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Take-Off abnormality

Posted: Thu May 10, 2018 11:34 am
by go2peter
F-4E ADV. .... full fuel load using all three outboard tanks .. no armaments.

Vertical stabilizer switch engaged.
Auto Pilot "off"

I lift off in a shallow climb (above 150 Kts.) using full Military power, but as soon as I raise the nose to"climb-out" (let us say at the end of the runway) the AOA luches up alarmingly, and I have to quickly engage the Roll ,Yaw and Auto Pilot switches to stabilize things. It's almost like the system is "suddenly" finding my flight stick for the first time, and sees it in a fully nose-up position.

What can I do to improve this situation ... I have tried adjusting parameters via MVAMS, but no improvement.

Peter A.

Re: Take-Off abnormality

Posted: Thu May 10, 2018 12:57 pm
by JonathanBleeker
First of all, you say you have the yaw SAS switch engaged, but you should have pitch and roll engaged as well. They aren't the autopilot (the A/P switches are those 2 for Att and Alt hold below the 3 SAS switches).

Secondly, trim nose down by 2 or 3 units before takeoff.

Re: Take-Off abnormality

Posted: Thu May 10, 2018 1:07 pm
by Dimus
Exactly what Jon says. Plus, from my experience during testing and the real pilot's feedback, continuous trim down will be needed as the speed increases, as well as gentle down stick, if your trimming rate is not enough. The plane's attitude is sensitive to speed.

Re: Take-Off abnormality

Posted: Fri May 11, 2018 5:13 am
by go2peter
Thanks Jon and Dimus ... yes, all three top switches are engaged on roll-out. I will try the trim adjustments next flight ... sounds logical so thanks again for your replies.

Peter A.