Wing and Tail plane design info needed (model aircraft) 1

[JRT]

We are building a model plane, unfortunately we ran in to some problems where we need to change the 2 dimensional data for the 'lift curve slope' (a1w) and the (a1t) values to 3 dimensional data. Can anyone provide information on this?
Also can anyone point me in the right direction of where I might get some data on the M06-13-128 airfoil.

 

[RonFreimuth]

AC Horiz Tail:

Lift Slope: dCl/dAoA ~ 2*Pi (AR/AR+1) * COS (sweep)

Sometimes AR/(AR+2) is used to convert from section lift data to finite wings.

In any case, the Aspect Ratio of the Horiz Stab is generally less than that of the Wing, so the lift slope is lower.

Pitch Damping is mainly due to the H. Stab, and varies as Sh/S * (Dh/MAC)^2. Thus, relative distance from the MAC/4 comes in squared.

Finally, tail efficiency has to be taken into account. Due to the shielding of the tail surfaces by the wing and fuselage dynamic pressure, q at the tail is generally lower than the freestream value. Values of 0.80 for efficiency seem typical, but a high H. Stab on the vertical fin may be near 100%.

The H. Stab generally has negative camber so it pushes the tail down to increase static pitch stability. The H. Stab can also be angled down at the LE. Enought so cruise trim is near zero.

Downwash angle, epsilon of air flowing aft of the main wing reduces the effective Ang of Incidence of the H. Tail surface. More positive lift/Incidence is required than would otherwise be the case. That may be enough so no camber and/or Angle of Incidence for the H. Stab is sufficient.

Ron Freimuth