C of G question

[hakan737 2]

hi again, sorry for late reply about test flight. I made a test flight as your settigns at saturday. As you said that, there were much more controllable commands in aircraft and olsa when engange A/P, sensitive makes trouble for a while still on elevetors but according me, much better than before.still aircrafts wants to pitch up during takeoff phase with flaps 1 or 5 (set EPR by calculator for t/o and climb), at that moment maximum speed was 200-230knts. I used a bit trim nose downi so thatwhy stab trim reached limt of green section.I did write wrong before, so maybe we need to move C/G toward to nose for stopping aircraft's intentions to pitch up.the worst; after takeoff, I can get control the aircraft with a bit trim for getting stable climb gradient . AS said that Bob before, control stick must be middle or in null zone for engaging A/P elevators. After that, as you said that aircraft begins pitch action (actualy generally diving. I'm sure we can find out correct settings :)

[Bob Scott 7,720]

The trim is set so that aircraft is trimmed for V2 at the weight and CG. For some, this seems to be an unnatural nose-up pitch tendency after liftoff, but that's how the FAA standards dictate it be set. The idea is that in an engine failure scenario, when you've got a handful of misbehaving airplane, the jet is pre-trimmed to seek the speed it should be flying (V2 to V2+10). In a normal takeoff, you're holding the nose down and trimming forward as you fly through the initial acceleration. It's that way in every r/w jet I've flown.The trim at cruise is ~1.5 units for me...a little low, probably, but I did not want to compress the usable trim range to fix earlier problems with oversensitivity of the trim. The trim will, however, trim out control forces in the entire range of allowable CGs up to Vmo/Vmmo.Also, w/r/t trim oversensitivity, there's info in the FAQ regarding pitch sensitivity and control acceleration that's worthy of reading.If the aircraft is diving after A/P actuation, you probably have a null zone issue. The stick/yoke axis has to be at zero (null) to engage the axes...but if, after actuation, there is even a tiny amount of nose-down input, the CWS will continue to slowly drive the nose down. You can use FSLook (a utility contained in the FSUIPC SDK) to watch your control axis inputs in FS.RegardsBob ScottATP IMEL Gulfstream II-III-IV-VSantiago de Chile

[hakan737 2]

thank you Bob, be sure I'm checking subjects and new topics every 2 or 3 days in Tinmouse forum. I did do everything like as in F&Q. maybe fslook can show me josytick null zone mistaken if I have. When I can get stable climb vario, I'll be so happy :)thanks for helps.

[Guest sandro becker]

I noticed this behavior too but never reported.