Reflexed Flaps

[skippydiesel]

 Does reflexing the flaps, by a few degrees (1-6) have a;

 

• significant improvement to cruise speed ?
• detrimental effect on stall speed WITH flap ?

 

😈

[Thruster88]

Significant improvement in speed, no. If there was every manufacturer would be doing it. Maybe it is some times used to correct a design that is not quite right.

 

Change in stall speed with full flap? I presume you mean if there is 5° reflex your max flap is reduced from say 40° to 35°. The last bit of flap travel does little for stall speed reduction, it just adds more drag so negligible change in stall speed.

[Freizeitpilot]

A good thread on reflexed flaps from way back in 2014. 
 

https://www.recreationalflying.com/forums/topic/23881-reflex-flaps-and-ailerons/

[skippydiesel]

2 hours ago, Freizeitpilot said:

A good thread on reflexed flaps from way back in 2014. 
 

https://www.recreationalflying.com/forums/topic/23881-reflex-flaps-and-ailerons/

It was pretty inconclusive back then, with about equal for & against (assuming against includes those who felt no significant benefit/effect).

 

A few commentators seemed to think that the European small aircraft manufactures supported/included this feature in their aircraft (I was one). 

 

I would ask -

• If this feature works for the EU why not AU & US (etc)?
• That the 11 years since that debate may have found some more evidence for & against?
• Could the main wing aerofoil have an influence on reflex being a significant benefit ?

😈

Edited July 8, 2025 by skippydiesel