Do mini-wings/wing fairings really help?

[MonkeyClaw]

I've seen some designs with either small projections like wings or other designs (like the AR1 that I've ordered) with strut fairings shaped like small wings. The claim is that they help with efficiency at higher speeds. I presume they theoretically provide a small amount of lift, allowing the rotor to be tilted forward and creating less drag.

I'm curious if this has been studied, what the effects are (if any), etc. Do they really do anything?

 

[Jean Claude]

If your wings have an aspect ratio of 2.5 and work with a Cl of 0.5, then we can estimate that their Cl/Cd of the wing alone will be about 10 taking into account the interactions on the fuselage.
Since a typical rotor has a Cl/Cd of almost 9 at around 90 mph, relieving the rotor with this wing not significantly decreases the gyroplane's drag.

 

[Smack]

Jean Claude, I would enjoy reading your thoughts comparing and contrasting the possible efficiency gains of a flying machine with either:
1) small wings
2) partially-powered rotor

Which would increase the machine's efficiency more at 90 mph?

Thank you.
Brian

 

[Jean Claude]

Brian,
1) Small wings, of sufficient aspect ratio and area, can improve speed performance, but since the wing is now effectively relieving the rotor, then the rrpm decreases dangerously. Therefore it becomes necessarry include an automatic pitch change, like this Pitcairn PCA2


2) Yes, a partially motorized rotor needs less airflow through it to ensure autorotation and the required disk A.o.A is thus reduced, which reduces the drag and the power required on the propeller.

But the total power (rotor + propeller) is only lowered if the rotor pitch is readjusted in flight to keep the same Rrpm.
Without this, the Rrpm increases due to the additional torque applied on its shaft, and the extra profil losses of the blades almost exactly cancels the expected benefit.