[Rick RV-4]

Howdy all . . .

I followed Van's guidance for setting the angle of incidence for the wings. When all was said and done (and the rear spar bolt holes were drilled), it looks as if my flaps won't come all the way up - I miss it by about 1-2 degrees for my left flap. In my case, the bottom flap skin bumps into the bottom of the fuselage a little too early. This is due to the fact that I had to raise my left wing's rear spar up about 1/8" to get the angle of incidence the same for both wings. This was enough to cause the interference.

Vans says the fix for this is to cut off the small amount of skin that lies under the fuselage. This will let the flap come up as much as you would want them to.

Did anyone else have to do this? And if so, was it a big deal? It seems as if the negatives for doing this would be better than having the flaps hanging down 1-2 degrees. The negatives (as I see it) are that (1) you'll be able to see the flap actuator push-rod hole with the flaps in the up position, and (2) there might be a little bit of drag (and airflow into the cockpit) when the flaps are up since the hole is now exposed to the air.

My thought is to quit worrying and cut away. It seems like most folks park their RVs with the flaps down anyway, so the only difference would occur while airborne.

Any thoughts?

Rick
RV-4 3541

 

[szicree]

Joggle

I put a slight joggle in the flap skin at this location. I can't remember exactly how I did it, but I think I used seaming pliers. I think Checkoway's site might describe the same fix.

 

[Squeak]

Flaps

Rick, This same thing happens to me on my RV7A standard build. My wing incidence for the wings were right on but when I installed the flaps was surprised that the flaps would not able to rise without hitting the bottom of the fuselage and they were hitting my steps. So after rechecking the incidence and looking and asking other builders I decided to cut the flap to clear the fuselage and the step. After talking to some very experienced builders in Florida I found out that the step needed to be sit back aft ?? more on the fuselage than the plans call for. Cut and build on my 7A fly?s great.
Good luck,
Squeak
Indiana
RV-7A

 

[Rick RV-4]

Tried the "joggle"

Thanks Steve,

I actually tried to joggle the skin, but to get the amount of bend I needed, it was starting to stress the bottom aft end of the flap skin more than I was willing to accept.

I was thinking of removing the original skin from the bottom for the flap, then putting a thin spacer (1/8 inch maybe?) between the flap and a new piece of aluminum, and then riveting in a new 1.5 inch by 10 inch piece of 0.016 metal to be used to cover the bottom of the fuselage. Not sure if this would be "prettier" than just removing the aluminum altogether, and just leaving it.

Funny thing is, the military jet I fly for a living doesn't have near the fit and finish of the typical RV!

Thx,

Rick

 

[jsharkey]

Here is what I just did on my -6.
I'm not totally happy with it - seeming a joggle isn't easy! - and I might end up cutting off the lip all together and doing something else to cover the flap rod hole - or not.
Jim Sharkey