Flap Gap Seals

As I build my EX-3, I am looking at a set of flap gap seals that came with the kit. When I was active with the 180/185 crowd, they were a popular mod. But, opinion was mixed as to whether they did anything or not. I seem to remember that they were sold as a speed mod. But many said there was no difference before and after. Meanwhile, some said they adversely affected slow speed handling.

Cubs are different. Any opinions out there?

Thanks, John

I can't speak to the EX-3 or what they (CC) are calling "flap gap seals".

On a PA-18 and other high wing fabric covered Pipers, there is a fairing which attaches to the upper trailing edge of the wing which closes the gap to the flaps when the flaps are up. When the flaps are down this fairing provides a streamlined venturi shaped opening to funnel and accelerate the higher pressure air under the wing over the flap to enhance the performance. This fairing is sometimes call a flap gap seal. It is also reported when this fairing is not installed, there is an increase in tail shaking. It is definitely a requirement on these wings.

That kit which was approved on several different Cessna models was supposed to be a speed mod. At the time that mod was popular, Cessna marketing decided to have it installed on the 206. A friend who was a Cessna test pilot told me that the cruise speed was increased by about one mph. At the same time, the stall speed was also increased by the same amount because the fairing disturbed the smooth air flow up through the gap and over the flap.