ORIGINAL: YellowAircraft
ORIGINAL: CraigG
ORIGINAL: HarryC
No it doesn't. For a symmetrical section pivoted at its aerodynamic centre, the moment coefficient of pitching is zero so there is no aerodynamic force making the stabs go level into the airflow.
Harry
Full scale aircraft balance all their flying surfaces to mimimize control input, improve control response and to avoid flutter. We usually get away with not balancing our surfaces because of the tremendous torque of our servos and the relatively slower speeds we fly.
But, we have all seen/heard flutter on high speed passes which in many cases may have been prevented if the offending control surface had been balanced. Most manufactures take this into account, either by calculation or trial and error, and will adjust their designs accordingly. I know BV adds lead to the leading edge of the stabs on their F-4 and the Cook Firebird balances all the flying surfaces. If you follow the manufactures recommendations and stay within the design speed envelope, you should be OK.
Craig
Hi,
I know we've been here before (many times), and I don't mean to argue, but I'm not aware of any fullsize production aircraft that have full-flying stabs that are balanced on the pivot. Conversely, I can think of many (every) full-size aircraft with full-flying stabs that are tail-heavy and droop to the rear when powered down. In fact, most full-size aircraft with full-flying stabs do just what the gentleman stated above; that is having stabs that aerodynamically balance at a certain airspeed.
I didn't say they were balanced "on the pivot", just that they were balanced. The aerodynamics of stabilator control is complex and changes significantly as you progress from light aircraft with mechanical antiservo tabs and balance weights to supersonic jets with computer "fly-by-wire" and "irreversible" hydraulic power cylinder control. I can assure you "every" full-size aircraft has taken stab balance into account.
I'll stand by my comment that for our jets, following the manufacturers guidelines is the best course of action.