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Reflex Flaps in the RV-12?

Bill_H

Well Known Member
There is a fair amount of discussion here about reflex (negative) flap settings, and their effect, mostly for the RV10. Not mentioned for the RV12. When my flap(eron)s are fully retracted, I can push the button and move the handle down a bit. It won't stay there unless held (no slot) but it makes for about a 3 to 4 degree change on the flaperon. If I do it in flight, I get a substantial pitch up- about 5 degrees.

I haven't done an extended cruise check, I am wondering if anyone else has (or the factory.) Might this work out to a knot or two or three if cruising in this position? (Oops, I mean the benefit of cutting power to stay at a 120 kt cruise...) :D

I intend to run a check the next time I go up. Others?

Bill H N412BR "Sweetie"
 
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The airfoil used on the RV-10 was specifically designed with a reflex in the shape at the aft portion (the ailerons are always in this reflex position).

The RV-12 uses the common NACA23XXX series airfoil (used on many aircraft from the Cub to DC-3). I don't think reflexing the flapperons on that airfoil will cause any reduction in induced drag.
 
After completing my RV-12 and while flying off the 5 hours, I climbed to 10,000 feet to do one of the test procedures. Upon reaching altitude and leveling off, there was a loud bang and airplane porpoised. That was very unnerving. I thought that I must have made a mistake building the plane and it was falling apart. It took me a couple of days to realize that the flap handle must have been below the retracted position. Leveling off made it snap into the detent.
Joe Gores
 
I did not like that little extra free play in the flaperon lever between the floor and the first notch -- it seemed a strange and somewhat annoying design feature for the reason cited by Joe above. By filing a bit of a ramp in the bottom flaperon notch and/or adding a bit of a flaps UP "limit stop" (AFTER your cert inspection of course ;)), this is no longer an issue for me.
 
After completing my RV-12 and while flying off the 5 hours, I climbed to 10,000 feet to do one of the test procedures. Upon reaching altitude and leveling off, there was a loud bang and airplane porpoised. That was very unnerving. I thought that I must have made a mistake building the plane and it was falling apart. It took me a couple of days to realize that the flap handle must have been below the retracted position. Leveling off made it snap into the detent.
Joe Gores

I'd have needed to spend those couple of days replacing upholstery. Just sayin'.
 
Mine has popped a few times. I took some evil delight in seeing the expression on my hot-shot retired fighter pilot friend's face when he was on a flight with me and it happened. :D
 
I tried it at cruise at about 4000 feet. I think holding the handle to the floor at the same RPM and altitude cost me about 1 Knot.
 
Sea Level on a Standard Day

Might this work out to a knot or two or three if cruising in this position? (Oops, I mean the benefit of cutting power to stay at a 120 kt cruise...) :D

Bill,
The 120 Kt limit only applies at Sea Level, on a Standard Day, at Max Continuous power. Change any one of those three factors and your limiting number is Vne. Whether or not that is prudent is another matter.

Tom
 
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