In a message dated 11/1/2007 6:52:11 A.M. Central Daylight Time, bill_kennedy_3@hotmail.com writes:

Question 1: If your 320/360MKII tail is fast, what is the angle between the longeron and top of flap at inboard end? I'd really like to know where the flap should be for clean, fast flying. I could live with a crappy stall, but I'm hoping to have my cake and eat it too.

Question 2: If you know where the text book "faired" position is supposed to be, what is the angle between the longeron and top of flap at inboard end with the flap in it's faired position?

Bill,

 

I can't answer you questions directly because:

 

1) I don't have a MKII tail.

 

2) My flap top surface is somewhat curved and it would be difficult to get that measure. I will try and get the angle for both sides - they are probably different on my plane.

 

You do not specify whether your craft is fast or slow built.  My slow built had the tip of the filet fairing (faired in position) 1/2" higher from lateral level and side to side.  This was discovered after I finished building the plane.  Rigging the flaps required more than a few flights since the angle of the bulkhead supporting the stub wing bell cranks (63 degrees from the centerline) was difficult to get exactly right.  Thus, it took a great deal of effort to get the flaps to move down at the same rate from side to side (important should a stall occur at some flap position other than up).  They are not quite rigged to meet the filet tip because of relieving some of the heavy left wing condition exacerbated because the wing trailing edge is defined as a straight line from the filet tip to the TE of the wing tip (properly jigged) and when one filet tip is not laterally level with the other.  Also, in flight the reflexed flaps want to fly higher than where they are rigged because of flight forces and thus they will be forced to take up control lash - perhaps differently from side to side. 

 

Larry Henney tried to improve his speed by rigging his flaps higher than normal and found he could not measure any speed gains from doing that.

 

You might want to test the symmetry of your flaps.  They are such a crucial part of wing performance that you might want to consider rigging for best flight performance rather than to the faired in position.  You can always park with the flaps down so no one can tell if they match the fairing.