flap edge fairing

trib · #1 03-04-2009, 02:03 PM

I noticed on my friend's 8A project that the inbd flap top edge had a fairing attached to the fuselage, which was essentially an .025 aluminum angle, riveted to the fuselage. When the flap was full up, the top was flush against the fairing, sealing any gap. My 6A has nothing like this, although the gap is less than 1/8". The bottom of the flap seals against the fuselage, as typical. This fairing would be very easy to add, so I was looking for some input as to whether it provides any benefit. Anybody have an opinion?

scard · #2 03-04-2009, 02:07 PM

Beware that this area is quite sensitive to aerodynamic changes.

robertahegy · #3 03-04-2009, 04:06 PM

If the flaps are properly mounted and trimmed, you won't need a fairing.

Roberta

L.Adamson · #4 03-04-2009, 06:16 PM

Quote:

Originally Posted by scard

Beware that this area is quite sensitive to aerodynamic changes.

I put the fairing on my 6A, as many were doing it at the time. My flap also fits the fuselage very well. For some reason, my heavy 6A is just FAST. It must have something to do with that fairing!

L.Adamson --- RV6A

Sheldon · #5 03-05-2009, 05:26 AM

I made these for my 6A
http://picasaweb.google.com/lh/photo...eat=directlink

http://picasaweb.google.com/lh/photo...eat=directlink
Works great and looks good.. A fast 6A... Sheldon

Rick6a · #6 03-05-2009, 06:08 AM

For reference, the RV-8 series aft flap fairing is a bit more complicated than a simple angle with a 90? bend, the fairing wraps around and ties into the bottom of the fuselage. In the -8, the fairing serves another purpose by covering a large factory hole in the fuselage skin that an A model footstep would be installed in.

trib · #7 03-05-2009, 09:35 AM

Thanks Rick and Sheldon,

The RV-8 pic is just what I was referring to. Not needing the rest of the complicated wrap-around, only the angle for the flap fairing. Sheldon's example is just what I was thinking of. My flap was constucted with about 1/16"' gap at the fuselage. It seems inconsiquential, but the fairing would make it definitely so. Still on the fence as to its value, but Sheldon does say his plane goes very fast!! Maybe Bob Axom has some data on this

sglynn · #8 12-26-2009, 08:17 PM

Quote:

Originally Posted by robertahegy

If the flaps are properly mounted and trimmed, you won't need a fairing.

Roberta

Roberta, I'm triming my inboard flap edges to my fuselage now. How did you get your gap so smooth and consistant? My current process is using a file to trim back the edge and my line is wavy.

thanks

L.Adamson · #9 12-26-2009, 10:35 PM

Quote:

Originally Posted by sglynn

Roberta, I'm triming my inboard flap edges to my fuselage now. How did you get your gap so smooth and consistant? My current process is using a file to trim back the edge and my line is wavy.

I don't know how Roberta did her's, but I often used a 90 degree air driven die grinder with a 2" blue scotchbrite wheel. The kind you just twist on with a quarter turn. Probably used this more than any other tool for cleaning up the edge of skins, as it does a very smooth and clean edge. Just watch it, so it doesn't grab.

L.Adamson --- RV6A

robertahegy · #10 12-27-2009, 09:27 AM

Transfer a line that matches the curve to the flap and carefully sand down with dremel sanding drums. It is a slow trial and error, fitting process. A contour gage and/or an edge marker to mark the line helps. The fit and finish is always a bit of artistry.

I used machine tools to get things close and always followed by some hand work using sanding blocks and somethimes just sandpaper and elbow grease.

Roberta