Bump.

After nearly one year, Vichineu, a fellow modeler from Belgium, has made a visual/3D model of a DC-3 for the Reflex simulator. That caused me to revisit my virtual DC-3 models which were mere parameter sets with a dummy appearance.

Only recently I found out how to correctly set the wing incidence in the simulator. Now I removed the washout from the DC-3 models and set the wing incidence to 2 degrees geometric (true to original), what is about 4.2 degrees aerodynamic incidence with the NACA 2215 aifoil. Both 1:8 Ziroli versions, that with 43 lbs weight and the other with the ambitious 33 lbs weight, are docile flyers if only some caveats mentioned above are observed. Elevator throw is even reduced to 15 degrees, but still full throw should be used together with full flaps only. With no flaps the nasty stall described above will result.

One good effect of this setup is a scale-like level fuselage (zero deck angle) at cruise speed, which is only 20 m/s or 17 m/s, respectively. Two .91 four-stroke engines are well enough even for climb with full flaps and for a 50% to 60% cruise power. Take-offs look very scale-like, and landings do if done with approach power till full stop. Approach speed must be only slightly less than cruise speed.

That's all nice but not really worth mentioning. I'm writing here again because the 2 / 4.2 degrees geometric / aerodynamic decalage requires the C/G set where Nick Ziroli recommends, that is for a 20.7% static stability margin. I was surprised because I dislike so much stability, but in this case it seems to be just true-to-original, considering the wing incidence and level fuselage. A crash like shown in the video might simply come from too much elevator deflection. After all, 15 degrees seems extremely small as long as one doesn't know that the airplane's AOA range and hence speed range is so small. Even one dead engine isn't that critical knowing that and minding airspeed. Maybe model pilots are just not as smooth on the sticks as full-size pilots.

Now the C/G is quite near to the landing gear so the airplane is easy on the tailwheel when taxying. One issue described was that the model refuses to turn on the ground. To some extent I can copy that in the simulator and full up elevator really helps. But even better could be full down elevator and quite a bit of power, even if not full power. That will lift the tail and the rudder can swing the airplane around. I don't know if that is scale-like.

I failed to offer the simulator models so far. If someone happens to have the Reflex simulator and would like to try the DC-3 models, just PM me and I'll send an installer. The same holds for the file for the QFLR5 program (now called XFLR5).

Thanks again to the posters in this thread for several insights, even if I still don't get the point in Dick Hanson's last post.