Flap rigging

[Oscar Avalle]

I was wondering if this flap gap is normal or if my flaps have to be adjusted?

 

 

 

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[Hank]

That looks a lot like my flaps. You can always add flap gap seals . . . .

[Ragsf15e]

46 minutes ago, Oscar Avalle said:

 

I was wondering if this flap gap is normal or if my flaps have to be adjusted?

 

 

 

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Are you talking about the gap along the flap hinge or that the ailerons are slightly up compared to your flaps?

[GDGR]

1 hour ago, Hank said:

That looks a lot like my flaps. You can always add flap gap seals . . . .

Flap gap seals go on the underside of the flap. Not between the aileron and flap

[Davidv]

May need to be adjusted, in the neutral position your ailerons should be roughly flush with the flaps or even slightly below since they lift in flight.  Get an MSC to use a the boards on it and they will tell you if they need to be brought up.  It’s tough to tell in the picture but they look slightly down.  They should be around 0 to +1 degree. 

[EricJ]

Hard to say whether the flaps or ailerons need rigging.   Does it fly straight?   If it flies pretty straight it may not be worth disturbing it but if it doesn't fly straight you could have the rigging checked.   The M20J SMM does say to set the outside flap stops so that they're flush with the ailerons in a neutral position, but I think that assumes that the ailerons are properly rigged, too.   

The rigging can be checked with travel boards or a digital level or graduated level per the SMM. 

 

[Guest]

The flaps do look a bit low, often there is contact between the flap and the wing skin.  You need travel boards to be sure of the correct “up” position.

Clarence

[0TreeLemur]

11 minutes ago, M20Doc said:

The flaps do look a bit low, often there is contact between the flap and the wing skin.  You need travel boards to be sure of the correct “up” position.

Clarence

Agree.  With ailerons in neutral position, the end of the flaps on our C are about 1/8" (3 mm) further off the floor than the ends of the ailerons.

Photo: flap-gap seals after install.   They seemed to improve climb performance a bit, with no noticeable difference in cruise speed.

[Oscar Avalle]

Thank you! The ailerons are rigged, but the flaps seem to be on the lower side... and obviously must the creating some drag.


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[0TreeLemur]

2 hours ago, Oscar Avalle said:

Thank you! The ailerons are rigged, but the flaps seem to be on the lower side... and obviously must the creating some drag.


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Yes, but creating more lift than drag and a bit of a nose down pitching moment, causing your elevator to create negative lift as a compensation in level flight.  All that will slow you down a wee bit.

[RobertGary1]

21 hours ago, 0TreeLemur said:

Yes, but creating more lift than drag and a bit of a nose down pitching moment, causing your elevator to create negative lift as a compensation in level flight.  All that will slow you down a wee bit.

In gliders you try to keep a slight slip in your turn to offset this aileron drag. It’s not inconsequential, there are various articles on it in the gliding community.  

[PT20J]

If you are SURE your ailerons are correct, it’s a trivial matter to adjust the outboard flap stops. Ailerons tend to float up at higher speeds and you are allowed up to 2 deg down on each side to compensate. I would observe the flap aileron mismatch in flight as well and if it increases at cruise speed, consider lowering the ailerons instead of raising the flaps. No matter what you do, I’d be surprised to see a noticeable speed improvement from such a small change.

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