If "all flying rudders" for LSA aircraft need 33%-40% less area than a typical vertical tail (stabilizer and rudder) ( subject to final stability analysis), what about "all flying elevators" (stabilators) with:
- anti-servo trim tab?
- no anti-servo trim tab?
I understand anti-servo tabs add stability to "all flying rudders/elevators" by automatically centering the rudder/elevator.
According to a design guide from Zenith: Flying on Your Own Wings, by Chris Heintz, pg 229:
The vertical tail area should be 12 to 15% of the wing area (15% if the rear fuselage has a small rounded section, and 12% if the rear fuselage has large flat sides). These percentages may be reduced to 7% and 10% for an "all flying rudder".
A wing is a wing, no matter what attitude, whether it be horizontal or vertical. So I should be able to reduce my horizontal tail area by roughly 33-40% when using only a "all flying elevator" (stabilator) (subject to final stability analysis). Is this correct?
My personal view:
My personal view is that a Zenith can fly a lot slower with an all flying rudder, down to 39mph or lower, and that is why Heintz makes the above recommendations based on the type of aircraft he manufactures: basically LSA types, @ 1320lbs MTOW, 39-45mph stall speed. Somewhere I read that a Zenith 701 won a STOL competition in Australia with a 25' takeoff. I've also heard that a 3 second takeoff is fairly common and by the time you have full throttle, you're in the air ( just in ground effect I'm sure).
I understand the Zenith CH200 had a classic vertical tail, but that most or all current designs use an all flying rudder.
Summary: So I assume that Heinz's above recommendation is for sizing a rudder at a 39mph stall speed which would need to be bigger for slow speed handling than for a plane that stalls at 60mph.
So would an "all flying elevator" be more efficient at 39mph than a typical horizontal stabilizer and elevator arrangement at that speed, thus allowing it to be 33% to 40% smaller?