Nose high after T/O. Any advice please?

[martinlest]

Hi. New to this a/c - I wonder if someone could kindly let me know the settings they use for T/O: every time i pull the joystick back at VR (Saitek X52), albeit smoothly (as required), after a few seconds the nose goes up to between 25-35 degs (!). I have to push the joystick very well forward very quickly to get to a more normal situation, but by then the speed has of course dropped dramatically. 

As I say, I am gentle on the joystick (similar movement to say, Zibo 738, but I 'play it by ear' of course as the a/c rotates and starts to climb), and I have trim set as per the FMC. My GW = c.120K/CoG=20%, so trim is usually around 4.2....

What values work best in the 773 to get a nicely controlled take off when hand-flying? Is there a 'sweet spot'? I have tried several practice takeoffs now and the nose always angles up to at least 25 degs before I can push the nose down again and the speed starts to climb away from a stall.

I shouldn't need to underset the trim, should I? If I do so, by at least 0.5, that helps. You get a warning if it's too far off.

I assume I don't touch the weight/balance settings in XP's own menu - just use the IXEG input menus?

Thank you for any advice specific to this 733. 

Edited August 29, 2020 by martinlest

[Litjan]

Hi Martin,

something definitely wrong with your setup.

With the CG at default - around 20% MAC (doublecheck on the "GROUND SERVICES" menu) - a trim of around 4 should not give you any problems. At the recommended trim, the speed is stable at around V2+20 kts.

Initial rotation should require a definite nose-up input (up to 2/3 of full elevator), once the nose starts going up you can relax that to just a slightly nose-up input to rotate with ca. 3 deg/second. The full rotation to ca. 18 deg nose up should take you 6 seconds, roughly.

Make sure you run with the "experimental flight model ON" - the plane is "tuned" for this new setting, it will soon become the default X-Plane flight model.

Cheers, Jan

 

Edited August 30, 2020 by Litjan

[martinlest]

Hi Jan,

Thank you. After rotation I push the joystick forward, as smoothly as possible, nothing too aggressive, but so far I haven't been able to prevent the nose form reaching up to 30 degs, it happens too fast. Makes for a rather inelegant takeoff, compared say to the Zibo 738 or the FF 767... Yes, CG is 20% and I now fly rather heavier than before, I make the GW around 120K-LBS. Helps a little, as I mentioned.

I will try flying the 733 today with 'Experimental Flight Model' on ((it has been 'off' so far) and post back as to whether that helps.

 

Edited August 30, 2020 by martinlest