...i have the bracked option. As i note, the value in the brackes prasents the GW of the aircraft. When i press LSK1 key, i get a wrong value, that i replace with the value from the brackets! When i compare this value with the value inside FS9, it is the same then the GW.

Iam a bit confused about the source of the correct data. You wrote many times before we must use the data from the air-file??? But this file is binaer.
In the aircraft.cfg i found the netto-weight but never the payload.

When you allow, i would send you the cdu-file and the aircraft.cfg, so you can see what i have done.

Thomas

>thanks for the quick answer. Its easy to describe what i see...just after takeoff, i must trim down about 5 units (near 0). Otheerwise the aircraft goes over 20 degrees nose up and run into stall.

Hi

Then the problem is simple, the initial trim set was wrong. Or the weight and balance is wrong. Remember the trim is just a scale - it means nothing. If the zero is the correct trim for your weight and balance after rotation, you must use this value, and adjust your scale to reflect the 4 indication. You have to reverse your thinking.

>Ok...i have the bracked option. As i note, the value in the brackes prasents the GW of the aircraft. When i press LSK1 key, i get a wrong value, that i replace with the value from the brackets! When i compare this value with the value inside FS9, it is the same then the GW.

At start-up, *after* you enter your *correct* ZFW (you need to check this) your GW will be calculated and shown. It should match the bracketed value, if it does not, then there is a problem / mistake with your entries somewhere. Most common is people enter the wrong values lbs in the type.txt file. I would cross check this. Do not over-rule the GW entry by entering your own, that does nothing other than force the CDU to an incorrect GW.

>In the aircraft.cfg i found the netto-weight but never the payload.

I mean the aircraft.cfg if you don't have access to the air. This is what the docs outline. And it is actually written in the type.txt file re where the ref should be sourced. There is a section in the main PM docs about weight and balance which might be useful.

From now - I switch to PM support - because I have to double my responce otherwise.

Regards
Jonathan Richardson