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Subject: Fistful of Knots
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Scott's results are interesting and readily explainable.

<<In level flight (under auto pilot control, smooth air) at 8500 feet, 74%=20
power
 175 IAS, 197 TAS AOA=3D2.4*, Longeron (L)=3D0*>>

A good baseline

<< and then the weight is transferred to the FS 84 Location. The auto pilot=20
requests trim assist and the Reichel trim wheel is rotated forward (nose dow=
n)=20
about 1/6th of a turn.  176 IAS, 197 TAS AOA=3D 2.2* to 2.4*, L=3D0* to -.2*=
.>>

The tail needs to provide less down force to keep the airplane level.  The=20
wing needs to generate less lift since the tail is pushing down less.  Since=
 the=20
wing needs to provide less lift, the required AoA decreases.  Since the trim=
=20
angle of attack decreases, the trim system needs to be adjusted.  (Airplanes=
=20
are not trimmed to fly at constant speed, they are trimmed to fly at constan=
t=20
AoA.  Phugoid oscillations, for example, are varying airspeed maneuvers wher=
e=20
the angle of attack is constant.)  Since the tail and the wing are generatin=
g=20
less lift, they also generate less drag, and the speed increases.=20

<<Leaving the weight in the back, the power was reduced to 62%.  161 IAS, 18=
0=20
TAS AOA=3D 2.7* to 2.9*, L=3D.4*>>

Less power makes the plane slow down (duh) and the angle of attack must=20
increase to generate the same lift.

<<The weight was moved back to the front and the nose was trimmed up.  161=20
IAS, 181 TAS AOA=3D2.7* to 2.9*, L =3D.4* to .6*>>

No significant change.  The airspeed change here is the wrong way but I=20
submit it is too small to be real.

<<Conclusion: I won=E2=80=99t be abnormally shifting weight to try to increa=
se=20
speed.>>

Works for me!

By the way, changing the tail incidence angle has an even lesser effect than=
=20
this.  The plane needs to be balanced with a certain amount of down force fr=
om=20
the tail.  Does it really matter if you have a more cambered airfoil=20
(deflected elevator) or a less camberes airfoil at a higher angle of attack=20=
(changing=20
the tail incidence angle)?  Well, yes, there's more drag with the less=20
cambered airfoil at higher alpha but the far larger effect is the drag-due-t=
o-lift.

Don't go cutting off your tails and reattaching them to win races.  You'd go=
=20
faster by losing ten pounds, and live longer, too.  (And yes, I'm still tryi=
ng=20
but it's not working for me either!)

- Rob Wolf