I have a problem with the calculated values of the V-Speeds. The liftoff takes place far beyond the calculated rotation speed with the 737NG. Assuming the R-Speed is calculated as 107 kts, the plane leaves the ground not before 160 kts. I guess I do something wrong here. Thanks for any help.Andreas

HiTwo things to check immediately.1. flaps in takeoff position2. takeoff trim setAlso, check your takeoff gross-weight, and cross check V-speeds from tables. Note that the v-speeds are different for different (takeoff)flap-settings.regards,Tero

Do what is suggest above, but I also set trim to 9 so that rotate actually occurs at rotate, then 500ft after lift off I readjust it back down to 5.5 such that the aircraft climbs at V2+15~20. Unfortunately this is a necessary work around that I have had to use, otherwise I get the exact same problem as you.Gary.

Sounds like problems with CoG MAC position in the flight model. I have to say, that I'm not familiar with the NG trim settings, but 9 units sounds way way excessive. I'd guess 3.5-5 is the proper range.Tero

Also make shure you'r fs and pmdg both are using the same values (kg or ibs).

It was the trim setting!5,5 to 6 works for me now.Thanks for the help,Andreas

Yes 9 is excessive, but that's around the value I have found to be required to need mimimal coaxing of the yoke to get her to rotate at the advertised speed. I guess I have been spoilt by 767 PIC, where you set the advertised trim setting and rotate speed match up like they should. Gary

Hi Gary,When I was flying the old KC135, we pushed the yoke down to maintain nose gear contact. Trim setting of 9 is way excessive, that would cause the nose to come up by itself and you DON"T want that to happen. My experience is that there IS a lot of yoke movement when you rotate. What you have set could cause an over rotation causing the plane to stall at the worst point, a couple of hundred feet off the ground.My procedure is 5 degrees of trim, I rotate right on the numbers and then pull back on the yoke, adjust trim on how she is handling during the climb. This bird really handles well with manual flying.For the simmer having problems with rotation, at 160K, that is either a trim error, bad fuel loading (wrong amount of fuel), or flaps set incorrectly. I flew from PANC to RJAA the other day which reqired a full fuel load. My rotation speed even with all that fuel was 142K with flaps at 5, that was at sea level and 32 degrees. Remember that temp and altitude have a great affect on rotation speed as well as you GW.CheersBob

Hi,Yeah, it is SOP to hold forward pressure in a 737/757/767 also, until 80 kts.Now, a couple of things more popped into mind about the rotation problems.First off, the thread starter should probably be a bit more specific as to what aircraft he was flying and at what TOW.Browsing through the 736 takeoff performance tables he might have been around 105 tonnes on a FLAPS5 takeoff. As I don't know :( whether or not PMDG bird models CoG MAC correctly, I'm not sure what trim value to quote here, but it's enough to say that the proper trim range is about 2.5-7.5 units with that particular aircraft/weight/flaps configuration. Normally the CoG numbers are around 18-24 % which yields a trim of 4.5-5.75. However, if the CoG MAC was 13 or below, then a trim setting of almost 8 would have been needed. If so, the observations about "not rotating" could have been right. Add to that an improper rotation technique, and you've got "I need 9 units for takeoff" -problem.Proper takeoff (and rotation) technique. Both engines operative:1. Check your loading carefully before takeoff. Adjust stabilizer trim to exactly match the value of the tables. If your weight is above/below the table values, just interpoloate between the values. Failure to do this will result in improper takeoff performance and handling, possibly a tailstrike OR a very late rotation.2. Keep a light forward pressure on the yoke until 80 kts, after which you slowly release it to neutral3. Around 5 kts BEFORE V1 make the V1 call in your head and remove the other hand from the throttles.4. AT V1 start a light pull on the yoke so as to START rotation at VR.5. Pull the yoke steadily to rotate around 2.5-3 degrees / second. Don't chase the flight director before liftoff has occurred. Aim initially to 15 degrees mark on the ADI. Once positive rate (VSI shows positive climb rate AND altimeter is indicating increasing altitude), raise the landing gear.6. Aim for V2+15-25 climbout speed. If you go past target, don't pull nose further up to slow down, but instead stop acceleration to the speed you are able to.7. At 400ft AGL engage lateral AFDS mode8. At 1000 ft AGL (or 1500ft for some airlines), lower the nose and engage FL CH speed (speed to FLAPS UP maneuvering speed) OR VNAV to accelerate and clean up the aircraft. Verify climb thrust!Ok, that's it. I hope this helps.Teroedit: I just noticed, in case someone wonders, there's an error in the takeoff performance table provided by PMDG. The weights in the 736 wet runway takeoff speeds chart are of course in 1000 LBS, not 1000 KGS as stated there.