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  #1  
Old 11-02-2021, 09:37 AM
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GatorsR1 GatorsR1 is offline
 
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Location: Owens Cross Roads, AL
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Default flaperon droop

Early KAI pg 32-10 (rev 0) specified aligning & clamping wing and flaperon edges prior to drilling torque tubes, but a later revision (rev 1) added shims to provide for 1/8" flaperon droop on both sides.
Just wondering what caused that change?
In trying to think it through, wouldn't that be akin to having a small amount of flaps down (with associated increase of lift & drag)?
The runup to this question occurred during the ongoing 1st Condition Inspection.
I had built to the rev but sometimes wonder about my precision in some measurements.
So I took the flap pushrods out just to doublecheck (38 3/4).
Both were a skosh short so adjusted the rod ends out (left 1/2 & right 1 turn) to meet the spec length.
Anxiously awaiting getting back in the air to see what change in flight characteristic there may be.
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  #2  
Old 11-02-2021, 09:57 AM
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rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Quote:
Originally Posted by GatorsR1 View Post
Early KAI pg 32-10 (rev 0) specified aligning & clamping wing and flaperon edges prior to drilling torque tubes, but a later revision (rev 1) added shims to provide for 1/8" flaperon droop on both sides.
Just wondering what caused that change?
There is a bit of elasticity in the system. With the higher pressure that is present in flight, on the bottom of the flapperons, it is enough to deflect the flapperons upward slightly so they are no longer in neutral trail to the wing.
Making the adjustment specified, compensates for the slight deflection that will occur.
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  #3  
Old 11-02-2021, 10:27 AM
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Default

As always, many thanks to Scott.
I was hoping he'd chime in & give The Van's answer.
Simple & makes perfect sense (now).
Now get back to work on that prototype, we're all waiting to see it
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  #4  
Old 11-02-2021, 03:26 PM
JwWright57 JwWright57 is offline
 
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Quote:
Originally Posted by rvbuilder2002 View Post
There is a bit of elasticity in the system. With the higher pressure that is present in flight, on the bottom of the flapperons, it is enough to deflect the flapperons upward slightly so they are no longer in neutral trail to the wing.
Making the adjustment specified, compensates for the slight deflection that will occur.
Thanks Scott. Great information like always.
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  #5  
Old 11-02-2021, 10:11 PM
RFSchaller RFSchaller is offline
 
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Has anybody experienced a dropping wing when you raise flaps? Mine rolls right as I raise flaps, but flies straight when they are raised or down.
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  #6  
Old 11-02-2021, 11:53 PM
seagull seagull is offline
 
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Quote:
Originally Posted by RFSchaller View Post
Has anybody experienced a dropping wing when you raise flaps? Mine rolls right as I raise flaps, but flies straight when they are raised or down.
Are you saying that during transition you get an un-commanded roll?
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  #7  
Old 11-03-2021, 10:45 PM
RFSchaller RFSchaller is offline
 
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Yes, during transition from flaps 1 to flaps 0.
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  #8  
Old 11-04-2021, 02:30 PM
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I have noticed that if I push the flap handle all the way to the floor (below the lowest detent), the resulting flaperon position is nearly neutral to the wing tips. In that position the plane is much more sensitive in roll, to the point that it is very tiring to fly for more than a few minutes. Also, the autopilot can not maintain a steady attitude and it constantly rolls from side to side. I came to the conclusion that the flaperon droop was thus introduced to increase the stability in the roll axis.

-dbh
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  #9  
Old 11-04-2021, 03:17 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by dbhill916 View Post
I have noticed that if I push the flap handle all the way to the floor (below the lowest detent), the resulting flaperon position is nearly neutral to the wing tips. In that position the plane is much more sensitive in roll, to the point that it is very tiring to fly for more than a few minutes. Also, the autopilot can not maintain a steady attitude and it constantly rolls from side to side. I came to the conclusion that the flaperon droop was thus introduced to increase the stability in the roll axis.

-dbh
By all the way to the floor I assume you mean past the flaps fully retracted detent notch?

If so, that position is not intended to be used. The flaps are supposed to be adjusted positioned trailing edge slightly below nominal with the flap hand in the bottom detent notch.
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  #10  
Old 11-07-2021, 06:10 PM
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Default Hands off !

Got some hours in this weekend after completing the 1st Condition Inspection and then waiting for field to reopen (resurfacing).
Adjusting the tube lengths to exactly 38 3/4 made a world of difference.
No more "heavy" wing and having to maintain (slight) stick pressure against roll.
Another bonus improvement - loosened nose gear castellated nut to reduce the fork pressure (per KAI rev) and taxiing is great, much less differential braking required.
This 12 is becoming even more of a dream machine !
(all I had to do was follow directions!)
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