Composite-ARF Impact question

[Bill Glaze]

We agree that any airplane is in trim for a given set of conditions 
existing at that time.  As my primary instructor said: " the rudder is a 
trimming device."  (Perhaps a little too simplistic, but a good starting 
point.)
We are constantly looking for the perfect combination that requires the 
least work from the pilot, to achieve the most precision of results.  
Probably a matter of taste, largely.
As I recall, this thread started because of one flyer noticing the 
asymmetrical airfoil on his new fuselage. While certainly not original 
in aviation, I must admit that I've not seen this before in the modeling 
world.  Or, probably, it's just that I've not noticed it before.  I sure 
hope he keeps us updated as to how it works in the real world of modeling.

Bill Glaze

Bob Richards wrote:

> Bill,
>  
> I don't think it is uncommon for full-scale planes to have offset or 
> asymmetrical fins. However, they are designed with the right amount 
> *for cruise*. Any other speed/power setting will change things. Since 
> they are after the most efficiency in cruise conditions (better 
> range), they will probably want the least amount of offset thrust as 
> possible, and will trim the rudder/fin accordingly. If they expect the 
> fin to be providing a constant yaw force, it would make sense to give 
> it an asymmetrical airfoil for the most efficiency. Let the pilots 
> deal with the other situations.
>  
> I personally think the right-thrust is the correct way to go. I can't 
> argue with what others have said about throttle mix working for them, 
> but I don't see how it would work. I think you will have less 
> slipstream effect happening at full throttle in level flight than you 
> would at full throttle in a climb. As the prop unloads with increasing 
> airspeed, the slipstream effect should decrease.
>  
> Of course, I remember the very detailed trim instructions that came 
> with my Great Planes Cap21. Something like: "Pull the nose up until 
> pefectly vertical. If the plane yaws off to the left, add weight to 
> the right wingtip". There was no mention ANYWHERE about engine thrust. 
> Tossed that in the trash. :-)
>  
> Bob R.
>
> Bill Glaze <billglaze at triad.rr.com> wrote:
>
>     Adam:
>     This may be a little bit off the mark, but just a little bit. During
>     WW2, the Italian firm Fiat produced a very good series of fighters
>     with
>     exactly the characteristics you mention, that is, an asymmetrical
>     fin/rudder airfoil. Seemed to work well for them; other nations
>     handled
>     the problem differently.
>     Bill Glaze
>
>
>
> Bob Richards
> bob at toprudder.com
> http://www.toprudder.com 

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