Was lead to this thread by Google, because I've got the same need to make a very slow flying craft,

but it's because I fly a remote control video plane through the camera (wireless downlink)

and want to simulate that slow speed flight (20-50knots).

I've almost got the speed and mass down with the following settings.

The power settings are scaled down, but still overpowered for slow cruise. If I want to cruise at 30 knots for instance I'm running at only 10% power or so.%

% Cirrus SR22.

%

model_name = 'Cirrus SR22'

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Minimum eye distance to objects.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

d_E_min = 1

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Approach speed, power and flap setting.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

V_approach = 13

D_F_approach = .2

D_P_approach = .4

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Cruise speed, power and flap setting.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

V_cruise = 19

D_F_cruise = .0

D_P_cruise = .7

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Constants for terrain elevation filters.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

spring_e_T = 80

damper_e_T = 15

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Spring/damper constants for camera rotation.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Critical damping: spring = damper^2/4.

spring_vertical = 80

damper_vertical = 15

spring_horizontal = 80

damper_horizontal = 15

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Collision vertices.

% VREF: Zero is below the nose on the ground.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

p_v = [

% Main wheels.

[ -2.9 -1.6 -.3 ]

[ -2.9 1.6 -.3 ]

% Nosewheel.

[ -1 0 -.3 ]

% Tail skid.

[ -7 0 -1.5 ]

% Top of cockpit.

[ -3 0 -2 ]

]

% Fixed gear installation.

first_fixed = 0

% Spring/damper format:

% [ C_0 C_s C_d f F_max ]

spring_damper = [

[ 2500 5e4 1e4 .05 2e5 ]

[ 2500 5e4 1e4 .05 2e5 ]

[ 500 3e4 1e4 .05 1e5 ]

[ 500 5e3 3e3 .05 3e4 ]

]

% Contact patch format:

% [ C_r_0 C_r C_b C_y K_s K_d C_max_x C_max_y b dalpha_dDR ]

contact_patch = [

% Main wheels.

[ 200 8e-4 2e3 6e3 2.1e4 1.2e4 .8 .8 1.1 0 ]

[ 200 8e-4 2e3 6e3 2.1e4 1.2e4 .8 .8 1.1 0 ]

% Nosewheel. Only some Y force, no static friction.

[ 0 0 0 6e3 0 0 0 .8 -1 .7 ]

]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Power plant.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

P_max = 21e3

F_max = 600

P_ratio_reverse = 0

P_ratio_alpha = 1.4

p_T_v = [ [ -.2 0 -1 ] ]

d_T_v = [ [ 1 -.02 0 ] ]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Eye point.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Pilot sits on the left.

p_E_v = [ -2 -.5 -1.8 ]

% Reference values.

b = 11.7

c_bar = 1.15

% collision model values, leave at 1 for now.

d_ref = 1

v_ref = 1

F_ref = 1

% Mass/cm/inertia.

m = 100

J = [

[ 300 0 0 ]

[ 0 125 0 ]

[ 0 0 335 ]

]

p_CM_v = [ -2.6 0 -1 ]

p_AC_v = [ -2.6 0 -1 ]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Aerodynamics

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%

% Forces.

alpha_z_0_deg = -4.5

dalpha_z_deg_dDF = -2.5

C_D_0 = 0.0278108

dC_D_dDG = 0

dC_D_dDF = .03

dC_L_dalpha_deg = .095

dC_L_dS = -1.5

C_L_max_0 = 1.42

dC_L_max_dDF = .5

d2C_D_dC_L2 = 0.124852

d2C_D_dC_Y2 = .1

dC_Y_dDR = .001

dC_Y_dbeta_deg = .025

dC_Y_dp_hat = .0001

dC_Y_dr_hat = -.0001

% *** Moments ***

% *** Pitch ***

C_m_0 = 1e-5

dC_m_dDE = .25

dC_m_dDE_T = .06

dC_m_dDF = .03

dC_m_dDG = 0

dC_m_dS = -.025

dC_m_dq_hat = -12

dC_m_dalpha_deg = -.013

d2C_m_dbeta2 = -7e-1

d2C_m_dq_hat2 = -10

% *** Roll ***

dC_l_dDA = .05

dC_l_dDR = -1e-5

dC_l_dbeta_deg = -1e-4

dC_l_dp_hat_0 = -.43

dC_l_dp_hat_max = .03

dC_l_dr_hat_0 = .16

ddC_l_dp_hat_0_dS = 2.3

ddC_l_dr_hat_0_dS = 1.3

d2C_l_dp_hat2 = -12

% *** Yaw ***

dC_n_dDA = -.01

dC_n_dDR = .1

dC_n_dbeta_deg = 5e-3

dC_n_dp_hat = 0

dC_n_dr_hat = -.8

d2C_n_dr_hat2 = -1

Now I'm trying to make some sense of the aerodynamics and moments settings so I can speed up the controls. I'm posting this here as it is

because my slow control responses would be just fine for your

submarine. They're just not very useful for a small R/C aircraft flying

close to terrain.

If anyone knows how to increase the roll and pitch response for a slow, light weight craft, post it up here.

I've found that it doesn't take much tweaking to produce settings that just crash GE outright.

ian