I'll update the results in the first posting (only the Reynolds Numbers are affected).
Torsten,
I too think it makes sense to use the normal component (v*sin(deg)) for calculating the Reynolds number for the form drag case and to use the tangential component velocity (v*cos(deg)) in computing the Reynolds number for the skin drag case.
The tilt angle on the fly leg for Paul's and Lasse's distance cast seems to be around 9 degrees so using a normal velocity of 40*sind(9)=6.2 m/s would give a calculated Reynolds number of 500 to 700 using the other estimates given in your original post.
Air density = 1.204 kg/m³
Tangential velocity = 39.51 m/s
Normal velocity = 6.26 m/s
Skin friction coefficent = 0.005
Form drag coefficent = 1.0
Line inclination = 9.0°
--
Line length = 10.0 m
Line diameter = 1.72 mm
Reference mass = 2.00e-02 Kg
Reference area (skin friction) = 0.054 m²
Reference area (form drag) = 0.017 m²
Reference volume = 2.33e-05 m.^3
Reynolds Number Re (form drag) = 7.10e+02
Reynolds Number Re (skin friction) = 2.61e+07
Skin friction force Fdt = 0.2540 N
Form drag force Fdn = 0.4056 N
--
Line length = 20.0 m
Line diameter = 1.22 mm
Reference mass = 2.00e-02 Kg
Reference area (skin friction) = 0.076 m²
Reference area (form drag) = 0.024 m²
Reference volume = 2.33e-05 m.^3
Reynolds Number Re (form drag) = 5.02e+02
Reynolds Number Re (skin friction) = 5.21e+07
Skin friction force Fdt = 0.3592 N
Form drag force Fdn = 0.5736 N
--
Force difference = 0.2732 N
Those Reynolds numbers would still produce an expected form drag coefficient around 1.0 but the drag forces are larger by a factor of (sind(6)/sind(3)).^2=4 because of the normal velocity differences.
There would be another sind(deg) factor to get the drag force in the x direction. Thus the relative drag in the x direction is somewhat sensitive to the tilt angle as (sind(6)/sind(3)).^3 is a factor of around 8.
As Grunde pointed out years ago, the form drag on an inclined section of line is not negligible because its drag coefficient of Cd_n=1
1 is so much larger than the nominal skin drag coeffiecent of Cd_t=.005. You would expect the x directed drag from form drag would equal the x directed drag from skin drag for a tilt angle of around 14 degrees.
Gordy